JP6890886B2 - Plasma etching equipment - Google Patents

Description

The present invention relates to a plasma etching apparatus used when processing an workpiece such as a wafer.

In electronic devices such as mobile phones and personal computers, a device chip equipped with an electronic circuit is an indispensable component. The device chip, for example, divides the surface of a wafer made of a semiconductor material such as silicon by a plurality of planned division lines (streets), forms an electronic circuit in each region, and then divides the wafer along the streets. can get.

This wafer is often divided by a method such as cutting or laser ablation. Further, in recent years, for the purpose of reducing the size and weight of the device chip, there are increasing opportunities to thin the wafer after the electronic circuit is formed by a method such as grinding. However, when the wafer is processed by these methods, chipping, debris, distortion, and the like occur, and the bending strength of the device chip tends to decrease.

Therefore, a technique for removing chipping, debris, strain, etc. remaining on the wafer by a method called plasma etching in which the wafer is exposed to highly reactive plasma has been proposed (see, for example, Patent Document 1). The plasma etching apparatus used for this plasma etching usually includes a vacuum chamber in which a pair of flat plate electrodes parallel to each other are arranged inside.

By depressurizing the inside of the vacuum chamber with the wafer placed between the electrodes and applying a high-frequency voltage while supplying a reactive gas, plasma containing ions and radicals is generated, and chipping and debris remaining on the wafer, Distortion and the like can be removed. As a result, the bending strength of the device chip is increased.

Japanese Unexamined Patent Publication No. 2000-353676

After removing chipping, debris, strain, etc. remaining on the wafer by the above method, the vacuum chamber is opened to the atmosphere and the wafer is carried out. On the other hand, reactive gas may remain inside the vacuum chamber. Therefore, in the conventional plasma etching apparatus, a cover surrounding the entire vacuum chamber is provided so that the reactive gas does not flow out to the outside environment, and then the inside of the cover is exhausted.

However, in such a plasma etching apparatus, a large air volume is required in order to reliably exhaust the entire inside of the cover.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a plasma etching apparatus that does not require a large air volume to discharge the gas flowing out from the carry-in / out port of the vacuum chamber. is there.

According to one aspect of the present invention, a vacuum chamber which is a plasma etching apparatus and has a carry-in / out port for carrying in / out a work piece, and an electrostatic chuck table for holding the work piece in the vacuum chamber. A gas supply unit that supplies a reactive gas for plasma etching into the vacuum chamber and a work piece are carried in from the vacuum chamber, or when the work piece is carried out from the vacuum chamber, the work piece is carried out from the carry-in port. comprising an exhaust means for discharging the outflowing gas, and exhaust means, with only a portion of the vacuum chamber containing the該搬entrance smaller space than the volume of the processing space inside the enclosed viewed vacuum chamber therein A plasma etching apparatus having an exhaust box is provided.

In one aspect of the present invention, the exhaust means may further include an exhaust air volume adjusting unit that adjusts the exhaust air volume for discharging the gas flowing out from the carry-in port. Further, in one aspect of the present invention, a gas detection unit for detecting the gas flowing out from the carry-in port of the vacuum chamber may be further provided.

The plasma etching apparatus according to one aspect of the present invention is an exhaust means for discharging the gas flowing out from the carry-in / out port of the vacuum chamber when the work piece is carried into the vacuum chamber or the work piece is carried out from the vacuum chamber. The exhaust means has an exhaust box that surrounds only a part including the inlet / outlet of the vacuum chamber.

That is, in the plasma etching apparatus according to one aspect of the present invention, since it is only necessary to exhaust the exhaust box that surrounds only a part of the vacuum chamber, as compared with the conventional structure that exhausts the cover that surrounds the entire vacuum chamber. Does not require a large air volume. As described above, according to one aspect of the present invention, it is possible to provide a plasma etching apparatus that does not require a large air volume to discharge the gas flowing out from the carry-in / out port of the vacuum chamber.

It is sectional drawing which shows typically the structural example of the plasma etching apparatus.

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view schematically showing a configuration example of the plasma etching apparatus 2 according to the present embodiment. In FIG. 1, some components are shown by functional blocks.

The plasma etching apparatus 2 includes a vacuum chamber 6 in which a processing space 4 is formed. A carry-out port 8 for carrying the plate-shaped workpiece 11 into the vacuum chamber 6 or carrying out the workpiece 11 from the vacuum chamber 6 is formed in a part of the side wall 6a of the vacuum chamber 6. There is. A gate 10 for opening and closing the carry-in / out port 8 is arranged outside the carry-in / out port 8.

An opening / closing mechanism 12 is provided below the gate 10, and the gate 10 moves up and down by the opening / closing mechanism 12. By moving the gate 10 downward by the opening / closing mechanism 12 to open the carry-in / out port 8, the work piece 11 is carried into the processing space 4 of the vacuum chamber 6 through the carry-in / out port 8, or the work piece 11 is evacuated. It can be carried out from the processing space 4 of the chamber 6.

An exhaust port 14 is formed on the bottom wall 6b of the vacuum chamber 6. The exhaust port 14 is connected to an exhaust unit 16 such as a vacuum pump. Further, in the processing space 4 of the vacuum chamber 6, the lower electrode 18 and the upper electrode 20 are arranged so as to face each other. The lower electrode 18 is made of a conductive material and includes a disk-shaped holding portion 22 and a columnar support portion 24 extending downward from the center of the lower surface of the holding portion 22.

The support portion 24 is passed through an opening 26 formed in the bottom wall 6b of the vacuum chamber 6. In the opening 26, an insulating bearing 28 is arranged between the bottom wall 6b and the support portion 24, and the vacuum chamber 6 and the lower electrode 18 are insulated from each other. The lower electrode 18 is connected to the high frequency power supply 30 outside the vacuum chamber 6.

A recess is formed on the upper surface of the holding portion 22, and an insulating table (electrostatic chuck table) 32 for holding the workpiece 11 is provided in the recess. A suction hole 32a penetrating from the upper surface to the lower surface is formed in the table 32, and the suction hole 32a is connected to the suction source 36 via a flow path 34 or the like formed inside the lower electrode 28. ..

A plurality of electrodes 32b are embedded inside the table 32. By supplying electric power to the electrodes 32b, an electrostatic force can be applied between each electrode 32b and the workpiece 11 to adsorb and hold the workpiece 11. When the processing space 4 of the vacuum chamber 6 is depressurized, the workpiece 11 cannot be held by a method utilizing the negative pressure of the suction source 36. Therefore, the work piece 11 is held by using the force of static electricity.

A cooling flow path 38 is formed inside the holding portion 22. One end of the cooling flow path 38 is connected to the circulation unit 42 via a refrigerant supply path 40 formed in the support portion 24, and the other end of the cooling flow path 38 is a refrigerant discharge path formed in the support portion 24. It is connected to the circulation unit 42 via 44. When the circulation unit 42 is operated, the refrigerant flows in the order of the refrigerant supply path 40, the cooling flow path 38, and the refrigerant discharge path 44, and cools the lower electrode 18.

The upper electrode 20 is made of a conductive material, and has a disk-shaped gas supply unit 46 for supplying plasma etching gas (reactive gas) to the processing space 4 of the vacuum chamber 6 and a gas supply unit. A columnar support portion 48 extending upward from the center of the upper surface of the 46 is included. The support portion 48 is passed through an opening 50 formed in the upper wall 6c of the vacuum chamber 6.

In the opening 50, an insulating bearing 52 is arranged between the upper wall 6c and the support portion 48, and the vacuum chamber 6 and the upper electrode 20 are insulated from each other. The upper electrode 20 is connected to the high frequency power supply 30 outside the vacuum chamber 6. A support arm 58 connected to the elevating mechanism 56 is attached to the upper end of the support portion 48, and the elevating mechanism 56 and the support arm 58 move the upper electrode 20 up and down.

A plurality of gas outlets 60 are provided on the lower surface of the gas supply unit 46. The gas outlet 60 is connected to the gas supply source 64 via a flow path 62 or the like. The gas supply source 64 is composed of, for example, an SF ₆ (fluorine-based gas) supply source, an O ₂ (oxygen-based gas) supply source, a He supply source, and the like, and SF ₆ , O ₂ , and He are mixed. Supply reactive gas (reactive gas). However, the type of gas supplied from the gas supply source 64 is changed according to the type of the workpiece 11 and the like.

An exhaust unit (exhaust means) 66 for discharging the gas (for example, hydrogen fluoride (HF)) flowing out from the carry-in / out port 8 is provided on the outside of the vacuum chamber 6. The exhaust unit 66 has an exhaust box 68 that surrounds the carry-in / out port 8 of the vacuum chamber 6. The exhaust box 68 is formed so as to cover a part of the side wall 6a provided with the carry-in / out port 8, for example. That is, the exhaust box 68 surrounds only a part of the vacuum chamber 6 including the carry-in / out port 8, and does not surround the entire vacuum chamber 6.

A carry-out port 72 is formed in a part of the exhaust box 68 for carrying the work piece 11 into the space 70 in the exhaust box 68 or carrying out the work piece 11 from the space 70 in the exhaust box 68. Has been done. A gate 74 for opening and closing the carry-out port 72 is arranged outside the carry-out port 72.

An opening / closing mechanism 76 is provided below the gate 74, and the gate 74 moves up and down by the opening / closing mechanism 76. By moving the gate 74 downward by the opening / closing mechanism 76 to open the carry-in / out port 72, the work piece 11 is carried into the space 70 of the exhaust box 68 through the carry-out port 72, or the work piece 11 is moved into the exhaust box. It can be carried out from space 70 of 68.

An exhaust port 78 for exhausting the gas in the space 70 is formed in the upper part of the exhaust box 68. The exhaust port 78 is connected to an exhaust air volume adjusting unit 80 including a valve or the like for adjusting the air volume required for exhausting the space 70.

In the plasma etching apparatus 2 configured in this way, in order to exhaust the gas flowing out from the carry-in / out port 8 of the vacuum chamber 6, it is sufficient to exhaust the exhaust box 68 surrounding only a part of the vacuum chamber 6. That is, a large air volume is not required as compared with the conventional structure in which the cover surrounding the entire vacuum chamber is exhausted. Specifically, the air volume of the exhaust can be reduced to about 1/10 to 1/5 as compared with the conventional plasma etching apparatus. Therefore, the exhaust system connected to the plasma etching apparatus 2 can be miniaturized to reduce the cost.

Further, in the plasma etching apparatus 2 of the present embodiment, since the volume (volume) of the space 70 of the exhaust box 68 is small, the carry-in / out port 8 of the vacuum chamber 6 is compared with the conventional structure having a cover that surrounds the entire vacuum chamber. The gas flowing out of the chamber is difficult to dilute. Therefore, a slight outflow of gas can be appropriately detected without changing the performance of the gas detection unit (not shown). The gas detection unit is provided, for example, in the space 70 of the exhaust box 68, the exhaust port 78, the downstream side of the exhaust air volume adjusting unit 80, and the like.

Further, in the plasma etching apparatus 2 of the present embodiment, when the workpiece 11 is carried into the vacuum chamber 6 or when the workpiece 11 is carried out from the vacuum chamber 6, the exhaust box 68 is exhausted to create a vacuum. Mixing of air into the processing space 4 inside the chamber 6 is suppressed. As a result, when the workpiece 11 is etched, it is possible to suppress the generation of harmful hydrogen fluoride (HF) due to the influence of water in the atmosphere.

The present invention is not limited to the description of the above embodiment, and can be implemented with various modifications. For example, the exhaust unit (exhaust means) 66 may be controlled so as to constantly exhaust the space 70 of the exhaust box 68, or the space 70 of the exhaust box 68 may be controlled in accordance with the timing of loading and unloading the workpiece 11. It may be controlled to exhaust.

Further, in the above embodiment, the type of plasma etching apparatus 2 that generates plasma in the vacuum chamber 6 is described, but the plasma etching apparatus according to the present invention uses the plasma generated outside the vacuum chamber in the vacuum chamber. It may be a so-called remote plasma etching apparatus supplied inside.

In addition, the structure, method, etc. according to the above-described embodiment can be appropriately modified and implemented as long as the scope of the object of the present invention is not deviated.

2 Plasma etching equipment 4 Processing space 6 Vacuum chamber 6a Side wall 6b Bottom wall 6c Upper wall 8 Opening 10 Gate 12 Opening and closing mechanism 14 Exhaust port 16 Exhaust unit 18 Lower electrode 20 Upper electrode 22 Holding part 24 Support part 26 Opening 28 Bearing 30 High frequency power supply 32 table (electrostatic chuck table)
32a Suction hole 32b Electrode 34 Flow path 36 Suction source 38 Cooling flow path 40 Refrigerant introduction path 42 Circulation unit 44 Refrigerant discharge path 46 Gas supply section 48 Support section 50 Opening 52 Bearing 56 Lifting mechanism 58 Support arm 60 Gas outlet 62 Flow path 64 Gas supply source 66 Exhaust unit (exhaust means)
68 Exhaust box 70 Space 72 Carry-in / out port 74 Gate 76 Opening / closing mechanism 78 Exhaust port 80 Exhaust air volume adjustment unit 11 Work piece

Claims (3)

It is a plasma etching device
A vacuum chamber with an inlet / outlet for loading / unloading the work piece,
An electrostatic chuck table that holds the workpiece in the vacuum chamber,
A gas supply unit that supplies a reactive gas for plasma etching into the vacuum chamber,
It is provided with an exhaust means for discharging the gas flowing out from the carry-in / out port when the work piece is carried into the vacuum chamber or the work piece is carried out from the vacuum chamber.
Exhaust means, plasma etching apparatus characterized by having an exhaust box with only a portion of the vacuum chamber containing the該搬entrance smaller space than the volume of the processing space inside the enclosed viewed vacuum chamber therein. The plasma etching apparatus according to claim 1, wherein the exhaust means further includes an exhaust air volume adjusting unit for adjusting an exhaust air volume for exhausting the gas flowing out from the carry-in port. The plasma etching apparatus according to claim 1 or 2, further comprising a gas detection unit for detecting gas flowing out from the carry-in port of the vacuum chamber.

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