Substrate-processing apparatus

Abstract

A substrate-processing apparatus (100) comprises: a processing chamber (10); a base (21) which is disposed in the processing chamber and to which high-frequency power is applied; an electrostatic chuck (22) on which a substrate (1) is mounted; a first ring member (71) which is formed in an annular shape so as to cover, from above, the circumferential edge of the substrate mounted on the electrostatic chuck, and which is disposed above and separated from the substrate; a second ring member (23b) which is disposed so as to overlap the first ring member in a plan view, is disposed below the substrate, and is formed in an annular shape so as to surround the electrostatic chuck; and a third ring member (23a) which is formed in an annular shape so as to surround the electrostatic chuck, and which is disposed below the first ring member. The second ring member is formed of a material having a dielectric constant lower than that of the third ring member.

Description

Substrate processing equipment

[0001] This invention relates to a substrate processing apparatus, and more particularly to a substrate processing apparatus that processes a substrate using plasma.

[0002] Conventionally, substrate processing apparatuses that process substrates using plasma are known. Such substrate processing apparatuses are disclosed, for example, in Japanese Patent Publication No. 4616605.

[0003] Japanese Patent Publication No. 4616605 discloses a plasma processing apparatus (substrate processing apparatus) comprising a processing vessel, a mounting table disposed inside the processing vessel to which high-frequency power is applied, and an electrostatic chuck disposed on the mounting table on which a substrate to be plasma processed is placed. Furthermore, the plasma processing apparatus of Japanese Patent Publication No. 4616605 is provided with a focus ring that surrounds the substrate and the electrostatic chuck in a plan view, and is used to mitigate the difference between the central and peripheral portions of the in-plane bias potential of the substrate.

[0004] Patent No. 4616605

[0005] In the substrate processing apparatus described in the above-mentioned Japanese Patent Publication No. 4616605, a gap is created between the focus ring and the substrate. As a result, plasma enters the gap between the focus ring and the substrate, and products resulting from the plasma that enters the back surface of the substrate and the sides of the electrostatic chuck adhere to and accumulate there.

[0006] When deep etching of a silicon oxide film on a substrate is performed using a processing gas containing carbon and fluorine (CF-based processing gas), the plasma treatment needs to be performed for a longer time to accommodate the deeper etching. In this case, the amount of product deposited on the back surface of the substrate and on the electrostatic chuck also increases. After processing the substrate, chamber cleaning is performed to remove the deposited product by dry etching, but if the amount of deposited product is large, it may not be completely removed and some may remain. Therefore, it is desirable to suppress the deposition of plasma-induced products on the sides of the electrostatic chuck.

[0007] This invention was made to solve the above-mentioned problems, and one of its objectives is to provide a substrate processing apparatus that can suppress the deposition of plasma-induced products on the side surface of an electrostatic chuck.

[0008] To achieve the above objective, a substrate processing apparatus according to one aspect of the present invention comprises: a processing chamber; a base disposed within the processing chamber to which high-frequency power is applied; an electrostatic chuck disposed on the base on which a substrate to be plasma processed is placed; a first ring member formed in an annular shape so as to cover the peripheral edge of the substrate placed on the electrostatic chuck from above in a plan view, and positioned above and spaced apart from the substrate; a second ring member positioned so as to overlap the first ring member in a plan view, positioned below the substrate, and formed in an annular shape so as to surround the electrostatic chuck in a plan view; and a third ring member formed in an annular shape so as to surround the electrostatic chuck in a plan view, positioned below the first ring member, and covering the upper part of the second ring member, wherein the second ring member is made of a material with a lower dielectric constant than the third ring member.

[0009] In a substrate processing apparatus according to one aspect of the present invention, as described above, a first ring member is provided that is formed in an annular shape so as to cover the peripheral edge of the substrate placed on the electrostatic chuck from above in a plan view, and is positioned above and spaced apart from the substrate; a second ring member is positioned so as to overlap with the first ring member in a plan view, is positioned below the substrate, and is formed in an annular shape so as to surround the electrostatic chuck in a plan view; and a third ring member is formed in an annular shape so as to surround the electrostatic chuck in a plan view, is positioned below the first ring member, and covers the top of the second ring member. Furthermore, the second ring member is made of a material with a lower dielectric constant than the third ring member. As a result, the peripheral edge of the substrate can be covered by the first ring member, so that even if there is a gap around the outer circumference of the electrostatic chuck on which the substrate is placed, plasma can not enter the gap. In addition, the second ring member surrounding the electrostatic chuck can reduce the gap around the outer circumference of the electrostatic chuck, so this can also suppress plasma from entering the gap. Furthermore, by forming the second ring member from a material with a relatively low dielectric constant, the combined capacitance of the region where the second ring member is located in a plan view can be reduced. As a result, the bias potential acting on the region where the second ring member is located can be made less effective. This suppresses the attraction of plasma to the second ring member, thus preventing plasma from entering the gap between the second ring member and the electrostatic chuck. As a result, the accumulation of plasma-induced products on the side surface of the electrostatic chuck can be suppressed. This prevents abnormalities in substrate adsorption, such as leakage of He gas (a cooling gas for the substrate) from the back surface of the substrate due to weakened adsorption force of the substrate pushed from below by the accumulated deposits, caused by the accumulation of products on the electrostatic chuck. In addition, the time required to remove accumulated products from the side surface of the electrostatic chuck by dry etching cleaning of the processing chamber between substrate processing can be reduced. As a result, a decrease in processing efficiency can be suppressed when processing multiple substrates continuously.Furthermore, the bias potential can be made less effective on the first ring member that overlaps the second ring member, thereby suppressing the action of the plasma. As a result, it is possible to suppress the generation of particles by etching reaction products generated on the surface of the first ring member by reaction with radicals in the plasma due to collisions with ions in the plasma. This suppresses the scattering of plasma-derived products from the first ring member onto the substrate. In addition, since the bias potential is less effective in the region where the second ring member is positioned in a plan view, the bias potential can be made more effective on the substrate side, thereby improving the processing rate of etching and other processes on the substrate.

[0010] In the substrate processing apparatus according to the first aspect described above, preferably, the first ring member is formed to cover the peripheral edge of the substrate with a width of 1 mm to 10 mm in plan view. With this configuration, by covering the peripheral edge of the substrate with the first ring member by 1 mm or more, the gap outside the electrostatic chuck on which the substrate is placed can be effectively covered, thereby effectively suppressing plasma from entering the gap on the side of the electrostatic chuck. Furthermore, by covering the peripheral edge of the substrate with the first ring member by 10 mm or less, it is possible to prevent the width covering the peripheral edge of the substrate from becoming too large, thereby preventing the processing area of ​​the substrate from becoming excessively small.

[0011] In the substrate processing apparatus according to the first aspect described above, preferably, a recess for arranging the second ring member is formed on the inner circumference of the third ring member. With this configuration, the second ring member can be easily placed in the recess provided in the third ring member.

[0012] In the substrate processing apparatus according to the first aspect described above, preferably the second ring member is made of quartz (SiO ２ It is formed by ). With this configuration, the combined capacitance of the region where the second ring member is located in a plan view can be easily reduced.

[0013] In the substrate processing apparatus according to the first aspect described above, preferably, a gas supply unit is further provided to supply a processing gas containing carbon and fluorine compounds to the processing chamber on which the base is provided. With this configuration, when dry etching is performed using a processing gas containing carbon and fluorine compounds (CF-based processing gas), the deposition of plasma-induced products on the side surface of the electrostatic chuck can be suppressed.

[0014] According to the present invention, as described above, it is possible to provide a substrate processing apparatus that can suppress the deposition of plasma-induced products on the side surface of the electrostatic chuck.

[0015] This is a schematic diagram showing the general configuration of a substrate processing apparatus. This is an enlarged cross-sectional view of the vicinity of the outer edge of a substrate placed in the substrate processing apparatus.

[0016] Embodiments of the present invention will be described below with reference to the drawings.

[0017] The substrate processing apparatus 100 of this embodiment will be described with reference to Figure 1.

[0018] (Substrate Processing Apparatus) The substrate processing apparatus 100 is a plasma processing apparatus that forms plasma in a processing chamber 10 and performs plasma processing on a substrate 1. The substrate 1 is a semiconductor wafer formed from a material such as silicon oxide, silicon, quartz glass, borosilicate glass, silicon carbide, gallium arsenide, or sapphire.

[0019] In this embodiment, in Figures 1 and 2, the vertical direction is defined as the Z direction, with the upward direction being the Z1 direction and the downward direction being the Z2 direction. Furthermore, the radial direction centered on the center of the substrate 1 in a plan view is defined as the R direction, with the outward direction from the center being the R1 direction and the direction toward the center being the R2 direction. Additionally, the circumferential direction centered on the center of the substrate 1 is defined as the θ direction, with the counterclockwise direction being the θ1 direction and the clockwise direction being the θ2 direction.

[0020] The substrate processing apparatus 100 comprises a processing chamber 10, a substrate mounting section 20, a gas supply device 30, a plasma generator 40, an exhaust device 50, a high-frequency power supply 60, and a protective member 70.

[0021] The processing chamber 10 has a closed space, and the substrate mounting section 20 is housed within this closed space. The processing chamber 10 consists of an upper chamber 11 and a lower chamber 12, which have interconnected internal spaces.

[0022] The substrate mounting section 20 has a mounting surface 20a on which the substrate 1 is placed. The substrate mounting section 20 has a disc shape and includes a base 21, an electrostatic chuck 22 installed on the base 21, and an annular member 23 surrounding the electrostatic chuck 22. The substrate mounting section 20 is provided to move up and down within the processing chamber 10 by a lifting cylinder 25. High-frequency power is applied to the base 21. The base 21 is made of aluminum. The electrostatic chuck 22 is made of aluminum oxide (alumina). The electrostatic chuck 22 is connected to an electrostatic adsorption power supply (not shown) that applies a voltage for electrostatic adsorption. When a voltage is applied to the electrostatic chuck 22, the substrate 1 is attracted to the mounting surface 20a, which is the upper surface of the electrostatic chuck 22, by electrostatic induction. Furthermore, the substrate mounting section 20 is provided with internal piping (not shown), and a chiller device (not shown) is attached to this internal piping to introduce a predetermined refrigerant and circulate the refrigerant while controlling its temperature (for example, to 40°C). This cools the substrate mounting section 20 during the plasma processing. In addition, during the plasma processing, cooling gas (an inert gas such as He gas) is supplied to the back surface of the substrate 1 from a predetermined cooling gas supply pipe (not shown) via an electrostatic chuck 22, thereby cooling the substrate 1.

[0023] When the substrate mounting section 20 is in the lowered position (see solid line) by the lifting cylinder 25, the substrate mounting section 20 moves below the protective member 70. When the substrate mounting section 20 moves to the raised position (see dashed line) by the lifting cylinder 25, the upper surface of the annular member 23 comes into contact with the lower surface of the protective member 70, and the protective member 70 covers the peripheral edge of the substrate 1 from above. The protective member 70 may also move up and down relative to the substrate mounting section 20.

[0024] As shown in Figure 2, the annular member 23 includes a ring member 23a and a quartz ring member 23b. The ring member 23a is formed in an annular shape so as to surround the electrostatic chuck 22 in a plan view. The ring member 23a is a single continuous member around its entire circumference. The ring member 23a is positioned below the ring member 71. In other words, the ring member 23a is positioned on the base side relative to the ring member 71. The ring member 23a is positioned so as to cover the top of the quartz ring member 23b. The ring member 23a is made of aluminum oxide (alumina). A recess 231a is formed on the inner circumference of the ring member 23a in which the quartz ring member 23b is positioned. Note that the ring member 23a is an example of the "third ring member" of the claims.

[0025] The quartz ring member 23b is made of quartz (SiO ２ It is formed of (dielectric constant: approximately 3.9). In other words, the quartz ring member 23b is formed of a material with a lower dielectric constant than the ring member 23a (alumina oxide (dielectric constant: approximately 10)). Furthermore, the quartz ring member 23b is formed in an annular shape so as to surround the electrostatic chuck 22 in a plan view. Furthermore, the quartz ring member 23b is a single continuous member around its entire circumference. Furthermore, the quartz ring member 23b is positioned so as to overlap with the ring member 71 in a plan view. Furthermore, the quartz ring member 23b is positioned below the substrate 1. In other words, the quartz ring member 23b is positioned on the opposite side of the substrate 1 from the ring member 71. Note that the quartz ring member 23b is an example of the "second ring member" in the claims.

[0026] Furthermore, the quartz ring member 23b is positioned in the recess 231a of the ring member 23a. That is, the radially outer side and the upper side of the quartz ring member 23b are covered by the ring member 23a. The lower side of the quartz ring member 23b abuts against the base 21. The radially inner side of the quartz ring member 23b faces the base 21 and the electrostatic chuck 22 with a gap between them. The quartz ring member 23b has a length L2, which is the radial width of the substrate 1. For example, the length L2 is between 5 mm and 60 mm. Also, the length L2 is greater than the length L1 of the width that the ring member 71 covers the peripheral edge of the substrate 1. Furthermore, in region A1 of the ring member 71 located inside (R2 direction) of the quartz ring member 23b (R1 direction) rather than on the radially outer side (R1 direction), the quartz ring member 23b reduces the combined capacitance of the ring member 71, ring member 23a, and quartz ring member 23b in the vertical direction (Z direction) of region A1. As a result, the bias potential becomes less effective. Therefore, plasma is less likely to be drawn in. Consequently, in region A1 of the ring member 71, it is possible to suppress the generation of particles by etching reaction products generated on the surface of the ring member 71 by reaction with radicals in the plasma due to collisions with ions in the plasma. In addition, because the quartz ring member 23b suppresses the drawing of plasma into region A1 of the ring member 71, more plasma can be drawn into the substrate 1 inside region A1, making it possible to perform plasma processing on the substrate 1 efficiently. In other words, it is possible to effectively improve the etching rate of the substrate 1.

[0027] Furthermore, the upper surface of the quartz ring member 23b is positioned above the interface between the base 21 and the electrostatic chuck 22 in the vertical direction. Alternatively, the upper surface of the quartz ring member 23b may be positioned at approximately the same location as or below the interface between the base 21 and the electrostatic chuck 22 in the vertical direction. The quartz ring member 23b also has a thickness of length L4 in the vertical direction (Z direction). For example, the length L4, which is the thickness of the quartz ring member 23b, is 2 mm or more and 6 mm or less. Preferably, the length L4 is 4 mm or more and 6 mm or less.

[0028] The gas supply device 30 supplies a processing gas (etching gas) into the processing chamber 10. The gas supply device 30 supplies C as an etching gas ４ F ８ gas supply unit 31 that supplies C ４ F ８ gas, and a C ２ F ６ gas supply unit 32 that supplies C ２ F ６ gas as an etching gas. Each gas supply unit is connected into the processing chamber 10 from the upper surface of the upper chamber 11 via a branched gas supply pipe 33. C ４ F ８ gas and C ２ F ６ gas are supplied into the processing chamber 10 via the supply pipe 33. That is, the gas supply device 30 supplies a processing gas of a compound containing carbon and fluorine (CF-based processing gas) into the processing chamber 10 provided with the base 21. Note that the gas supply device 30 is an example of the "gas supply unit" in the claims.

[0029] The plasma generation device 40 is a device that generates inductively coupled plasma (ICP) from the processing gas supplied into the processing chamber 10. The plasma generation device 40 includes a spiral coil 41 provided on the outer periphery of the upper chamber 11, and a high-frequency power source 42 that supplies high-frequency power to the coil 41. By supplying high-frequency power to the coil 41 from the high-frequency power source 42, the processing gas supplied into the upper chamber 11 is turned into plasma.

[0030] The exhaust device 50 reduces the pressure inside the processing chamber 10. The exhaust device 50 includes a vacuum pump 51 that exhausts gas inside the processing chamber 10, and an exhaust pipe 52 that connects the vacuum pump 51 to the inside of the processing chamber 10. The vacuum pump 51 exhausts the gas inside the processing chamber 10 via the exhaust pipe 52, bringing the inside of the processing chamber 10 to a predetermined pressure state close to vacuum.

[0031] The high-frequency power source 60 supplies high-frequency power for bias potential to the substrate mounting unit 20. The high-frequency power source 60 applies a bias potential between the substrate mounting unit 20 (the base 21) and the plasma by supplying high-frequency power to the base 21 of the substrate mounting unit 20.

[0032] The protective member 70 is positioned above the substrate mounting section 20 within the processing chamber 10. The protective member 70 has an annular shape and a flat plate shape. The protective member 70 is supported by a plurality of support columns 73 rising from an annular base portion.

[0033] As shown in Figure 2, the protective member 70 includes an annular ring member 71 and an annular support member 72 that detachably supports the outer peripheral end of the ring member 71. The ring member 71 is formed in an annular shape so as to cover the peripheral edge of the substrate 1, which is placed on the electrostatic chuck 22, from above in a plan view. The ring member 71 is a single continuous member around its entire circumference. The ring member 71 is also positioned above the upper surface of the substrate 1. Specifically, the ring member 71 is positioned on the opposite side of the substrate 1 from the electrostatic chuck 22 by a distance L3. For example, the length L3 is 0.2 mm or more and 1.2 mm or less. Preferably, the length L3 is about 0.3 mm. Note that the ring member 71 is an example of the "first ring member" of the claims.

[0034] The ring member 71 is made of aluminum oxide (alumina). The ring member 71 is formed to cover the peripheral edge of the substrate 1 with a width of length L1 in a plan view. For example, the length L1 is 1 mm or more and 10 mm or less. The inner end face of the ring member 71 is formed in a curved shape.

[0035] The support member 72 supports the ring member 71 from below. The support member 72 is formed in an annular shape. The outer circumference of the support member 72 is supported by a plurality of support columns 73 (see Figure 1).

[0036] In a substrate processing apparatus 100, in order to deeply etch the substrate 1 (for example, about 10 μm to 100 μm), the substrate 1 may be subjected to an etching process for a long time (for example, about 1 hour to 2 hours). In this case, when plasma acts on regions other than the substrate 1, products are more likely to be deposited on regions other than the substrate 1 due to the long processing time. For example, when plasma processing is performed using a CF-based gas, if plasma acts on a member made of aluminum oxide (alumina), aluminum fluoride (AlF) is generated and mixed with CF-based deposits and deposited. When removing the CF-based deposits mixed with the deposited aluminum fluoride by plasma processing using oxygen gas (a cleaning process in the processing chamber 10), it takes a long time (for example, 2 hours or more). In addition, if products are deposited on the electrostatic chuck 22 that adsorbs the substrate 1, if the deposits are not removed, a gap will be formed in the adsorption of the next substrate 1 to be processed, which easily causes problems such as leakage of cooling gas (for example, He gas).

[0037] Therefore, in the substrate processing apparatus 100 of the present embodiment, in order to prevent problems caused by plasma acting on regions other than the substrate 1, as described above, there are provided: an annular ring member formed to cover, from above, the peripheral edge portion of the substrate 1 placed on the electrostatic chuck 22 in a plan view, and disposed spaced apart upward from the substrate 1; a quartz ring member disposed overlapping the ring member in a plan view, disposed below the substrate 1, and formed in an annular shape so as to surround the electrostatic chuck 22 in a plan view; and an annular ring member formed in an annular shape so as to surround the electrostatic chuck 22 in a plan view, disposed below the ring member and covering an upper portion of the quartz ring member. The quartz ring member is formed of a material having a lower dielectric constant than that of the ring member.

[0038] (Effects of the Present Embodiment) In the present embodiment, the following effects can be obtained.

[0039] In this embodiment, as described above, a ring member 71 is formed in an annular shape to cover the peripheral edge of the substrate 1 placed on the electrostatic chuck 22 from above in a plan view, and is positioned spaced above the substrate 1; a quartz ring member 23b is positioned so as to overlap with the ring member 71 in a plan view, positioned below the substrate 1, and formed in an annular shape to surround the electrostatic chuck 22 in a plan view; and a ring member 23a is formed in an annular shape to surround the electrostatic chuck 22 in a plan view, positioned below the ring member 71, and covers the top of the quartz ring member 23b. Furthermore, the quartz ring member 23b is made of a material with a lower dielectric constant than the ring member 23a. As a result, the peripheral edge of the substrate 1 can be covered by the ring member 71, so that even if there is a gap on the outer circumference of the electrostatic chuck 22 on which the substrate 1 is placed, plasma can be prevented from entering the gap. Furthermore, the quartz ring member 23b surrounding the electrostatic chuck 22 reduces the gap around the outer circumference of the electrostatic chuck 22, thereby suppressing plasma from entering the gap. Additionally, by forming the quartz ring member 23b from a material with a relatively low dielectric constant, the combined capacitance of the region where the quartz ring member 23b is located in a plan view can be reduced. As a result, the bias potential acting on the region where the quartz ring member 23b is located can be made less effective. This suppresses the attraction of plasma to the quartz ring member 23b, thus suppressing plasma from entering the gap between the quartz ring member 23b and the electrostatic chuck 22. As a result, the accumulation of plasma-induced products on the side surface of the electrostatic chuck 22 can be suppressed. This prevents abnormal adsorption of the substrate 1, such as leakage of He gas (the cooling gas for the substrate 1) from the back surface of the substrate 1, due to the weakening of the adsorption force of the substrate 1 being pushed from below by the accumulated products on the electrostatic chuck 22. Furthermore, by cleaning the processing chamber 10 between substrate processing cycles using dry etching, it is possible to suppress the time required to remove the product deposited on the side surface of the electrostatic chuck 22. As a result, when processing multiple substrates 1 continuously, it is possible to suppress a decrease in processing efficiency.Further, also for the ring member 71 overlapping the quartz ring member 23b, the bias potential can be made less likely to act, so that the action of plasma can be suppressed. As a result, it is possible to suppress the generation of particles caused by etching of reaction products generated by reaction with radicals in plasma on the surface of the ring member 71 due to collision of ions in the plasma. Accordingly, scattering of products caused by plasma from the ring member 71 onto the substrate 1 can be suppressed. Further, since the bias potential is less likely to act on the region where the quartz ring member 23b is arranged in plan view, the bias potential can be made more likely to act on the substrate 1 side, so that the processing rate such as etching for the substrate 1 can be improved.

[0040] Furthermore, in the present embodiment, as described above, the ring member 71 is formed so as to cover the peripheral edge of the substrate 1 with a width of 1 mm or more and 10 mm or less in plan view. Accordingly, by covering the peripheral edge of the substrate 1 by 1 mm or more with the ring member 71, the gap outside the electrostatic chuck 22 on which the substrate 1 is placed can be effectively covered, so that plasma entering the gap on the side surface of the electrostatic chuck 22 can be effectively suppressed. Further, by covering the peripheral edge of the substrate 1 by 10 mm or less with the ring member 71, an excessive increase in the width covering the peripheral edge of the substrate 1 can be suppressed, so that an excessive reduction in the processing region of the substrate 1 can be suppressed.

[0041] Furthermore, in the present embodiment, as described above, a recess 231a in which the quartz ring member 23b is arranged is formed on the inner peripheral portion of the ring member 23a. Accordingly, the quartz ring member 23b can be easily arranged in the recess 231a provided in the ring member 23a.

[0042] Furthermore, in the present embodiment, as described above, the quartz ring member 23b is formed of quartz. Accordingly, the combined capacitance of the region where the quartz ring member 23b is arranged in plan view can be easily reduced.

[0043] Furthermore, in this embodiment, as described above, a gas supply device 30 is provided in the processing chamber 10 on which the base 21 is located to supply a processing gas containing carbon and fluorine compounds. This makes it possible to suppress the accumulation of plasma-induced products on the side surface of the electrostatic chuck 22 when dry etching is performed using a processing gas containing carbon and fluorine compounds (CF-based processing gas).

[0044] (Example) Next, we will describe an experiment (example) conducted to confirm the effect of plasma processing using the substrate processing apparatus of this embodiment.

[0045] In the experiments (Examples 1 and 2), the same substrate processing apparatus 100 was used to perform the same etching process with different widths of the ring member 71 covering the peripheral edge of the substrate 1. The leakage amount of cooling gas (He gas) was measured, and the presence or absence of deposits on the electrostatic chuck 22 was confirmed. In comparative examples 1 to 3, the etching process was performed with a configuration that did not include the ring member 71. The leakage amount of cooling gas (He gas) was measured, and the presence or absence of deposits on the electrostatic chuck 22 was confirmed.

[0046] In Examples 1 and 2, an annular member 23 was provided to surround the electrostatic chuck 22. In Examples 1 and 2, the annular member 23 consisted of a ring member 23a and a quartz ring member 23b. In Examples 1 and 2, a ring member 71 was provided to cover the peripheral edge of the substrate 1 from above.

[0047] An etching process was performed on the silicon oxide film obtained by thermal oxidation of a silicon wafer, which served as substrate 1, under the conditions shown in Table 1.

[0048] Furthermore, after the etching process, the inside of the processing chamber 10 was cleaned by dry etching under the conditions shown in Table 2.

[0049] The results shown in Table 3 were obtained in Examples 1 and 2 and Comparative Examples 1 to 3.

[0050] (Example 1) In Example 1, the width of the ring member 71 covering the peripheral edge of the substrate 1 was set to 4 mm. In Example 1, as shown in Table 3, in the processing of the first substrate 1, the amount of He leakage before processing was 5.15 (Pa / min), and the flow rate of He on the back surface before processing was within the appropriate range (normal). The processing was completed normally. Furthermore, there were no deposits on the edge of the back surface of the substrate after processing. Furthermore, the amount of He leakage before processing of the second substrate 1 after cleaning was 4.55 (Pa / min), and the flow rate of He on the back surface before processing was within the appropriate range (normal). Note that in Example 1, the second substrate 1 was not processed. Also, in Example 1, after cleaning (after only checking the substrate adsorption state with the second substrate unprocessed), there were no deposits on the electrostatic chuck 22 in the processing chamber 10.

[0051] (Example 2) In Example 2, the width of the ring member 71 covering the peripheral edge of the substrate 1 was set to 2 mm. In Example 2, as shown in Table 3, in the processing of the first substrate 1, the amount of He leakage before processing was 4.75 (Pa / min), and the flow rate of He on the back surface before processing was within the appropriate range (normal). The processing was completed normally. Also, there were no deposits on the edges of the back surface of the substrate after processing. Furthermore, the amount of He leakage before processing of the second substrate 1 after cleaning was 3.56 (Pa / min), and the flow rate of He on the back surface before processing was within the appropriate range (normal). Note that in Example 2, the second substrate 1 was not processed. Also, in Example 2, there were no deposits on the electrostatic chuck 22 in the processing chamber 10 after the cleaning process. Additionally, in Example 2, four substrates 1 were processed continuously, with cleaning processes interspersed between etching processes of the silicon oxide film on the substrates 1. The processing of each substrate was completed successfully, and there were no deposits on the edges of the back surface of the substrates after processing. Furthermore, after the cleaning process following the processing of the fourth substrate 1, there were no deposits on the electrostatic chuck 22 in the processing chamber 10.

[0052] (Comparative Example 1) In Comparative Example 1, the ring member 71 was not provided, and an annular member 23 was provided surrounding the electrostatic chuck 22. Also, in Comparative Example 1, the quartz ring member 23b was not provided. In Comparative Example 1, as shown in Table 3, in the processing of the first substrate 1, the He leak amount before processing was 6.73 (Pa / min), and the He flow rate on the back surface before processing was within the appropriate range (normal). Also, the processing was completed normally. Also, there was deposits on the edge of the back surface of the substrate after processing. Also, the He leak amount before processing of the second substrate 1 after cleaning exceeded 60 (Pa / min), and an abnormality in substrate suction occurred. Also, the He flow rate on the back surface before processing exceeded the upper limit of the appropriate range. Note that in Comparative Example 1, the second substrate 1 was not processed. Also, in Comparative Example 1, after cleaning (after only checking the substrate suction state with the second substrate unprocessed), there were deposits on the electrostatic chuck 22 in the processing chamber 10.

[0053] (Comparative Example 2) In Comparative Example 2, the cleaning process was performed for twice the time of Comparative Example 1, using the same configuration as in Comparative Example 1. In Comparative Example 2, as shown in Table 3, in the processing of the first substrate 1, the He leak amount before processing was 4.75 (Pa / min), and the He flow rate on the back surface before processing was within the appropriate range (normal). An abnormality occurred 118 minutes from the start and the process stopped. The He flow rate on the back surface at the time of the abnormality exceeded the upper limit of the appropriate range. In addition, there was deposits on the edge of the back surface of the substrate after the abnormality stopped. Furthermore, the He leak amount before processing of the second substrate 1 after cleaning exceeded 60 (Pa / min), and an abnormality in substrate 1 adsorption occurred. Furthermore, the He flow rate on the back surface before processing exceeded the upper limit of the appropriate range. Note that in Comparative Example 2, the second substrate 1 was not processed. Also, in Comparative Example 2, after the cleaning process (after only checking the substrate adsorption state with the second substrate unprocessed), there were deposits on the electrostatic chuck 22 in the processing chamber 10.

[0054] (Comparative Example 3) In Comparative Example 3, the ring member 71 was not provided, and an annular member 23 was provided surrounding the electrostatic chuck 22. In Comparative Example 3, a quartz ring member 23b was also provided. In Comparative Example 3, as shown in Table 3, in the processing of the first substrate 1, the He leakage amount before processing was 6.34 (Pa / min), and the He flow rate on the back surface before processing was within the appropriate range (normal). The processing was completed normally. In addition, there was deposits on the edge of the back surface of the substrate after processing. In addition, the He leakage amount before processing of the second substrate 1 after cleaning was 5.35 (Pa / min), and the He flow rate on the back surface before processing was within the appropriate range (normal). Note that in Comparative Example 3, the second substrate 1 was not processed. In addition, in Comparative Example 3, after cleaning (after only checking the substrate adsorption state with the second substrate unprocessed), there were no deposits on the electrostatic chuck 22 in the processing chamber 10.

[0055] Next, we will describe the results of experiments measuring the etching rate of the silicon oxide film on substrate 1. In Examples 3 and 4, the same substrate processing apparatus 100 was used to perform the same etching process, but with different widths of the ring member 71 covering the peripheral edge of substrate 1, and the etching rate was measured. In Comparative Examples 4 and 5, the etching process was performed without the ring member 71, and the etching rate was measured.

[0056] In Examples 3 and 4 and Comparative Examples 4 and 5, the results shown in Table 4 were obtained.

[0057] (Example 3) In Example 3, similar to Example 1, the width of the ring member 71 covering the peripheral edge of the substrate 1 was set to 4 mm. In Example 3, the etching rate was 0.539 (μm / min), which is larger than that of Comparative Examples 4 and 5.

[0058] (Example 4) In Example 4, similar to Example 2, the width of the ring member 71 covering the peripheral edge of the substrate 1 was set to 2 mm. In Example 4, the etching rate was 0.546 (μm / min), which is larger than that of Comparative Examples 4 and 5.

[0059] (Comparative Example 4) In Example 4, similar to Comparative Example 1, the ring member 71 was not provided, and an annular member 23 was provided surrounding the electrostatic chuck 22. Also, in Comparative Example 4, the quartz ring member 23b was not provided. In Comparative Example 4, the etching rate was 0.504 (μm / min).

[0060] (Comparative Example 5) In Example 5, similar to Comparative Example 3, the ring member 71 was not provided, and an annular member 23 was provided surrounding the electrostatic chuck 22. In Comparative Example 5, a quartz ring member 23b was provided. In Comparative Example 5, the etching rate was 0.513 (μm / min).

[0061] From the results of Examples 3 and 4 and Comparative Examples 4 and 5, it is possible to reduce the combined capacitance in the region where the quartz ring member 23b is placed (the region corresponding to L2 in Figure 2) by combining the ring member 71 (first ring member), the quartz ring member 23b (second ring member), and the ring member 23a (third ring member) compared to the conventional method (third ring member only). This reduces the bias potential and allows ions to be concentrated on the substrate 1. As a result, it is possible to improve the etching rate of the silicon oxide film on the substrate 1.

[0062] (Modifications) It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than the description of the embodiments above, and further includes all modifications (modifications) within the meaning and scope equivalent to the claims.

[0063] For example, in the above embodiment, the ring member 71 (first ring member) covering the upper part of the peripheral edge of the substrate was shown as a single continuous member extending around the entire circumference, but the present invention is not limited to this. In the present invention, the first ring member may be composed of a combination of multiple arc-shaped members.

[0064] Furthermore, in the above embodiment, the quartz ring member 23b (second ring member) arranged on the outer circumference of the electrostatic chuck 22 was shown as a single continuous member extending around the entire circumference, but the present invention is not limited to this. In the present invention, the second ring member may be composed of a combination of multiple arc-shaped members.

[0065] Furthermore, in the above embodiment, the ring member 23a (third ring member) arranged on the outer circumference of the electrostatic chuck 22 was shown as a single continuous member extending around the entire circumference, but the present invention is not limited to this. In the present invention, the third ring member may be composed of a combination of multiple arc-shaped members.

[0066] Furthermore, although the above embodiment shows an example in which the quartz ring member 23b (second ring member) is formed of quartz, the present invention is not limited thereto. In the present invention, the second ring member may be formed of a material other than quartz, as long as it is made of a material with a lower dielectric constant than the third ring member.

[0067] Furthermore, although the above embodiment shows an example in which the ring member 71 (first ring member) covering the upper part of the peripheral edge of the substrate is formed of aluminum oxide (alumina), the present invention is not limited to this. In the present invention, the first ring member may be formed of a material other than aluminum oxide (alumina). For example, the first ring member may be formed of quartz.

[0068] Furthermore, although the above embodiment shows an example of a configuration in which plasma treatment is performed using a CF-based treatment gas, the present invention is not limited thereto. In the present invention, plasma treatment may be performed using a treatment gas other than a CF-based gas. For example, plasma treatment may be performed using a treatment gas such as hydrofluorocarbon gas or chlorofluorocarbon gas.

[0069] Furthermore, although the above embodiment shows an example of a configuration for etching a silicon oxide film, the present invention is not limited thereto. In the present invention, a silicon oxide film or silicon nitride film formed on a silicon wafer, or a glass substrate or quartz substrate, may be etched.

[0070] Furthermore, the above embodiment shows an example of a configuration in which the quartz ring member 23b (second ring member) is placed in contact with the recess of the ring member 23a (third ring member) so as to have no gap in the vertical direction, but the present invention is not limited to this. In the present invention, the second ring member may be placed spaced apart from the third ring member in the vertical direction to create a space between the second ring member and the third ring member. As a result, the space between the second ring member and the third ring member becomes an atmospheric gas, making it possible to further lower the dielectric constant. However, since providing a space makes it easier for discharge to occur in the space, it is preferable to fill and place an insulator with a low dielectric constant (second ring member) in the space.

[0071] [Embodiments] The exemplary embodiments described above will be understood by those skilled in the art to be specific examples of the following embodiments.

[0072] (Item 1) A substrate processing apparatus comprising: a processing chamber; a base disposed within the processing chamber to which high-frequency power is applied; an electrostatic chuck disposed on the base on which a substrate to be plasma processed is placed; a first ring member formed in an annular shape so as to cover the peripheral edge of the substrate placed on the electrostatic chuck from above in a plan view, and positioned above and spaced apart from the substrate; a second ring member positioned so as to overlap the first ring member in a plan view, positioned below the substrate, and formed in an annular shape so as to surround the electrostatic chuck in a plan view; and a third ring member formed in an annular shape so as to surround the electrostatic chuck in a plan view, positioned below the first ring member, and covering the upper part of the second ring member, wherein the second ring member is made of a material with a lower dielectric constant than the third ring member.

[0073] (Item 2) The substrate processing apparatus according to Item 1, wherein the first ring member is formed to cover the peripheral edge of the substrate with a width of 1 mm to 10 mm in a plan view.

[0074] (Item 3) The substrate processing apparatus according to item 1 or 2, wherein a recess for which the second ring member is arranged is formed in the inner circumference of the third ring member.

[0075] (Item 4) The substrate processing apparatus according to any one of items 1 to 3, wherein the second ring member is made of quartz.

[0076] (Item 5) The substrate processing apparatus according to any one of items 1 to 4, further comprising a gas supply unit that supplies a processing gas containing carbon and fluorine into the processing chamber on which the base is provided.

[0077] 1: Substrate, 10: Processing chamber, 20: Substrate mounting section, 21: Base, 22: Electrostatic chuck, 23a: Ring member (third ring member), 23b: Quartz ring member (second ring member), 30: Gas supply device (gas supply section), 70: Protective member, 71: Ring member (first ring member), 100: Substrate processing device, 231a: Recess

Claims

1. A substrate processing apparatus comprising: a processing chamber; a base disposed within the processing chamber to which high-frequency power is applied; an electrostatic chuck disposed on the base on which a substrate to be plasma processed is placed; a first ring member formed in an annular shape so as to cover the peripheral edge of the substrate placed on the electrostatic chuck from above in a plan view, and positioned above and spaced apart from the substrate; a second ring member positioned so as to overlap the first ring member in a plan view, positioned below the substrate, and formed in an annular shape so as to surround the electrostatic chuck in a plan view; and a third ring member formed in an annular shape so as to surround the electrostatic chuck in a plan view, positioned below the first ring member, and covering the upper part of the second ring member, wherein the second ring member is made of a material with a lower dielectric constant than the third ring member.

2. The substrate processing apparatus according to claim 1, wherein the first ring member is formed to cover the peripheral edge of the substrate with a width of 1 mm to 10 mm in a plan view.

3. The substrate processing apparatus according to claim 1 or 2, wherein a recess for which the second ring member is arranged is formed in the inner circumference of the third ring member.

4. The substrate processing apparatus according to any one of claims 1 to 3, wherein the second ring member is formed of quartz.

5. The substrate processing apparatus according to any one of claims 1 to 4, further comprising a gas supply unit for supplying a processing gas containing carbon and fluorine into the processing chamber on which the base is provided.

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