Q & A on Rapid Thermal Annealing Systems

1. Q: Which model should I purchase?
A: Normally your biggest substrate size determines the model. AccuThermo AW610M is up to 6 inch; AccuThermo AW810M, AccuThermo AW820M, AccuThermo AW820V (NOT RECOMMENDED) are up to 8 inch.

2. Q: Can I use AccuThermo AW610M,AccuThermo AW810M for 2,3,4,5 inch substrate?
A: Yes. You can.

3. Q: Which type of RTP should I purchase, Atmospheric or Vacuum (NOT RECOMMENDED)?
A: You can run most processes by Atmospheric RTP. Atmospheric RTP has much better performance ( repeatability, stability, uniformity) than traditional vacuum RTP because of atmospheric RTP’s compact chamber design, isolated quartz tube, top&bottom lamp heat, pure gas purge, 40 years approval. The ownership cost and usage cost of Atmospheric RTP are lower. If you are not sure that you have to use vacuum RTP because of O2, you can buy atmospheric RTP with forming gas to get 2 to 12 PPM O2 environment instead of vacuum RTP. Bad performance ( repeatability, stability, uniformity) and contamination issue are vacuum RTP fatal problems.

4. Q: What are the differences in Allwin21 vacuum RTPs?
A: AccuThermo AW820V is up to 8 inch wafer. It comes with top and bottom lamp  heating ( 27 lamps ,1.5 KW ea, TOP 13 lamps, BOTTOM 14  ,10 bank zones control). The maximum temperature is 1250C @ 10 minutes.  According to our 40 years RTP experience, we do not recommend vacuum RTP.

5. Q: Should I have to use susceptor for transparent substrate?
A: Normally transparent substrate can not absorb lamp heat since it is transparent. You have to use carrier which can absorb lamp heat and transfer the heat to transparent substrate. Susceptors can be made of SiC, Silica,Graphite,or Si. They can be costly. You can use a Si wafer as carrier if your process is applicable. You can us a Si wafer with pocket, instead of susceptor, if your budget is tight. A susceptor will lower the ramp rate and cooling rate significantly because of its size and thickness. 

6. Q: Which material of susceptor should I purchase?
A: Traditionally people use graphite with SiC coating for susceptor. Graphite susceptor is for up to 950C with lower ramp rate. Silica susceptor is for up to 1100C with higher ramp rate. Sintered SiC susceptor is for up to 1100C with lower ramp rate. Si susceptor is less expensive and up to 750C with lower ramp rate. The bigger the size of susceptor, the lower the ramp&cooling rate.Susceptors made of Graphite with SiC Coating are the most popular in the market.

7. Q: Should I purchase an ERP Pyrometer as high temperature sensor?
A: Thermocouples (TC’s) are the traditional temperature sensor for lower than 1050C. But TC will react with Si wafer at 750C. Our non-contact patented ERP Pyrometer can work at 400~1250C with precise measurement after calibration by AW technology. TC has to contact the substrate for temperature measurement while ERP Pyrometer is non-contact. TC cost is lower while ERP Pyrometer’s is higher (more than $15K with calibration tools (TC wafer and omega meter). TC will evaporate at high temperature causing contamination. Shield TC with SiC cap for 200-1100C is only for low budget customers.

8. Q: Can I measure the temperature uniformity by multiple points TC wafer?
A: If the temperature is lower than 500C, you can measure the temperature uniformity by TC wafer directly. If the temperature is higher than 500C, you have to measure other parameters’ uniformity to reflect the process uniformity. The influence of lamp, chamber, the structure of TC wafer etc is significant at higher than 500C. Semiconductor industry measures sheet resistance. LED industry measures voltage.

9. Q: Can I have a demo before purchase?
A: We have AccuThermo AW 610M demo systems in our facility in USA. We can do demo one time for you if you can send your wafer to us and our facilities are applicable. But be aware that you cannot evaluate the performance by a few demo results because of the following. (1) The demo condition might not be good enough; (2) Your recipe parameters might not be applicable because RTP temperature number in recipe is relative, not real.

10. Q: What is the most important feature for RTP system?
A: Production proven repeatability. If the RTP system performance is not repeatable, the RTP is a concept one and it will be “Rapid Trash Process”. It is crucial to buy an RTP that has been produced and verified by many customers, because we cannot buy expensive semiconductor equipment based on the product brochures, nor can we verify a semiconductor equipment based on one or two users.

11. Q: How many gas lines can Allwin21 RTP come with?
A: AccuThermo AW 610M, AccuThermo AW820M, AccuThermo AW820V come with 6 gas lines with 1 to 6 of MFCs while AccuThermo AW810M, comes with 4 gas lines with 1 to 4 of MFCs. Customizing is optional. The popular MFCs are 10 SLM N2, Ar, O2 and 5 SLM NH3, N2O2.

12. Q: Can customer install the RTP by themselves?
A: Yes. Our RTP systems are customer-install design. We sold our RTP systems to more than 35 countries. Most customers installed our RTP systems by themselves according to our professional manuals. We provide free technical supports by email, phone, skype, APPs etc. We have local reps who can provide 24/7 service in some countries if applicable.

13. Q: Why should we purchase an RTP from Allwin21?
A: (1) Best production proven performance( Repeatability, Uniformity, Stability).
(2) Our system hardware and software technology have been approved based on 40 years of semiconductor industry development.
(3) It can cost a lot money and time to test an unpopular or new concept RTP systems .
(4) Allwin21 focuses on RTP as our main business. We professionally provide high quality RTP system and technical support.
(5) Reasonable price accepted by thousands of customers from 40 countries. Many options at different costs for different configurations, meeting different customers’ budget.
(6) Industry-leading lead time (2 to 8 weeks).

(7)  Options: Double O Ring and/or O2 Sensor/Analyzer for O2 sensitive applications and saving GaAs, InP, GaN, GaInP, SiC and other valuable compound material wafers 

(8) PowerSum Function: Save valuable compound material wafers.

(9) Option: Non-contact ERP Pyrometer, AG Associates Patented Parts, for best RTP performance for 400-1250C.