JPH06306648A - Dry etching device - Google Patents

Abstract

PURPOSE:To provide an etching device capable of maintaining a high working rate and capable of preventing an effect of a gas remaining after dry cleaning on a wafer. CONSTITUTION:This dry etching device is provided with an etching chamber 31 having a gaseous etchant blowoff port 33 and an exhaust port 37, electrodes 32 and 35 for etching a wafer 36 set on the blowoff port 33 side, heaters 38 and 39 for preventing the deposition of a reaction product set on the blowoff port 33 side, a cleaning part 40 for depositing the reaction product set on the exhaust port 37 side and a dry-cleaning electrode 44 for removing the reaction product at the cleaning part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry etching apparatus for removing reaction products generated during etching.

[0002]

2. Description of the Related Art In recent years, dry etching equipment requires fine processing, and anisotropic etching utilizing deposition of reaction products on a wafer is often used. An example of a conventional dry etching apparatus will be described below with reference to the drawings. That is, FIG. 3 shows a sectional view of a conventional dry etching apparatus. In FIG. 3, 1 is an etching chamber made of a suspension, 2 is an aluminum upper electrode attached to the upper part of the etching chamber 1, 3 is an etching gas outlet made in the upper electrode 2, and 4 is attached to the upper electrode 2. The etching gas introducing pipes 5 are lower electrodes attached to the lower portion of the etching chamber 1, and the wafer 6 is placed on the lower electrodes 5 for etching. 7 is an exhaust port for exhausting the gas introduced from the etching gas outlet 3 into the etching chamber 1, 8 is a heater installed in the upper electrode 2 to prevent the adhesion of etching reaction products to the upper electrode 2, A heater 9 is attached to the etching chamber 1 to prevent the etching reaction product from adhering to the inner wall surface of the etching chamber 1.

The operation of the dry etching apparatus having the above structure will be described below by taking a polysilicon etcher as an example. First, for example, HBr gas 50sc
cm is introduced from the etching gas outlet 3 to keep the inside of the etching chamber 1 at, for example, 300 mT, and a high frequency voltage of, for example, 13.56 MHz, 1.5 W / cm ^2, is applied between the upper electrode 3 and the lower electrode 5. To etch. At this time, Si _X Br _Y adheres to the inner wall surface of the etching chamber 1 and the upper electrode 3 as a reaction product. In order to reduce this, the etching chamber 1 and the upper electrode 3 are heated to, for example, 100 ° C. by the heaters 8 and 9. However, since the adhesion of the reaction products cannot be completely prevented, for example, after etching 1000 wafers 6, for example, CF _{4 is used} as an etching gas for the reaction products.
A gas of 30 sccm and an O ₂ gas of 100 sccm were introduced from the etching gas outlet 3 to remove the etching chamber 1.
The inside is kept at, for example, 300 mT, and the upper electrode 3 and the lower electrode 5 are
During this period, a high frequency voltage of 13.56 MHz, for example, is applied for 10 minutes to remove the reaction product Si _X Br _Y attached to the lower portion of the etching chamber 1 by etching (hereinafter, this reaction product etching is referred to as dry cleaning). Call.).

According to this conventional example, as compared with the method of returning the inside of the etching chamber 1 to the atmospheric pressure and cleaning the inside of the etching chamber 1 with pure water or alcohol.
The cleaning time can be shortened and the operation time of the device can be increased.

[0005]

However, in the above configuration, the gas used during dry cleaning becomes plasma in the etching chamber 1, so that the gas adheres to the inner wall of the etching chamber 1 and the gas is etched. Since it comes out into the chamber 1 (hereinafter, this gas is referred to as a residual gas), there is a problem that the subsequent etching of the wafer 6 adversely affects the etching rate and the like.

Therefore, in view of the above problems, it is an object of the present invention to maintain the operating rate of the apparatus at a high level and to prevent the residual gas during dry cleaning from affecting the etching of the wafer. It is to provide a device.

[0007]

According to a first aspect of the present invention, there is provided a dry etching apparatus including an etching chamber having an etching gas outlet and an exhaust port, an etching electrode for etching a wafer installed on the etching gas outlet side.
A heater installed on the side of the etching gas outlet to prevent reaction products from adhering to parts other than the wafer, a cooling unit installed on the side of the exhaust port to adhere reaction products, and a reaction product of this cooling unit It is provided with a dry cleaning electrode for removing a substance.

A dry etching apparatus according to a second aspect of the present invention is the dry etching apparatus according to the first aspect, which has a gas inlet for dry cleaning on the exhaust port side.

[0009]

According to the dry etching apparatus of the present invention, the heater is heated to cool the cooling portion, gas is introduced from the etching gas outlet and voltage is applied between the electrodes to perform etching on the wafer. Dry etching is performed by introducing an etching gas of the reaction product and applying a voltage between the electrodes for dry cleaning.

In this case, since the reaction product generated during the etching of the wafer is positively attached to the cooling part, the reaction product to the part heated by the heater is compared with the case where the cooling part is not provided. The effect of preventing adhesion is enhanced. In addition, since the reaction products adhering to the cooling part are removed by the etching gas and the dry cleaning electrode, the plasma generated between the dry cleaning electrodes is at the exhaust port side and does not go around to the etching gas outlet side. The gas does not adhere to the etching gas outlet side and therefore does not adversely affect the etching of the wafer. Further, since the reaction product is removed by dry cleaning, the operating rate of the device can be kept high.

According to the dry etching apparatus of the second aspect, since the dry cleaning gas introducing port is provided on the exhaust port side in the first aspect, the reaction product can be obtained simultaneously with the etching process of the wafer in addition to the action of the first aspect. Can be removed, so that the operating rate of the device can be further increased.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A dry etching apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a sectional view of the dry etching apparatus. In FIG. 1, 31 is an etching chamber made of a suspension, 32 is an aluminum upper electrode for etching attached to the upper part of the etching chamber 31, 33 is an etching gas outlet made in the upper electrode 32, and 34 is an upper electrode 32. An etching gas introducing pipe 35 is attached to the lower electrode 35, and an etching lower electrode 35 is attached to a lower portion of the etching chamber 31. A wafer 36 is placed on the lower electrode 35 to perform etching. Reference numeral 37 denotes an exhaust port for exhausting the gas introduced from the etching gas outlet 33 into the etching chamber 31, and 38
Is a heater installed in the upper electrode 32 to prevent the adhesion of etching reaction products to the upper electrode 32, 39
Is a heater mounted on the etching gas outlet 33 side of the etching chamber 31, that is, on the relatively upper side of the etching chamber 31 in order to prevent the adhesion of etching reaction products to the etching chamber 31, and 40 is an exhaust port 37 of the etching chamber 31. On the side, it is a cooling liquid introducing pipe that constitutes a cooling portion formed below the wafer 36. This is because the heater 39 causes the etching chamber 31
Of the etching chamber 31 by the heated portion and the cooling liquid introducing pipe 40 to positively attach the reaction product to the cooled portion. In the case of no cooling, The effect of preventing the reaction product from adhering to the heated portion is higher than that of. Since the reaction products attached to the cooled portion are below the wafer 36,
There is no effect on the etching of the wafer 36.

Reference numeral 41 is an insulator made of, for example, Teflon for thermally isolating a portion of the etching chamber 31 heated by the heater 39 and a portion of the etching chamber 31 cooled by the cooling liquid introducing pipe 40. , 42 are used to maintain the degree of vacuum in the etching chamber 31 and the etching chamber 31 and the insulator 41.
An O-ring mounted between the lower electrodes 35 and a ceramic ring 43 mounted around the lower electrode 35.

Reference numeral 44 is a dry cleaning electrode having one electrode in the cooled portion of the etching chamber 31 and a counter electrode around the ceramic. Wafer 36
Of the etching chamber 31 to remove reaction products attached to the cooled portion of the etching chamber 31 during the etching of
Dry cleaning electrode 4 to the cooled part of 1
Install 4. A gas capable of removing a reaction product is introduced from the etching gas outlet 33, a high frequency voltage is applied to the dry cleaning electrode 44 to generate plasma, and the reaction product attached to the cooled portion of the etching chamber 31 is removed. . As a result, the inside of the etching chamber 31 can be cleaned without being exposed to the atmosphere, and the plasma is trapped on the side of the exhaust port 37 below the wafer 36. Therefore, the plasma does not enter the inside of the etching chamber 31 above the wafer 36. Wafer 36
Has little effect on etching.

The operation of the dry etching apparatus configured as described above will be described below with reference to FIG.
First, an etching gas is introduced from the etching gas outlet 33, a high frequency voltage is applied between the upper electrode 32 and the lower electrode 35 to generate plasma, and the wafer 36 is etched. Although plasma reaction products are formed during etching, the heaters 38 and 39 attached to the etching chamber 31 prevent the etching reaction products from adhering to the etching gas outlet 33 side of the etching chamber 31 and thus the cooling liquid. It adheres to the cooling part with the introduction pipe 40. As described above, the heated portion of the etching chamber 31 is formed by the heater 39 and the cooled portion of the etching chamber 31 is formed by the cooling liquid introducing pipe 40, so that the reaction product is positively attached to the cooled portion. Therefore, the effect of preventing the reaction product from adhering to the heated portion is higher than that in the case without cooling. Since the reaction products attached to the cooled portion are below the wafer 36,
Even if the reaction product becomes dust, it does not affect the wafer 36.

After the etching of the wafer 36 is completed, the wafer 3
6 is taken out of the etching chamber 31. Then, a gas capable of removing the reaction product is introduced from the etching gas outlet 33, a high frequency voltage is applied to the dry cleaning electrode 44 to generate plasma, and the reaction product attached to the cooled portion of the etching chamber 31 is removed. Remove. As a result, the inside of the etching chamber 31 can be cleaned without being exposed to the atmosphere, and the plasma is confined to the exhaust port 37 side below the wafer 36, so that the plasma does not enter the etching chamber 31 above the wafer 36. Therefore, the residual gas from the plasma generated by the dry cleaning remains only in the portion below the wafer 36 in the etching chamber 31. Therefore, the influence on the subsequent etching of the wafer 36 is small.

Next, in the first embodiment of the present invention,
The operation of the Li etching system is performed by using the polysilicon etcher.
The case applied to the above will be described with reference to FIG. example
For example, HBr gas of 50 sccm is used as the etching gas outlet 33.
Further, the inside of the etching chamber 31 is, for example, 300
It is maintained at mT, and between the upper electrode 32 and the lower electrode 35, for example
High frequency voltage of 13.56MHz 1.5W / cm²Apply
Then, the wafer 36 is etched. At this time, Si_XB
r_YIs an inner wall of the etching chamber 31 as a reaction product.
It adheres to the surface and the upper electrode 32. Etch to prevent this
The heating chamber 31 and the upper electrode 32 to the heaters 38 and 39.
More, for example, heating to 100 ° C. Furthermore, 1
The water cooled to 0 ° C is introduced into the cooling liquid introducing pipe 40.
Circulate and cool the bottom of the etching chamber 31.
And positively attach the reaction product. Cool
Compared to the case of shi, reaction generation to the heated part
It also has a high effect of preventing adhesion of objects. Then, for example, 1000 sheets
After etching the wafer 36, for example, CF_FourGas 30
sccm, O₂Blowing etching gas with 100 sccm of gas
Introduced from the outlet 33, comparing the inside of the etching chamber 31
For example, keep it at 300 mT and use dry cleaning electrode 44 as an example.
For example, apply a high frequency voltage of 13.56MHz for 10 minutes,
Reaction product S attached to the bottom of the etching chamber 31
i _XBr_YAre removed by etching. This allows
Cleaning the etching chamber 31 without exposing it to the atmosphere
Further, the plasma is exhausted below the wafer 36 at the exhaust port 37.
Since it is confined to the side, etching above the wafer 36
The plasma does not enter the inside of the chamber 31. That
Therefore, the residue from the plasma generated during dry cleaning
Distilled gas from the wafer 36 in the etching chamber 31
It remains only in the lower part. Therefore, the subsequent wafer 36
Has little effect on etching.

As described above, according to the first embodiment, the reaction product generated during the etching of the wafer 36 is positively adhered to the cooling part, so that the heater is not provided with the cooling part. 38 and 39 enhance the effect of preventing the reaction product from adhering to the heated portion. Further, since the reaction product attached to the cooling portion is removed by the etching gas and the dry cleaning electrode 44, the plasma generated between the dry cleaning electrodes 44 is on the side of the exhaust port 37 and the etching gas outlet 33.
Since the gas does not wrap around to the side, the residual gas does not adhere to the side of the etching gas outlet 33, and therefore the etching of the wafer 36 is not adversely affected. Further, since the reaction product is removed by dry cleaning, the operating rate of the device can be kept high.

A dry etching apparatus according to the second embodiment of the present invention will be described with reference to FIG. FIG. 2 shows a sectional view of the dry etching apparatus. Reference numerals 31 to
Reference numeral 44 is the same as in FIG. 1 of the first embodiment. Reference numeral 45 denotes a gas inlet for dry cleaning which is attached to the exhaust port 37 side of the etching chamber 31, that is, at the lower part, separately from the etching gas outlet 33.

The operation of the dry etching apparatus having the above structure will be described with reference to FIG. That is, the etching gas is introduced from the etching gas outlet 33, a high frequency voltage is applied between the upper electrode 32 and the lower electrode 35 to generate plasma, and the wafer 36 is etched. Simultaneously with the etching of the wafer 36, a gas capable of removing reaction products is introduced from the dry cleaning gas introduction pipe 45, and a high frequency voltage is applied to the dry cleaning electrode 44 to generate plasma. As a result, the reaction products can be removed at the same time as the etching process of the wafer 36, so that it is not necessary to clean the inside of the etching chamber 31, and the operation rate of the apparatus can be increased. Further, since the gas and plasma are confined to the exhaust port side below the wafer 36, the plasma does not enter the etching chamber 31 above the wafer 36 at all. Therefore, the residual gas from the plasma generated by the dry cleaning remains only in the portion below the wafer 36 in the etching chamber 31. Therefore, there is no effect on the etching of the wafer 36.

The description of the case where the dry etching apparatus according to the second embodiment is applied to a polysilicon etcher will be described with reference to, for example, CF from the dry cleaning gas introduction port 45 as an etching gas for reaction products at the same time when the wafer 36 is etched. ₄ gas 30 sccm and O ₂ gas 100 sccm are introduced, and reaction products are removed at the same time as the wafer 36 is etched.

According to the second embodiment, since the dry cleaning gas introduction port 45 is provided on the exhaust port 37 side, reaction products can be removed at the same time as the etching process of the wafer 36, so that the operating rate of the apparatus is further increased. be able to.

[0023]

According to the dry etching apparatus of the first aspect of the present invention, since the reaction product generated during the etching of the wafer is positively adhered to the cooling portion, the heater by the heater is used as compared with the case where the cooling portion is not provided. The effect of preventing the reaction product from adhering to the towed portion is enhanced. In addition, since the reaction products adhering to the cooling part are removed by the etching gas and the dry cleaning electrode, the plasma generated between the dry cleaning electrodes is at the exhaust port side and does not go around to the etching gas outlet side. The gas does not adhere to the etching gas outlet side and therefore does not adversely affect the etching of the wafer. Further, since the reaction product is removed by dry cleaning, there is an effect that the operating rate of the apparatus can be maintained high.

According to the dry etching apparatus of the second aspect, since the dry cleaning gas introducing port is provided on the exhaust port side in the first aspect, in addition to the effect of the first aspect, the reaction product is formed at the same time as the wafer etching process. Can be removed, so that the operating rate of the device can be further increased.

[Brief description of drawings]

FIG. 1 is a sectional view of a dry etching apparatus in a first embodiment of the present invention.

FIG. 2 is a sectional view of a dry etching apparatus in a second embodiment.

FIG. 3 is a sectional view of a conventional dry etching apparatus.

[Explanation of symbols]

 Reference Signs List 31 etching chamber 32 upper electrode for etching 33 etching gas outlet 35 lower electrode for etching 36 wafer 37 exhaust port 38, 39 heater 40 cooling liquid introduction pipe for cooling part 44 dry cleaning electrode

Claims (2)

[Claims] 1. An etching chamber having an etching gas outlet and an exhaust port, an etching electrode for etching a wafer installed on the etching gas outlet side, and an etching chamber installed on the etching gas outlet side other than the wafer. A heater for preventing the reaction product from adhering to the part, a cooling part installed on the exhaust port side for adhering the reaction product, and a dry cleaning electrode for removing the reaction product in the cooling part. Dry etching equipment. 2. The dry etching apparatus according to claim 1, further comprising a gas inlet for dry cleaning on the exhaust port side.