>>> 'technics-a' problem from hsin -- Thu Dec  7 18:10:55 1989 <<<

Dr. Du used the technics-a to deposit SiO2 film on Wednesday.
He found the index ( Nf ) of the film is too high : 1.78!!!
The BHF can not remove it!!  ( Actually the etching rate is
very slow, around 200 angstrom/ min.)  Therefore only two 
possible things happened: 1). Contamination occured in the 
chamber 2). Composition of the gas has been changed.

Could Phil take a look at the technics-a to see if it is dirty
in the chamber or there is a leakage somewhere?? 

If you have any more questions on the problem, please contact 
Dr. Du. I send this message for him because of his request.

Wei Hsin

>>> 'technics-a' problem from phillip -- Fri Dec  8 06:43:56 1989 <<<

P: SiO2 deposition parameters contaminated.
S: Switched machine from 'PE' chamber gas control
   to 'PD' gas controller gas control.
   
This should fix the problem as reported by Dr. Du.

>>> 'technics-a' problem from phillip -- Mon Dec 11 07:57:30 1989 <<<

the -a machine is being tested for uniformity this a.m.
It is unavailable for use until testing is complete (by noon).
From hebert Mon Dec 11 10:49:16 1989
Received: by argon (5.57/1.16)
	id AA08238; Mon, 11 Dec 89 10:49:05 PST
Date: Mon, 11 Dec 89 10:49:05 PST
From: hebert (David Hebert)
Message-Id: <8912111849.AA08238@argon>
To: bob, phillip, technics-a, technics-b, voros
Subject: technics-a comments 
Status: RO

I checked SiO2 deposition process in Technics-a using the recipe
that I use in Technics-b.

The chamber was cleaned with methanol and clean room wipes. It was then
pumped out and a CF4+O2 plasma was run until the electrode heated up.
The CF4+O2 was set at 150 mTorr and the power set at 75 W RF. The setpoint
for the heater was set at 350 deg C. When the temp reached 340 deg C, the
CF4+O2 plasma was turned off and the process was changed from PE mode
to PD mode. The N20 line was pumped out so until the flow thru the MFC
was less than 0.5 sccm N2O. The N2O bottle was then opened (i.e. I had
pumped the line out to the regulator). The N2O flow was adjusted to
63.0 sccm. The SiH4 flow was then adjusted to 8.0sccm. A predep was done
to coat the chamber using 10 W RF for about 15 minutes. A 100 mm wafer was
then loaded at the 4 o'clock electrode position. SiO2 was deposited for
13 minutes, the wafer removed to measure film Nf and XOX by ellips,
and then the wafer was placed on the electrode rotated 180 deg from the
original orientation, and SiO2 was deposited for another 13 minutes.
The results follow:

N2O  63.0 sccm
SiH4  8.0 sccm
Power 10 Watts
Set T  350 deg C
Start dep T: greater than 310 deg C


dep t= 13.0 minutes 
100 mm wafer   Center  1702 A   Nf=1.47
               Top     1505        1.47
               Bottom  1857        1.47
               Left    1673        1.47
               Right   1697        1.47
Dep rate: 130 A/min   Thickness variation: 20.9%

Rotate wafer 180 deg and deposit for an additional 13.0 minutes:
100 mm wafer   Center   3257 A   Nf= 1.48
               Top      3194         1.48
               Bottom   3334         1.47
               Left     3264         1.47
               Right    3370         1.48

dep Rate (ave for 26 minutes): 126 A/min   
Thickness variation (for 26 min dep with rotation): 5.4%

This is the same dep process that I use in Technics-b with the same
results. I've checked the breakdown voltage of 2000 A SiO2 films:
No breakdown below 100 V, and leakage current is typically less than
10E-7 amperes up to 100 V.

The chamber pressure rate of rise does NOT indicate a leak to the Technics-a
chamber. Film uniformity and Nf are very good for this type of CVD chamber
using the above recipe. Increasing the power to 30 W will increase
the dep rate by about 20% while having a deliterious effect on thickness
uniformity. Decreasing the temp below 300 deg C will effect Nf and 
thickness uniformity and dep rate. It is possible to get Nf below
1.60 using temps as low as 250 deg C, but a different recipe is required.
Accepted Nf for SiO2 deposited in this type of system is anything 
below 1.60. I ususally can get 1.46 to 1.49 quite easily. If Nf is too
high, I suggest reducing SiH4 flow and keeping N2O flow constant. In the
above recipe, silane flow can vary between 7.0 and 8.0 sccm.


>>> 'technics-a' problem from voros -- Tue Dec 12 15:37:36 1989 <<<

tehnics-a has been characterized by Dave Hebert and the recipe,
which is identical to the recipe for technics-b, has been entered
in the manual.

>>> 'technics-a' problem from parrish -- Wed Mar 14 13:10:22 1990 <<<

problem    nitrogen not flowing into roughing-pump

cause:     rotometers of inferior quality

solution:  removed old rotometers, and replaced with good quality one.

>>> 'technics-a' problem from liang -- Mon Apr  2 20:48:29 1990 <<<

there is no power for plasma in both etching and deposition mode.
chunlin

>>> 'technics-a' problem from phillip -- Tue Apr  3 08:12:50 1990 <<<

P: No plasma.
S: Flushed cooling lines to and from plasma
   interlock. Replaced blocked section of
   water line.
The -a machine is up and available for use.

>>> 'technics-a' problem from micro -- Fri Jun 15 16:48:07 1990 <<<

sorry...this is just a test

>>> 'technics-a' fix from micro -- Fri Jun 15 16:48:34 1990 <<<

this is just a test...
