GaAs Wet Etch AWS
Single Wafer Wet Etch Processing
GaAs Wet Etch Veeco’s single wafer wet etch technology provides a highly uniform, highly controlled wet etch process with typical 1% uniformity in field use, both within wafer and wafer to wafer. Veeco’s 3300 series of wet etch systems provides fully automatic, dry-in/dry-out operation. These systems may be configured to handle multiple wafer sizes, such as 100 mm and 150 mm, with only a PC recipe change between sizes, and scaled from manual load systems to multi-chamber systems capable of processing up to 100 wafers per hour.
Spindle Tooling Application-specific spindle tooling is available for single- or double-sided processing. The single-sided tooling (Patent Pending) protects the base material from etching by wet solutions or vapors, through use of a gas seal, while the patterned, structured wafer undergoes the wet etch process.
Single-sided gas seal tooling enables active side etching while protecting the GaAs wafer backside from etching.
Double-sided Tooling with Backside Rinsing
Dispensing Technology Etch rate and uniformity are optimized by maintaining constant dwell times across the wafer surface. This is accomplished by use of non-linear motion profiles. A hyperbolic profile ensures equal dwell time across the wafer, whether dispensing is at the center or edge of a wafer. Speed, acceleration, deceleration, time, and nozzle height are all programmed by recipe for highest precision.
Etch Dispense Control Both flow rate for stream dispensing, and pressure, which determines spray pattern and location, are under fully PC programmable control, with programmable pressure interlocks. There are no moving parts in this system, resulting in the cleanest, most reliable performance. Stream processing with flow control is available using either standard 1/4" or 3/8" ID tubing. The nozzle position over the wafer, including height, is also programmable, to achieve highly uniform wet etching.
PC Programmable Flow Rate Control for Stream Dispensing and PC Programmable Pressure Control for Spray Dispensing
Temperature Control Etch rate and uniformity are optimized in part by etch chemistry temperature. Veeco systems are engineered with on-the-fly temperature control, which is programmable by process recipe. Chemistry is heated as it is dispensed, avoiding the degradation associated with batch heating and enabling per recipe temperature selection. Temperature controllers are sized according to the chemistry flow rate, temperature rise, and uniformity process requirements.
Chemical Separation and Recirculation For etch solution recirculation in processes with longer cycle time, Veeco’s patent pending, in-situ chemical separation system enables the purest recirculation of the solutions. Drainage is entirely by gravity. The solution collection can be programmed to start and stop at any point in the recipe. Etch-ending DI quench and secondary etch steps can be included, with absolutely no cross-contamination with the recirculated solution. Open Position
Advanced Plumbing System Veeco plumbing systems utilize both pressure and vacuum transport of wet chemistry, which decreases contamination and maintenance, and provides for the most reliable operation. PC programmable pressure, flow rate, and temperature ensure the tightest process control available. To control etch rate and uniformity, chemistries may be blended by recipe, using closed loop, volumetric chemical mixing. Veeco systems may be configured for dilutions from 10,000:1 to ppb mixtures, with accuracy greater than that of purchased, premixed chemistry. Further chemical mixing feedback is provided by point-of-use, non-contact resistance monitors, in addition to integration of optical monitors.
WaferChekTM The WaferChek system is an in-situ color CCD camera that is utilized to manage the wet etching process by analyzing the optical properties of the wafer. This system is ideal for complete removal of one layer over another layer within a pattern. Such etches include Gate Recess Etch, Stress Relief, and InGaP.
Closed Position
GaAs-Specific Wet Etch Processes Chemistry Selective to InGaP
H3PO4:H2O2:DI 1:1:20
InGaP Etch Selective to GaAs
HCl: H3PO4 3:1
MESA Etch • The MESA process is a patterned GaAs etch process used to isolate the conductive areas of each device from another.
Temperature (°C)
Etch Rate (Å/min)
24
1,625
Ambient
800
Temperature (°C)
Etch Rate (Å/min)
HF:H2O2:H2O 1:9:90
20
4,000
H2SO4:H2O2:DI 1:8:160
25
5,000
NH4OH:H2O2:DI 1:1:1000
20
250
20-40
Å/min up to 3 µm/min
Chemistry
H3PO4:H2O2:DI (Across spectrum)
Gate Recess Etch—FCSL Current Process • The gate etch process is a patterned, selective GaAs:AlGaAs 100:1 etch process used to define the device gate recesses. • The process requires a HCl:H2O 1:10 pre-treat, rinse, and dry immediately before etch is commenced. Chemistry Citric acid monohydrate: tri-potassium Citrate Monohydrate:H2O 7:7:3:1
Temperature (°C)
Etch Rate (Å/min)
22
1,750
(1 Molar solutions) Citric:H2O2:DI 4:1:1
22
4,000
Citric:H2O2:DI 5:1:75
22
150
Citric:H2O2 10:1
18
2,100
Deposition Pre-treat/Gate Etch Pre-treat • The deposition pre-treat process is used to remove oxide from wafers prior to metal deposition processes and as a pre-treatment prior to gate etch. Chemistry HCl:DI 1:10
Temperature (°C) 20
InP Chemistry
Temperature (°C)
Etch Rate (Å/min)
200 Å GaAs over InP
H3PO4:H2O2:DI 1:1:20
24
1,625
3,000 Å InP over InGaAs
H3PO4:HCl 9:1
20
850
InGaP Etch
InGaP vs. GaAs
Chemistry
Temperature (°C)
Etch Rate (Å/min)
HCI 37%
20
1,800
Stress Relief • The stress relief process is a GaAs etch process used to remove up to 25 μm of material from the rear surface of the wafer post grinding. • The wafers are thinned (50-125 μm) and typically
Learn more about Veeco’s single wafer process capabilities at www.veeco.com/PSP
Chemistry
Temperature (°C)
Etch Rate (µm/min)
35
2
H3PO4:H2O2:DI 15:20:5
Veeco Precision Surface Processing 185 Gibraltar Road Horsham, PA 19044 USA +1 215-328-0700
©2017 Veeco Instruments Inc. All rights reserved. Veeco, the Veeco logo, WaferStorm, WaferEtch and WaferChek are either registered trademarks of Veeco Instruments Inc. in the United States and/or other countries. Patents pending. Veeco reserves the right to change specifications and other product information without notice.
GaAs Wet Etch Veeco’s single wafer wet etch technology provides a highly uniform, highly controlled wet etch process with typical 1% uniformity in field use, both within wafer and wafer to wafer. Veeco’s 3300 series of wet etch systems provides fully automatic, dry-in/dry-out operation. These systems may be configured to handle multiple wafer sizes, such as 100 mm and 150 mm, with only a PC recipe change between sizes, and scaled from manual load systems to multi-chamber systems capable of processing up to 100 wafers per hour.
Spindle Tooling Application-specific spindle tooling is available for single- or double-sided processing. The single-sided tooling (Patent Pending) protects the base material from etching by wet solutions or vapors, through use of a gas seal, while the patterned, structured wafer undergoes the wet etch process.
Single-sided gas seal tooling enables active side etching while protecting the GaAs wafer backside from etching.
Double-sided Tooling with Backside Rinsing
Dispensing Technology Etch rate and uniformity are optimized by maintaining constant dwell times across the wafer surface. This is accomplished by use of non-linear motion profiles. A hyperbolic profile ensures equal dwell time across the wafer, whether dispensing is at the center or edge of a wafer. Speed, acceleration, deceleration, time, and nozzle height are all programmed by recipe for highest precision.
Etch Dispense Control Both flow rate for stream dispensing, and pressure, which determines spray pattern and location, are under fully PC programmable control, with programmable pressure interlocks. There are no moving parts in this system, resulting in the cleanest, most reliable performance. Stream processing with flow control is available using either standard 1/4" or 3/8" ID tubing. The nozzle position over the wafer, including height, is also programmable, to achieve highly uniform wet etching.
PC Programmable Flow Rate Control for Stream Dispensing and PC Programmable Pressure Control for Spray Dispensing
Temperature Control Etch rate and uniformity are optimized in part by etch chemistry temperature. Veeco systems are engineered with on-the-fly temperature control, which is programmable by process recipe. Chemistry is heated as it is dispensed, avoiding the degradation associated with batch heating and enabling per recipe temperature selection. Temperature controllers are sized according to the chemistry flow rate, temperature rise, and uniformity process requirements.
Chemical Separation and Recirculation For etch solution recirculation in processes with longer cycle time, Veeco’s patent pending, in-situ chemical separation system enables the purest recirculation of the solutions. Drainage is entirely by gravity. The solution collection can be programmed to start and stop at any point in the recipe. Etch-ending DI quench and secondary etch steps can be included, with absolutely no cross-contamination with the recirculated solution. Open Position
Advanced Plumbing System Veeco plumbing systems utilize both pressure and vacuum transport of wet chemistry, which decreases contamination and maintenance, and provides for the most reliable operation. PC programmable pressure, flow rate, and temperature ensure the tightest process control available. To control etch rate and uniformity, chemistries may be blended by recipe, using closed loop, volumetric chemical mixing. Veeco systems may be configured for dilutions from 10,000:1 to ppb mixtures, with accuracy greater than that of purchased, premixed chemistry. Further chemical mixing feedback is provided by point-of-use, non-contact resistance monitors, in addition to integration of optical monitors.
WaferChekTM The WaferChek system is an in-situ color CCD camera that is utilized to manage the wet etching process by analyzing the optical properties of the wafer. This system is ideal for complete removal of one layer over another layer within a pattern. Such etches include Gate Recess Etch, Stress Relief, and InGaP.
Closed Position
GaAs-Specific Wet Etch Processes Chemistry Selective to InGaP
H3PO4:H2O2:DI 1:1:20
InGaP Etch Selective to GaAs
HCl: H3PO4 3:1
MESA Etch • The MESA process is a patterned GaAs etch process used to isolate the conductive areas of each device from another.
Temperature (°C)
Etch Rate (Å/min)
24
1,625
Ambient
800
Temperature (°C)
Etch Rate (Å/min)
HF:H2O2:H2O 1:9:90
20
4,000
H2SO4:H2O2:DI 1:8:160
25
5,000
NH4OH:H2O2:DI 1:1:1000
20
250
20-40
Å/min up to 3 µm/min
Chemistry
H3PO4:H2O2:DI (Across spectrum)
Gate Recess Etch—FCSL Current Process • The gate etch process is a patterned, selective GaAs:AlGaAs 100:1 etch process used to define the device gate recesses. • The process requires a HCl:H2O 1:10 pre-treat, rinse, and dry immediately before etch is commenced. Chemistry Citric acid monohydrate: tri-potassium Citrate Monohydrate:H2O 7:7:3:1
Temperature (°C)
Etch Rate (Å/min)
22
1,750
(1 Molar solutions) Citric:H2O2:DI 4:1:1
22
4,000
Citric:H2O2:DI 5:1:75
22
150
Citric:H2O2 10:1
18
2,100
Deposition Pre-treat/Gate Etch Pre-treat • The deposition pre-treat process is used to remove oxide from wafers prior to metal deposition processes and as a pre-treatment prior to gate etch. Chemistry HCl:DI 1:10
Temperature (°C) 20
InP Chemistry
Temperature (°C)
Etch Rate (Å/min)
200 Å GaAs over InP
H3PO4:H2O2:DI 1:1:20
24
1,625
3,000 Å InP over InGaAs
H3PO4:HCl 9:1
20
850
InGaP Etch
InGaP vs. GaAs
Chemistry
Temperature (°C)
Etch Rate (Å/min)
HCI 37%
20
1,800
Stress Relief • The stress relief process is a GaAs etch process used to remove up to 25 μm of material from the rear surface of the wafer post grinding. • The wafers are thinned (50-125 μm) and typically
Learn more about Veeco’s single wafer process capabilities at www.veeco.com/PSP
Chemistry
Temperature (°C)
Etch Rate (µm/min)
35
2
H3PO4:H2O2:DI 15:20:5
Veeco Precision Surface Processing 185 Gibraltar Road Horsham, PA 19044 USA +1 215-328-0700
©2017 Veeco Instruments Inc. All rights reserved. Veeco, the Veeco logo, WaferStorm, WaferEtch and WaferChek are either registered trademarks of Veeco Instruments Inc. in the United States and/or other countries. Patents pending. Veeco reserves the right to change specifications and other product information without notice.
