JP2010192488A - Plasma processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing apparatus capable of preventing process gas or reactive products from remaining on the upper side at the outer peripheral side edge of a substrate, and capable of uniformly applying a bias potential to a base stage. <P>SOLUTION: A plasma processing apparatus 1 includes a process chamber 11, a base stage which is arranged in the process chamber 11 and on which a substrate K is placed, a gas supply device for supplying process gas, a plasma generating device 40 for causing the supplied process gas to be plasma, a high frequency power source 45 for applying a high frequency voltage to an electrode 17 of the base stage, a protective member 25 which is formed in ring and plate, to cover the upper surface at the outer peripheral side edge of the substrate K placed on the base stage from the inner peripheral side edge, and a driving device 23 which drives the base stage so that the substrate K on the base stage is raised/lowered between a protective position where the substrate K on the base stage is covered with the protecting member 25 and an escape position not covered with the protecting member. The protective member 25 is formed in such plate thickness so that the height from the upper surface of the substrate K to the upper surface of the protective member 25 is 1-5 mm when the base stage is moved to the protective position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus that supplies a predetermined processing gas into a processing chamber to generate plasma, and processes a substrate in the processing chamber with the plasma processing gas.

  As an example of the plasma processing, there is an etching processing, and a resist film or an oxide film may not be formed on the upper surface of the outer peripheral side edge of a substrate (for example, a silicon substrate) to be subjected to the etching processing. In this case, after the substrate is placed on a base placed in the processing chamber, a processing gas is supplied into the processing chamber and converted into plasma, and a bias potential is applied to the base to perform plasma processing on the substrate. As a result, the annular portion of the upper surface of the substrate where no resist film or oxide film is formed is etched.

  However, it may be necessary to prevent this portion from being etched. In such a case, for example, it is effective to hold the substrate by a holder described in Japanese Patent Laid-Open No. 5-347362.

  The holder is attached to the stage, a circular stage on which the substrate is placed, a ring-shaped presser that holds the upper surface of the outer peripheral side edge of the substrate placed on the stage, and the presser that moves up and down. Since the upper surface of the outer peripheral side edge of the substrate is pressed by the pressing member, the upper surface of the outer peripheral side edge of the substrate is subjected to ion incidence by a bias potential applied to the stage. Thus, etching is prevented.

Japanese Patent Laid-Open No. 5-347362

  However, the above-mentioned holder has problems as described below, although etching of the upper surface of the outer peripheral side edge of the substrate is prevented. That is, since the thickness of the presser is thick and the height from the upper surface of the substrate on the stage to the upper surface of the presser is high, the processing gas consumed in the etching process and the reaction products generated by the etching process are generated at the inner periphery of the presser. Therefore, they are likely to stay above the outer peripheral edge of the substrate, and they cannot be exhausted smoothly. It is difficult to apply a bias potential to the outer peripheral edge of the stage, and the bias potential applied to the stage is not good. There was a problem of uniformity. And due to these problems, the sidewalls of holes and grooves formed by etching are not perpendicular to the top surface of the substrate, but are inclined, and the etching shape becomes poor and the substrate cannot be etched with high accuracy. It was.

  The present invention has been made in view of the above circumstances, and prevents the processing gas spent in the plasma processing and the reaction product generated in the plasma processing from staying on the upper peripheral edge of the substrate. It is another object of the present invention to provide a plasma processing apparatus that can apply a bias potential uniformly to a base on which a substrate is placed.

To achieve the above object, the present invention provides:
A processing chamber having an enclosed space;
An electrode to which a high-frequency voltage is applied, and an insulator provided on the electrode and on which a substrate is placed, and a base disposed in the processing chamber;
An adsorbing means for adsorbing and fixing the substrate placed on the insulator of the base on the base;
Gas supply means for supplying a processing gas into the processing chamber;
Plasma generating means for converting the processing gas supplied into the processing chamber into plasma;
Voltage applying means for applying a high frequency voltage to the electrode of the base;
Exhaust means for exhausting the gas in the processing chamber to depressurize the interior;
A protective member which is formed in an annular and plate shape and covers the upper surface of the outer peripheral side edge of the substrate placed on the base by the inner peripheral side edge thereof;
Drive means for moving up or down one of the base and the protection member and moving the base between a protection position where the substrate on the base is covered by the protection member and a retracted position where it is not covered A plasma processing apparatus,
The plasma processing is characterized in that at least a portion of the protective member covering the substrate is formed with a plate thickness such that a height from the upper surface of the substrate to the upper surface of the protective member is 1 mm or more and 5 mm or less at the protection position. Related to the device.

  According to the present invention, after the substrate is placed on the insulator of the base and fixed on the base by the suction means, either the base or the protection member is driven by the driving means from the retracted position. When the upper surface of the outer peripheral side edge of the substrate on the base is covered with the inner peripheral side edge of the protective member, the processing gas is supplied and supplied into the processing chamber by the gas supply means. The processing gas is turned into plasma by the plasma generating means, and a high frequency voltage is applied to the base electrode by the voltage applying means, and a potential difference (bias potential) is generated between the electrode and the plasma of the processing gas. The gas in the processing chamber is exhausted by the exhaust means, and the internal pressure is reduced to a predetermined pressure.

  The substrate on the base is subjected to a predetermined plasma treatment by radicals in the plasma and ions in the plasma that are moved and incident on the substrate side by a bias potential. Ion incidence on the upper surface is prevented by the protective member, whereby the substrate is subjected to plasma processing except for the upper surface of the outer peripheral edge.

  The protection position is a position where the substrate on the base is covered by the protection member, and the retracted position is a position where the substrate on the base is not covered by the protection member. Examples of the plasma treatment include an etching treatment, an ashing treatment, and a film formation treatment. Examples of the substrate to be subjected to such treatment include a silicon substrate and a glass substrate. it can.

  In the plasma processing apparatus, as described above, the plate thickness of at least the portion of the protective member covering the substrate is formed such that the height from the upper surface of the substrate to the upper surface of the protective member is 1 mm or more and 5 mm or less at the protection position. ing. This is because if the thickness is smaller than 1 mm, the plate thickness becomes thin and the strength is insufficient. If the thickness is larger than 5 mm, the processing gas consumed in the plasma processing and the reaction product generated in the plasma processing are protected. There is a problem that the inner periphery of the member tends to stay above the outer peripheral edge of the substrate, which cannot be exhausted smoothly, and the bias potential between the electrode and the plasma at the outer peripheral edge of the substrate. This is because there is a problem that the bias potential is not uniform and the generated bias potential becomes non-uniform.

  Therefore, if it is within the above range, the gas flow can be improved to prevent the processing gas spent in the plasma processing and the reaction products generated by the plasma processing from staying, and the outer peripheral side edge of the substrate. In this case, it is possible to prevent the bias potential from being easily generated between the electrode and the plasma, to uniformly generate the bias potential, and to effectively perform the plasma treatment. In addition, as a more preferable range, it is the plate | board thickness from which the said height will be 1 mm or more and 2 mm or less.

  The electrode of the base is formed so that the outer diameter thereof is larger than the outer diameter of the substrate, and the outer peripheral portion projects outward from the substrate fixed on the base. Preferably it is. In this way, it becomes possible to more effectively prevent the bias potential from being generated between the electrode and the plasma at the outer peripheral edge of the substrate, and to generate the bias potential more uniformly. Plasma treatment can be effectively performed.

  Moreover, it is preferable that the electrode of the said base is comprised so that the protrusion amount from the board | substrate on the said base of the outer peripheral part may be 29 mm or less. As described above, it is desirable to provide the electrode so that the outer peripheral portion protrudes outward from the substrate on the base. However, if the protruding amount is too large, the opposite effect is obtained. This is because the magnitude of the bias potential generated when a certain high-frequency voltage is applied to the electrode decreases as the surface area of the upper surface of the electrode increases, so that the generated bias potential decreases as the overhang amount increases. is there. From such a viewpoint, the overhang is preferably 29 mm or less, and within this range, a bias potential of a predetermined level or higher can be generated when a constant high-frequency voltage is applied to the electrode.

  In addition, the base insulator and the protective member are made of the same material, and the thickness of the base insulator is the thickness of the portion corresponding to the central region from the outer peripheral edge of the substrate (X ) Is formed thicker than the thickness (Y) of the portion corresponding to the region near the outer peripheral edge of the substrate, and the thickness (X) is the thickness (Y) of the portion covering the substrate. It is preferable that it is substantially equal to the total value of the plate thickness (Z) of the protective member. In this way, the insulator existing between the electrode and the plasma can have the same property (for example, the same relative dielectric constant), and either the base or the protection member has moved to the protection position. In this state, since the thickness of the insulator existing between the electrode and the plasma can be made the same at the peripheral edge of the substrate, the generated bias potential can be made uniform over the entire surface of the substrate. .

  As described above, according to the plasma processing apparatus of the present invention, it is possible to prevent stagnation of processing gas and reaction products and to uniformly generate a bias potential. Thereby, the plasma treatment can be effectively performed on the substrate.

It is sectional drawing which showed schematic structure of the etching apparatus which concerns on one Embodiment of this invention. It is a top view of the arrow A direction in FIG. FIG. 2 is a detailed view of part B in FIG. 1. It is sectional drawing which showed schematic structure of a part of the board | substrate holding | maintenance apparatus which concerns on other embodiment of this invention. It is the graph which showed the relationship between the distance from the center of a silicon substrate, and the side wall inclination angle of the hole or groove | channel formed by an etching. It is sectional drawing which showed schematic structure of a part of the board | substrate holding | maintenance apparatus concerning a prior art example. It is explanatory drawing for demonstrating a side wall inclination angle.

  Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. 1 is a cross-sectional view showing a schematic configuration of an etching apparatus according to an embodiment of the present invention, FIG. 2 is a plan view in the direction of arrow A in FIG. 1, and FIG. FIG.

  As shown in FIGS. 1 to 3, an etching apparatus 1 as a plasma processing apparatus of this example includes a processing chamber 11 having a closed space, a substrate holding apparatus 15 that holds a silicon substrate K to be etched, and a substrate holding apparatus. 15, a protective member 25 that covers the upper surface of the outer peripheral side edge of the silicon substrate K held by 15, a support member 26 that supports the protective member 25, an exhaust device 30 that reduces the pressure in the processing chamber 11, A high-frequency voltage is applied to the gas supply device 35 for supplying the processing gas to the plasma, the plasma generation device 40 for converting the processing gas supplied into the processing chamber 11 into plasma, and the first electrode 17 and the second electrode 21 of the substrate holding device 15. A base high frequency power supply 45 to be applied is provided.

  The processing chamber 11 includes a lower container 12 and an upper container 13 having internal spaces communicating with each other. The upper container 13 is formed smaller than the lower container 12.

  The substrate holding device 15 includes a first electrode 17 having a disk shape, a first insulator 18 formed on the upper surface of the first electrode 17, and a silicon substrate K placed on the upper surface, and a first electrode 17. A DC power source 19 for applying a DC voltage, and applying a DC voltage to the first electrode 17 by the DC power source 19 causes an adsorption force between the silicon substrate K and the first insulator 18 to generate the silicon substrate K. An electrostatic chuck 16 for adsorbing and holding the first electrode 17, a disk-like lower member 20 on which the first electrode 17 is disposed on the upper surface, the first electrode 17 is disposed inside the ring, and the inner peripheral surface is the first electrode 17. A second electrode 21 provided on the lower member 20 so as to be in contact with the outer peripheral surface of the second electrode 21, a second insulator 22 provided on the lower member 20 so as to cover the upper surface and the outer peripheral surface of the second electrode 21, and a lower member The lower member 20 is connected to the lower surface of The first electrode 17, the first insulator 18, the lower member 20, the second electrode 21, and the second insulator 22 are formed in the lower portion. Located in the container 12.

  The outer periphery of the first electrode 17 and the first insulator 18 is smaller inward than the outer periphery of the silicon substrate K, and the upper surface of the second insulator 22 is the first insulator. It is lower than the upper surface of 18. In addition, a gap S is formed between the second insulator 22 and the outer peripheral surface of the silicon substrate K. If the gap S is small, it is difficult to generate a bias potential uniformly. For example, it is preferable that it is about 1.5 mm-3.5 mm. The second electrode 21 has an outer peripheral portion protruding outward from the silicon substrate K attracted and held on the electrostatic chuck 16, and the protruding amount P is 29 mm or less.

  The first electrode 17 and the second electrode 21 are made of, for example, aluminum, and the first insulator 18 and the second insulator 22 are made of, for example, a ceramic (for example, a ceramic made of aluminum oxide). The The structure including the first electrode 17, the first insulator 18, the lower member 20, the second electrode 21, and the second insulator 22 functions as a base on which the silicon substrate K is placed. The first electrode 17 and the second electrode 21 constitute one electrode, and the first insulator 18 and the second insulator 22 constitute one insulator. Further, as shown in FIG. 4, the substrate holding device 15 omits the second electrode 21 and provides only the second insulator 22 on the outer periphery of the first electrode 17 and the first insulator 18. You may do it.

  The protective member 25 is composed of a ring-shaped and plate-shaped member made of anodized aluminum or ceramic (for example, ceramic made of aluminum oxide), and the lower member 20 is at the rising end position. Further, the upper surface of the outer peripheral side edge of the silicon substrate K attracted and held on the electrostatic chuck 16 is covered with the inner peripheral side edge. Further, when the lower member 20 is at the rising end position, the protective member 25 has a height H from the upper surface of the silicon substrate K to the upper surface of the protective member 25 of 1 mm to 5 mm, more preferably 1 mm to 2 mm. It is formed in such a thickness. The protective member 25 is preferably made of the same material as the first insulator 18 and the second insulator 22, and in this example, is made of the same material.

  Further, the protective member 25 is configured such that when the lower member 20 is in the rising end position, a part of the lower surface on the inner peripheral side comes into contact with the upper surface of the second insulator 22, and the first insulation The thickness (X) of the body 18, the thickness (Y) at the inner peripheral edge of the second insulator 22 (near the outer peripheral edge of the silicon substrate K), and the plate thickness at the inner peripheral edge of the protective member 25 The relationship (Z) is such that the thickness (X) is substantially equal to the sum of the thickness (Y) and the plate thickness (Z). The rising end position of the lower member 20 is a protection position where the silicon substrate K on the electrostatic chuck 16 is covered by the protection member 25, and the falling end position of the lower member 20 is on the electrostatic chuck 16 by the protection member 25. The silicon substrate K is in a retracted position that is not covered, and is moved to the protection position and the retracted position by the elevating cylinder 23. Further, a gap is formed between the protective member 25 and the outer peripheral side upper surface and the outer peripheral surface of the silicon substrate K, and the clearance T between the protective member 25 and the outer peripheral surface of the silicon substrate K is, for example, It is preferably about 1 mm to 3 mm. Further, the protective member 25 is formed with a through hole 25a for venting gas through the front and back.

  The support member 26 includes an annular base 27 disposed on the bottom surface of the lower container 12, and a plurality of support posts 28 erected on the base 27 and whose upper ends support the lower surface on the outer peripheral side of the protection member 25. The lower member 20 and the like are arranged inside each column 28.

  The exhaust device 30 includes an exhaust pump 31 and an exhaust pipe 32 that connects the exhaust pump 31 and the side surface of the lower container 12. The exhaust device 30 exhausts the gas in the lower container 12 through the exhaust pipe 32, and 11 is set to a predetermined pressure. The gas supply device 35 includes a gas supply unit 36 that supplies a gas containing an etching gas as the processing gas, and a supply pipe 37 that connects the gas supply unit 36 and the upper surface of the upper container 13. Process gas is supplied from the section 36 into the upper container 13 through the supply pipe 37.

  The plasma generator 40 includes a plurality of coils 41 disposed on the outer periphery of the upper container 13 and a coil high-frequency power source 42 that applies a high-frequency voltage to each coil 41. By applying a high frequency voltage to 41, the processing gas supplied into the upper container 13 is turned into plasma. The base high-frequency power source 45 applies a high-frequency voltage to the first electrode 17 and the second electrode 21, thereby causing a potential difference between the first electrode 17 and the second electrode 21 and the plasma in the processing chamber 11. (Bias potential) is generated.

  According to the etching apparatus 1 of the present example configured as described above, first, the silicon substrate K is carried into the lower container 12 of the processing chamber 11 and placed on the upper surface of the first insulator 18 of the electrostatic chuck 16. After that, the DC voltage is applied to the first electrode 17 by the DC power source 19 to attract and hold the silicon substrate K, and the lower member 20 is moved from the lower end position to the upper end position by the elevating cylinder 23. The upper surface of the outer peripheral side edge of the silicon substrate K is covered with the inner peripheral side edge of the protection member 25.

  Next, a processing gas is supplied into the processing chamber 11 by the gas supply device 35, and a high frequency voltage is applied to the coil 41 by the high frequency power supply 42 for the coil so that the supplied processing gas is turned into a plasma. A high frequency voltage is applied to the first electrode 17 and the second electrode 21 by the high frequency power supply 45 for generating a bias potential. At this time, the inside of the processing chamber 11 is adjusted to a predetermined pressure by the exhaust device 30.

  The silicon substrate K on the electrostatic chuck 16 is etched by radicals in the plasma and ions in the plasma that are moved and incident on the silicon substrate K side by the bias potential. At this time, the outer peripheral side of the silicon substrate K is etched. Since the incidence of ions on the upper surface of the edge is prevented by the protective member 25, the silicon substrate K is etched at a portion other than the upper surface of the outer peripheral edge.

  Thereafter, when the etching is completed, the lower member 20 is moved from the raised end position to the lowered end position by the elevating cylinder 23, and the silicon substrate K is carried out of the lower container 12.

  By the way, in the etching apparatus 1, as described above, the thickness H of the protective member 25 from the upper surface of the silicon substrate K to the upper surface of the protective member 25 when the lower member 20 moves to the rising end position. It is formed to be 1 mm or more and 5 mm or less (more preferably 1 mm or more and 2 mm or less). This is because if the thickness is smaller than 1 mm, the plate thickness becomes thin and the strength is insufficient. If the thickness is larger than 5 mm, the processing gas consumed in the etching process and the reaction product generated in the etching process are protected. The first electrode 17 tends to stay on the inner peripheral portion of the member 25 and above the outer peripheral side edge of the silicon substrate K, and these cannot be smoothly exhausted, or the first electrode 17 at the outer peripheral side edge of the silicon substrate K. This is because it is difficult to generate a bias potential between the second electrode 21 and the plasma, and the generated bias potential becomes non-uniform.

  Therefore, if it is in the above range, it is possible to improve the gas flow and prevent the process gas spent in the etching process and the reaction products generated in the etching process from staying, and the outer peripheral side of the silicon substrate K. It is possible to prevent the bias potential from being easily generated between the first electrode 17 and the second electrode 21 and the plasma at the edge portion, and to generate the bias potential uniformly. Thus, the silicon substrate K can be etched with high accuracy by preventing the sidewalls of the holes and grooves formed by etching from being inclined.

  In addition, the second electrode 21 is provided on the outer periphery of the first electrode 17 so that the outer diameter of the structure including the first electrode 17 and the second electrode 21 is larger than the outer diameter of the silicon substrate K. Since the outer peripheral portion of the structure projects outward from the silicon substrate K on the electrostatic chuck 16, the outer peripheral side edge of the silicon substrate K is between the first electrode 17 and the second electrode 21 and the plasma. It becomes possible to more effectively prevent the bias potential from being generated more effectively and to generate the bias potential more uniformly, and the silicon substrate K can be etched more accurately.

  In addition, the amount of overhang P of the outer peripheral portion of the second electrode 21 is 29 mm or less is that the magnitude of the bias potential generated when a certain high-frequency voltage is applied to the first electrode 17 and the second electrode 21 is This is because the surface areas of the upper surfaces of the first electrode 17 and the second electrode 21 become smaller as the surface area becomes larger. Accordingly, the larger the overhang P, the larger the surface area and the smaller the generated bias potential. However, if the overhang P is in this range, a constant high-frequency voltage is applied to the first electrode 17 and the second electrode 21. When applied, a bias potential of a predetermined level or higher can be generated.

  Further, the first insulator 18, the second insulator 22, and the protective member 25 are made of the same material, and the thickness (X) of the first insulator 18 and the thickness at the inner peripheral side edge of the second insulator 22. (Y) and the relationship between the thickness (Z) at the inner peripheral edge of the protective member 25, the thickness (X) is approximately equal to the sum of the thickness (Y) and the thickness (Z). Since it is made equal, the insulator which exists between the 1st electrode 17 and the 2nd electrode 21, and plasma can be made into the same property (for example, the same dielectric constant), and the lower member 20 raises. When moved to the end position, the thickness of the insulating material existing between the first electrode 17 and the second electrode 21 and the plasma can be made the same at the outer peripheral side edge of the silicon substrate K. The bias potential can be made uniform over the entire surface of the silicon substrate K.

  Incidentally, when the height H is changed and etching is performed so that a hole having a diameter of 500 μm and a depth of 400 μm is formed in a 6-inch silicon substrate K, the distance from the center of the silicon substrate K and the inclination angle of the side wall of the hole The experimental results as shown in FIG. 5 were obtained for the relationship with γ. In FIG. 5, the height H is 7.8 mm as Experimental Example 1, the height H is 6 mm as Experimental Example 2, the height H is 5 mm as Experimental Example 3, and the height H is 4 mm as Experimental Example 4. A height H of 3 mm is shown as Experimental Example 5 and a height H of 2 mm is shown as Experimental Example 6. In Experimental Example 1, a substrate holding device 15 ′ according to a conventional example as shown in FIG. In 2-6, the board | substrate holding | maintenance apparatus 15 as shown in FIG. 4 was used. FIG. 5 also shows the experimental results when the height H is 2 mm and the substrate holding device 15 as shown in FIG.

  The inclination angle γ of the side wall of the hole is calculated as follows. That is, as shown in FIG. 7, the shift amounts W1 and W2 at the bottom of the hole 50 between the side walls 51 and 53 and the actual side walls 52 and 54 when the side wall of the hole 50 is formed vertically are calculated as follows. After measuring the L direction and the R direction of the side wall and calculating the inclination angles α and β by the following expression 1, the inclination angle γ is determined by the following expression 2. In addition, the inclination angles α and β are calculated as positive angles when the side walls 52 and 54 are inclined in the L direction relative to the side walls 51 and 53, and as negative angles when the side walls 52 and 54 are inclined in the R direction. In FIG. 7, the symbol D is the depth of the hole, and the symbol M is a mask.

(Formula 1)
α = tan ⁻¹ (W1 / D), β = tan ⁻¹ (W2 / D)

(Formula 2)
γ = (α + β) / 2

  As shown in FIG. 5, from Experimental Examples 1 to 6, as the distance from the center of the silicon substrate K increases, that is, the closer to the outer peripheral side of the silicon substrate K, the inclination angle γ increases, but the height H increases. Is low, the inclination angle γ is small even when the distance from the center of the silicon substrate K is large. It should be noted that although Experimental Example 1 and Experimental Examples 2 to 6 are different in the substrate holding devices 15 ′ and 15 used, it is considered that the experimental results are not so affected.

  When the distance from the center of the silicon substrate K is about 40 mm or more and the height H is 2 mm to 5 mm, the height H is 2 mm to 3 mm and the height H is 3 mm to 4 mm. Increasing the height H, such as from 4 mm to 5 mm, increases the inclination angle γ at substantially the same rate, but when the height H is 6 mm and 7.8 mm, the height H is 2 mm to 5 mm. The rate at which the inclination angle γ increases is higher than in the previous cases.

  From these facts, it can be seen that by setting the height H to 5 mm or less, preferably 2 mm or less, the inclination angle γ is kept to a certain angle or less and a highly accurate etching shape can be obtained. Therefore, it can be seen that the retention of the processing gas and the reaction product can be prevented and the bias potential can be generated uniformly.

  Further, from Experimental Examples 6 and 7, the inclination angle γ is further reduced by increasing the outer peripheral portion of the structure including the first electrode 17 and the second electrode 21 to the outside of the outer peripheral portion of the silicon substrate K. I understand that. Therefore, it can be seen that the bias potential is generated more uniformly, and as a result, a highly accurate etching shape can be obtained.

  As mentioned above, although one Embodiment of this invention was described, the specific aspect which this invention can take is not limited to this at all.

  In the above example, the first electrode 17 and the second electrode 21 are configured as separate members, but may be configured integrally. In addition, the protective member 25 is not fixed, but a structure including the first electrode 17, the first insulator 18, the lower member 20, the second electrode 21, and the second insulator 22 is fixed, and the protective member 25 is fixed. May be moved up and down between the protection position and the retracted position.

  The protective member 25 has a height H from the upper surface of the silicon substrate K to the upper surface of the protective member 25 of 1 mm or more and 5 mm or less, more preferably 1 mm or more and 2 mm or less when the lower member 20 is at the rising end position. The entire plate thickness may be formed in the plate thickness, but only the portion of the protective member 25 that covers the silicon substrate K is formed to such a plate thickness, or the protective member 25 covers the silicon substrate K. The inner peripheral side including the part may be formed in such a plate thickness. In this case, it is preferable that the plate | board thickness in the other part of the protection member 25 is 8 mm or less.

  Further, as described above, the protective member 25, the first insulator 18 and the second insulator 22 are preferably made of the same material. However, if the material is the same, the protective member 25, The thicknesses (X) of the first insulator 18 and the thickness (Y) at the inner peripheral edge of the second insulator 22 are protected by adjusting the thicknesses of the first insulator 18 and the second insulator 22. This is because the bias potential generated can be made uniform over the entire surface of the silicon substrate K simply by making the plate thickness (Z) at the inner peripheral edge of the member 25 substantially equal to the total value. . However, the thickness (X), the thickness (Y), and the plate thickness (Z) are respectively adjusted in consideration of the physical property values of the materials constituting the protective member 25, the first insulator 18, and the second insulator 22. Thus, if the generated bias potential can be made uniform over the entire surface of the silicon substrate K, the protective member 25, the first insulator 18 and the second insulator 22 may be made of different materials. There is no problem.

  In the above example, the etching process is described as an example of the plasma process. However, the present invention is not limited to this, and the present invention can be applied to an ashing process, a film forming process, and the like. Further, the substrate K to be processed is not limited to a silicon substrate, and may be any substrate such as a glass substrate.

DESCRIPTION OF SYMBOLS 1 Etching device 11 Processing chamber 15 Substrate holding device 16 Electrostatic chuck 17 1st electrode 18 1st insulator 19 DC power supply 20 Lower member 21 2nd electrode 22 2nd insulator 23 Lifting cylinder 25 Protection member 26 Support member 30 Exhaust device 35 Gas supply device 40 Plasma generator 41 Coil 42 High frequency power source for coil 45 High frequency power source for base

Claims (4)

A processing chamber having an enclosed space;
An electrode to which a high-frequency voltage is applied, and an insulator provided on the electrode and on which a substrate is placed, and a base disposed in the processing chamber;
An adsorbing means for adsorbing and fixing the substrate placed on the insulator of the base on the base;
Gas supply means for supplying a processing gas into the processing chamber;
Plasma generating means for converting the processing gas supplied into the processing chamber into plasma;
Voltage applying means for applying a high frequency voltage to the electrode of the base;
Exhaust means for exhausting the gas in the processing chamber to depressurize the interior;
A protective member which is formed in an annular and plate shape and covers the upper surface of the outer peripheral side edge of the substrate placed on the base by the inner peripheral side edge thereof;
Drive means for moving up or down one of the base and the protection member and moving the base between a protection position where the substrate on the base is covered by the protection member and a retracted position where it is not covered A plasma processing apparatus,
The plasma processing is characterized in that at least a portion of the protective member covering the substrate is formed with a plate thickness such that a height from the upper surface of the substrate to the upper surface of the protective member is 1 mm or more and 5 mm or less at the protection position. apparatus.   The electrode of the base is formed so that the outer diameter thereof is larger than the outer diameter of the substrate, and the outer peripheral portion projects outward from the substrate fixed on the base. The plasma processing apparatus according to claim 1.   The plasma processing apparatus according to claim 2, wherein the electrode of the base is configured such that a protruding amount of an outer peripheral portion of the electrode from the substrate on the base is 29 mm or less. The insulator of the base and the protective member are made of the same material,
The thickness of the insulator of the base is such that the thickness (X) of the portion corresponding to the region on the center side from the outer peripheral edge of the substrate is the thickness of the portion corresponding to the region near the outer peripheral edge of the substrate. Thicker than (Y),
The said thickness (X) is substantially equal to the value which totaled the said thickness (Y) and the plate | board thickness (Z) of the said protection member of the part which covers the said board | substrate. Plasma processing equipment.

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