Specific Process Knowledge/Thin film deposition/Furnace LPCVD PolySilicon

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LPCVD (Low Pressure Chemical Vapor Deposition) PolySilicon

At the moment there is one furnace for PolySilicon depositions at Danchip. The furnace is a Tempress horizontal furnace. The process is a batch process meaning you can run a batch of 25 wafers at a time. The deposition takes place at temperatures of 800-835 degrees Celsius. The reactive gases are Ammonia and dichlorsilane. The LPCVD nitride has a good step coverage and the film thickness is very uniform over the wafer. We have two standard LPCVD nitride processes: One for depositing stoichiometric nitride (Si₃N₄) and one for deposition of low stress nitride (SNR). To get information on how to operate the furnace please read the manual which is uploaded to LabManager.

Process Knowledge

Please take a look at the process side for deposition of Silicon Nitride using LPCVD: Deposition of Silicon Nitride using LPCVD

Overview of the performance of LPCVD Silicon Nitride and some process related parameters

Purpose	Deposition of silicon nitride	Stoichiometry: Si₃N₄ SRN SRN: Silicon Rich Nitride
Performance	Film thickness	Si₃N₄:~50Å - ~3000Å SRN: ~50Å - ~10000Å
	Step coverage	Good
	Film quality	Dense film Few defects
Process parameter range	Process Temperature	800-835 ^oC
	Process pressure	80-230 mTorr
	Gas flows	SiH $_{2}$ Cl $_{2}$ :10-100 sccm NH $_{3}$ :10-75 sccm
Substrates	Batch size	1-25 4" wafer per run Deposition on both sides of the substrate
Substrates	Substrate material allowed	Silicon wafers (new from the box or RCA cleaned) with layers of silicon oxide or silicon (oxy)nitride (RCA cleaned) Quartz wafers (RCA cleaned)