JPH11281307A - Electrode plate, manufacture of electrode plate and measuring method of surface roughness of its small diameter hole inner wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode plate and its manufacturing method wherein surface roughness of a small diameter hole inner wall of an electrode plate in which many small diameter holes for straightening reaction gas flow are bored is accurately and precisely measured, an electrode plate in which smoother and more precise boring work is performed is formed, and a high quality semiconductor device in which contamination of particles and impurities is not generated when the plate is used can be formed. SOLUTION: In a measuring method of surface roughness of a small diameter hole 11 inner wall of an electrode plate 10 having many small diameter holes for straightenting reaction gas, flow, the small diameter holes 11 of the electrode plate 10 are filled with liquid rubber, which is cured. Small diameter hole inner wall patterns are transferred to the rubber, which is taken off. Surface roughness of the rubber is measured, thereby measuring surface roughness of the small diameter hole inner wall of the electrode plate. Inner wall surface roughness Ra of bored small diameter holes is measured by this measuring method, and is finished to within the range of 0.01-2.0 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode plate having a large number of small holes used in an etching device, an ashing device, a sputtering device, etc. for manufacturing a semiconductor device, a method for manufacturing the same, and a measurement of the inner wall surface roughness of the small holes. About the method.

[0002]

2. Description of the Related Art Conventionally, for example, in a plasma dry etching apparatus or the like used in a semiconductor process, a semiconductor wafer is mounted on a flat electrode connected to a high frequency power supply in a reaction chamber, and a counter electrode facing the semiconductor wafer is placed on the flat electrode. There is known a technique in which a large number of small diameter holes are formed, a reaction gas is rectified and introduced into a reaction chamber through the small diameter holes, and plasma is generated between a plane electrode and a counter electrode to perform an etching process.

In recent years, miniaturization of semiconductor devices,
As the degree of integration increases, the performance required for electrode plates has also become more advanced, and the materials used are made of conventional aluminum, aluminum alloy, glassy carbon (also called glass impregnated carbon material), etc. Electrode plates made of silicon, which are excellent in reducing particle generation and heavy metal contamination, have attracted attention and have been used.

[0004] Among the advanced performances required for electrode plates,
In particular, prevention of generation of contamination and particles,
There is an emphasis on improvement of uniformity (uniformity of etching rate), and there are some demands. Therefore, in recent years, heavy metal has been changed by changing the electrode plate material from sintered carbon, glassy carbon, aluminum, etc. obtained by sintering conventional powder to a silicon electrode plate of the same material as the semiconductor silicon wafer to be processed. Although the occurrence of such contamination as above could be significantly reduced, the reduction of particles and the improvement of uniformity were still incomplete.

For example, in an actual process in which the electrode plate itself is manufactured using single crystal silicon, and the electrode plate itself is also consumed, the surface of the inner wall of the small-diameter hole is rough if the surface roughness is rough. Are not uniformly consumed, become a source of particles, the uniformity is deteriorated, and the yield is reduced in the manufacture of semiconductor devices.

To solve this problem, Japanese Patent Application Laid-Open No. 7-273 discloses
In the technology disclosed in Japanese Patent Application Laid-Open No. 09-94, an electrode plate is proposed in which the surface roughness Rmax of a portion consumed by plasma is 10 μm or less. According to the embodiment of the present invention, a small-diameter hole having a diameter of 0.8 mm is machined. However, when the hole has a smaller diameter, the stylus of the stylus-type surface roughness measuring instrument does not enter the hole, and the hole is drilled. The stylus could not be brought into contact with the inner wall even in a concave section in which the hole was cut vertically, and measurement of the surface roughness was impossible.

Since the surface of the electrode plate is usually mirror-polished, generation of particles from this surface is hardly recognized. Since most of the particles are generated from the part of the inner wall of the small-diameter hole where the mirror polishing is difficult, the relationship between the surface roughness of the small-diameter hole and the state of particle generation needs to be investigated in detail. Based on the results, it is necessary to consider how much the surface roughness of the small-diameter hole is to be finished.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve such a problem, and it is an object of the present invention to provide an electrode plate having a large number of small holes for rectifying a reaction gas. Developed a method to accurately and accurately measure surface roughness, and provided a smoother and more accurate perforation process.When used as an electrode plate, there was no occurrence of contamination of particles or impurities and good quality. It is an object of the present invention to provide an electrode plate capable of manufacturing a semiconductor device and a method for manufacturing the same.

[0009]

SUMMARY OF THE INVENTION In order to solve such a problem, the invention described in claim 1 of the present invention is directed to an electrode plate having a large number of small holes for rectifying a reaction gas. In the method for measuring the thickness of the electrode plate, the small-diameter hole of the electrode plate is filled with liquid molding rubber and cured, and the inner wall pattern of the small-diameter hole is transferred and removed, and the surface roughness of the molding rubber is measured. Is a method for measuring the surface roughness of the inner wall of the small-diameter hole.

As described above, in the method in which the inner wall pattern of the small diameter hole is transferred to the liquid molding rubber filled in the small diameter hole, the cured rubber is removed, and the surface roughness is measured, the cured rubber has mold release properties. Therefore, the rubber can be easily extracted from the hole without cutting the hole, and the part to be measured becomes a bar-shaped and convex part. The entity can be easily and accurately measured.

In this case, when the addition type liquid silicone rubber is selected as the liquid molding rubber as described in claim 2, the surface and the interior are uniformly cured, and the rubber is essentially excellent in releasability. The desired pot life and shelf life,
Curing conditions can be set, shrinkage ratio after curing is extremely small, and it has characteristics such as high precision replicas.Therefore, to transfer a fine pattern like the present invention with high precision It is suitable.

According to a third aspect of the present invention, there is provided a method for manufacturing an electrode plate having a large number of small-diameter holes for rectifying a reaction gas. A method for producing an electrode plate, comprising measuring the inner wall surface roughness Ra of a small-diameter hole and finishing the Ra within a range of 0.01 to 2.0 μm.

As described above, the inner wall surface roughness Ra of the small-diameter hole of the electrode plate measured by the measuring method of the present invention is from 0.01 to 0.01.
If drilling and finishing are performed so as to be finished within the range of 2.0 μm, particles are generated from the electrode plate and adhere to the wafer at the time of manufacturing the semiconductor device, the quality is hardly deteriorated, and the flow of the reaction gas is sufficient. Rectification improves the uniformity of the etching rate, enables stable processing, and improves the yield and productivity of semiconductor device manufacturing.

Next, the invention described in claim 4 of the present invention is:
In the electrode plate having a large number of small diameter holes for rectifying the reaction gas, the surface roughness Ra of the small diameter hole inner wall pattern transferred to the cured liquid molding rubber was 0.01 to 2.0 μm.
Characterized in that the electrode plate is finished within the range of (1).

As described above, the electrode plate for rectifying a reactive gas has a small-diameter hole inner wall surface roughness Ra of 0.01 to 2.0 μm.
m, the generation of particles due to the rough surface roughness is significantly reduced,
The high smoothness improves the uniformity of the etching rate, and can significantly improve the yield, productivity, and cost in manufacturing semiconductor devices.

In this case, it is preferable to select single-crystal silicon or polycrystalline silicon as the material of the electrode plate. If single-crystal silicon or polycrystalline silicon is used as the material of the electrode plate,
Even in a highly corrosive reaction gas atmosphere during the manufacture of semiconductor devices, there is almost no particle generation because of its excellent corrosion resistance, and when the semiconductor wafer to be processed is silicon, the same material is used, and impurities Contamination can be suppressed, which contributes to improvement in productivity of semiconductor device production, improvement in yield, and reduction in cost. Among them, single-crystal silicon is low in the content of the doping material for electric resistivity adjustment and mechanical strength.
It is superior to polycrystalline silicon in quality control and is advantageously used as a material for manufacturing an electrode plate.

According to a sixth aspect of the present invention, the electrode plate having the small-diameter hole for rectifying the reaction gas is used for a plasma etching apparatus, a reactive ion etching apparatus, a plasma ashing apparatus, a sputtering apparatus, or It could be used for a plasma CVD device.

The electrode plate manufactured in accordance with the above-mentioned specified value is a counter electrode plate for generating plasma and applying other high-frequency waves in any of these apparatuses, and also serves as a rectifier for the reaction gas. This is because it can act effectively. In particular, the same silicon as the silicon wafer to be treated is selected for the material, so that contamination of impurities can be suppressed, and the surface roughness of the small-diameter hole inner wall has been finished with high precision. Almost no particles are generated and adhered, and the productivity, the yield, and the quality of the semiconductor device can be improved.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings, but the present invention is not limited thereto. Here, FIG. 1 is a plan view showing an example of an electrode plate manufactured by the manufacturing method of the present invention.
FIG. 1 is a schematic diagram of a plasma dry etching apparatus as an example of an apparatus to which this electrode plate is applied.

The present inventors have determined that the surface roughness of the inner wall of a small-diameter hole drilled in an electrode plate can be accurately measured, which is almost impossible to measure with a stylus-type surface roughness measuring instrument using a direct contact needle. As a method of measuring with accuracy, a small diameter hole is filled with liquid molding rubber,
The inventors have conceived that it is only necessary to cure this, transfer and remove the inner wall pattern of the small-diameter hole, and measure the surface roughness of the molding rubber, and have scrutinized various conditions to complete the present invention.

Here, an example of the electrode plate manufactured by the manufacturing method of the present invention will be described with reference to FIG. 1. This disk-shaped electrode plate 10 has small holes 11 for various gas distributions of several hundred to several thousand. It was perforated individually. An electrode plate mounting hole 12 is formed in the outer periphery of the electrode plate. The size of the electrode plate is usually 200 to 40 in diameter corresponding to the size of the object to be processed.
A small hole having a diameter of 0 mm and a thickness of several mm to several tens mm is used, and the small diameter hole has a diameter of several tens μm to several hundred μm.

FIG. 2 shows a dry etching apparatus 20 for applying a high frequency as an example of an apparatus to which this electrode plate is applied. Here, a state in which the electrode plate 21 manufactured by the manufacturing method of the present invention is set in the plasma dry etching apparatus 20 is shown. An electrode plate 22 is provided, and a high frequency is applied between both electrodes. On the other hand, the etching gas enters the internal gas container 25 from the gas supply system 26, is rectified by the small-diameter hole of the electrode plate 21, and jets out toward the wafer 23, where plasma is generated to etch the wafer surface. It has become.

The semiconductor device is further miniaturized,
As the degree of integration has increased, characteristics other than the essential electrical performance have also been required for this electrode plate. As one of them, there is a problem of so-called contamination in which a semiconductor wafer to be processed is contaminated by impurities such as heavy metals. The material of the various parts that make up the semiconductor processing equipment is greatly involved in this, and the electrode plate is no exception, especially when the material of the electrode plate is silicon when the wafer is single crystal silicon. The same material was used, and the problem of impurity contamination could be solved. The silicon of this electrode plate may be single-crystal silicon or polycrystalline silicon, but single-crystal silicon is more preferable in terms of adjustment of mechanical strength and specific resistance and quality control.

Other problems include generation of particles and deterioration of uniformity of etching rate (also referred to as uniformity). It has been found that the main cause of these problems lies in the electrode plate, particularly the surface roughness of the inner wall of the small-diameter hole. If the surface roughness is rough, the corrosive gas, such as an etching gas, will not uniformly erode the bumps on the rough surface and generate particles, which are scattered and adhere to the wafer, or have an uneven surface roughness. If it is uniform, the flow of the etching gas will be disturbed and the etching rate will be non-uniform, resulting in a decrease in the yield of semiconductor devices.

Therefore, in order to investigate the relationship between the surface roughness of the inner wall of the small diameter hole of the electrode plate and the number of generated particles, a method of measuring the surface roughness of the inner wall of the hole was investigated. as a result,
With a stylus-type surface roughness measuring device that is normally used, the stylus does not enter the hole when the hole has a small diameter of 0.8 mm or less, and it can be touched even in a concave section where the hole is cut vertically. The needle could not contact the inner wall, making it impossible to measure the surface roughness.

On the other hand, according to the measuring method of the present invention, the liquid molding rubber is injected into the small diameter hole of the electrode plate, filled and cured.
It is a method of transferring and removing the small diameter hole inner wall pattern and measuring the surface roughness of the molding rubber with a stylus type surface roughness measuring instrument.According to this method, since the cured rubber has mold release properties, The rubber can be easily extracted from the hole without cutting the hole, and the part to be measured has a bar-like convex shape, so there are no restrictions on the device of the surface roughness measuring device, and the actual surface of the processed surface can be reduced. It can be easily and accurately measured.

The numerical value measured by this measuring method can be regarded as substantially representing the inner wall surface roughness of the small-diameter hole. Therefore, this measuring method can be effectively applied to a product inspection of a finished surface that has been drilled and polished to a desired hole diameter and surface roughness, or an intermediate inspection during drilling, polishing and finishing.

The liquid molding rubber used for molding the small-diameter hole inner wall pattern of the electrode plate of the present invention is usually referred to as an addition-type liquid silicone rubber. Is formed from a hydrogen organopolysiloxane, and is subjected to an addition reaction using chloroplatinic acid as a catalyst to become an elastomer.
These include silicone rubber KE-1300 as a commercial product
(Trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like are preferably used.

This liquid-molded silicone rubber is low-viscosity and adapts well to the fine mold surface, the surface and the interior are uniformly cured, has essentially excellent releasability, and has a desired pot life and storage stability. , Curing conditions can be set, shrinkage ratio after curing is very small, and a replica with high precision is obtained. It is suitable for accurate and accurate transfer.

In the method of manufacturing an electrode plate according to the present invention, first, a hole is formed by a diamond drill (hereinafter, referred to as diamond processing). As the tool, a diamond tool in which diamond abrasive grains or the like are fixed to the tip of a normal cemented carbide drill or the like by nickel electrodeposition or the like is used. In this case, in order to remove heat generated by cutting and reduce frictional resistance, it is common to flow cutting oil or cooling water over the drill and the workpiece.

However, there is a limit in the diamond tool processing, and if the grain size of the diamond abrasive grains is reduced in order to finish the surface roughness Ra finely and smoothly, it takes a long time for drilling, and conversely, the grain size of the diamond abrasive grains is increased. Then, drilling can be done in a short time, but there is a phenomenon that the surface roughness of the workpiece to be processed becomes rough.If high precision and smooth surface roughness is required, drilling and finishing polishing or reamer Generally, two-stage processing is performed.

Alternatively, the holes may be formed by ultrasonic processing.
Ultrasonic machining is a method of pressing a tool that vibrates ultrasonically to a workpiece through an abrasive slurry and processing the workpiece through abrasive grains by ultrasonic vibration. A processing jig called a horn with a stainless steel pin standing upright corresponding to the position is attached to the ultrasonic processing machine so that the vibration from the ultrasonic transmitter is transmitted to the processing jig and the tip of the pin Is brought into contact with a workpiece, and at the same time, an ultrasonic vibration is applied while flowing an abrasive slurry in which abrasive grains are dispersed in water or the like to the tip of the pin. Then, the abrasive grains present between the workpiece and the pin by the ultrasonic vibration grind the workpiece, and when the pin is processed and fed, a hole slightly larger than the diameter of the pin is formed in the workpiece. .

Next, the finished state of the inner wall surface roughness of the small-diameter hole of the electrode plate which has been subjected to the perforation and polishing processing as described above is inspected by the measuring method of the present invention, and then the pass / fail is determined.
When the surface roughness Ra of the inner wall of the small-diameter hole is finished in the range of 0.01 to 2 μm in terms of a molding rubber surface roughness, for example, when used as an electrode plate of a plasma dry etching apparatus, the flow of the reaction gas is reduced. The flow is sufficiently rectified, and the entire surface of the wafer to be processed is uniformly etched. In addition, since the surface becomes smooth, particles are hardly generated, and the yield of the semiconductor device is improved. Here, if the surface roughness exceeds 2 μm, the uniformity of the reaction gas passing through the small-diameter hole is impaired, the etching is also likely to be non-uniform, particles and contamination are easily generated, and the yield of the semiconductor device is reduced. Further, in order to increase the surface roughness Ra to an accuracy of less than 0.01 μm, processing becomes extremely difficult and the quality becomes excessive.

[0034]

EXAMPLES The present invention will be described in detail below with reference to examples of the present invention and comparative examples, but the present invention is not limited to these examples. Here, the surface roughness Ra (μm) refers to a center line average roughness and is represented by an average of absolute values of deviations from the center line. The surface roughness Rmax (μm) refers to the maximum height, and is the largest value of the difference between the peak and the bottom.

(Examples 1 to 3) A single-crystal silicon disk having an outer diameter of 203.2 mm and a thickness of 5 mm was subjected to a processing for forming a small-diameter hole having a diameter of 1.0 mm, and the inner wall surface roughness Ra of the small-diameter hole was measured.
And three kinds of disk samples having different Rmax. Next, liquid molding silicone rubber KE is placed in the small diameter hole of each disk.
-1300 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) is filled with a liquid rubber to which a curing agent has been added and cured, and then the cured rubber is extracted and the surface roughnesses Ra and Rma of the rubber are extracted.
When x was measured with a stylus type surface roughness measuring instrument, the results shown in Table 1 were obtained. Table 1 shows that after removing the cured rubber, the small-diameter hole was cut vertically with a diamond cutter until the stylus could be contacted, and the inner wall surface roughness was measured using the stylus type surface roughness. The values (R'a and R'max) actually measured by the measuring instrument are also shown.

Then, the electrode plate 10 having the small diameter hole manufactured as described above is mounted on a plasma dry etching apparatus 20 as shown in FIG. 2, and the CF ₄ gas sent from the gas supply system 26 is passed through the small diameter hole 11. Along with the ejection, a high frequency was applied to generate plasma, and the silicon oxide film on the semiconductor silicon wafer 23 was etched. The number of particles attached to the silicon wafer at the time of etching was counted. Small hole inner wall surface roughness Ra and Rma
Table 1 shows the relationship between x and the number of attached particles. As a result, almost no particles were generated and the etching rate was uniform over the entire surface.

(Comparative Examples 1 and 2) Small hole inner wall surface roughness Ra
And Rmax are different, and the same single crystal silicon disk as in the example was processed to form a small-diameter hole of 1.0 mm, except that two kinds of samples slightly rougher than the example were prepared. The surface roughness of the inner wall of the hole was measured and also shown in Table 1. These electrode plates were placed on a plasma dry etching apparatus, and the number of particles adhering to the silicon wafer when the silicon wafer was etched was counted. The relationship between the surface roughness of the inner wall of the small-diameter hole and the number of particles was shown in Table 1.
It was also described in.

[0038]

[Table 1]

From Table 1, the values of the small hole inner wall surface roughness R'a and R'max measured by a stylus type surface roughness measuring instrument by cutting the electrode plate lengthwise with respect to the small diameter hole are shown in Table 1. It can be seen that the surface roughness Ra and Rmax were accurately transferred. In addition, when the electrode plate is made of silicon and the surface roughness Ra of the inner wall of the small-diameter hole is 2.0 μm or less, the number of generated particles is 5 or less, indicating that the performance is remarkably improved.

The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and has the same effect. Within the technical scope of

For example, in applying the method for measuring the surface roughness of the inner wall of a small-diameter hole of an electrode plate according to the present invention, it is preferable as a method for measuring a reaction gas rectification electrode plate in a plasma dry etching apparatus to which a high frequency is applied. The present invention is not limited to such an example, and substantially the same effect can be obtained as a method for measuring an electrode plate for a reactive ion etching apparatus, a plasma ashing apparatus, a sputtering apparatus, or a plasma CVD apparatus. Can be used effectively.

[0042]

According to the present invention, the surface roughness of the inner wall of the small-diameter hole of the electrode plate for a plasma device to which a high frequency is applied can be measured accurately and with high accuracy. In addition, if the electrode is manufactured to have a specific range of surface roughness by this measurement method and is used as an electrode plate for manufacturing a semiconductor device, the effect of rectifying various reactive gases is excellent, and the effect on the device is uniform, so that particles and There is no generation of impurity contamination, and the process can be stably operated, so that the production yield, quality and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an electrode plate manufactured by a method of the present invention.

FIG. 2 is a schematic view of a plasma dry etching apparatus as an example of an apparatus provided with an electrode plate manufactured according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Electrode plate, 11 ... Small diameter hole, 12 ... Mounting hole, 20 ... Plasma dry etching apparatus, 21 ... Electrode plate, 22 ... Flat electrode plate, 23 ... Semiconductor wafer, 24 ... Chamber,
25: internal gas container, 26: gas supply system, 27: gas discharge system.

Claims (6)

[Claims] 1. A method for measuring the surface roughness of the inner wall of a small-diameter hole of an electrode plate having a large number of small-diameter holes for rectifying a reaction gas, wherein the small-diameter hole of the electrode plate is filled with a liquid molding rubber, cured, and cured. A method for measuring the surface roughness of an inner wall of a small-diameter hole of an electrode plate, wherein a pattern is transferred and removed, and the surface roughness of a molding rubber is measured. 2. The method according to claim 1, wherein said liquid molding rubber is an addition liquid silicone rubber. 3. A method of manufacturing an electrode plate having a large number of small holes for rectifying a reaction gas, comprising measuring the inner wall surface roughness Ra of the small holes drilled by the measuring method according to claim 1 or 2. A method for producing an electrode plate, wherein Ra is finished within a range of 0.01 to 2.0 μm. 4. An electrode plate having a large number of small-diameter holes for rectifying a reaction gas, wherein the surface roughness Ra of the small-diameter hole inner wall pattern transferred to the cured liquid molding rubber is 0.01%.
An electrode plate finished within a range of from 2.0 μm to 2.0 μm. 5. The electrode plate according to claim 4, wherein the material of the electrode plate is single crystal silicon or polycrystalline silicon. 6. An electrode plate for a plasma etching apparatus, a reactive ion etching apparatus, a plasma ashing apparatus, a sputtering apparatus, or a plasma C apparatus.
The electrode plate according to claim 4, wherein the electrode plate is used for a VD device.