Tungesten - Dry Etching

Tungesten - Dry Etching

Material Name: Tungesten
Recipe No.: 10353
Primary Chemical Element in Material: Ti
Sample Type: Layer
Uses: Etching
Etchant Name: None
Etching Method: Dry etching
Etchant (Electrolyte) Composition: Three different etching equipment are used.
1. A Cobrain swafer--Power, at 25 kHz frequency, is applied at the lower electrode leaving the upper electrode grounded in the RIE mode, or at the upper electrode leaving the lower electrode floating in a PE mode.
2. A Tegal HRe-system--Permanent magnets are placed around the cylindrical wall and above the upper electrode. The upper electrode is always grounded. It is possible to apply power at 13.56 MHz at the wall os the reactor (PE mode) or at the lower electrode (RIE mode).
3. A few experiments were performed using MATRIX 303 equipment--A remote plasma is created in the upper part of the reactor, while the wafer is placed in the lower part, on a heated chuck. Both parts of the reactor are divided by a grid made of aIumina.
Procedure (Condition): No data
Note: No data
Reference: Patrick Verdonck, et al., Analysis of The Etching Mechanisms of Tungsten in Fluorine Containing Plasmas, J. Electrochem. Soc., Vol. 142, No. 6, June 1995, pp. 1971-1976.

Table 1: Tungsten etch rates, uniformities, and selectivities toward resist as a function of pressure and power in the SWAFER reactor in RIE mode.

Figure 1: Tungsten and polysilicon etch rates as a function of oxygen flow, for NF3-O2 plasmas in the RIE mode, at 150 mTorr pressure, and 50 W power in the SWAFER reactor.

Figure 2: Tungsten profile after RIE etching with a pure NF3 plasma using a PECVD oxide mask.

Figure 3: Tungsten and polysilicon etch rates as a function of oxygen flow, for NF3-02 plasmas in PE mode, at 150 mTorr pressure and 50 W power in the SWAFER reactor.

Table 2: Tungsten etch rates and uniformities as a function of power in the SWAFER reactor in PE mode.

Figure 5: Remaining PECVD oxide thickness as a function of distance from a large resist area after a PE mode etching with a NF3-O2 plasma in the SWAFER reactor.

Figure 6: Tungsten profile after PE mode etching with a NF3-O2 plasma, using a PECVD oxide mask.

Figure 7: Tungsten and polysilicon etch rates as a function of oxygen flow and etching mode. Total flow, 96 sccm: pressure, 10 mTorr: power, 400 W in the TEGAL HRe-reactor.

Figure 8: Fluorine consumption for tungsten and polysilicon etch processes as a function of oxygen flow and etching mode in the SWAFER.

Figure 9: Fluorine consumption for tungsten and polysilicon etch processes as a function of oxygen flow and etching mode in the Tegal HRe-.