Oxford ICP 2-step DRIE SOP

Transcription

1 Oxford ICP 2-step DRIE SOP Oxford ICP 2-step DRIE SOP Page 1 of Scope 1.1 This document provides operating procedures for the Oxford 100 ICP 2-step DRIE. 2. Table of Contents 1. Scope Table of Contents Reference Documents Referenced within this Document External Documents Equipment and/or Materials Safety Setup Procedures Record Information in Log Book Turn on Burn Box Hook up Liquid Nitrogen... 3

2 Oxford ICP 2-step DRIE SOP Page 2 of Turn on Chiller Vent Load Lock Load Wafer Pump Down Load Lock step Deep Etching Procedure Set Up and Edit Process Recipe Start Etch Process step Smooth Shallow Etching Procedure Set up and Edit Process Recipe Start the Etch Process Shutdown Procedures Vent Load Lock Shutdown System Maintenance Procedures Chamber Cleaning Check He Leak Rate Check Chamber Leak Rate Troubleshooting Process Notes Typical Etch Characteristics Process Summary Revision History Figure 1, Liquid Nitrogen Tank... 3 Figure 2, Chiller... 3 Figure 3, Pump Control Page... 4 Figure 4, Load Lock... 4 Figure 5, Temperature Controller... 5 Figure 6, Recipe Editor Page... 7 Figure 7, Process Control Page... 9 Figure 8, Etch Rate for 10 um Trenches Figure 9, Etch Rate for 2 um Trenches Figure 10, Etch Rate for 4 um Pillars Figure 11, 2-step Etching SEM Analysis Table 1, Deep Etch Recipe... 6 Table 2, Smooth Etch Recipe Reference Documents 3.1 Referenced within this Document Ecosys Burn Box SOP 3.2 External Documents None

3 Oxford ICP 2-step DRIE SOP Page 3 of Equipment and/or Materials 4.1 Wafer/Sample 4.2 Oxford Liquid Nitrogen 5. Safety 5.1 Follow all Nanofab safety procedures. 6. Setup Procedures 6.1 Record Information in Log Book Record all processing and characterization information in log book The log sheet is an excel sheet on the computer. It should already be open. 6.2 Turn on Burn Box Follow the procedure in the Ecosys Burn Box SOP to turn on the burn box. LN2 Valve 6.3 Hook up Liquid Nitrogen Figure 1, Liquid Nitrogen Tank If the LN2 hose on the back of the Oxford 100 is not connected to the LN2 tank, connect it Remove filler hose, if attached Connect Oxford 100 hose. See Figure 1, Liquid Nitrogen Tank Open the LN2 valve. 6.4 Turn on Chiller Go into the chase behind the Oxford Turn the power switch to start on the chiller. See Figure 2, Chiller. Power Switch Figure 2, Chiller

4 Oxford ICP 2-step DRIE SOP Page 4 of 13 System Button Process Buttton Load Lock Controls Main Chamber Controls Do Not Touch Evacuate Stop Vent 6.5 Vent Load Lock Click on System icon. See Figure 3, Pump Control Page Click on pump page Press stop button corresponding to the load lock mechanical pump. See Figure Press vent button. See Figure Wait for load lock to vent. The pressure will read above 600 Torr and the time will be Open load lock lid Press stop button. See Figure Load Wafer Figure 3, Pump Control Page Place wafer in load lock against the two pins on the transfer arm with the wafer facing the two pins. The wafer should touch the two pins. See Figure 4, Load Lock. Figure 4, Load Lock

5 Oxford ICP 2-step DRIE SOP Page 5 of Pump Down Load Lock Close load lock lid Select the evacuate button. See Figure Enter an ID name or number for your wafer Wait for the load lock to pump down (~1 min) Ensure that the chuck is cooling down. See Figure 5, Temperature Controller. Actual Temperature Set point Figure 5, Temperature Controller 7. 2-step Deep Etching Procedure NOTE: This recipe can be used to etch deep trenches or vias in 100 mm wafers. It is strongly advised that you do a test run on a practice wafer before working with your device wafer. 7.1 Set Up and Edit Process Recipe Click Process button. See Figure Click Recipes page Click on the New button. See Figure 6, Recipe Editor Page Chose Yes to clear the current recipe Click Load to open your recipe Select recipe and click ok If you don t have a recipe, open the Bosch_Template recipe and rename the file The recipe steps will be displayed on the left side of the screen Set the number of etch cycles Click on the Repeat step. See Figure Choose Repeat Step from the menu. See Figure Enter the number of times to repeat the etch and deposition step The etch rate is approx. 1 micron per cycle Click OK.

6 Oxford ICP 2-step DRIE SOP Page 6 of The deep etch recipe is as follows: Table 1, Deep Etch Recipe Step C 4 F 8 SF 6 Pressure ICP Power RF Power Temp. Time (C) Flow 40sccm 0 15mT s C 4 F 8 Strike 40sccm 0 15mT 500W 30W 15 3s Plasma Etch 0 70sccm 1mT 500W 25W 15 11s Deposit 95sccm 0 1mT 500W 10W 15 5s Final Etch 0 70sccm 1mT 500W 25W 15 11s The Final Etch step removes material from the last deposition step In all steps the He backing is To change process time or other parameters, click on the process step and select Edit Step and set the parameter to the desired amount After changing the file name, click Save and Click OK. 7.2 Start Etch Process Click the Run button. See Figure 6. NOTE: The wafer transfer will begin automatically and the etch process will start when the wafer is loaded and the chuck is at the correct temperature. The wafer will automatically transfer to the load lock when the process is complete Listen closely to the machine during the first steps If the machine makes a repetitive clicking sound, restart the process Press Stop Return the wafer to load lock Click the Run button Monitor the parameters during the first steps of the process Go to the Process Control page Monitor the Reflected Power. It should be 0. See Figure 7, Process Control Page step Smooth Shallow Etching Procedure 8.1 Set up and Edit Process Recipe Click Process button. See Figure 3, Pump Control Page Click Recipes page Click on the New button. See Figure 6, Recipe Editor Page Chose Yes to clear the current recipe.

7 Oxford ICP 2-step DRIE SOP Page 7 of Click Load to open your recipe Select recipe and click ok If you don t have a recipe, open the Bosch_Smooth_Template recipe and rename the file The recipe steps will be displayed on the left side of the screen Set the number of etch cycles Click on the Repeat step. See Figure Choose Repeat Step from the popup menu. See Figure Enter the number of times to repeat the etch and deposition step Click OK. Run Button Repeat Step Button The smooth etch recipe is as follows: Figure 6, Recipe Editor Page Table 2, Smooth Etch Recipe Step C 4 F 8 SF 6 Pressure ICP Power RF Power Temp. Time (C) Flow 40sccm 0 15mT s C 4 F 8 Strike 40sccm 0 15mT 400W 30W 15 3s Plasma Etch 0 52sccm 1mT 400W 25W 15 4s Deposit 65sccm 0 1mT 400W 10W 15 3s Final Etch 0 52sccm 1mT 400W 25W 15 4s NOTE: The Final Etch step removes material from the last deposition step.

8 Oxford ICP 2-step DRIE SOP Page 8 of 13 NOTE: In all steps the He backing is To change process time or other parameters, click on the process step and select Edit Step and set the parameter to the desired amount After changing the file name, click Save and Click OK. 8.2 Start the Etch Process Click the Run button. See Figure 6. NOTE: The wafer transfer will begin automatically and the etch process will start when the wafer is loaded and the chuck is at the correct temperature. The wafer will automatically transfer to the load lock when the process is complete. NOTE: The etch rate for aspect ratios less than 5:1 (the depth is 5 times greater than the width) is ~ 1.46 um/min. The average surface roughness is 1.96 nm. The sidewall roughness is approx. 30 nm Listen closely to the machine during the first steps If the machine makes a repetitive clicking sound, restart the process Press Stop Return the wafer to load lock Click the Run button Monitor the parameters during the first steps of the process Go to the Process Control page Monitor the Reflected Power. It should be 0. See Figure 7, Process Control Page.

9 Oxford ICP 2-step DRIE SOP Page 9 of 13 Reflected Power Figure 7, Process Control Page 9. Shutdown Procedures 9.1 Vent Load Lock Click OK when the software says Process completed Vent load lock Press stop button corresponding to the load lock mechanical pump. See Figure Click ok when it says Wafer has finished processing Press vent button. See Figure Wait 3 min. for the load lock to vent Pull up to open load lock lid. Do not force it open, once it is vented it should open easily. If it does not open easily, press stop, then vent, and wait 3 minutes again Press stop button to stop venting Remove wafer. 9.2 Shutdown System Close knob on liquid nitrogen dewar. See Figure Pump down load lock Close load lock lid.

10 Oxford ICP 2-step DRIE SOP Page 10 of Select the evacuate button. See Figure Press cancel when software asks for ID #. 10. Maintenance Procedures 10.1 Chamber Cleaning Chamber cleaning should be done after every 3-5 hours of etching or as needed The cleaning recipe parameters are as follows: SF6 = 10sccm O2 = 40sccm ICP power = 1000W RF power = 100W He backside pressure = 0mT Pressure = 20mT T = Room Temperature 10.2 Check He Leak Rate Check chamber pressure Check icon to make sure wafer is clamped Set He pressure to 10 mt (pressure greater than 20 Torr can damage thin substrates) Check He flow rate. It should be less than?? sccm Check chamber pressure, it should have risen less than 7 mtorr Check Chamber Leak Rate Click on Chamber Click on leak detection Pump down over night Run leak test (step time) for 20 minutes Log interval 5 sec Pumping to 7e-7 Torr Click return to process 10.4 Troubleshooting To remove clamped wafer when the system doesn t recognize there is a wafer in the chamber: Pump down load lock Click on service mode Click on location where the wafer is located in the chamber.

11 Oxford ICP 2-step DRIE SOP Page 11 of Click add wafer Exit service mode Click on green wafer and blue arrow should appear Pump down load lock Click on center of load lock to transfer wafer to load lock. 11. Process Notes 11.1 Typical Etch Characteristics Figure 8, Etch Rate for 10 um Trenches

12 Oxford ICP 2-step DRIE SOP Page 12 of 13 Figure 9, Etch Rate for 2 um Trenches Figure 10, Etch Rate for 4 um Pillars

13 Oxford ICP 2-step DRIE SOP Page 13 of Process Summary Ex. 1-Bosch Template Recipe Ex. 2-Bosch Smooth Template Recipe Figure 11, 2-step Etching SEM Analysis 12. Revision History Rev Date Originator Description of Changes 1 01 Jun 2010 Sam Bell