STS ICP DRIE Study

A parameter study was conducted with the STS. This is intended to help users tune there recipes based on the desired profile of the etch. Click on each parameter to view photos. A detailed spreadsheet with measurement will be published here soon.

 

Table 1: Parameters measured. Standard DRIE Parameters

Etch Power (W)	2500, 2650, 2800, 3150, 3500
Deposition Power (W)	1500, 1625, 1875, 2000, 2200
Etch Time (sec)	5, 6, 7, 8, 9
Deposition Time (sec)	2, 3, 4, 5, 6
Etch Flow (SF6, sccm)	350, 400, 450, 500, 550
Dep Flow (C4F8, sccm)	100, 150, 200, 250, 300

Etch Power (W)

As the Etching power is increased, the etch rate increases and levels out. The 20$\mu$m and 10$\mu$m dip out the trend at the standard parameter, which is probably because the standard sample was done at a separate time. 

The initial increase in etch depth/rate is due to the higher energy of the reactive ions, which leads for more efficient material removal. The level etch performance at higher power can be explain by several different phenomenon include; Ion deflection and scattering, aspect ratio-dependent etching, and charge buildup and deflections.

Except for the discrepancies found with the 20$\mu$m and 10$\mu$m lines, the 2800W setting seems to be the optimum and fastest parameter. If a slower etch rate is desired, then a lower etch power may be used.

20 $\mu$m (2000 Magnification)

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2500 W

2650 W

2800 W

3150 W

3500 W

10 $\mu$m (3000 Magnification)

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2500 W

2650 W (2000)

2800 W

3150 W (2000)

3500 W (2000)

8 $\mu$m (3000 Magnification)

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2500 W

2650 W (2000)

2800 W

3150 W (2000)

3500 W (2000)

7 $\mu$m (3000 Magnification)

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2500 W (4000)

2650 W

2800 W

3150 W

3500 W

5 $\mu$m (3000 Magnification)

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2650 W

Deposition Power (W)

As the Deposition Power is increased, the etch depth/rate starts decreasing, most reaching a minimum at 1875W, then increasing slightly.

As the deposition power increases, the passivation layer thickens which can attenuate the energy of the incoming ions, thus reducing the etch rates. The slight increase in the etch rate at the end may be due to increasing ion bombardment that can lead to sputter of the passivation layer. This will thin the later and slightly improving the etch rate.

While the standard parameter of 2000W provides a local maximum, the 1500W would provide a better basis for the standard process. It provides the maximum etch rate without compromising the surface finish, and if a lower rate is needed then the power can just be increased.

20 $\mu$m (2000 Magnification)

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1500 W

1625 W

1875 W

2000 W

2200 W

10 $\mu$m (3000 Magnification)

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1500 W (2000)

1625 W

1875 W

2000 W

2200 W

8 $\mu$m (3000 Magnification)

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1500 W (2000)

1625 W

1875 W

2000 W

2200 W

7 $\mu$m (3000 Magnification)

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1500 W (2000)

1625 W

1875 W

2000 W

2200 W

Etch Time (sec)

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20 $\mu$m (2000 Magnification)

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5 sec

6 sec

7 sec

8 sec

9 sec

10 $\mu$m (3000 Magnification)

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5 sec

6 sec

7 sec

8 sec

9 sec

8 $\mu$m (3000 Magnification)

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5 sec

6 sec

7 sec

8 sec

9 sec

7 $\mu$m (3000 Magnification)

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5 sec

6 sec

7 sec

8 sec

9 sec

5 $\mu$m (3000 Magnification)

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5 sec

6 sec

7 sec

Deposition Time (sec)

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20 $\mu$m (2000 Magnification)

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2 sec

3 sec

4 sec

5 sec

6 sec

10 $\mu$m (3000 Magnification)

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2 sec

3 sec

4 sec

5 sec (2000)

6 sec

8 $\mu$m (3000 Magnification)

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2 sec

3 sec

4 sec

5 sec (2000)

6 sec

7 $\mu$m (3000 Magnification)

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3 sec

4 sec

5 sec (2000)

6 sec

5 $\mu$m (3000 Magnification)

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4 sec

5 sec (2000)

6 sec

Etch Flow (SF_6, sccm)

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20 $\mu$m (2000 Magnification)

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350 sccm

400 sccm

450 sccm

500 sccm

550 sccm

10 $\mu$m (3000 Magnification)

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350 sccm

400 sccm

450 sccm

500 sccm

550 sccm

8 $\mu$m (3000 Magnification)

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350 sccm

400 sccm

450 sccm

500 sccm

550 sccm

7 $\mu$m (3000 Magnification)

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350 sccm

400 sccm

450 sccm

500 sccm

550 sccm

Deposition Flow (C₄F₈, sccm)

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20 $\mu$m (2000 Magnification)

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100 sccm

150 sccm

200 sccm

250 sccm

300 sccm

10 $\mu$m (3000 Magnification)

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100 sccm

150 sccm

200 sccm

250 sccm

300 sccm

8 $\mu$m (3000 Magnification)

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100 sccm

150 sccm

200 sccm

250 sccm

300 sccm

7 $\mu$m (3000 Magnification)

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100 sccm

150 sccm

200 sccm

250 sccm

300 sccm

5 $\mu$m (3000 Magnification)

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200 sccm