Chapter 4.11

SVGCOAT  4” Photoresist Coat Tracks

(svgcoat1 and svgcoat2)

1.0   Title

SVGCOAT1 and SVGCOAT2

2.0   Purpose

This document has specific information about SVG8626 coat tracks. These tracks are capable of performing coat operations on 4-inch wafers (Y2).

3.0   Scope

SVGCOAT1 and SVGCOAT2 both are four-inch coat modules capable of spinning G-line and I-line resists on track 1 and track 2. In addition, SVGCOAT1 and SVGCOAT2 are capable of spinning thick SPR 220 Photoresist on track 1and track 2. 

4.0   Applicable Documents

Revision History

SVG 8626PC/ 8636HPO Operation Manual available in the Microlab Office.

5.0   Definitions & Process Terminology

5.1         Coat Track 1: First track (closest to operator) used for coat process steps.

5.2         Coat Track 2: Second track (furthest from operator) used for coat process steps also.

5.3         Hot plates: There are total of two hot plates available on these tracks that are used for soft-bake process steps.

5.4         Chill Plates: process station following the hot plate designed to cool the wafers.

5.5         Control Panels: Two control panels designed to receive input from the operator.

5.6         Indexer Module: Cassette platforms used for wafer load and unload operations.

5.7         Transport: Belts transfer wafers between stations and/or indexer stations.

5.8         Millipore Pump Control Module: This module controls resist volume, speed and suck back on all our resist lines.

6.0   Safety

Follow general safety guidelines in the lab as well as the specific safety rules as per follows:

6.1         Do not operate the spin coat station with the protection cover off.

6.2         Do not place your hand in the path of track’s moving parts, robots and or indexer module. Never operate the spin modules without the cover.

6.3         Do not access the electronic and high power supplies inside the machine.

7.0   Statistical/Process Data

7.1         Process monitor data on the Microlab home page.

7.2         Problem and comment section under the equipment section of the wand.

7.3         Equipment enable message of the wand.

7.4         Detail SPR 220 – 7.0 photoresist processing can be found on MOD 29.

7.5         Refractive index for SPR 220 – 7.0 photoresist- 1.73 at 365 nm, 1.30 at 405 nm, 1.67 at 436 nm, 1.63 at 633 nm.

8.0   Available Processes

8.1         Spin Coat Process: The SVG8626 can dispense three types of photoresists on four-inch wafers. These are: FujiFilm OCG 825 (G-line resist), OCG OiR 897-10i (I-line resist) and Rohm Haas SPR 220 (broadband resist) for track 1 & 2. 

8.2         Bake Processes: There is one bake-station available on each track. The bake station can control the temperature within 0.1ºC from the set point.

8.3         Post-exposure bake and hard bake process steps for I-line and G-line resists can be done on the developer track (svgdev) if 120ºC is desired.

9.0   SVG8626PC/ 8636HPO Operation

There are two tracks available on the SVG8626 system. The both tracks are designed to perform spin-coat and soft-bake operations.

9.1    General Coat Operation

9.1.1          Enable the system (svgcoat1 or svgcoat2) on the wand.

9.1.2          Verify that the power to the system is ON.

9.1.3          Verify that desired SVG track (svgcoat1 or svgcoat2) is in AUTO mode. This can be checked on the pertinent control panel (pads) in front of the machine, Figures 1-2 (Section 11). The LED next to the word AUTO should be illuminated on the Manual-single-Auto key (switch). If not, press this key to toggle through the other options (SINGLE or MANUAL) until AUTO is selected.

9.1.4          Select your desired dispense program (see Section 9.3).  Note that there are 2 separate display windows on the control panel:  COATER AND OVEN.  In order to select the dispense program, the COATER display must be selected.  When the COATER display is selected, an asterisk appears at the left of the COATER display and when the OVEN display is selected, a plus sign appears at the left of the OVEN display.  You can toggle between the two using the STATION SELECT button on the control panel keyboard.  With the COATER display active, press the PROGRAM SELECT button on the control panel keyboard to toggle through the available programs (1-9).  Alternatively, you can press the desired program number key followed by the PROGRAM SELECT button to select the program directly.

9.1.5          Verify the appropriate oven program is selected.  As with the dispense program, the OVEN display must be active in order to select different programs (see above instructions).

9.1.6          If necessary, press INDEX RESET button once to bring the send indexers up (starting position) or twice for the receive indexer to come up.  (Note that if you press the INDEX RESET button, you must lift the cassettes completely off the elevator and then replace them in order to proceed, i.e. for the cassette to go down.) These actions reset the send & receive elevator and can help user to alleviate/resolve cassette indexer problems.

9.1.7          Load an empty cassette onto the receive indexer (right side for the coater track). Load the cassette containing your wafers and 3 dummy wafers on the send indexer (left side). Make sure that the cassettes are properly seated on the indexers.

Note:    The coater track processes wafers from left to right (first track, closest to operator and second track, further away from operator), while facing the machine.

9.1.8          Press the START button on keypad.  The receive cassette will lower and the send cassette will lower until it senses a wafer.  The wafer will then be transported to the spindle station for the dispense procedure, then to the bake station for soft baking, and finally to the chill plate and receive cassette.

Note:    If the receive cassette does not lower, remove the cassette and then replace it. Hit START and the cassette should lower.  SPR 220 – 7.0 photoresist bake skips the cooling step to avoid thermal shock which induces photoresist cracking.

9.2         Other Functions on the Control Panel

Beside the switch functions described above, i.e. Power, Start, Index Reset, Station Select and Program Select; there are other useful functions, which are described below:

9.2.1          INDEX RESET: Depressing the Index Reset once, will return the Send indexer to top position. Receive indexer will not reset until any wafer in process enters the receive cassette. Depressing the Index Reset twice, will return the Receive cassette to top position immediately unless there is a wafer between the processing station and the receive cassette. The Send cassette is unaffected.

9.2.2          (COATER, OVEN) STOP: Ends processing immediately. Pressing START will resume processing with the next operation programmed.

9.2.3          TRANSFER STOP: Immediately stops all indexer and carriage O-rings. Wafers in transit between stations will remain in place until START will complete processing and will come to the top position waiting for the START command.

9.2.4          EVENT SELECT: Used to verify the sequence of operations and associate parameters for the selected program. The events will be shown in sequence, but depressing the number followed by the event select key can also access a particular event.

9.2.5          WAFER LOST: Allows the operator to resume wafer processing if a wafer is removed or broken during processing or if a sensor fails to see a transfer. The key is only functional when a wafer has not been received at its next station after a 6 sec delay.

9.2.6          CLEAR: Used to resume processing when machine is in programming, diagnostic or calibration mode. Used to turn off Wafer Lost alarm.

9.2.7          DIAGNOSTIC SELECT: Used to access machine and sensor state diagnostics. Machine State messages for the send indexer and processing station will be displayed in the upper display window. Machine State messages for the receive indexer are displayed in the lower display window. Sensor State messages are displayed in the top display window only. See Section 4 for a listing of machine and sensor state codes.

9.3         SVGCOAT1 and SVGCOAT2 Programs

There are several coat and bake programs available on these tracks. The standard positive resist processes use OiR 10i I-line and OCG 825 G-line Positive Photoresists. Appendix 2 provides exact content of each recipe (program) at the end of this chapter.

9.3.1          SVGCOAT1 Programs

Table 1 - Coater 1 Programs

Program

(#)

Resist Type

Spin Speed

(RPM)

Refractive Index

Thickness

(um)

*1

OiR 10i (I-Line)

4100

Default value ~1.631

~1.1

*2

OCG 825 (G-Line)

5000

Default value ~1.631

~1.3

3

OiR 10i (I-Line)

2000

Default value ~1.631

~1.6

4

OCG 825 (G-Line)

2200

Default value ~1.631

~2.0

5

OiR 10i (I-Line)

1300

Default value ~1.631

~2.0

6

OiR 10i (I-Line)

820

Default value ~1.631

~2.8

7

None

 

 

 

**8

SPR 220 - 7.0 (Broadband)

1800

Default value ~1.631

~10.0

9

Edge Bead Removal (EBR)

600

Default value ~1.631

N/A

 *  Standard Programs

 ** Standard Thick Resist Program:   Must run EBR program #9 before softbake on coater 1.

                                                      If decided not to use EBR program, then softbake must be done on hotplates in Y1.

Table 2 – Oven 1 Programs

Program

(#)

Bake Temp.

(ºC)

Bake Time

(sec.)

Chill Time

(sec.)

*1

90

60

6

2

90

90

6

3

90

120

6

7

90

180

6

**8

115

300

0

9

No Bake

0

0

                               *  Standard Programs

                               ** Standard Thick Resist Program

Note:  Users must adjust program #8 bake temperature to 115ºC manually and then return to 90ºC after finish baking wafers.

9.3.2          SVGCOAT2 Programs

 

Table 3 - Coater 2 Programs

Program

(#)

Resist Type

Spin Speed

(RPM)

Refractive Index

Thickness

(µm)

*1

OiR 10i (I-Line)

4100

Default value ~1.631

~ 1.1

*2

OCG 825 (G-Line)

5000

Default value ~1.631

~ 1.3

3

OiR 10i (I-Line)

2000

Default value ~1.631

~ 1.6

4

OCG 825 (G-Line)

2200

Default value ~1.631

~2.0

5

OiR 10i (I-Line)

1300

Default value ~1.631

~2.0

6

OCG 825 (G-Line)

6000

Default value ~1.631

~1.1

7

None

 

 

 

**8

SPR 220 - 7.0 (Broadband)

1800

Default value ~1.631

~10.0

9

Edge Bead Removal (EBR)

600

 

N/A

  *   Standard Programs

  **  Thick Resist Program:   Must run EBR program #9 before softbake on coater 2. 

                                          If decided not to use EBR program, then softbake must be done on hotplates in Y1.

Table 4 – Oven 2 Programs

Program

(#)

Bake Temp.

(ºC)

PEB Time

(sec.)

Chill Time

(sec.)

*1

90

60