JPH04299529A - Dry etching device - Google Patents

Abstract

PURPOSE:To lessen attachments in a reaction chamber to contrive a reduction in dust and to make possible the improvement of the maintainability at the time of cleaning in the reaction chamber and the improvement of productivity. CONSTITUTION:In a dry etching device, in which chlorine gas or bromine gas is used, at least the sidewall surfaces 9 of the surface in a reaction chamber 4 are made of an aluminum material subjected to alumite treatment.

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 using chlorine gas or bromine gas in the field of manufacturing semiconductor integrated circuits and the like.

0002

2. Description of the Related Art In the manufacture of semiconductor integrated circuits, for example, dry etching equipment generally has an upper electrode 22 and a lower electrode 26 in a reaction chamber 24, as shown in FIG. It is configured such that it is connected to a power source 27 and a substrate to be processed 25 is placed on this lower electrode 26. This apparatus utilizes a reactive ion etching method in which glow discharge is caused in the reaction chamber 24 for etching. During this etching, the temperature of the upper and lower electrodes 22, 26 is normally maintained at around 20°C. Further, the reaction chamber 24 is made of stainless steel (for example, SUS316) or the like in consideration of corrosion resistance.

By the way, the monocrystalline silicon film (Si film) or polycrystalline silicon (Polycrystalline silicon film) formed on the substrate 25 to be processed is
The reactive gas used for dry etching of the silicon oxide insulating film (Si02 film) is selected from consideration of the miniaturization of etching dimensions due to higher integration of devices, the anisotropy of the Si film, etc., and the dry etching of the underlying silicon oxide insulating film (Si02 film). Due to the demand for high selectivity, etc., Cl2
, HCl, Br2, HBr gas, or other chlorine-based gas or bromine-based gas is used. As a result, the side wall surface and upper electrode 22 in the reaction chamber 24 of the dry etching apparatus have
The chlorine-based or bromine-based reaction product D, which is difficult to vaporize, became more likely to adhere.

0004

In the above-mentioned dry etching apparatus, since the chlorine-based gas or bromine-based gas has a high vapor pressure, its reaction products tend to form deposits and adhere to the inside of the reaction chamber. In addition, chlorine-based gas or bromine-based gas tends to corrode stainless steel walls, and reaction products tend to adhere to the walls. Therefore, when the number of etching processes increases, the amount of dust due to peeling of attached deposits increases, resulting in a decrease in the yield of semiconductor integrated circuits, and the need to periodically return the inside of the reaction chamber to the atmosphere and clean it using water or alcohol. This has led to a problem in that maintainability has deteriorated.

[0005] In view of the above-mentioned problems, the present invention aims to reduce the amount of deposits in the reaction chamber to reduce dust, and to make it possible to improve maintainability during cleaning of the reaction chamber and improve productivity. There is.

[0006]

[Means for Solving the Problems] The first invention of the present application is a dry etching apparatus using chlorine-based gas or bromine-based gas, characterized in that at least the side wall surface of the interior of the reaction chamber is made of an alumite-treated aluminum material. do.

[0007] The second invention of the present application is characterized in that, in addition to the structure of the first invention, the side wall surface inside the reaction chamber is constructed with an aluminum cover treated with alumite.

[0008] A third invention of the present application is characterized in that, in addition to the structure of the first invention, the temperature of the side wall surface in the reaction chamber is controlled to 10°C or more and 40°C or less.

A fourth invention of the present application is characterized in that the temperature of the upper electrode is controlled to 40° C. or higher in a dry etching apparatus using chlorine-based gas or bromine-based gas.

0010

[Operation] According to the first invention of the present application, since at least the side wall surface of the reaction chamber is made of an alumite-treated aluminum material, it is less likely to react with chlorine-based gas or bromine-based gas than with a conventional stainless steel material. Since the surface condition is smooth and the amount of deposits on the side wall surface is reduced, productivity can be improved by reducing dust.

According to the second invention of the present application, since the side wall surface of the reaction chamber is constructed with an aluminum cover treated with alumite, in addition to the effect of the first invention, the cover can be replaced with another cover at the time of maintenance, and cleaning at the time of replacement is facilitated. It is possible to easily reduce the amount of dust in the reaction chamber without the need for such procedures, and it is possible to further improve maintainability.

According to the third invention of the present application, in addition to the effect of the first invention, by lowering the temperature of the side wall surface in the reaction chamber to 40° C. or less, deposits are prevented from being vaporized, and other parts of the reaction chamber are prevented from being vaporized. In addition, by keeping the temperature at 10° C. or higher, it is possible to prevent the amount of deposits on the side wall surfaces from increasing.

According to the fourth invention of the present application, by heating the upper electrode in the reaction chamber to 40° C. or higher, even if a deposit adheres to the surface of the upper electrode, it is immediately vaporized and the substrate to be processed is heated. It is possible to prevent deposits from being deposited on the surface of the upper electrode located directly above, and to prevent deposits peeled off from the upper electrode from adhering to the substrate to be processed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a dry etching apparatus according to a first embodiment of the present invention. In FIG. 1, 1 is a gas supply port;
2 is an upper electrode made of aluminum, 3 is an end point detection port, 4 is a reaction chamber made of stainless steel (SUS316), 5 is a substrate to be processed, 6 is a lower electrode, 7 is a high frequency power source connected to the lower electrode 6, 8 9 is an exhaust port, and 9 is a cover disposed to cover the entire inner side wall of the reaction chamber 4. This cover 9 is made of aluminum (for example, A5052) whose surface is alumite-treated, and the thickness of the alumite-treated portion is preferably about 50 μm.

HBr gas and HC are supplied from the gas supply port 1.
A mixed gas of 1 gas is supplied.

The graph of FIG. 2 shows the experimental results of dust adhering to the substrate 5 to be processed in the dry etching apparatus having the above configuration. Figure 2 shows (a) the results when only the conventional stainless steel chamber is used, and (b) the results when the new alumite-treated aluminum cover is installed. are counted and shown. For dust measurement, an ordinary laser dust counter (0.3 μm or more) was used to investigate the increase in dust on the test silicon substrate due to introduction of a reaction gas without discharge and transportation including evacuation. The etching conditions were as follows: a mixed gas of HBr and HCl was used, the upper electrode temperature was set at 20°C, and the reaction chamber pressure was set at 20°C.
The test was carried out at mTorr and RF power of 300W. As can be seen from FIG. 2, in the case of only a conventional stainless steel chamber, the adhesion of bromine-based reaction products is particularly large, and therefore the number of dust particles increases when the number of processed sheets exceeds about 400 sheets. 500 again
When the reaction chamber was returned to the atmosphere and the side walls of the chamber were inspected, many brown deposits were found. On the other hand, when an alumite-treated aluminum cover was installed, the dust count remained low and stable even after 1,000 sheets were processed. The reaction chamber was also observed at this point, and although a small amount of deposits was observed compared to the stainless steel chamber alone, the amount was much smaller. It is presumed that this is because the manner in which deposits such as reaction products (for example, SiBrx) generated during etching adhere differs depending on the material inside the reaction chamber and the surface condition.

Note that by making the surface roughness of the cover 9 even smoother (surface roughness of 1 μm or less), the number of dust counts can be further reduced.

FIG. 3 shows a second embodiment of the present invention, and this embodiment is characterized in that it has a temperature control device 10 that can adjust the temperature of the alumite-treated aluminum cover 9. ing. The temperature control device 10 is one that circulates a heat medium liquid (for example, water) through a jacket 11 formed inside the cover 9 to maintain the surface temperature of the cover 9 at a predetermined temperature. be able to.

Table 1 shows the number of substrates to be processed, 200 and 1, due to the temperature change of the alumite-treated aluminum cover 9.
The figure shows the results of a comparison between the number of dust particles and the amount of adhesion on the cover 9 when 1,000 sheets were printed. From Table 1,
Although the number of dust particles was relatively small at 5° C., many deposits were observed on the aluminum cover 9. On the other hand, when the temperature reached 45° C. or higher, the amount of dust deposited on the aluminum cover 9 was small, but the number of dust particles increased. This is because when the temperature of the aluminum cover 9 is lowered, reaction products tend to adhere to the aluminum cover 9 and are less likely to separate, resulting in a relatively small number of dust particles. This is considered to be because the dust particles adhere to other parts of the interior of the device 4 that are at a low temperature, such as the upper electrode 2, which results in an increase in the number of dust particles. Therefore, by controlling the temperature of the aluminum cover 9 to a predetermined temperature in the range of 10° C. to 40° C., the reaction chamber 4 can be brought into an optimal state.

[0020]

[Table 1]

Table 2 compares the adhesion of deposits at various locations within the reaction chamber 4 when the surface temperature of the alumite-treated aluminum cover 9 is maintained at 25° C. with that of a conventional stainless steel wall. It shows. Table 2 shows that the present example and the conventional example were processed under the same conditions,
The amount of deposits was investigated after processing 1,000 substrates, and the difference in deposits in the end point detection port 3 and on the upper plate of the reaction chamber 4 was remarkable, and this study According to the embodiment, there is an effect that the amount of deposits not only on the side wall surface constituted by the aluminum cover 9 but also on other parts is reduced.

[0022]

[Table 2]

FIG. 4 shows a third embodiment of the invention. This reaction chamber 4 is made of stainless steel as in the conventional example shown in FIG. 5, and the inner surface is made of stainless steel walls. The feature of this embodiment is that the temperature of the upper electrode 2 is controlled by the temperature adjustment device 15 to 40°C or higher (for example, the set temperature is set to 50°C).
℃. ). Temperature adjustment device 15
As an example, it is possible to use one in which a heating medium is circulated through the upper electrode 2 or a heater is built into the upper electrode 2 to control the temperature thereof.

Table 3 shows the number of dust adhering to the substrates 5 to be processed when the temperature of the upper electrode 2 is changed in relation to the number of substrates to be processed (processing conditions are as shown in FIG. 2). (The same is true for experiments conducted to obtain results.) As is clear from Table 3, the temperature of the upper electrode 2 was set at 40°C.
With the above settings, the number of dust particles is low even when processing 1,000 sheets, and the number of attached dust particles can be significantly reduced compared to the conventional setting temperature of 20°C.

[0025]

[Table 3]

[0026] Note that the first embodiment or the second embodiment of the present invention
The temperature of the upper electrode 2 in the example was set at 40°C as in the third example.
When the temperature is above ℃, it is possible to more efficiently reduce dust and deposits.

The present invention can be constructed in various ways other than those shown in the above embodiments. For example, in the first and second embodiments described above, the side wall surface of the reaction chamber 4 is constructed of an aluminum cover 9 treated with alumite, but the surface inside the reaction chamber 4 itself may be made of an aluminum material treated with alumite. is also possible. In addition, polycide film (WSi
/Poly-Si, MoSi/Poly, TiSi/P
Process a substrate with an aluminum alloy film (Al-Si film, Al-Si-Cu film, etc.) containing an aluminum film using a chlorine-based gas or a bromine-based gas. The present invention can be applied to a dry etching apparatus.

[0028]

[Effects of the Invention] According to the present invention, deposits in the reaction chamber can be reduced, so it is possible to reduce dust.
Since the dust count is stably maintained, it is possible to continuously process more than 1,000 substrates, and the cost of reaction chamber materials and the fact that the alumite-treated aluminum cover can be replaced reduces costs. and maintenance time was shortened, and mass-produced dry etching equipment was implemented.
A dramatic improvement in productivity can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a dry etching apparatus in a first embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the number of processed substrates and the number of dust particles.

FIG. 3 is a schematic diagram showing a dry etching apparatus in a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing a dry etching apparatus in a third embodiment of the present invention.

FIG. 5 is a schematic diagram showing a conventional dry etching apparatus.

[Explanation of symbols]

2 Upper electrode 4 Reaction chamber 5 Object to be treated 6 Lower electrode 9 Cover 10 Temperature control device 15 Temperature adjustment device

Claims (4)

[Claims] 1. A dry etching apparatus using chlorine-based gas or bromine-based gas, characterized in that at least the side wall surface of the inside surface of the reaction chamber is made of an alumite-treated aluminum material. 2. The dry etching apparatus according to claim 1, wherein a side wall surface of the reaction chamber is constructed of an aluminum cover treated with alumite. 3. The dry etching apparatus according to claim 1, wherein the temperature of the side wall surface in the reaction chamber is controlled at 10° C. or more and 40° C. or less. 4. A dry etching apparatus using chlorine-based gas or bromine-based gas, characterized in that the temperature of the upper electrode is controlled to 40° C. or higher.