ELECTROGLAS EG 4085X wafer probe or prober

Transcription

4085CXE OVERVIEW
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OVERVIEW
The 4085 is a precision wafer positioning system capable of positioning for
probe 5" through 8" wafers (125mm- 200mm). The robotic handler can handle up
to 50 wafers. The basic job 'of the prober is to extract a wafer from a chosen cassette, read its ID string, if any, and position the wafer in X, Y, Z and 9 against a
fixed set of probe needles. Added to this basic task are various user selectable
modes of operation and prober-host duties. With the addition of a Clean Air
Management System (CAMS), the 4085X creates a certified Class 1 environment
within the probers when the prober is located in up to Class 10,000 areas. The
4085 can also be configured to work with a Standard Machine interface (SMIF)
wafer handler.
Since the 4085X is a direct descendant of the 3001X, the operation of the
4085X Prober is very much like 3001CXE with Real Time Mapping (RTM). The
main operational difference is in the loading process. The 3001 has a drawer
which opens to the front and the 4085 has a cover which opens to the side.
-3001CXE I 4085X COMPARISON
The monitor displays and keyboard are generally as described in the documentation for the Real Time Mapping Option (RTM), found in Section 17 of the
technical reference manual (300 1CXE volume I). The few 4085 specific key functions and menus are described in sections 18.2.5 (Immediate Operations Menu)
and 18.3 .2 (Loading/Unloading from the Keyboard SMIF).
Virtually all software dependent operation if the 3001CXE remains unchanged
except that, because of the requirements of the clean environment, the printer
option of the 3 001 CXE is not included in the 4085X.
Physical differences between the machines are readily apparent because of the
enclosed fans and HEPA filters required. to support the clean environment of the
4085.
Access to the interior of the 4085X is through doors located - facing the
machine - on the left front, right front, right side, and top right (cover), depending
on the configuration.
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The left front door of the prober provides access to the forcer for harboring and
manual wafer load access to the chuck. The manual load style is the same as for
the 3001CXE, specifically, with the chucktop brought to probe center forward.
The disk drive is also reached through this door. On non-SMIF machines, a single
wafer load station is located on the right, facing the prober.
On standard CAMS machines (without the SMIF option), the right panel supports the manual load door for cassette loading/unloading from the top. On SMIFequipped versions, loading and unloading of full pod-enclosed cassettes can also
be done from the top of the prober; the right front drawer provides a loading
option, and guides are provided to help place the cassettes in the correct positions.
This location also provides emergency access to the cassette (port) plate. Loading
can be done from the right side, as well
Also, on the 4085X, the former operator console, consisting of joystick and
small keyboard have been integrated into the single monitor unit, mounted on the
monitor pedestal.
The cassette drawer of the 3001X has been replaced in the design of the
4085X, and the principal difference between the two probers is, as stated earlier, in
the loading process.
A new feature available for the 4085X is a wafer ID reader type called the
Back Side Bar Code (BSBC) reader. The handler software uses its PCB, located in
the handler drawer, to determine whether it is installed in a 2010X, a 3001X or a
4085X.
To understand the 4085X, it is best to consider it broken down into five subsystems. Each subsystem is responsible for a particular set of tasks, usually operating independently of the other subsystems, and conununicate with each other via
RS232.
The five main subsystems are:
The Executive Subsystem
The X-Y Motion Subsystem
The Theta, Z Motion Subsystem
The Material Handling Subsystem
The Vision Subsystem
Clean Air Management System (CAMS) in the 4085 and Real Time Mapping
(RTM) could be considered subsystems as well. However, the CAMS is not so
much a part of the prober as an environment in which the prober operates. It really
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has nothing to do with the operation of the prober. RTM perfonns the same function as the CRT ill in non-RTM 300I's and is, therefore, included in the Executive
Subsystem.
The Vision and Material Handling subsystems are both considered external to
the base prober logic. The vision subsystem is based upon the Cognex 2000 vision
processor board, and is mounted in a separate drawer within the prober table. The
material handling subsystem is also mounted in its own drawer within the table,
and is based upon a 68000 processor board with up to 512K of its own memory.
PROBER AND HANDLER
The 4085X Prober and Handler are separate entities, each with its own main
CPU, etc. The handler does, however, receive its ail-, vacuum, and DC power from
the prober. The handler communicates to COM 2 of the Display Control Module
(DCM) via an RS232 link. The handler has its own menus that reside inside the
handler and have nothing to do with the prober.
Since the prober and handler each have an operator interface link to the DCM,
a software switch is used to toggle between the two separate menu systems·:' i.pris
switch is enabled by the <F9> (PROBEIHDLR) function key. In the case of a nonRTM equipped 3001X, the CRT ill would handle the switching. Switching would
be accomplished by the <PROBEIHDLR> key on the monitor keyboard.
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RS-232 interconnections
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CLEAN Am MANAGEMENT SYSTEM
The Clean Air Management System (CAMS) combines an air moving system,
an air filtration system (HEPA filters) and double-layer, sealed external skins that
direct air flow.
·
FILTER
INTERFACE
CHAMBER
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- ·---····---·----··-···----··--·--------·-·-···-·l!»o·
CLEAN CHAMBER
..-·-·-·-·-·-··------
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UTIUTY
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CHAMBERS
EXHAUST
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Clean Air Management System
SUBSYSTEMS
THE EXECUTIVE SUBSYSTEM
The Executive Subsystem synchronizes and manages the other subsystems,
and directs them to perform various tasks. It does much of the thinking and decision making. It is the brain of the prober.
The central figure of this brain is a 68020 microprocessor running at 24 Mhz,
located on the Al board. This board holds up to 4 Megabytes of RAM memory.
A separate printed circuit board (PCB) located in the A3 slot, holds up to
768Kbytes of PROM memory. At startup, the microprocessor will display the following as part of its initialization:
BIOS .. 020
REV-D
5
10-22-92
RAM TEST 02048K
CPU SYSTEM TIMER
INTERRUPT SYSTEM
CHECKSUM BIOS_2
:PASSED
:PASSED
:PASSED
:25DB
If an error occurs between the CPU and the hard drive, the CPU will resort to
its local EPROM. This memory contains the boot sequence and a debugger program called "ELECTROBUG". ELECTROBUG will display the problem encountered, and register contents.
This debug program is only of minimal use to technicians because it requires
large numbers of keystrokes to accomplish even small functions. Its true utility is
for software engineers to debug the program, not for technicians to diagnose a system fault.
INTERFACES
The Executive Subsystem is also responsible for communication to the outside
world. It is able to talk to operators, host computers, testers, printers, hot chuck
controller, wafer I.D. readers, and SECS hosts. The hardware for these channels is
located on the A4 PCB (for tester and host I/0), the A 7 PCB (for SECS, hot chuck,
printer, and wafer I.D. reader I/0) and the Display Control Module to support the
keyboards and monitor for the operator interface.
Al
System
CPU
WrJer ID ruct.r (not ...ad)
A9
Teinp
MUX
Platen
Therrnistor
Executive Subsystem (PCM portion)
EXTERNAL I/0 PORTS
There are three I/0 ports on the A4, Tester Interface, board. One RS232 (for
host communication), one IEEE-488 (also for host communication) and one discrete port that ascribes to no particular standard or protocol (for tester communication). The operator can select through the menus either the RS232 or the IEEE-
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488 port for the host, but not both. In addition, the menus offer control of most of
the configuration aspects of the RS232 and IEEE-488 ports (e.g.; baud rate, terminators, time-outs, polling, etc.)
The tester communication port is not technically a "port", but instead is a group
of signal wires grouped together into one cable. Each wire carries a particular signal, such as "TEST START", or "TEST CO~LETE", rather than data bits. It is
referred to here as "discrete" only because the word "parallel" brings to mind a
GPIB port.
The A7, 4-Port Serial I/0, board has four independent RS232 ports, each with
jwnper-selectable baud rate, to connect ·with the printer, hot chuck controller,
wafer I.D. reader, or SECS host. Each port is dedicated to a particular function
and is not interchangeable ~ith any other. The Wafer I.D. reader is not used in the
4085X. It remains on the board to provide backward compatibility with 2001X
systems. The term "SECS" refers to the "Semiconductor Equipment Communication Standard" protocol established by SEMI Books are available on this subject
from SEMI.
HUMAN INTERFACE
To speak to hwnans, the Executive Subsystem uses the monitor screen to display menus, prompts, and messages. The operator uses a keyboard to respond to,
or initiate contact with the prober.
VGA
Monitor
System
Memory
Display
Control
Module
System
CPU
Executive Subsystem (DCM Portion)
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RTM
"Real Time Map" (RTM) is optional on 2000 and 3000 series probers and standard on the 4085. This system is based upon an 80386 computer, called the Display Control Module (DCM) and a membrane, full ASCII keyboard and a standard
PC VGA monitor. The VGA monitor also allows a full color map of the wafer to
be displayed while the probing is proceeding.
It also requires a new Theta Z function (AS) board. This is to process the key
board on the Operator console which is no longer coiUlected to the CRT Controller
via the monitor keyboard as in earlier Electroglas probers. This information is now
passed directly to the Theta Z function board.
THE X-Y MOTION SUBSYSTEM
The purpose of the X-Y Motion Subsystem is to execute X-Y moves. It is not
concerned with the purpose of the moves, but only the moves themselves.
Included in this subsystem are the A2 board (the Motion Control Logic PCB) and
the two Power DAR II boards. The A2 does the thinking and controlling, and creates digital move pulses called ".6P's". The Power DAR boards then take the digital pulses and converts them to analog waves to drive the X-Y Motor (called the
"forcer").
Although not a complex subsystem from a surface view (consisting of only
three boards (two of which are identical), and a motor), the X-Y Motion Subsystem is the hardest for most people to comprehend fully. This is because of the
motor used. In this case, the motor is a "linear induction motor" that floats on air
and cruises magnetically over an iron grid. Controlling this subsystem is a bit different than for other types of motors.
X
Power DAR IT
X-Y Motion Subsystem
Because of the motor used, and the resolution and accuracy demanded of it,
EG employs digital pulses, D/A conversion to waves made up of effectively tiny
de levels, constant current amplifiers (4 phases per axis), a special circuit called
the "Washer" to reduce stray magnetic fields, and another circuit called the
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"Damp" circuit to reduce motor ringing after moves are complete. In addition,
other pulses, called "burst pulses 11 are used to alter the torque of the motor during
changes of velocity.
All of this is controlled by the A2 PCB, which contains a 6803 microcomputer
and a program in EPROM. After each commanded move is completed, the A2
processor reports back to the Al main CPU ("Motion Complete").
One key point is that each Power DAR board bas three PROMs and the Motion
Control Logic PCB (A2) has one EPROM containing stepping correction data
determined at the factory for that particular motor/platen set. These PROMs and
EPROM MUST remain with that motor/platen set, or stepping error will result. It
is okay to swap DAR boards or A2 boards between systems as lopg as the correc~
tion PROMs remain with the original systems.
THE THETA, Z MOTION SUBSYSTEM
This subsystem often seems to the casual observer to be the dumping ground
for all the functions that don't clearly fit somewhere else, but might be better
understood as the functional extension of the Executive Subsystem. It has,.no sub~
processor, so is controlled directly by the main prober CPU and contains the hard~
ware to allow executive control of aligning and probing functions. It consists of
the Theta, Z Function II PCB (AS) and the Theta, Z Inker Driver PCB (All), along
with the Inker Box, Chuck IfF PCB, and the Profiler.
It is the residence of such functions as Z axis movement, chucktop rotation,
and in.ker actuation, but also included is responsibility for the joystick, theta
switch, chucktop vacuum control, microscope/camera lamp control, edge sensing,
and profiling.
Driving the chucktop up and down requires a motor and feedback mechanism
to ensure that this critical movement is occurring properly. The motor is controlled through the latches on the AS (Theta, Z Function II PCB) and the drivers on
the All (Theta, Z Inker Driver PCB). Mounted to the motor shaft is an optical
encoder to provide positional feedback pulses through the All to the AS. These
pulses are counted by the AS, and the CPU (A3) checks in periodically to verify
that it is receiving the correct number of feedback pulses to match the move it bas
commanded.
Theta (rotation) movement of the chucktop is controlled in the same manner
(latches on the AS; drivers on the All), except that there is no encoder as failure
would cause no damage.
Firing inkers is simple. The AS latches the line of the inker to be frred, and the
transistor on the All passes the inker supply voltage out to that particular inker.
The inker supply voltage is selectable by means of a toggle switch on the Inker
Power Supply PCB (beneath the main fuse block in the prober power module).
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The joystick and theta switch both are cabled directly to the A5 at P 109. The
AS will latch in the status of the switches so that the CPU may read them at its leisure. However, before latcrung, the inputs are debounced by MC14490 devices
(U4, 6 and 7). Check these devices upon any joystick failure.
Chucktop vacuum is also controlled here via a latch on the AS. This signal
then goes to the AI 0 (Solenoid Driver) to fire the correct transistor and communicate a ground path to solenoid valve #1 (SVl).
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Once the wafer is vacuum-locked to the chucktop, vacuum is unable to escape
and is felt through a sense tube back to a vacuum switch inside the Power Module.
When the vacuum trapped in the chucktop pulls this switch closed, the CPU (A3)
is able to read this status through the AS and determine that a wafer is on the
chucktop.
Also seen through the All to the AS, and thence to the A3, is the edge sensor
status (open= On Wafer). Be sure to set the switch properly on the edge sensor/
inker box so that your edge sensors will work either in parallel or serial. If you
have a single edge sensor, use the "paraller• position. Use "serial" if you have two
edge sensors on your probe card. Also, be aware of the 114A micro fuse inside the
edge sensorfmker box. It is used for isolated edge sensors, and will cause that type
of edge sensor to appear open at all times.
Even the microscope and camera lamps are controlled through the Theta, Z
Motion Subsystem. Through the AS and All runs a signal to the motherboard to
control a solid state relay mounted atop a transformer in the Power Module. This
relay passes 110/120VAC to both the camera lamp transformer and the microscope lamp outlet at the rear of the Power Module. The microscope lamp has its
own transformer to convert the 110/120 to the appropriate voltage for the lamp.
Note that late in 1989 some software control was added over the camera lamps,
and that to accommodate this control the camera lamps are now plugged into the
back of the vision processor instead of the prober Power Module. This effectively
removes the Theta, Z Motion Subsystem from control of the camera lamps.
And finally, we have the Profiler (also called "NCES", for Non Contact Edge
Sensor, but listed in configuration sheets as "AWP" - Automatic Wafer Profiler).
This device was made to replace the edge sensor because of the inherent unreliability of such a mechanical switch. The profiler senses the surface and edges of
the wafer by blowing air at the wafer and measuring the back pressure felt. This
involves no physical contact, and is much more reliable than an edge sensor.
Many users report savings on probe card repair and increased throughput when
using the profiler.
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THE MATERIAL HANDLING SUBSYSTEM 13ft~@v·
The purpose of a material handling subsystem is to reduce the need for a
human operator to continually feed the prober fresh wafers, and also to reduce the
amount of wafer breakage by human handling. So, all the facets of loading and
unloading wafers from the prober are controlled by the Material Handling Subsystem.
From the viewpoint of the prober CPU, the handler resides at the A6 slot in the
logic cage. For the 4085X robotic handler, the A6 board is the Handler Communications PCB, merely an RS232 port used to talk to the handlers own system
CPU (a 68000).
In addition to delivering wafers to the prober and retrieving them, the material
handler is tasked with prealigning the wafer. This involves rotating the wafer to
align the flat or notch to a user selected azimuth within± 2<? (actually the.accuracy
is much better, but± 2° is the original published spec.).
THE VISION SUBSYSTEM
The Vision Subsystem is compriseQ. of a camera and optics, and a vision processor. Its main job is to precisely·align the streets of the wafer to the grid lines of
the platen (auto alignment). It also may do optical inspection of ink dots and probe
marks, as well as Optical Character Recognition (OCR) or Bar Code Reading
(BCR) for reading wafer I.D. strings.
Auto alignment
Auto alignment is done by pattern recognition, and is a cooperative process
between the vision subsystem and the prober CPU.. The prober makes the decisions and performs the theta corrections through its motion subsystems. The
Vision Subsystem is tasked with the pattern storage and comparison.
The camera and optics feed live video (of a spot on the wafer) to the vision
processor, who then digitizes the video and compares it to a previously stored pattern (selected by the human user). The results then go to the prober CPU (A3 P103; RS232 link@ 9600 baud), who will determine whether the match is good
enough. If not, the prober will move another portion of the wafer under the camera
for presentation to the vision processor, and the process starts again.
When a good match is seen, the prober uses location information from the
vision processor to adjust the target pattern to the optical center. The prober then
indexes and again has the vision system search for the pattern. Correction is made
to bring the target back to optical center. When the prober can index, and the target doesn't leave optical center, wafer alignment is complete.
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----
- - - · - ---~--------- --- --
The vision processor used is called the "Vision Module", and is made by Cognex. It has pixel resolution of0.15625 mils, and 64 shades of gray. It is capable of
wafer alignment, optical character recognition, ink dot inspection and probe mark
inspection. It can also control the camera lighting, and perform automatic gain
adjustments for the video input.
In addition to automatic alignment, the Vision Module may perform Ink Dot
Inspection ("IDI") and Probe Mark Inspection ("PMI"). These features are based
upon a "blob analysis" algorithm in the Cognex unit. Because ink dots are very
large compared with probe marks, the optics system has a 4: 1 motorized zoom lens
to magnify the probe mark image.
Ink Dot Inspection
Ink dot inspection is used to check the quality of the inking process, and aid in
initial inker setup (since the assembly plants receive wafers from various sort sites,
each lot of wafers received by assembly can have the ink dots placed in different
position on the die. Using the ink dot inspection function to set up inkers uniformly will usually pay off at assembly).
a
With ink dot inspection, the vision system will identify the presence of the
mark, its area, placement, etc., and will record any failures and other essential data
on a summary. These are user selectable parameters, and the user may specify
which should cause the probing process to halt.
In some instances it makes sense to probe wafers with one set of probers, and
send these probed wafers with their wafer maps to a prober dedicated to inking
only (this is called "off-line inking"). Under these circumstances the camera is
moved to the probing area, and thus every die on the wafer may be inspected.
Probe Mark Inspection
Probe mark inspection is used to catch problems with probe to pad alignment
and to check for sufficient scrub, and operates similarly to ink dot inspection
except that the optics automatically zoom in to see the mark As with the Ink Dot
Inspection, this feature also involves user selection of acceptable placement, area,
and halt criteria. Properly set up, the probe mark inspection feature will catch
probe alignment or planarity problems before they cause yield problems.
Optical Character Recognition (OCR)
Optical Character Recognition, or "OCR", is used to read a string of identification characters scribed onto the wafer. It differs from Bar Code Reading in that the
characters for OCR are alphanumeric- all of the letters of the English alphabet and
the numbers 0-9.
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OCR is performed using a Cohu CCD camera at the prealign station at a user
programmable prealign orientation. For best results, SEMI spec. OCR marking is
highly recommended - this will set the aspect ratio, spacing, line width, and character style to the optimum for the Electroglas reader. The system may be trained
by the Electroglas factory to accept another type of font, however.
lliwnination is important for OCR reading - Electroglas offers both coaxial and
oblique illumination for this purpose. Generally, coaxial will be best for most situations.
Cameras
There have been various tube cameras used in the past (Ryokosha, RCA, Hitachi), but the camera of choice today is a CCD camera made by Cohu. It is the best
CCD camera available today- the memory cells are behind, not beside, the capacitors so it has a tighter array structure (no "blind" spots). It is a direct replacement
for those cameras previously used by Electroglas. The only exception to this is in
the case of Optical Character Recognition ("OCR"). Electroglas had used the
Panasonic CCD camera for this purpose until about 7/90, but now supports the
Cohu in this instance as well.
THE HANDLER
Although the Material Handling Subsystem has already been discussed, it has
-been from the point of view of the prober. To the handler, it is a stand-alone wafer
handling machine that merely happens to be hooked up to a prober. It has its own
68000 mlcroprocessor running at lO:MHz, and up to 512K of memory. It has four
RS232 I/0 ports for the Prober, the Display Control Module, the Wafer I.D.
Reader, and for debug. It runs its own program, has its own menus, and performs
its own diagnostic routines.
Like the prober, the handler also is divided into specific subsystems. These
are:
The Executive Subsystem
The X Motion Subsystem
The Theta, Z Subsystem
The Prealign Subsystem
Each subsystem has its own microprocessor, and runs its own programs resident in EPROM. The Executive Subsystem is the brain, or general manager, and
runs the three other subsystems.
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THE HANDLER EXECUTIVE SUBSYSTEM
The handler motherboard, the "Main System Board", contains the central brain
(68000 J..LP) and memory (512K), as well as the four RS232 ports. The ports for the
prober and CRT I/0 are hard wired for 19.2K baud, the debug port may be jumpered for 9600/19.2K, and the I.D. Reader port may be jumpered for 300/1200/
9600/19 .2K. The solenoid drivers and I/0 latches for the subsystem reside on a
separate PCB called the "Main System I/0 Board", plugged into the Main System
Board parallel bus. Each of the other subsystem PCBs is also plugged into this bus
for conununication with this Main System brain.
Plugged into the Main System Board, but on a different bus, is the "'Solenoid; II
0 Interface". This little board connects all solenoid signals straight through, and
also contains opto-isolator chips to support the I/0 lines of a fifth port called the
"Customer I/0" port which conforms to no standard protocol. Its purpose is left to
the customer - Electroglas has provided eight input lines and eight output lines, all
opto-isolated. These lines could be considered as a byte or bits. As long as the I/0
is TTL, then the customer may request that Electroglas write some code to operate
this port in the method devised by the customer.
The main memory of this system is divided into two sections of 256K each.
One section is dedicated for RAM, and the other is jumperable for EPROM or
RAM. All machines now in the field have EPROM in this section for the main
program.
In addition to supervising the other subsystems, the Executive Subsystem is
responsible for many mundane items, such as monitoring various switches and
sensors. It is to perform the monitoring functions that this system needs the Main
System I/0 Board.
The Main System I/0 Board is a direct hardware extension of the Main System
Board, and has no microprocessor itself - the main system processor runs this
board completely - but merely is a compilation oflatches and drivers. It allows the
executive subsystem to verify whether the main cassette drawer is open or closed,
the cassette platform is up or down, the status of the quick loader arm and hold station, and if there are any cassettes present in the system.
THE LINEAR MOTION SUBSYSTEM
Very similar to the X-Y subsystem of the prober, this subsystem is responsible
for driving a linear motor. However, this linear motor has only one axis instead of
two. The PCB responsible for this is called "The X Motor Subsystem CPU",
clearly an appropriate name for a motor that moves exclusively in the Y axis.
Actually, the reason for this is that the handler was first developed for the 2010X
handler, and that assembly had a motor dedicated exclusively to the X axis.
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This board has a 6303 microcomputer and a 27C256 EPROM holding its program. It accepts commands from the Main System Board (Executive Subsystem)
and executes those directions. When complete, it reports status back
The primary actions of this board are to create the digital motor pulses
(Ms) to drive the motor, monitor the encoder strip to verify motor position at all times,
and to operate the solenoid providing air to the motor to create its air bearing.
Just as the prober needed DAR boards to change the motor pulses (DPs) to
sinusoidal waves, this system uses an almost identical board called the "X, Theta
Driver Board" to do the digital-to-analog conversion. The difference is that this
board is shared with the Theta, Z Subsystem, which uses a separate circuit on the
board to do digital-to-analog conversion for the transfer ann theta drive.
THE TRANSFER ARM (THETA, Z) SUBSYSTEM
This subsystem handles the transfer arm of the handler. It drives the Z axis and
Theta axis, and monitors each by rotary encoders mounted atop each drive motor.
Also, the Z axis has two zero positions, each determined by a flag and optical
switch, and this subsystem is responsible for sensing either zero position. The
theta axis also has two position sensors, arranged mechanically to sense which
movement quadrant the arm is in at the time.
The board responsible for all this activity is the "Transfer Arm Subsystem
CPU", and is based upon another 6303 microcomputer with 27C256 EPROM.
Running its own programs, but taking direction from the Main System Board, it
will turn on or off the air and vacuum solenoids for the transfer arm, and detect the
presence of a wafer on the arm with a vacuum switch.
Although the Z axis is driven by a standard motor controller and motor driver
chip set, the theta axis is ·d riven in microstepped fashion just as a linear motor is.
The Transfer Arm Subsystem CPU board creates motor pulses (tJ>s) and sends
them to the X Theta Driver board for conversion to sinusoidal waves.
THE PREALIGN SUBSYSTEM
This ·subsystem is dedicated to prealigning the wafer, and is concerned with
nothing else. It is based upon another 6303 with EPROM, and controls the prealign motor and the solenoids for providing air or vacuum to the prealign spindle
and crescent operation. It also monitors a Banner optical detector to determine if a
wafer is on the prealign station. As with the other subsystems, this one has its own
PCB called the Prealign Subsystem CPU and is plugged into the bus. It is directed
by the main system, and merely reports back status after completion of its mission.
- - -- - - - -
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THE INITIALIZATION PROCESS
There is no "beep" with RTM systems (no CRT III). You will first see the normal PC boot up screens showing BIOS rev, memory checks, etc. Next, the RTM
screen is presented with Prober messages on the left and Handler messages on the
right. The Prober microprocessor will display the following as part of its initialization:
BIOS .. 020
REV-D
10-22-92
:PASSED
:PASSED
:PASSED
:25DB
RAM TEST 02048K
CPU SYSTEM TIMER
INTERRUPT SYSTEM
CHECKSUM BIOS_2
The 68020 based prober is loading the software from the PROMs to RAM on
the CPU system PCB for faster operation.
The next indication is a listing of the files being loaded as the microprocessor
calls for the product files from the hard drive. These include wafer and die information, auto-align target, PMI information, learn lists, etc.
Independent of the material handling section initialization, the prober forcer
will "biank" (become free on the platen), and the chucktop will drop 10 mils. At
that point, the Run Time Display will appear on the monitor screen, and the message "X-Y MOTOR BLANK" will be displayed on the bottom of the screen:
HAllllL&R
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Intiialization
16
:
PROSLE!IS:
SECS ........DIS
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sales@semista.reorp. com
Once the "X-Y MOTOR BLANK" message has appeared on the monitor,
the prober CPU loops, waiting for the Forcer Reset key to be pressed. This
key is actually a button on the left side of the Operator Console Goystick
console). Press this key, and the initialization will continue: The forcer
will lock down ("reset"), and then the chucktop will rotate to find theta
zero. Once theta zero has been found, the chucktop will drop to find Z
zero. At that point, the "X-Y MOTOR BLANK" message will disappear,
and the processor will be 11IDLE".
Chuck t op drops to
find Z z ero
I
•
Initialization, Z-Stage
HANDLER INITIALIZATION
While the prober initializes, watch the handler section closely. It will also
undergo its own initialization routine, which involves the handler's main system
processor interrogating its subprocessor boards, its own memory, and system functionality. Solenoid valves will cycle on and off with the processor watching for
.failures; switches and sensors will be checked (system air and vacuum supply, for
instance) and the presence or absence of wafers within the handler will be verified.
Note that if there are wafers in the system (on the arm, for instance) then the
sequence may be altered. Also, one event doesn't necessarily relate to another on
the chart. The fact that the linear motor reference initiates prior to theta zeroing
does not mean that the linear motor ze~o position must be found before theta may
be found - they are independent.
Depending on the status of the handler, you may get the message "Press Enter
to continue Initialization". Remember that the Enter key is ''attached" to which
ever part of the RTM window is highlighted. If the Prober is highlighted, press
"PROBEIHDLR" (F9), then "Enter. 11
After further initialization steps, the handler ceases motion. At this time press
the F6 key ("XFER WAFER") and follow the directions on the screen.
- -- - - -- -
17
--------
I
4085 Handler Initialization
Power on
1. Main system board LED's cycle on, then off. LED's 1 through 4 on the three
subsystem CPU boards switch on.
2. LED's 1,2,3,4,6,7 on the main system IJO board cycle on and off in sequence
quickly.
3. LED's 1-3 on the transfer arm and prealign subsystem CPU boards now switch
off, leaving LED 4(green) on by itself.
4. LED's 1-3 on the X motor subsystem CPU now switch off, leaving LED
4(green) on.
5. LED 5 on the X motor Subsystem board switches on (air bearing on)
6. LED's 5-7 on the transfer arm subsystem board cycle on, then off.
7. LED's 5 and 7 on the ptealign subsystem board cycle on then off.
This leaves LED 4 on for each of the subsystem boards and LED 5 on as well
for the X motor subsystem board, signifying that the forcer air bearing is activated. The RUN lamp should be on for the main system board, and possibly a
task lamp indicating power up self test.
"Please open cassette cover"
8. After the user opens the cover/drawer, LED on the main system I/0 board
switches on (cover/drawer latch solenoid is activated.
"Press enter to continue"
9. LED 6 on the transfer arm subsystem board switches on (checking transfer arm
vacuum switch to se if there is a wafer on the arm).
10. LED 5 on the transfer arm subsystem board switches on (checking mapping
sensor to verify no wafer on the arm).
11. LED 5 and 6 now switch off(since no wafer on the arm).
12. LED 1 on the main system IJO board cycles on, then off (checking quick loader
arm for presence of a wafer).
13. X motor starts to initialize to its home position.
14. Theta motor drives arm to theta zero.
15. Z motor drives arm to Z zero.
16. LED 6 on main system IJO board switches on, and the cassette platform raises
(LED 6 indicates status of platform air solenoid).
18
PCB B ASIC FuNCTIONS
P ROBER SECTION
Al
•
68020 System CPU PCB (251411-002)
Runs Prober's Main System Program
Controls All PCBs on the Prober Bus
Communicates Prober Data to/from DCM or CRT Controller ill via J1 02
Stores Programmed Parameters/Operational Variables in RAM (Non-RTM)
Operates all Prober I/0 Ports (A4, A7)
•EG Hot Chuck Controller (TC-2000)
•Wafer I.D. Reader
•Printer
•SECS Host I/0
•
Communicates with Robotic Handler via A6 PCB
•
Communicates with Vision Module via J1 03:
•Controls Auto alignment Routine
Controls EG Hot Chuck Controller (via A7)
• Performs Temperature Compensation
~
Theta-Z Subsystem Controller:
•Operates PZ6 Z and Theta, Profiling, Inking, Edge Sensing
•Controls Chuck Vacuum, Microscope/Camera Lamp Relay
A2
Motion Control Logic P CB (102944-010)
Control Logic for Prober's X-Y Motor
•
Creates Motor Drive Pulses (DP)
•
Controls Motor Velocity (DP Frequency)
•
Controls Travel Distance (DP Quantity)
Controls Axis ofMovement
•
Controls Direction of Movement (DIR Signal)
•
Retains Linear Error Correction Data
• Actuates Washer Circuit on DAR Boards
•
Actuates Damper Circuit on DAR Boards
19
A3 System Memory PCB (248981-004
•
= 768K EPROM/RAM)
Contains Main System Program for the Prober (not the Handler)
A4 Tester Interface PCB (244288-001)
•
Interfaces Prober System to Tester:
•Test Start~ Test Complete, Reject Lines
•
Interfaces Prober System to Host Controller:
•RS232 Port or JEEE-488 Port
Note: Setup parameters for RS232 or IEEE-488 host ports are menu selectable through <F2> (SET MODE) key.
AS Theta, Z Function TI PCB (250262-001)
•
Interfaces Theta-Z Functions to System CPU:
•Latches Data for Theta-Z Inker Driver PCB
•Inking Signals
•Edge Sensor Inputs
•Z Drive Signals
•Theta Drive Signals
•Z Encoder Division and Input
•
Interfaces CPU to Solenoid Driver PCB:
•Latches Chuck Vacuum Solenoid (SVl) Control Signal
•
Interfaces CPU to Profiler: Latches 11AIR ON" Command Output
•Latches 11Z-Hl11/ 11Z=LO" Inputs
•Interfaces Joystick and Theta Switch to CPU:
•Debounces and Latches Input Signals
•Interfaces operator console keyboard in 4085 and RTM 3001 systems
A6 Handler Communications PCB (247265-001)
•
RS232 Port to Robotic Handler CPU (19 .2K Baud Hard wired)
•
Latches Control Signal to PZ6 Vacuum Pin Solenoid Driver (AIO PCB)
•
Recirculating Buffer to Determine if Handler "Option Installed"
•
A7 4-Port Serial I/0 PCB (246067-001)
20
•
RS232 Port to EG Hot Chuck Controller
•
RS232 Port to Printer
•
RS232 Port to SECS Host
•
RS232 Port to Wafer I.D. Reader (BCR Requires Extra Chip Set)
Note: All ports jumperable for 300/1200/2400/4800/9600/19.2K baud.
A9 TEMPERATURE COMPENSATION MULTIPLEXER PCB
(246713-001)
•
Multiplexes Platen Thermistor Bead and Hot Chuck Input
•
Sends MUXed Data to 4-Port I/0 Board (Hot Chuck Port)
A10 Solenoid Driver PCB (114824-001)
•
Actuates Solenoids For PZ6 Vacuum Pins and Chucktop Vacuum
•Transistors On This Board Give Ground Paths for Solenoid Coils
All Theta-z Inker Driver PCB (244428-001)
•
Converts Binazy Theta and Z Drive Input (from AS) to 4-Phase Output
•
Actuates Theta and Z Drive Power Boost (E RUN= +28Vdc unreg.)
•
Drives Inkers (E INK is switchable on In.ker Power Supply since 1985)
Power DAR PCBs (DAR CAGE A1 AND A2) (251074-002)
•
Each Board Controls One Axis of X-Y Motor
•
Converts Digital Input (&'form A2 PCB) to Analog Output (Sine
Waves)
•
Washer Circuit Reduces Residual Magnetism After Moves
•
Damper Circuit Reduces Motor Ringing After Moves
•
Temperature Sensor in Amplifier Section Guards Against Overheating
DISPLAY CONTROL MODULE
PC I/O
RS232 PORT TO PROBER CPU (COM 1)
•Data path for Menu Displays, etc.
RS232 Port to Handler (COM 2)
•Data path for Menu Displays, etc.
21
Printer capability (LPT 1)
PC Disk Controller
•
Controller for Hard Drive
•
Controller for 3.5" Floppy Drive
PC Video Board
•
Controls video to the monitor
•
Controls CameralAnalog video
Lamp Driver PCB
•
Controls lamp tower
•
Controls audio alarm
•
Commands switch between analog video and camera video
HANDLER SECTION
Main System Board (Motherboard/CPU) (247213-001)
•
Executive System Manager
•
Runs System Program and Tasks
•
Multitasking System
•
Controls All PCBs on the Bus
•
Communicates Data to DCM or CRT Controller III
•
Interprets ASCII Keyboard Data
•
Operates All I/0 Ports
RS232 to CRT Controller III@ 19.2K baud
•
RS232 to Debugger @ 9600119 .2K baud
•
RS232 to Wafer I.D. Reader@ 300/1200/9600/19.2K
•
RS232 to Prober CPU (via Handler Comm. PCB) 19.2K
Main System 1/0 PCB (247216-001)
•
Interfaces Main System CPU to Various Handler I/0
•
Monitors Cassette Cover Open/Closed Switches
•
Actuates Cassette Cover Latch
22
Monitors Inspection Cover Open/Closed
•
Detects Wafer on fuspection Station
•
Raises/Lowers Cassette Platforms
•
Detects Cassette Platform Up/Down Switches
•
Detects Presence, Location, and Size of Cassettes
Monitors System AirNacuum Input
•
Drives Quick Loader Motor
Monitors Quick Loader Arm Up/Down Sensors
•
Detects Presence of Wafer on Quick Loader Arm
Analog/Digital Conversion Of Mapping Sensor Input
Linear Motor Subsystem CPU PCB (247222-002)
Develops Control Signals for X Motor (&'s, DIR, etc.)
Monitors Optical Encoder for Positional Feedback
•
Actuates X Motor Air Bearing Solenoid
'fransfer Arm Subsystem CPU P CB (247225-001)
•
Controls Robotic Arm Z Motor
Develop s Control Signals (&'s) for Robotic Arm Theta Motor
Monitors Shaft Encoders for Theta/Z Positional Feedback
Monitors Quadrant/Zero Sensors for Theta and Z
Actuates Solenoids for Arm Vacuum, Air and Mapping Sensor Air
•
Detects Presence of Wafer on Robotic Arm
Pr ealign Subsystem CPU PCB (247219-001)
•
Controls Prealign Spindle Drive Motor
Monitors Flat-Find Optic
•
Detects Presence of Wafer on Prealign Station
•
Actuates Solenoids for Spindle AirNacuum, Crescent Out
Backside Bar -code (BSBC) P CB (4085)
Tells prober that its a 4085
Controls optional Backside Bar-code Reader
23
sales@semis tarcorp . com
--------------------------
X-Theta Driver PCB (247228-001)
•
Converts Robotic Ann Digital Drive Signals to Analog Waves
•
Converts Y-Motor Digital Drive Signals to Analog Waves
•
Y-Motor Blank Switch
Solenoid, 1/0 Interface PCB (247439-001)
•
Connects Handler Electronics to Pneumatic Module
•
Gathering Point for Solenoid Drive Signals
•
Input Point for System AlrNac Sensors
•
Input Point for Robotic Arm Wafer Detect Sensor
•
Input Point for Quick Loader Wafer Detect Sensor
•
Customer I/0 Signal Opto-Isolation
Prealign Interface PCB (247180-001)
•
Connects Prealign Subsystem CPU to Prealign Area
•
Flat-Find Optic
•
Wafer Present Banner Sensor
•
Prealign Spindle Motor Drive Connections
•
Displays Sensor Status
•
Flat-Find Status
•
Wafer Present Status
Quick Loader/wafer Sense IfF PCB (248228-001)
•
Connects Quick Loader to Main System I/0 PCB
•
Motor Drive Connections
•
Up/Down Sensor Connections
•
Connects Inspection Station to Main System I/0 PCB
•
Wafer Present Sensor
•
Connects Cassette Platform to Main System I/0 PCB
•
Cassette Size/Location Switches
•
Cassette Drawer Closed Switch to the Main System I/0 PCB
•
Cassette Drawer Open Switch to the Main System I/0 PCB
•
Pressure-to-Analog Conversion for Mapping Sensor
24
Linear Motor Interface PCB (247012-001)
•
Connects Linear Motor Subsystem CPU to Linear Motor
•
Motor Drive Signal Connection
•
Linear Motor Encoder Feedback
•
Connects Transfer Ann Subsystem CPU to Robotic Arm
•
Theta Motor Drive Signals
•
Z Motor Drive Signals
•
Theta Quadrant Sensors
•
Z Zero Sensors
SUMMARY O F KEY POINTS
PROBER X-Y M OTOR DRIVE
X-Y motor motion is based upon the 11 Sawyer Principle11 : Motion is achieved
by the controlled interaction of magnetic flux fields to produce tangential force
between motor and platen.
A. Forcer rests on air-bearing to eliminate friction.
B. Motor moves because magnetic force pulls the motor from tooth to tooth
across the platen.
Motor coils are driven by four phase-related stepped sine waves from the
Power DAR boards.
A. Motion Control Logic PCB (A2) creates Drive Pulses (DP)
B. Power DAR PCBs convert DPs to Stepped Sine Waves
Motor Resolution is determined by the formula: R=D/S Where: "R11 is Resolution 11D 11 is distance traveled 11 S 11 is the number of steps required
X-Y Motion Control is a process of command, then execution.
A. Move command may come from joystick, keyboard, or program.
B. Command is given to the Motion Control PCB by the CPU.
C. The Motion Control Logic PCB (A2) carries out the order by issuing DPs
and control signals to the Power DARs.
25
D. The two Power DAR PCBs actually drive the motor with four-phase
stepped sinusoidal waves.
AUTO-ALIGN
Auto alignment is performed by the prober CPU using a vision processor as a
slave to recognize video patterns. The patterns are user-selected and stored in the
vision system RAM.
A. The user teaches the vision system a target pattern.
B. The prober repeatedly moves the wafer under the camera and commands the
vision processor to search for the pattern. The vision processor always finds the
best match in its field of view, and communicates the location and correlation
value of that pattern.
C. The prober CPU then determines if that correlation value is high enough to
indicate an acceptable match.
D. If a match exists, the prober indexes and commands a new search. Using
the location data from the vision processor, the prober corrects deviations until the
wafer may be indexed without the pattern moving from optical center.
Target selection techniques must be modified to best apply to each customer
situation, but some general rules usually will help:
A. The target should be repeatable from die to die, but unique within any one
die. The target should contain information with sharply defined horizontal and
vertical edges, and should include large features.
"Second Reference" and "Find Edge" are used for First Die repeatability, and
do not affect theta alignment. "Second Reference" is greatly preferred over "Find
Edge".
A. Second Reference targets should be completely unique.
B. Find Edge should only be used as a last resort, and only on stepped wafers.
Prober Executive Subsystem
MC68020, 24 Mhz CPU (orMC68008, 8 Mhz CPU) runs the 3001X Prober
according to main program resident on separate memory PCB. Two memory
PCBs are used, with up to 768K possible.
Subsystem PCBs plug into parallel EXERCISER bus; each board has individual address decoding hardware.
External ports are RS232 and IEEE-488.
26
A. Port selection, protocol, modes, and messages are all selectable through the
SET MODE menu.
27

ELECTROGLAS EG 4085X wafer probe or prober

Transcription

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