JP2008130651A - Plasma etching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain the adhesion prevention and shaving prevention of a nonuniform reaction product on the internal surface of a breakdown-strength dielectric member in a well-balanced manner approximately uniformly without particularly complicating a device and without damaging the uniformity of a plasma on a substance to be treated. <P>SOLUTION: A plasma etching device has a first electrode 4 radiating the plasma 6 onto the substance to be treated 2 on a counter electrode 3 by generating the plasma 6 in a decompressive chamber 1 from a reaction gas through the breakdown-strength dielectric member 5 conducting plasma treatment such as etching to the plasma 6. The plasma etching device further has a second electrode 7 fitted between the first electrode 4 and the breakdown-strength dielectric member 5 to prevent the adhesion of the reaction product on the internal surface 5a of the breakdown-strength dielectric member 5. An electrode distance L2 from the internal surface 5a of the breakdown-strength dielectric member 5 for the second electrode 7 is set in response to a partial difference between the degree of adhesion of the reaction product on the internal surface 5a of the breakdown-strength dielectric member 5 and the quantity of the breakdown-strength dielectric member 5 shaven in each of the opposed regions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma etching apparatus used for manufacturing an electronic device that performs fine pattern processing. More specifically, the first etching is performed by generating plasma of a reactive gas in a chamber via a pressure-resistant dielectric member. And a second electrode for preventing the reaction product from adhering to the inner surface of the withstand voltage dielectric member during plasma etching.

  A plasma etching apparatus in which such first and second electrodes are combined is already known (see, for example, Patent Documents 1 and 2).

  Patent Document 1 particularly discloses a configuration in which the first electrode is a high-frequency antenna, and the second electrode is connected to the same high-frequency power source via a variable choke or a variable capacitor in parallel with the high-frequency antenna. In such a configuration, the first electrode generates plasma in the chamber via the withstand voltage dielectric member to process the object to be processed supported by the counter electrode in the chamber, and the second electrode has a withstand voltage. A uniform electric field is formed on the inner surface of the dielectric member to prevent the film from adhering to the inner surface of the withstand voltage dielectric member. In particular, the power supplied to the second electrode is supplied to the choke or variable capacitor. Thus, the inner surface of the withstand voltage dielectric member can be prevented from being etched during the process, and a cleaning process can be performed between the processes.

On the other hand, Patent Document 2 proposes that the second electrode is a divided electrode to which high-frequency power is applied independently, or that the second electrode is moved. In such a configuration, by adjusting the high-frequency voltage supplied to each of the divided electrodes according to the distribution of the adhesion thickness of the reaction product on the inner surface of the withstand voltage dielectric member, or by moving the second electrode, While preventing the region immediately below the first electrode on the inner surface of the dielectric material from being scraped, each region that remains in the chamber and tries to adhere to the inner surface of the dielectric material with a different thickness. The reaction product can be etched.
Japanese Patent No. 3429391 JP 2005-259836 A

  However, even if the high frequency power supplied from the power source c to the second electrode b is controlled as described in Patent Document 1, it is supplied to the entire second electrode b as described above, and the withstand voltage dielectric member. A uniform electric field is formed on the inner surface of d and a plasma e having a uniform density distribution is generated on the object to be processed, whereas the density of the plasma e under the inner surface of the withstand voltage dielectric member d is There are various differences depending on the generation area. For example, in the density distribution in which the density in the central portion is high and the density decreases toward the peripheral portion as exemplified in the fifth column, A to C, and E to G in FIG. 28, the withstand voltage dielectric member according to the distribution difference. The plasma e tends to increase in the central portion of the inner surface of d and decrease in the peripheral portion. Further, as illustrated in the fifth column of FIG. 28, D, there may be a density distribution that is higher in the peripheral portion than in the central portion, and there is a tendency that the plasma e in the peripheral portion is large and decreases in the central portion. A difference is given to the shaving of the inner surface of the withstand voltage dielectric member d. In addition, the degree of adhesion of the reaction product (deposited in the figure) to the withstand voltage dielectric member d may be higher in the central portion and lower toward the peripheral portion as illustrated in the fourth column of FIG. 28, AG. However, although not shown, it is not constant so that it may be high at the peripheral portion and lower at the central portion, which also causes unevenness of the shaving amount of the inner surface of the withstand voltage dielectric member d.

  Here, the density distribution pattern of the plasma e and the deposition amount distribution pattern of the reaction product are different from each other when they are superimposed as shown in the third column of FIGS. In correlation with the amount of abrasion on the inner surface of the dielectric member d, the distribution of the amount of abrasion (the abrasion rate in the figure) of the inner surface of the withstand voltage dielectric member d is determined as shown in the second column of FIGS. The actual cutting state corresponding to the distribution of these cutting amounts is exemplified in the first column, A to G in FIG.

  In FIG. 28B, there is almost no difference in level between the density distribution pattern of plasma e and the deposition amount distribution pattern of the reaction product, and the amount is small even if the inner surface of the withstand voltage dielectric member d is scraped. It is almost flat and can be said to be an ideal shaving condition. In FIG. 28F, there is a slight difference between the density distribution pattern of plasma e and the deposition amount distribution pattern of the reaction product, but the difference is almost uniform. Although it can be deeply cut, it can be said that the cutting conditions are almost flat and ideal. However, in A, C to E, and G of FIG. 28, the central portion and the peripheral portion are partially shaved, and there is a problem that the withstand voltage strength of the expensive withstand voltage dielectric member d is lowered early.

  On the other hand, as described in Patent Document 2, the second electrode b is used as a divided electrode independently of each other, and accordingly, high-frequency power having different power is supplied to each of the second electrodes b depending on the region on the inner surface of the withstand voltage dielectric member d. There is a problem that even if trying to cope with different adhesion amounts, it is impossible to cope with continuous changes, and each of the second electrode b, the power source c that supplies high-frequency power, and the drive system that turns on and off the power source c, Since the required number of the second electrodes b is required, the apparatus becomes expensive.

  The object of the present invention is to balance the prevention of adhesion of non-uniform reaction products and the prevention of scraping on the inner surface of a dielectric material without complicating, significant cost increase, and without impairing the uniformity of plasma and processing. It is an object of the present invention to provide a plasma etching apparatus that can be achieved substantially uniformly.

  In order to achieve the above object, according to a first aspect of the plasma etching apparatus of the present invention, a depressurizable chamber, a counter electrode provided inside the chamber and supporting an object to be processed, A first electrode which is provided outside a dielectric material member forming a partition wall of the chamber, and which generates plasma from a reaction gas in the chamber and etches a workpiece to be supported by the counter electrode; and the first electrode And a second electrode for preventing reaction products from adhering to the inner surface of the withstand voltage dielectric member, between the first electrode and the withstand voltage dielectric member. The electrode distance from the inner surface of the withstand voltage dielectric member is set according to a partial difference between the degree of adhesion of the reaction product to the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric. As one feature

  In such a configuration, the electrode distance from the inner surface of the withstand voltage dielectric member of the second electrode is a part of the degree of adhesion of the reaction product to the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric member. By setting according to the difference, plasma is generated in the chamber with a uniform density distribution on the workpiece side by the first electrode through the proof dielectric member and the uniform plasma etching is performed as usual. Without obstructing the operation, the degree of adhesion of the reaction product to the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric member with attenuation corresponding to the electrode distance of the power from the second electrode It works without excess or deficiency depending on the difference between them and sufficiently prevents the reaction products on the inner surface of the withstand voltage dielectric member from adhering to each part, and the inner surface of the withstand voltage dielectric member is partially scraped. There will be no such thing.

  According to the second aspect of the plasma etching apparatus of the present invention, the electrode distance is characterized in that the central portion is made larger than the peripheral portion or the peripheral portion is made larger than the central portion.

  Accordingly, it is possible to cope with the case where the amount of wear of the dielectric material is apt to be larger at the central portion than that at the peripheral portion, or the peripheral portion is apt to be larger than the central portion.

  According to a third aspect of the plasma etching apparatus of the present invention, the electrode distance is set by the flat inner surface of the withstand voltage dielectric member and the three-dimensional form of the second electrode.

  As a result, the change in the electrode distance corresponding to the degree of adhesion of the reaction product to the inner surface of the opposing withstand voltage dielectric member and the shaving amount of the withstand voltage dielectric member is satisfied in the three-dimensional shape of only the second electrode. be able to.

  According to a fourth aspect of the plasma etching apparatus of the present invention, the outer surface of the withstand voltage dielectric member has a three-dimensional form that follows or approximates the three-dimensional form of the second electrode.

  As a result, the withstand voltage dielectric member uses the space between the three-dimensional second electrode, and the thickness is increased at a larger electrode distance than at a smaller one, so that the reaction product from the second electrode The power for preventing the adhesion of the electrode is weaker at the electrode distance larger than the smaller electrode distance, and the difference between the degree of adhesion of the reaction product and the amount of wear of the withstand voltage dielectric member together with the three-dimensional shape of the second electrode It can correspond to. In addition, since the withstand voltage dielectric member becomes thicker as the amount of scraping is larger, it is possible to prevent the withstand voltage strength from being lower than that of the other portions even if the shaving is larger than the other portions.

  According to a fifth aspect of the plasma etching apparatus of the present invention, the electrode distance is set by the flat form of the second electrode and the three-dimensional form of the inner surface of the withstand voltage dielectric member. Yes.

  As a result, it is possible to cope with a partial difference between the degree of adhesion of the reaction product to the opposing second electrode and the amount of wear of the withstand voltage dielectric member in a three-dimensional shape such as integration or lamination only on the inner surface of the withstand voltage dielectric member. Therefore, the power for preventing the reaction product from adhering to the second electrode to be prevented from adhering to the change in the electrode distance can be weakened at the large electrode distance than at the small one, and the thickness of the withstand voltage dielectric member is It is possible to increase the tolerance for shaving at a large part of the tool than at a small part.

  According to a sixth aspect of the plasma etching apparatus of the present invention, the plasma etching apparatus further comprises distance adjusting means for adjusting a difference in electrode distance in each facing region between the second electrode and the inner surface of the withstand voltage dielectric member. It is said.

  Thus, even if the partial difference between the degree of adhesion of the reaction product to the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric member is not constant depending on the plasma processing conditions, For each area facing the inner surface of the dielectric member, it is possible to adjust the electrode distance according to the difference between the degree of adhesion of the reaction product to the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric member. it can.

  According to the seventh aspect of the plasma etching apparatus of the present invention, the distance adjusting means is characterized in that the partial height of the second electrode remains integral or is relatively changed for each divided body. .

  Accordingly, the degree of adhesion of the non-constant reaction product to the inner surface of the withstand voltage dielectric member and the withstand voltage dielectric can be changed depending on the form of the second electrode or by changing the partial height relative to each divided body. It is possible to adjust the electrode distance according to the difference from the scraping amount of the body member.

  According to the eighth aspect of the plasma etching apparatus of the present invention, a chamber capable of being depressurized, a counter electrode provided inside the chamber and supporting an object to be processed, and an outside of the withstand voltage dielectric member forming the partition of the chamber. Provided between the first electrode and the pressure-resistant dielectric member, the first electrode for generating a plasma made of a reactive gas in the chamber and etching the workpiece supported by the counter electrode. In a plasma etching apparatus comprising a second electrode for preventing the reaction product from adhering to the inner surface of the withstand voltage dielectric member, the degree of adhesion of the reaction product to the inner surface of the withstand voltage dielectric member and the withstand voltage dielectric And having at least one of a difference in dielectric constant, a difference in thickness, and a difference in arrangement density according to a partial difference with the amount of shaving of the body member, between the second electrode and the withstand voltage dielectric member An auxiliary dielectric member is placed on the It is set to another, characterized in that.

  In such a configuration, the auxiliary dielectric member positioned between the second electrode and the withstand voltage dielectric member has a degree of adhesion of the reaction product on the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric member. The plasma is caused to flow into the chamber as usual by the first electrode through the pressure-resistant dielectric member due to at least one of the difference in dielectric constant, the difference in thickness, and the difference in arrangement density corresponding to the partial difference of The power from the second electrode is applied to the inner surface of the withstand voltage dielectric member and the adhesion of the partial reaction product to the inner surface of the withstand voltage dielectric member. Because it is weakened according to the difference with the amount of scraping, it works without excess or deficiency according to the difference between the degree of adhesion of the reaction product at each part to the inner surface of the withstand voltage dielectric member and the amount of scraping of the withstand voltage dielectric member The reaction product on the inner surface of the dielectric material is attached. The was sufficiently prevented in each section, moreover, scraping of the inner surface of the pressure-resistant dielectric member can be prevented partially often it becomes possible.

  According to the ninth aspect of the plasma etching apparatus of the present invention, the auxiliary dielectric member is made of a combination of materials such as quartz and mica, and a combination including air in a space area where no auxiliary dielectric member is provided. The difference is set.

  As a result, the partial dielectric constant difference can be set with a sufficient width and change range.

  According to the tenth aspect of the plasma etching apparatus of the present invention, the auxiliary dielectric member is formed of the slit-shaped high-frequency transmitting portion that is annular and is radially cut from the outer periphery with a predetermined interval and a width smaller than the interval. One of the slit outer peripheral body having a slit, a slit outer peripheral body having a slit-shaped high-frequency transmission section, and an annular high-frequency transmission section inside the slit outer peripheral body or the split outer peripheral body. A slit-free central body that has a slit-shaped high-frequency transmitting portion that is radially cut with a predetermined interval from the outer periphery and a width that is smaller than the predetermined interval, and a slit-shaped high-frequency body. It is characterized in that a difference in arrangement density is set as a combination with one of the divided central bodies having a transmission portion and divided in the circumferential direction.

  Accordingly, various arrangement modes in the circumferential direction and the radial direction of the auxiliary dielectric member can be selected to set various partial arrangement density differences. Here, the slit inserted in the auxiliary dielectric member transmits the high frequency radiated into the chamber from the first electrode, and has an effect of preventing the auxiliary dielectric member from preventing the high frequency transmission.

  According to the eleventh aspect of the plasma etching apparatus of the present invention, a chamber capable of decompression, a counter electrode provided inside the chamber and supporting an object to be processed, and an outside of a withstand voltage dielectric member forming a partition wall of the chamber. Provided between the first electrode and the pressure-resistant dielectric member, the first electrode for generating a plasma made of a reaction gas in the chamber and etching the workpiece supported by the counter electrode. And the second electrode for preventing the reaction product from adhering to the inner surface of the withstand voltage dielectric member, the second electrode is a reaction to the inner surface of the withstand voltage dielectric member. Another feature is that it is provided with a difference in arrangement density in accordance with a partial difference between the degree of adhesion of the product and the amount of abrasion of the withstand voltage dielectric member.

  In such a configuration, the second electrode has a difference in arrangement density according to a partial difference between the degree of adhesion of the reaction product to the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric member. Therefore, the first electrode generates plasma in the chamber with a uniform density distribution on the object to be processed side as in the conventional manner through the withstand voltage dielectric member, so that the second electrode does not disturb the uniform plasma etching. Is weakened according to the difference between the degree of adhesion of partial reaction products on the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric member, and the reaction at each part to the inner surface of the withstand voltage dielectric member Since it works without excess or deficiency depending on the difference between the degree of product adhesion and the amount of chipping of the dielectric material, it is possible to prevent the reaction product from adhering to the inner surface of the dielectric material sufficiently. In addition, the inner surface of the dielectric material is partially cut away. Many become such a thing is no longer in. Further, at a circumferential position where the second electrodes formed for setting the arrangement density of the second electrodes are not located, and at a radial position, the entire transmission efficiency is improved by high-frequency transmission from the first electrode into the chamber. Enhanced.

  According to the twelfth aspect of the plasma etching apparatus of the present invention, the second electrode has a slit-like high-frequency transmission part and a central part cut radially from the outer periphery with a predetermined interval and a width smaller than this interval. A single unit with a hole-shaped high-frequency transmitting part punched out, a slit-shaped high-frequency transmitting part cut radially with a predetermined interval from the outer circumference and a width smaller than this interval, and a hole shape punched out at the center A single unit having a high-frequency transmission part having a radially protruding piece facing the center part, a slit-like high-frequency transmission part and a central part cut radially from the outer periphery with a predetermined interval and a width smaller than this interval. Peripheral body with punched hole-shaped high-frequency transmission part, and a hole in this outer peripheral body with a gap to become an annular high-frequency transmission part, and has a predetermined interval from the outer periphery and a width smaller than this interval The The combination of that has a slit-shaped high-frequency transmitting portion cut into shape morphism central body, it is characterized by setting the difference between the arrangement density in either.

  As a result, various arrangement modes in the circumferential direction and the radial direction of the second electrode can be selected to set various partial arrangement density differences.

  According to the thirteenth aspect of the plasma etching apparatus of the present invention, the second electrode has a high-frequency transmission part opened in a window shape between the slit-like high-frequency transmission parts and sets a difference in arrangement density. It is characterized by being.

  As a result, the arrangement density in the circumferential direction of the second electrode is further weakened by the high-frequency transmission part opened in a window shape between the slit-like high-frequency transmission parts, and the high-frequency transmission from the first electrode into the chamber Increases efficiency.

  According to the fourteenth aspect of the plasma etching apparatus of the present invention, the single electrode having the slit-like high-frequency transmission part cut radially from the outer periphery with a predetermined interval and a width smaller than this interval is provided as the second electrode. The high-frequency transmission part of the second electrode is filled with a dielectric material.

  As a result, even if the second electrode has a conductor proximity portion due to the high frequency transmission portion, it is possible to prevent the dielectric material filling the second electrode from being discharged between the conductor proximity portion instead of an air gap. The dielectric is effective as part of the auxiliary dielectric.

  Therefore, according to the fifteenth aspect of the plasma etching apparatus of the present invention, the dielectric filling the high-frequency transmission part of the second electrode is a part of the withstand voltage dielectric member.

  This realizes that the high-frequency transmitting portion of the second electrode is filled with the dielectric by utilizing the configuration in which the second electrode faces the withstand voltage dielectric member, and the second electrode, the withstand voltage dielectric member, Can be handled integrally, and when the second electrode is divided and divided into a plurality of pieces, it can be integrally supported by the withstand voltage dielectric member. Further, when the auxiliary dielectric member according to the eighth to tenth aspects is provided, it can be used as a dielectric that fills the high-frequency transmission part of the second electrode, like the withstand voltage dielectric member.

  According to the sixteenth aspect of the plasma etching apparatus of the present invention, the second electrode is characterized by rotating or reciprocatingly rotating.

  As a result, the second electrode portion and the high-frequency transmission portion that are dispersed in the circumferential direction by setting the arrangement density of the second electrode are rotated or reciprocated by the second electrode. Since the transmission position of the high frequency from the electrode and the output position of the power from the second electrode are moved in the circumferential direction, the generation of plasma in the chamber by the first electrode and the withstand voltage dielectric member by the second electrode The adhesion of the reaction product to the inner surface of the resin can be made more uniform.

  According to the plasma etching apparatus of the present invention, the second electrode is attached to the inner surface of the withstand voltage dielectric member with the partial adhesion degree of the reaction product while ensuring uniform plasma etching by the uniform density distribution of the plasma. It works properly according to the difference in the amount of abrasion of the dielectric material, and prevents the reaction product from adhering to the inner surface of the dielectric material sufficiently. There is no possibility that the surface wear is partially increased and the pressure-resistant life is lowered early. In addition, the same power may be supplied from the same power source regardless of whether the second electrode is a single unit or divided, and the electrode height from the inner surface of the withstand voltage dielectric member of the second electrode, the arrangement density, The difference in the dielectric constant, thickness, and arrangement density of the dielectric members on the chamber side of the two electrodes does not cause a particularly complicated structure and does not cause an increase in cost.

  Hereinafter, embodiments of the plasma etching apparatus of the present invention will be described with reference to FIGS. However, the following description is a specific example of the present invention and does not limit the content of the claims.

  As shown in FIG. 1, the plasma etching apparatus of the present embodiment is capable of reducing the pressure, supplies the reaction gas 10 from the supply port 1a, and exhausts the exhaust gas 20 from the exhaust port 1b. A counter electrode 3 that is provided and supports the object to be processed 2 and a withstand voltage dielectric member 5 that forms a partition wall of the chamber 1. A plasma 6 from the reaction gas 10 is generated in the chamber 1 to generate a plasma on the counter electrode 3. A first electrode 4 that causes the workpiece 2 to perform plasma processing such as etching, and an inner surface 5a of the withstand voltage dielectric member 5 provided between the first electrode 4 and the withstand voltage dielectric member 5. And the second electrode 7 for preventing the reaction product from adhering. Here, the first electrode 4 is an inductive coupling coil (ICP coil), forms a high frequency antenna, and generates a plasma 6 in the chamber 1 through a pressure-resistant dielectric member 5, and this plasma 6 is on the counter electrode 3. Plasma treatment such as etching is performed by acting on the surface of the workpiece 2. The second electrode 7 is a Faraday shield electrode (FS electrode), which forms a uniform electric field along the inner surface 5a of the withstand voltage dielectric member 5 and adheres reaction products generated during plasma processing. To prevent.

  For such a plasma treatment process, a high frequency is supplied to the counter electrode 3 from the power supply 15 via the variable capacitor 16 so that the plasma 6 is moved to the workpiece 2 side. The first electrode 4 is supplied with high-frequency power from a power source 11 via a variable capacitor 12 so that plasma processing can be performed at a predetermined etch rate. Further, the first electrode 4 is adjusted so that the plasma 6 is generated with a uniform distribution on the surface of the workpiece 2 including the three-dimensional arrangement as shown in FIG. Is uniformly plasma-treated at the set etching rate. The high frequency is generally 30 kHz to 300 GHz, while the high frequency range applied to the plasma generator is a narrow range of about 3 to 30 MHz called HF. The second electrode 7 is supplied with a high frequency similar to that of the first electrode 4 from the power source 13 via the variable capacitor 14 or a low frequency lower than the first electrode 4, and by adjusting the variable capacitor 14, It is possible to prevent the reaction product from adhering to the inner surface 5a.

  Here, as shown in FIG. 1, the power source 11 is connected to the first electrode 4 and the power source 13 is connected to the second electrode 7 separately. The two electrodes 7 may be connected in parallel to the same high-frequency power source via a variable choke or a variable capacitor (not shown). Alternatively, as shown in FIG. 29, a power source 11 is connected to the first electrode 4, a variable choke or a variable capacitor is connected to the second electrode 7, and the power oscillated from the power source 11 is supplied to the first electrode. The electric power ratio applied to each of the first electrode 4 and the second electrode 7 may be adjusted with a variable choke or a variable capacitor.

  However, as described above, the generation of the plasma 6 due to the action of the first electrode 4 can be controlled to have a uniform distribution on the surface of the workpiece 2, but the inner surface 5 a of the withstand voltage dielectric member 5. Below, the distribution tends to be biased such that the distribution at the center is higher than that at the periphery. On the other hand, the strength of the electric field formed along the inner surface 5 a of the withstand voltage dielectric member 5 by the action of the second electrode 7 can be adjusted by the variable capacitor 14. Since it is uniform along the surface 5a, the balance between the action of the plasma 6 and the action of the electric field on the inner surface 5a of the withstand voltage dielectric member 5 cannot be taken as it is. For this reason, partial adhesion of reaction products and partial shaving of the inner surface 5a of the withstand voltage dielectric member 5 occur.

  Therefore, in the present embodiment, the strength of the electric field formed on the surface of the inner surface 5a of the withstand voltage dielectric member 5 by the second electrode 7 is changed from the inner surface 5a of the withstand voltage dielectric member 5 of the second electrode 7. Therefore, the electrode distance L2 is set according to the difference between the reaction product adhesion degree on the inner surface 5a of the withstand voltage dielectric member 5 and the scraping amount of the withstand voltage dielectric member 5. As described above, the electrode distance L2 from the inner surface 5a of the second dielectric layer 7 to the inner surface 5a of the second dielectric layer 7 is determined by the degree of adhesion of the reaction product to the inner surface 5a of the dielectric layer 5 and the abrasion of the dielectric member 5. By setting in accordance with the partial difference from the amount, the plasma is caused to flow into the chamber 1 by the first electrode 4 via the withstand voltage dielectric member 5 with a uniform density distribution on the workpiece 2 as usual. Generation of reaction at each part to the inner surface 5a of the withstand voltage dielectric member 5 with attenuation corresponding to the electrode distance L2 of the power from the second electrode 7 without disturbing the generation of uniform plasma etching. Depending on the difference between the degree of adhesion of the object and the amount of shaving of the proof dielectric member 5, it works without excess and deficiency, sufficiently preventing the reaction products on the inner surface 5 a of the proof dielectric member 5 from adhering to each part, and The internal surface of the dielectric material member 5 is partially cut away Kunar such a thing is eliminated.

  As a result, the partial adhesion of the reaction product to the inner surface 5a of the withstand voltage dielectric member 5 and the withstand voltage dielectric are ensured while ensuring uniform plasma etching by the uniform density distribution of the plasma 6. Depending on the difference in the amount of scraping of the member 5, it works without excess or deficiency, and sufficiently prevents the reaction product from adhering to the inner surface 5 a of the withstand voltage dielectric member 5. The inner surface 5a is not partially scraped and the pressure-resistant life is not lowered early. Further, the same power may be supplied from the same power source 13 regardless of whether the second electrode 7 is a single body or divided, and the electrode distance L2 from the inner surface 5a of the withstand voltage dielectric member 5 of the second electrode 7. By giving a partial difference to the structure, the structure is not particularly complicated and does not cause an increase in cost.

  Specifically, in the example of FIG. 1, the electrode distance L <b> 2 is greater in the central portion than in the peripheral portion in contrast to the general tendency that the central portion of the inner surface 5 a of the withstand voltage dielectric member 5 is scraped more than the peripheral portion. We cope by making it larger. As a matter of course, when the shaving amount of the peripheral part of the dielectric material member 5 is larger than that of the central part, the electrode distance L2 can be dealt with by making the peripheral part larger than the central part. . In this way, even if the distribution of the difference between the degree of adhesion of the reaction product and the amount of scraping of the refractory dielectric member 5 is unbalanced, the electrode distance L2 that is inversely proportional to the distribution can be set. It should be noted that the electrode distance L2 may be partially different between the opposing regions of the second electrode 7 and the inner surface 5a of the withstand voltage dielectric member 5 even on the second electrode 7 side alone as in the example of FIG. The voltage-resistant dielectric member 5 can be used alone or both. The first electrode 4 also has a uniform density distribution on the surface of the workpiece 2 by setting the electrode distance L1 from the inner surface 5a of the withstand voltage dielectric member 5 to be small from the central portion to the peripheral portion. I am doing so. However, it is not limited to this.

  Correspondingly, the outer surface 5b of the withstand voltage dielectric member 5 conforms to the solid form of the second electrode 7 as shown in FIG. 2 or approximated by stacking as shown in the example of FIG. It can be in the form. As a result, the withstand voltage dielectric member 5 uses the space between the three-dimensional second electrode 7 to increase the thickness where the electrode distance L2 is large compared to the small area where the dielectric distance as shown in FIG. From the relationship between the body thickness and the etch rate, it is useful for the operation of the plasma etching uniformity by the first electrode 4 and also affects the power of the reaction preventive action of the reaction product by the second electrode 7. Where the electrode distance L2 is large, it is weaker than that where the electrode distance L2 is small, and the withstand voltage tolerance against scraping can be increased compared with the case where the thickness of the dielectric material member 5 is large where the electrode distance L2 is large.

  In the example shown in FIG. 4, the electrode distance L2 is set by the flat form of the second electrode 7 and the three-dimensional form of the inner surface 5a of the withstand voltage dielectric member 5, and the withstand voltage dielectric shown in FIGS. The second electrode 7 can be left as a flat plate by performing the same function as the member 5. Of course, the combination of the three-dimensional second electrode 7 in the example of FIGS. 2 and 3 and the withstand voltage dielectric member 5 having the three-dimensional inner surface 5a shown in FIG. You may make it give. This makes it easier to set a more complicated electrode distance L2. Further, there is an advantage that the required three-dimensionality of the second electrode 7 and the withstand voltage dielectric member 5 can be reduced.

  For example, as shown in FIGS. 6 to 17, the second electrode 7 has a partial difference between the adhesion degree of the reaction product on the inner surface 5 a of the withstand voltage dielectric member 5 and the shaving amount of the withstand voltage dielectric member 5. Accordingly, it can be provided with a difference in arrangement density. As described above, the second electrode 7 has a difference in arrangement density corresponding to a partial difference between the adhesion degree and the shaving amount of the withstand voltage dielectric member 5, so that the power by the second electrode 7 can withstand the withstand voltage. Since the working of the reaction product on the inner surface 5a of the dielectric member 5 and the amount of scraping of the withstand voltage dielectric member 5 work in accordance with a partial difference, it works on the inner surface 5a of the withstand voltage dielectric member 5. The reaction product is sufficiently prevented from adhering to each part, and the inner surface 5a of the refractory dielectric member 5 is not partially scraped. Further, at the circumferential position and the radial position where the second electrodes 7 formed for setting the arrangement density of the second electrodes 7 are not located, the entire structure is transmitted by high-frequency transmission from the first electrode 4 into the chamber 1. Can improve the transmission efficiency.

  Specifically, the second electrode 7 in the example of FIG. 6 has a slit-like high-frequency transmitting portion 7a cut radially and having a predetermined interval from the outer periphery and a width smaller than this interval, and a center portion is punched out. The second electrode 7 in each example shown in FIGS. 7, 8, and 9 has a predetermined interval from the outer periphery and a width smaller than this interval. An outer peripheral body 7d having a slit-shaped high-frequency transmitting portion 7a cut radially and a hole-shaped high-frequency transmitting portion 7b punched out at the center, and a ring-shaped high-frequency transmitting portion 7b of the outer peripheral body 7d. This is a combination of a central body 7f having a slit-shaped high-frequency transmitting portion 7a that is arranged with a gap to become a portion 7e and is radially cut from the outer periphery with a predetermined interval and a width smaller than this interval. . However, in order to adjust the arrangement density, a hole having a central portion as shown in FIG. 10 is used, and a radial projecting piece facing the central portion formed by a slit from the hole portion toward the peripheral portion is used. A single pattern having the high-frequency transmission part 7a may also be included. Various arrangement modes in the circumferential direction and radial direction of the second electrode 7 can be selected to set various partial arrangement density differences. Further, as shown in each example of FIGS. 14 to 16, there is a high-frequency transmission portion 7 g opened in a window shape between the slit-like high-frequency transmission portions 7 a in the second electrode 7, and a difference in arrangement density is set. Further, the arrangement density in the circumferential direction of the second electrode 7 is further weakened by the window-like high-frequency transmission part 7g between the slit-like high-frequency transmission parts 7a, and the high-frequency chamber from the first electrode 4 is reduced. The transmission efficiency into 1 can be increased.

  In particular, in each example shown in FIGS. 11 to 16, the high-frequency transmission portions 7 a, 7 b, 7 e, and 7 g formed with the various patterns described above are represented by cross-sections as represented by FIGS. 11B and 14B. As shown, it is filled with dielectrics 21 and 22. As a result, even if the second electrode 7 has a conductor proximity portion due to the high-frequency transmission portions 7a, 7b, 7e, and 7g, it is prevented from being discharged between the conductor proximity portions instead of an air gap due to the dielectric filling it. can do. Note that, when the second electrode 7 is divided into a plurality of pieces, the voltage application to the second electrode 7 may be divided according to the division.

  By the way, it can also have a distance adjusting means for adjusting the electrode distance L2, such as the screw 23 shown in the example of FIG. 17 and the example of FIG. As a result, even when the adhesion of the reaction product to the inner surface 5a of the withstand voltage dielectric member 5 is not constant depending on the plasma processing conditions, the electrode distance L2 is partially adjusted correspondingly. Can do. In the example of FIG. 17, the second electrode 7 is the divided body type described above, and the outer peripheral body 7 d and the central body 7 f are individually adjusted up and down by the individual screws 23 and 23, so that the mutual electrode distance L2 can be changed relatively. However, depending on the arrangement density pattern, as shown in FIG. 18, the outer periphery is fixed and the inner periphery can be moved up and down without difficulty by the screw 23, so that the relationship of the electrode distance L <b> 2 from the central portion to the peripheral portion is relatively It can be changed continuously. Further, in the case of the second electrodes 7 having an arrangement density pattern as shown in FIG. 6, although not shown, the central portion is fixed and the peripheral portion can be moved up and down without difficulty with a screw. The relationship of the electrode distance L2 can be changed relatively continuously.

  Further, the second electrode 7 can be rotated in one direction as shown by an arrow in the drawing, or can be rotated in a reciprocating arc. As a result, the high-frequency transmission portions 7a, 7b, 7e, and 7g are formed to be dispersed in the circumferential direction as described above by setting the arrangement density of the second electrodes 7, but the dispersion is performed by rotation or reciprocating arc rotation. By moving the position and moving the high-frequency transmission position in the circumferential direction, it is possible to make the generation of plasma in the chamber 1 and the prevention of adhesion of the reaction product to the inner surface 5a of the withstand voltage dielectric member 5 more uniform.

  Further, as representatively shown in the examples of FIGS. 19 to 21, a partial difference between the adhesion degree of the reaction product on the inner surface 5 a of the withstand voltage dielectric member 5 and the shaving amount of the withstand voltage dielectric member 5. The auxiliary dielectric member 31 is disposed between the second electrode 7 and the withstand voltage dielectric member 5 so as to have at least one of a difference in dielectric constant and a difference in arrangement density. it can. The difference in dielectric constant according to the partial difference between the degree of adhesion of the reaction product on the inner surface 5a of the withstand voltage dielectric member 5 of the auxiliary dielectric member 31 and the amount of abrasion of the withstand voltage dielectric member 5, and the arrangement Due to at least one of the density differences, the plasma is generated in the chamber 1 by the first electrode 4 via the proof dielectric member 5 in the chamber 1 with a uniform density distribution on the workpiece 2 side as in the past, and thus uniform plasma. Without interfering with the etching, the power from the second electrode 7 is weakened according to the difference between the degree of adhesion of the partial reaction product on the inner surface 5a of the withstand voltage dielectric member 5 and the amount of abrasion of the withstand voltage dielectric member 5. In addition, since it works in accordance with the difference between the degree of adhesion of the reaction product at each part to the inner surface 5a of the withstand voltage dielectric member 5 and the amount of abrasion of the withstand voltage dielectric member 5, the withstand voltage dielectric member 5 In each part, the reaction product of the inner surface 5a adheres. Preventing the minute, moreover, the scraping of the inner surface 5a of the pressure-resistant dielectric member 5 is partially many becomes like that is eliminated.

  Here, the auxiliary dielectric member 31 can set a partial dielectric constant difference by a combination of materials such as quartz and mica and a combination including an air layer in a space area where the auxiliary dielectric member 31 is not provided. As a result, the partial dielectric constant difference can be set with a sufficient width and change range.

  Specifically, the dielectric constant of mica is 7.0 kε, that of quartz is 3.8 kε, and that of air is 1.00054 kε. In the example shown in FIG. 19 using such a difference, the outer peripheral body 31a is made of quartz in the outer peripheral body 31a and the central body 31c in which the annular high frequency transmission portion 31b is arranged inside thereof. The central body 31c is mica. Thereby, the density distribution on the side of the withstand voltage dielectric member 5 of the plasma 6 due to capacitive coupling is lowered at the center portion, which is suitable for preventing the center portion of the inner surface 5a of the withstand voltage dielectric member 5 from being scraped. In the example of FIG. 20, the density distribution in the central portion of the plasma 6 is further suppressed in the combination in which the outer circumferential body 31 a is omitted and the central body 31 c is mica. In the example shown in FIG. 21, the density distribution at the periphery of the plasma 6 is centered by the combination of the outer peripheral body 31a made of mica and the air layer from which the central body 31c is omitted, contrary to the examples in FIGS. It becomes suitable for suppressing the abrasion in the peripheral part in the inner surface 5a of the pressure | voltage resistant dielectric member 5 by making it lower than a part.

  Note that it is preferable that the auxiliary dielectric member 31 has the same pattern of the high-frequency transmission portion 31 b together with the second electrode 7 under the condition setting that the high-frequency transmission from the first electrode 4 is not disturbed. Therefore, the combination of the second electrode 7 having the outer peripheral body 7d and the central body 7f in the example shown in FIGS. 8 and 9 without the dielectrics 21 and 22 as described above is better. The auxiliary dielectric member 31 having an arrangement density pattern corresponding to the high-frequency transmitting portions 7a, 7b, 7e, and 7g may be used. Therefore, as shown in FIG. 22 and FIG. 23, the outer peripheral body 31a having a slit and the slit-shaped outer peripheral body 31a having a slit-like high-frequency transmitting portion 31d radially cut with a predetermined interval from the outer periphery and a width smaller than this interval. The outer peripheral body 31a is divided in the circumferential direction with a ring-shaped high-frequency transmitting portion 31d, and the annular high-frequency transmitting portion 31b described above is provided inside the outer peripheral body 31a having slits or the outer peripheral body 31a. A slit-free central body 31c as shown in FIGS. 22 and 25, a slit shape cut radially from the outer periphery as shown in FIGS. 23 and 26 with a predetermined interval and a width smaller than this interval. Slit central body 31c having a high-frequency transmitting portion 31d, and a split central body 3 having a slit-shaped high-frequency transmitting portion 31d as shown in FIGS. As one of the combinations of c, it may be set the difference in arrangement density. Accordingly, various arrangement modes in the circumferential direction and the radial direction of the auxiliary dielectric member 31 can be selected to set various partial arrangement density differences.

  Here, the dielectrics 21 and 22 shown in FIGS. 11 to 16 filling the already described high-frequency transmitting portions 7a, 7b, 7e, and 7g of the second electrode 7 are the withstand voltage dielectric member 5 and the auxiliary dielectric. It can be a part of the member 31. Therefore, the high-frequency transmission portions 7a, 7b, 7e, and 7g of the second electrode 7 are made of the dielectrics 21 and 22 by using the configuration in which the second electrode 7 faces the withstand voltage dielectric member 5 and the auxiliary dielectric member 31. In addition, the second electrode 7 and the withstand voltage dielectric member 5 and the auxiliary dielectric member 31 can be handled integrally, and the withstand voltage dielectric when the second electrode 7 is divided and divided into a plurality of parts. The member 5 and the auxiliary dielectric member 31 can be integrally supported.

  In the plasma etching apparatus using the plasma electrode and the reaction product adhesion preventing electrode, the inner surface of the withstand voltage dielectric member can be partially scraped without impairing uniform plasma etching and adhesion prevention. Can be suppressed.

It is sectional drawing which shows one example of schematic structure of the plasma etching apparatus of embodiment which concerns on this invention. It is sectional drawing of the principal part which shows another example of schematic structure of the plasma etching apparatus of embodiment which concerns on this invention. It is sectional drawing of the principal part which shows the other example of schematic structure of the plasma etching apparatus of embodiment which concerns on this invention. It is sectional drawing of the principal part which shows another example of schematic structure of the plasma etching apparatus of embodiment which concerns on this invention. It is a graph which shows the relationship between the thickness of a dielectric material, and an etch rate. It is a top view which shows one example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 1st example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 2nd example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 3rd example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 4th example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 5th example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 6th example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 7th example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 8th example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 9th example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 10th example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 11th example of the 2nd electrode applied to the apparatus shown in FIGS. It is a top view which shows the 12th example of the 2nd electrode applied to the apparatus shown in FIGS. It is sectional drawing of the principal part which shows another example of schematic structure of the plasma etching apparatus of embodiment which concerns on this invention. It is sectional drawing of the principal part which shows another example of schematic structure of the plasma etching apparatus of embodiment which concerns on this invention. It is sectional drawing of the principal part which shows the further another example of schematic structure of the plasma etching apparatus of embodiment which concerns on this invention. It is a top view which shows the 1st example of the auxiliary dielectric member applied to the apparatus shown in FIGS. It is a top view which shows the 2nd example of the auxiliary dielectric member applied to the apparatus shown in FIGS. It is a top view which shows the 3rd example of the auxiliary dielectric member applied to the apparatus shown in FIGS. It is a top view which shows the 4th example of the auxiliary dielectric member applied to the apparatus shown in FIGS. It is a top view which shows the 5th example of the auxiliary dielectric member applied to the apparatus shown in FIGS. It is sectional drawing which shows the schematic structural example of the conventional plasma etching apparatus. It is explanatory drawing which shows the plasma generation | occurence | production state in a conventional apparatus, the reaction product adhesion state, and the abrasion state of the pressure | voltage resistant dielectric material member. It is sectional drawing of the principal part which shows the other example of the electric power application method to the 2nd electrode of schematic structure of the plasma etching apparatus of embodiment which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chamber 2 To-be-processed object 3 Counter electrode 4 1st electrode 5 Withstand voltage dielectric member 5a Inner surface 5b Outer surface 6 Plasma 7 2nd electrode 7a, 7b, 7e, 7g High frequency permeation | transmission part 7d Outer peripheral body 7f Central body 11, 13, 15 Power source 12, 14, 16 Variable capacitor 21, 22 Dielectric 23 Screw 31 Auxiliary dielectric member 31a Peripheral body 31c Central body 31b, 31d High frequency transmission part

Claims (16)

A chamber capable of depressurization, a counter electrode provided inside the chamber for supporting an object to be processed, and a pressure-resistant dielectric member that forms a partition wall of the chamber; A first electrode that etches the object to be processed supported by the counter electrode, and a reaction product is provided between the first electrode and the withstand voltage dielectric member and adhered to the inner surface of the withstand voltage dielectric member. In the plasma etching apparatus provided with the second electrode for preventing the
The electrode distance of the second electrode from the inner surface of the withstand voltage dielectric member depends on a partial difference between the degree of adhesion of the reaction product to the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric. A plasma etching apparatus characterized in that it is set. 2. The plasma etching apparatus according to claim 1, wherein the electrode distance is set such that the central portion is larger than the peripheral portion, or the peripheral portion is larger than the central portion. The plasma etching apparatus according to any one of claims 1 and 2, wherein the electrode distance is set by a flat inner surface of the withstand voltage dielectric member and a three-dimensional form of the second electrode. 4. The plasma etching apparatus according to claim 3, wherein an outer surface of the withstand voltage dielectric member has a three-dimensional form that conforms to or approximates the three-dimensional form of the second electrode. The plasma etching apparatus according to any one of claims 1 and 2, wherein the electrode distance is set by a flat form of the second electrode and a three-dimensional form of the inner surface of the withstand voltage dielectric member. 3. The plasma etching apparatus according to claim 1, further comprising a distance adjusting unit that adjusts a difference in electrode distance in each opposed region between the second electrode and the inner surface of the withstand voltage dielectric member. . The plasma etching apparatus according to claim 6, wherein the distance adjusting unit changes the partial height of the second electrode as a single unit or changes relative to each divided body. A chamber capable of depressurization, a counter electrode provided inside the chamber for supporting an object to be processed, and a plasma made of a reactive gas in a chamber provided outside a pressure-resistant dielectric member forming a partition wall of the chamber; A reaction product adheres to the inner surface of the first dielectric electrode that is provided between the first electrode that etches the workpiece supported by the counter electrode and the first electrode and the dielectric dielectric member. In the plasma etching apparatus provided with the second electrode for preventing
At least one of a difference in permittivity, a difference in thickness, and a difference in arrangement density according to a partial difference between the degree of adhesion of the reaction product to the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric And an auxiliary dielectric member is disposed between the second electrode and the withstand voltage dielectric member. 9. The plasma etching apparatus according to claim 8, wherein the auxiliary dielectric member sets a difference in dielectric constant including a difference in materials such as quartz and mica, and air in a space region where no auxiliary dielectric member is provided. The auxiliary dielectric member is a ring-shaped outer peripheral body having a slit-like high-frequency transmission portion that is annular and has a slit-like high-frequency transmission portion that is radially cut with a predetermined interval from the outer periphery and a width smaller than this interval, and has a slit-like high-frequency transmission portion. Then, one of the divided outer peripheral bodies divided in the circumferential direction, and a slit-free central body that is selectively disposed with the ring-shaped outer peripheral body or the inner periphery of the divided outer peripheral body and an annular high-frequency transmission part, predetermined from the outer periphery. And a slit central body having slit-like high-frequency transmission portions that are radially cut with a width smaller than this interval, and a split central body having slit-like high-frequency transmission portions and divided in the circumferential direction The plasma etching apparatus according to claim 8, wherein a difference in arrangement density is set as a combination with one of the above. A chamber capable of depressurization, a counter electrode provided inside the chamber for supporting an object to be processed, and a plasma made of a reactive gas in a chamber provided outside a pressure-resistant dielectric member forming a partition wall of the chamber; A first electrode that etches the object to be processed supported by the counter electrode, and a reaction product is provided between the first electrode and the withstand voltage dielectric member and adhered to the inner surface of the withstand voltage dielectric member. In the plasma etching apparatus provided with the second electrode for preventing the
The second electrode is provided with a difference in arrangement density according to a partial difference between the degree of adhesion of the reaction product to the inner surface of the withstand voltage dielectric member and the amount of abrasion of the withstand voltage dielectric member. A plasma etching apparatus. The second electrode is a single unit having a slit-shaped high-frequency transmitting portion cut radially with a predetermined interval from the outer periphery and a width smaller than this interval, and a hole-shaped high-frequency transmitting portion punched out from the center portion, A slit-shaped high-frequency transmitting portion cut radially with a predetermined interval from the outer periphery and a width smaller than this interval, and a high-frequency transmitting portion having a radial protruding piece toward the center in the shape of a hole punched out from the center A single body having a slit, a slit-shaped high-frequency transmitting portion cut radially with a predetermined interval from the outer periphery and a width smaller than this interval, and an outer peripheral body having a hole-shaped high-frequency transmitting portion punched out from the center portion, and this A center having a slit-shaped high-frequency transmitting portion that is arranged in a hole of the outer peripheral body with a gap to be an annular high-frequency transmitting portion and is radially cut from the outer periphery with a predetermined interval and a width smaller than this interval. The plasma etching apparatus of claim 11 in combination thereof, is set a difference in arrangement density in one of the. The plasma etching apparatus according to claim 12, wherein the second electrode has a high-frequency transmission part that opens in a window shape between the slit-shaped high-frequency transmission parts, and sets a difference in arrangement density. A single electrode having a slit-shaped high-frequency transmission portion cut radially from the outer periphery with a predetermined interval and a width smaller than the predetermined interval is included in the selection target of the second electrode, and the high-frequency transmission portion of the second electrode The plasma etching apparatus according to claim 12, which is filled with a dielectric. The plasma etching apparatus according to claim 14, wherein the dielectric filling the high-frequency transmission part of the second electrode is a part of the withstand voltage dielectric member. The plasma etching apparatus according to claim 12, wherein the second electrode rotates or reciprocates.

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