# US 2018/0323045 A1 · Manufacturing methods to reduce surface particle impurities after a plasma process

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- Number: US 2018/0323045 A1
- Document ID: US20180323045A1
- Status: Published application
- Kind: A1
- Application number: 15/969,472
- Filed: 2018-05-02
- Published: 2018-11-08
- Earliest claimed: 2017-05-02
- Assignees: Tokyo Electron Limited
- Applicants: Tokyo Electron Limited
- Inventors: Jason Marion; Yusuke Yoshida; Brendan Bathrick; Sergey Voronin; Alok Ranjan
- Web page: https://patentgrep.com/patent/US20180323045A1

## CPC

- H01J 37/32834: {Exhausting}
- H01J 37/32091: {the radio frequency energy being capacitively coupled to the plasma}
- H01J 37/32477: {characterised by the means for protecting vessels or internal parts, e.g. coatings}
- H01J 37/32816: {Pressure}
- H10P 72/0421: {for drying etching}
- H10P 72/72: using electrostatic chucks
- H01J 2237/0041: Neutralising arrangements
- H01J 2237/334: Etching
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Manufacturing methods are disclosed to reduce surface particle impurities after a plasma process (e.g., etch, deposition, etc.) by repelling particles trapped within particle wells to reduce surface particle impurities on microelectronic workpieces after termination of the plasma process. Rather than turn off pressure and source power at the termination of the plasma process, the disclosed embodiments first enter a sequence to adjust process parameters to repel particles in a particle well in order to reduce or eliminate the particle well prior to terminating the plasma process. During this particle repel sequence, certain disclosed embodiments adjust parameters to maintain an electrostatic field above the surface of the wafer utilizing low plasma density and ion energy conditions that help to repel particles from the microelectronic workpiece. The disclosed methods allow for the particle well to be exhausted well prior to the collapse of electrostatic forces when the plasma process is terminated.

## Claims

### Claim 1

A method of processing a microelectronic workpiece, comprising:
performing a plasma process on a microelectronic workpiece within a process chamber, the plasma process in part causing particles to be in electrostatic equilibrium within a particle well at an edge of a plasma sheath above a surface of the microelectronic workpiece;
before terminating the plasma process, performing a sequence to adjust process parameters to repel particles within the particle well away from the surface of the microelectronic workpiece; and
terminating the plasma process.

### Claim 2 (depends on 1)

The method of claim 1, wherein the plasma process comprises at least one of a plasma etch process or a plasma enhanced deposition process.

### Claim 3 (depends on 1)

The method of claim 1, wherein the sequence comprises maintaining an electrostatic field above the surface of the microelectronic workpiece.

### Claim 4 (depends on 3)

The method of claim 3, wherein the maintaining comprises generating a low plasma density condition and a low ion energy condition for the particle well for a predetermined period of time to allow the plasma sheath to extinguish before terminating the plasma process.

### Claim 5 (depends on 4)

The method of claim 4, wherein the maintaining further comprises generating a low pressure condition for the predetermined period of time.

### Claim 6 (depends on 1)

The method of claim 1, wherein a plurality of microelectronic workpieces are processed.

### Claim 7 (depends on 6)

The method of claim 6, wherein the performing of the sequence does not degrade a throughput or a yield for the processing of the plurality of microelectronic workpieces.

### Claim 8 (depends on 1)

The method of claim 1, further comprising exhausting the repelled particles along with gases during the sequence.

### Claim 9 (depends on 1)

The method of claim 1, wherein the process parameters comprise at least one of pressure, radio frequency (RF) bias power, or source power.

### Claim 10 (depends on 9)

The method of claim 9, wherein the process parameters comprise pressure, and wherein the pressure during the sequence is between 1 mT and 300 mT, and wherein the pressure during the plasma process is between 1 mT and 1000 mT.

### Claim 11 (depends on 10)

The method of claim 10, wherein the pressure is reduced during the sequence to reduce particle collisions and thereby allow particles within the particle well to be exhausted.

### Claim 12 (depends on 9)

The method of claim 9, wherein the process parameters comprise RF bias power, and wherein the RF bias power during the sequence and is between 1 W and 300 W, and wherein the RF bias power during the plasma process is between 5 W and 5000 W.

### Claim 13 (depends on 12)

The method of claim 12, wherein the RF bias power is maintained during the sequence to expand the plasma sheath and repel particles from the microelectronic workpiece.

### Claim 14 (depends on 13)

The method of claim 13, wherein the process parameters further comprise source power, and wherein the source power during the sequence is set to 0 W.

### Claim 15 (depends on 9)

The method of claim 9, wherein the process parameters comprise source power, and wherein the source power is adjusted during the sequence to be a value less than the value used during the plasma process.

### Claim 16 (depends on 15)

The method of claim 15, wherein the source power is set to 0 W during the sequence.

### Claim 17 (depends on 1)

The method of claim 1, further comprising performing the sequence for a predetermined period of time.

### Claim 18 (depends on 1)

The method of claim 1, wherein the microelectronic workpiece comprises a semiconductor substrate.

### Claim 19 (depends on 18)

The method of claim 18, wherein the semiconductor substrate comprises a semiconductor wafer.

### Claim 20 (depends on 19)

The method of claim 19, further comprising removing the semiconductor wafer from a chuck after terminating the plasma process.