JPH10287987A - Plasma etching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma etching device capable of suppressing the abnormal discharge by local etching of an insulation shielding member in an etching stage and the generation of particles occurring in an etching material. SOLUTION: This plasma etching device includes a vacuum vessel 1,a vacuum vessel 1, a lower electrode 9 arranged with in the vacuum vessel 1, an upper electrode 12 arranged via the insulation shielding member 20 on the upper wall of the vacuum vessel 1, a supply means for supplying the etching gas into the vacuum vessel and a discharge means connected to the vacuum vessel. The insulation shielding member 20 has a highly thermally conductive ceramic member for insulating the upper electrode and the vacuum vessel 1, a highly corrosion resistant ceramic member 22 arranged in the rear surface part of the upper electrode existing on the peripheral of the plasma 30 generation area within the vacuum vessel, the highly thermally conductive ceramic member 21 parted from the plasma 30 generation area and a low thermally expanding ceramic member 23 arranged to cover the rear surface of the upper electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma etching apparatus used for manufacturing semiconductor devices and the like.

[0002]

2. Description of the Related Art As a conventional plasma etching apparatus, for example, one having a structure shown in FIG. 2 is known. The vacuum vessel 31 made of a conductive material (for example, stainless steel)
A large-diameter hole 33 is opened in the upper wall 32, and a ground wire extraction hole 35 is opened near the center of the bottom 34. The annular insulating member 36 is arranged on the bottom 34 of the vacuum vessel 31 so as to be concentric with the outlet 35. A plurality of, for example, four exhaust holes 37 are opened through the annular insulating member 36 and the bottom 34 of the vacuum vessel 31.
The exhaust pipe 38 is provided at the bottom of the vacuum vessel 31 with the exhaust holes 3.
7 are connected to each other. A vacuum pump (not shown) is attached to the rear end of each exhaust pipe 38. For example, a lower electrode 39 having a disk shape is fixed on the annular insulating member 36. The lower electrode 39
Is connected to a ground wire 40 inserted from outside through the extraction hole 35.

[0005] An insulating shield member 41 having an edge on the upper outer periphery and a step on the inner periphery is fitted in a large-diameter hole 33 in an upper wall 32 of the vacuum vessel 31. The insulating shield member 41 is made of, for example, alumina. A bottomed cylindrical upper electrode 42 having an edge at the upper outer periphery and a step at the upper inner periphery is engaged with the step of the insulating shield member 41 and disposed therein. The upper electrode 42
A plurality of etching gas injection holes 43 are opened at the bottom of the nozzle. A heat sink 45 having a gas introduction hole 44 opened downward is opened in the vicinity of the center.
It is arranged on two steps. With such an arrangement of the heat sink 45, a closed disk-shaped space 46 is formed inside the upper electrode 42. The etching gas supply pipe 47 is connected to the introduction hole 44 of the heat sink 45. The shield cover 48 made of a flat annular alumina is disposed from the bottom surface of the shield member 41 to the bottom surface of the upper electrode 42 excluding the gas injection holes 43. The matching box 49 is connected to the heat sink 45, and the RF power supply 50 is connected to the matching box 49. The RF power supply 5
0 is grounded.

The load gate 51 is mounted on the side wall of the vacuum vessel 31, and the unload gate 52 is mounted on the side wall of the vacuum vessel 31 so as to face the load gate 51.

In the plasma etching apparatus having such a configuration, a substrate to be etched, for example, a semiconductor wafer 53 having a mask material such as a resist pattern formed on the surface thereof is placed on the lower electrode 39, and a vacuum pump (not shown) is operated. The gas in the vacuum vessel 31 is exhausted through the exhaust pipe 38 and the etching gas is supplied from the gas supply pipe 47. The etching gas is introduced into a sealed space 46 surrounded by the upper electrode 42 and the heat sink 45 through a gas introduction hole 44, and the plurality of gas injection holes 43 opened at the bottom of the upper electrode 42. The liquid is uniformly jetted toward the semiconductor wafer 53. The vacuum container 3
When a predetermined degree of vacuum is applied to the inside of the heat sink 1, when a high frequency power of, for example, 350 kHz is supplied from the RF power supply 50 to the heat sink 45 through the matching box 49, the upper electrode 42 and the lower electrode 39 connected to the heat sink 45 are supplied. Plasma 54 in the vacuum vessel 31 during
Occurs. The generation of the plasma 54 causes the upper electrode 4
The etching gas supplied from the second gas injection hole 43 is radicalized, and the radicalized etching gas causes the semiconductor wafer 53 placed on the lower electrode 39 to become radical.
The portion exposed from the mask material is etched.

In the above-described plasma etching, the shield cover 48 located near the lower surface of the upper electrode 42
The part is exposed to a high density plasma. Further, an etching substance adheres and deposits on the lower surface of the shield cover 48.

When such a shield cover 48 is exposed to high-density plasma, the shield cover 48 is locally formed by high-density plasma because the shield cover 48 is formed of alumina having excellent corrosion resistance. Etching can be suppressed.

On the other hand, when an etching substance is attached and deposited on the lower surface of the shield cover 48 and undergoes a heat cycle depending on the presence or absence of plasma, the shield cover 48 made of alumina has a relatively large coefficient of thermal expansion. The deposits are separated and float as particles, and adhere to the surface of the semiconductor wafer 53. Therefore, the yield when manufacturing semiconductor devices from the semiconductor wafer 53 is significantly reduced.

[0009]

SUMMARY OF THE INVENTION According to the present invention, it is possible to suppress abnormal discharge due to local etching of an insulating shield member during an etching process and to suppress generation of particles due to deposits of an etching substance. It is intended to provide a simple plasma etching apparatus.

[0010]

According to the present invention, there is provided a plasma etching apparatus comprising: a vacuum container having at least an upper wall and a bottom portion made of a conductive material; and a lower electrode serving also as a support for a substrate to be etched disposed in the vacuum container. And an upper electrode disposed on the upper wall of the vacuum vessel so as to face the lower electrode via an insulating shield member; supply means for supplying an etching gas into the vacuum vessel; and A plasma etching apparatus that includes a connected exhaust means and generates plasma between the upper electrode and the lower electrode to etch the substrate to be etched, wherein the insulating shield member includes the upper electrode and the vacuum A high thermal conductive ceramic member for electrically insulating the upper wall of the container, and the upper member located around a plasma generation region in the vacuum container; An annular high-corrosion-resistant ceramic member arranged on the lower surface portion of the electrode, an inner periphery of which comes into contact with the outer periphery of the high-corrosion-resistant ceramic member so as to cover the lower surface of the high-thermal-conductivity ceramic member and the upper electrode separated from the plasma generation region. And an annular low-thermal-expansion ceramic member arranged at the same position.

The high thermal conductive ceramic member is made of, for example, aluminum nitride. The high corrosion resistant ceramic member is made of, for example, alumina. The low thermal expansion ceramic member is made of, for example, quartz.

In the plasma etching apparatus according to the present invention having such a configuration, when plasma is generated in the vacuum vessel, the plasma is generated by the insulating shield member near the lower surface of the upper electrode located in the plasma generation region in the vacuum vessel. This produces a high density plasma. Since the portion of the shield member near the lower surface of the upper electrode is formed of a highly corrosion-resistant ceramic member, local etching by high-density plasma can be suppressed. As a result, it is possible to prevent deterioration of the insulation of the shield member, stop of the etching apparatus due to abnormal discharge, and damage to the substrate to be etched.

When plasma is generated in the vacuum vessel to etch the substrate to be etched provided on the lower electrode, an etching substance adheres and deposits on the lower surface of the insulating shield member away from the plasma generation region. Since the lower surface portion of the insulating shield member is formed of a low thermal expansion ceramic member, it is possible to prevent the deposit from peeling from the shield member even when subjected to a heat cycle due to the presence or absence of plasma. As a result, it is possible to prevent the deposit from peeling off and floating as particles, and adhering to the surface of the substrate to be etched.

Further, since the main part of the insulating shield member which is in direct contact with the upper electrode is formed of a highly heat conductive ceramic member having an insulating property, the heat of the shield member which is heated by plasma generation is reduced. By radiating heat well from the upper electrode through the high thermal conductive ceramic member, a temperature change of the shield member can be suppressed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIG. A rectangular vacuum vessel 1 made of a conductive material (for example, stainless steel) has a circular large-diameter hole 3 opened in an upper wall 2, and a ground wire outlet hole 5 opened near the center of a bottom 4. The annular insulating member 6 is arranged on the bottom 4 of the vacuum vessel 1 concentrically with respect to the extraction hole 5. A plurality of, for example, four exhaust holes 7 are opened through the annular insulating member 6 and the bottom 4 of the vacuum vessel 1. The exhaust pipes 8 are respectively connected to the bottom surface of the vacuum vessel 1 so as to communicate with the exhaust holes 7. A vacuum pump (not shown) is attached to the rear end of each exhaust pipe 8. For example, a disk-shaped lower plate electrode 9 is fixed on the annular insulating member 6. The lower plate electrode 9
Is connected to a ground wire 10 inserted from the outside through the extraction hole 5.

An annular metal support member 11 having an edge on the upper outer periphery and a step on the inner periphery is fitted in the large-diameter hole 3 in the upper wall 2 of the vacuum vessel 1. Upper electrode 12
Is disposed inside the support member 11 at a desired distance from the inner peripheral surface of the support member 11. The upper electrode 1
2 is a disk-shaped metal electrode main body 15 having an annular heat sink 13 protruding from the upper surface and having a cylindrical leg 14 widened stepwise outward at the lower portion, and a lower surface of the leg portion 14 of the main body 15. It comprises a metal bottom plate 17 which is fixed and has a plurality of gas injection holes 16 opened. In the vicinity of the center of the electrode main body 15, a gas introduction hole 18 is formed to expand downward. Further, by fixing the bottom plate 17 to the lower surface of the electrode body 15, a closed disk-shaped space 19 is formed inside the upper electrode 12.

The insulating shield member 20 is provided on the support substrate 1.
1 and the upper electrode 12 and the upper electrode 1
2 is electrically insulated from the vacuum vessel 1. The insulating shield member 20 includes an annular insulating block 2 made of aluminum nitride fitted between the support member 11 and the electrode body 15 such that a bottom surface thereof is flush with the bottom plate 17.
1, an annular first shield cover 22 made of alumina coated on the lower surface of the bottom plate 17 located near the plasma generation region, the lower surface of the bottom plate 17 and the insulating block 21
A second shield cover 23 made of quartz, which covers the lower surface and the vicinity of the lower surface of the support member 11 and whose inner peripheral surface is in contact with the outer peripheral surface of the first shield cover 22, is provided.

The gas supply pipe 24 is connected to the introduction hole 18 of the electrode body 15. Matching box 25
Are connected to the electrode body 15, and the RF power supply 26 is connected to the matching box 25. In addition,
The RF power supply 26 is grounded. Road gate 27
Is mounted on the side wall of the vacuum vessel 1, and the unload gate 28 is provided on the side wall of the vacuum vessel 1.
7 is attached to face.

Next, the operation of the above-described plasma etching apparatus will be described. The load gate 27 is opened, and a substrate to be etched, for example, a semiconductor wafer 29 on the surface of which a mask material such as a resist pattern is formed is transferred into the vacuum vessel 1 and placed on the lower electrode 9. By operating a vacuum pump (not shown), the gas in the vacuum vessel 1 is exhausted through the exhaust pipe 8, and an etching gas is supplied from the gas supply pipe 24. The etching gas is introduced into a sealed space 19 surrounded by the electrode body 15 and the bottom plate 17 through a gas introduction hole 18 of the electrode body 15, and the gas of the vacuum vessel 1 is passed through a plurality of gas injection holes 16 opened in the bottom plate 17. The liquid is uniformly jetted toward the semiconductor wafer 29. The vacuum container 1
When the inside reaches a predetermined degree of vacuum, high-frequency power of, for example, 350 kHz is supplied from the RF power source 26 to the matching box 2
When supplied to the upper electrode 12 through 5, the plasma 30 is generated in the vacuum vessel 1 between the lower electrode 9 and the upper electrode 12. The etching gas supplied from the gas injection holes 16 of the upper electrode 12 is radicalized by the generation of the plasma 30, and is exposed from the mask material of the semiconductor wafer 29 placed on the lower electrode 9 by the radicalized etching gas. The part is etched. After the completion of the etching, the supply of the etching gas, the supply of the high frequency power, and the operation of the vacuum pump are stopped, and for example, nitrogen gas is introduced from the gas supply pipe 24 to the vacuum vessel 1.
When the inside gas is replaced with nitrogen gas and the inside of the vacuum vessel 1 becomes a normal pressure state, the unload gate 28 is opened and the etched semiconductor wafer 29 placed on the lower electrode 9 is removed from the vacuum vessel 1. Take out outside of 1.

In the above-described plasma etching of the semiconductor wafer 29, the density of the plasma increases around the first shield cover 22 of the insulating shield member 20 located in the upper electrode 12 (bottom plate 17) portion near the region where the plasma 30 is formed. . Since the first shield cover 22 is made of alumina having excellent corrosion resistance, local etching due to generation of high-density plasma can be suppressed. As a result, it is possible to prevent the insulation property of the insulating shield member 20 from deteriorating, stopping the etching apparatus due to abnormal discharge, and preventing damage to the semiconductor wafer 29.

Further, a plasma 30 is generated in the vacuum vessel 1 and the semiconductor wafer 2 set on the lower electrode 9 is formed.
When etching 9, the etching material is plasma 30
And adheres and deposits on the lower surface of the second shield cover 23 of the insulating shield member 20 that is separated from the second shield cover 23. Since the second shield cover 23 is made of low thermal expansion quartz, the plasma 3
The degree of expansion of the second shield cover 23 can be significantly reduced when subjected to a heat cycle depending on the presence or absence of 0,
The separation of the deposit from the second shield cover 23 can be suppressed for a long period of time. As a result, generation of particles due to the separation of the deposits can be suppressed, so that particles are prevented from adhering to the surface of the semiconductor wafer 29, and the yield of semiconductor devices manufactured from the semiconductor wafer 29 can be improved.

Further, the upper electrode 12 (electrode body 1)
5) Since the annular insulating block 21 of the insulating shield member 20 that is in direct contact with the insulating shield member 20 is made of aluminum nitride having high thermal conductivity, even if the annular insulating block 21 is heated with the generation of the plasma 30, the insulating shield member is The heat of 20 is transmitted to the upper electrode 12 through the annular insulating block 21 and can be radiated well from the heat sink 13. As a result, a temperature change of the insulating shield member 20, particularly the second shield cover 23 can be suppressed. Therefore, it is possible to more effectively suppress the detachment of the deposit attached to the second shield cover 23 and to reduce the thermal shock to each component of the insulating shield member 20.

[0023]

As described above in detail, according to the plasma etching apparatus according to the present invention, abnormal discharge due to local etching of the insulating shield member during the etching process,
The generation of particles due to the deposition of the etching substance can be suppressed for a long period of time, and thus, a stable etching operation can be performed for a long period of time, and the yield of devices such as semiconductor devices manufactured from the substrate to be etched can be improved. Effect.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a plasma etching apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional plasma etching apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum container, 9 ... Lower electrode, 12 ... Upper electrode, 20 ... Insulation shield member, 21 ... Annular block made of aluminum nitride, 22 ... First shield cover made of alumina, 23 ... Second shield cover made of quartz, 26: RF power supply, 29: Semiconductor wafer, 30: Plasma.

Claims (2)

[Claims] A vacuum container having at least an upper wall and a bottom portion made of a conductive material; a lower electrode serving as a support for a substrate to be etched disposed in the vacuum container; and an insulating shield member on an upper wall of the vacuum container. An upper electrode disposed so as to face the lower electrode via a supply electrode, a supply unit for supplying an etching gas into the vacuum container, and an exhaust unit connected to the vacuum container. A plasma etching apparatus that generates plasma between the lower electrode and the lower electrode to etch the substrate to be etched, wherein the insulating shield member has a high thermal conductivity for electrically insulating the upper electrode from the upper wall of the vacuum vessel. A ceramic member and an annular high-corrosion-resistant ceramic disposed on a lower surface portion of the upper electrode located around a plasma generation region in the vacuum vessel Material, the inner periphery of which is in contact with the outer periphery of the high corrosion resistant ceramic member, the high thermal conductive ceramic member separated from the plasma generation region and the annular low thermal expansion ceramic member arranged to cover the lower surface of the upper electrode. A plasma etching apparatus, comprising: 2. The plasma according to claim 1, wherein said high thermal conductive ceramic member is made of aluminum nitride, said high corrosion resistant ceramic member is made of alumina, and said low thermal expansion ceramic member is made of quartz. Etching equipment.