Member for semiconductor manufacturing apparatus

Abstract

A member 10 for a semiconductor manufacturing apparatus is provided with: a ceramic plate 20 having a circular wafer placement surface 22a and an annular FR placement surface 24a provided on the outer periphery of the wafer placement surface 22a at a level lower than the wafer placement surface 22a; and a cooling plate 30 provided on the lower surface of the ceramic plate 20. A connecting part (cone frustum part 22) connecting the wafer placing surface 22a and the FR placing surface 24a has a cone frustum side surface (conical surface 23a) whose diameter increases from the wafer placing surface 22a to the FR placing surface 24a.

Description

Technical Field This invention relates to components for semiconductor manufacturing apparatus. Background Technology Components for semiconductor manufacturing apparatuses are used to perform CVD, etching, and other processes on wafers using plasma. For example, a component for a semiconductor manufacturing apparatus disclosed in Patent Document 1 includes a ceramic plate and a cooling plate disposed on the lower surface of the ceramic plate. The ceramic plate has a circular wafer mounting surface disposed on its upper surface and an annular focusing ring mounting surface disposed at a position one level lower than the wafer mounting surface on the outer periphery of the wafer mounting surface. The connecting portion connecting the wafer mounting surface and the focusing ring mounting surface has a side surface perpendicular to the wafer mounting surface. The focusing ring, placed on the focusing ring mounting surface, has a step along its inner periphery at its upper end in a manner that does not interfere with the wafer. The wafer, placed on the wafer mounting surface, is mounted in a state of overhanging from the wafer mounting surface. Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2023-27641 Summary of the Invention When processing a wafer using the components of the aforementioned semiconductor manufacturing apparatus, the wafer contains heat input from the plasma; however, the wafer is cooled by a cooling plate. However, the outer periphery of the wafer, being suspended from the wafer mounting surface, sometimes does not receive sufficient cooling and instead reaches locally high temperatures. The present invention was implemented to solve the above-mentioned problems, and its main objective is to improve the ability to cool the outer periphery of the wafer.

[0001] The semiconductor manufacturing apparatus component of the present invention includes: A ceramic plate having a circular wafer mounting surface and an annular focusing ring mounting surface disposed at a position one level lower than the wafer mounting surface on the outer periphery of the wafer mounting surface; and A cooling plate is disposed on the lower surface of the ceramic plate. The connecting portion that connects the wafer mounting surface and the focusing ring mounting surface has a truncated cone side surface whose diameter increases as it moves from the wafer mounting surface toward the focusing ring mounting surface. In this component of the semiconductor manufacturing apparatus, the connecting portion that links the wafer mounting surface and the focusing ring mounting surface has a truncated cone-shaped side surface whose diameter increases as it moves from the wafer mounting surface toward the focusing ring mounting surface (i.e., from top to bottom). Therefore, compared to the case where the side surface of the connecting portion is perpendicular to the wafer mounting surface, the heat path from the outer periphery of the wafer mounting surface toward the cooling plate increases. Consequently, the ability to cool the outer periphery of the wafer is improved. Here, the term "lateral surface of a frustum" includes not only cases where it is strictly speaking the lateral surface of a frustum, but also cases where the lateral surface of a frustum is convex and cases where the lateral surface of a frustum is concave (the same applies below).

[0002] In the semiconductor manufacturing apparatus component of the present invention (the semiconductor manufacturing apparatus component described in [1] above), the diameter of the wafer mounting surface can be smaller than the diameter of the wafer being mounted. In this case, the outer periphery of the wafer is particularly prone to reaching high temperatures, therefore, the application of the present invention is of great significance.

[0003] In the semiconductor manufacturing apparatus component of the present invention (the semiconductor manufacturing apparatus component described in [1] or [2] above), the angle between the side of the connecting portion and the focusing ring placement surface can be 70° or less. Accordingly, the thermal path from the outer periphery of the wafer placement surface to the cooling plate can be sufficiently increased.

[0004] The semiconductor manufacturing apparatus component of the present invention (the semiconductor manufacturing apparatus component described in any one of [1] to [3] above) may include: a focusing ring placed on the focusing ring mounting surface, wherein the portion of the inner peripheral surface of the focusing ring facing the side of the connecting portion is a side of a frustum-shaped cone whose diameter increases from top to bottom. For example, when the wafer placed on the wafer mounting surface is configured to cover the inner peripheral portion of the focusing ring from top to bottom, the inner peripheral portion of the focusing ring does not receive heat input from the plasma, and therefore cools down more easily than other portions. However, since the portion of the inner peripheral surface of the focusing ring facing the side of the connecting portion is a side of a frustum-shaped cone whose diameter increases from top to bottom, less heat is carried away by the cooling plate. As a result, excessive cooling of the inner peripheral portion of the focusing ring, which is usually easy to cool down, can be suppressed.

[0005] In the semiconductor manufacturing apparatus component of the present invention (the semiconductor manufacturing apparatus component described above [4]), the angle of the portion relative to the focusing ring mounting surface can be greater than the angle of the side surface of the connecting portion relative to the focusing ring mounting surface. Accordingly, the gap between the side surface of the connecting portion of the ceramic plate and the portion of the inner peripheral surface of the focusing ring that faces the side surface of the connecting portion tends to be larger towards the top, thus making it easier to prevent the focusing ring from contacting the ceramic plate.

[0006] In the semiconductor manufacturing apparatus component of the present invention (the semiconductor manufacturing apparatus component described above [4]), the angle of the portion relative to the focusing ring mounting surface can be smaller than the angle of the side surface of the connecting portion relative to the focusing ring mounting surface. Accordingly, the contact area between the lower surface of the inner peripheral side of the focusing ring and the focusing ring mounting surface can be sufficiently reduced, and thus, excessive cooling of the inner peripheral portion of the focusing ring, which is usually prone to cooling, can be suppressed more effectively. Attached Figure Description Figure 1This is a longitudinal cross-sectional view of component 10 for a semiconductor manufacturing apparatus. Figure 2 This is a plan view of component 10 for a semiconductor manufacturing apparatus. Figure 3 yes Figure 1 A magnified view of a portion of the image. Figure 4 This is a magnified view of the comparison method. Figure 5 This is a partially enlarged view of another embodiment. Figure 6 This is a partially enlarged view of another embodiment. Detailed Implementation Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a longitudinal cross-sectional view of component 10 for a semiconductor manufacturing apparatus (a cross-sectional view cut along a surface including the central axis of component 10 for a semiconductor manufacturing apparatus). Figure 2 This is a plan view of component 10 for a semiconductor manufacturing apparatus. Figure 3 yes Figure 1 Enlarged view of a part ( Figure 1 (Enlarged view of the part enclosed by the circle). In the following description, we sometimes use terms such as up and down, left and right, front and back, etc., but these are just relative positional relationships. The semiconductor manufacturing apparatus component 10 is a component used for performing CVD, etching, and other processes on a wafer W using plasma, and is fixed to a mounting plate 84 disposed inside a semiconductor process chamber 80. The semiconductor manufacturing apparatus component 10 includes: a ceramic plate 20, a cooling plate 30, a bonding layer 40, and a focusing ring 60. Hereinafter, the "focusing ring" is abbreviated as "FR". The ceramic plate 20 has a circular wafer mounting surface 22a and an annular FR mounting surface 24a located at a lower position than the wafer mounting surface 22a on the outer periphery of the wafer mounting surface 22a. A wafer W is mounted on the wafer mounting surface 22a, and an FR60 is mounted on the FR mounting surface 24a. The ceramic plate 20 is formed of a ceramic material such as alumina or aluminum nitride. The ceramic plate 20 is formed into a shape obtained by stacking a frustum-shaped portion 22 on the upper surface of a flat cylindrical portion 24. In the ceramic plate 20, the upper surface of the frustum-shaped portion 22 is the wafer mounting surface 22a, and the annular surface of the upper surface of the cylindrical portion 24, excluding the frustum-shaped portion 22, is the FR mounting surface 24a. The frustum-shaped portion 22 also serves as a connecting portion that connects the wafer mounting surface 22a and the FR mounting surface 24a. Therefore, the connecting portion has a truncated cone-shaped side surface (conical surface 23a) whose diameter increases as it approaches the FR mounting surface 24a from the wafer mounting surface 22a. The angle α of the conical surface 23a relative to the FR mounting surface 24a (refer to...) Figure 3Angle α is less than 90°, preferably less than 80°, and more preferably less than 70°. There is no particular limitation on the lower limit of angle α, but angle α is preferably 20° or more. If angle α is 20° or more, the end of FR60 will not become an excessively acute angle, reducing concerns about FR60 cracking, and is therefore preferred. The diameter of the wafer mounting surface 22a is smaller than the diameter of the wafer W (e.g., 300 mm). A wafer adsorption electrode 25 is built into the frustum-shaped portion 22 of the ceramic plate 20. The wafer adsorption electrode 25 is formed of a material containing, for example, W, Mo, WC, MoC, etc. The wafer adsorption electrode 25 is a unipolar electrostatic electrode in the shape of a disc or a mesh. The layer in the ceramic plate 20 above the wafer adsorption electrode 25 functions as a dielectric layer. A DC power supply for wafer adsorption (not shown) is connected to the wafer adsorption electrode 25. An FR adsorption electrode 26 is embedded in the cylindrical portion 24 of the ceramic plate 20. The FR adsorption electrode 26 is implanted in the cylindrical portion 24 opposite to the FR placement surface 24a. The FR adsorption electrode 26 is formed of a material containing, for example, W, Mo, WC, MoC, etc. The FR adsorption electrode 26 is a ring-shaped or mesh-shaped unipolar electrostatic electrode. The layer in the ceramic plate 20 above the FR adsorption electrode 26 functions as a dielectric layer. A DC power supply for FR adsorption (not shown) is connected to the FR adsorption electrode 26. The cooling plate 30 is a circular plate component having an internal refrigerant flow path 32 for refrigerant circulation. The refrigerant flow path 32 is formed in a single stroke from one end to the other, covering the entire surface of the ceramic plate 20 when viewed from above. In this embodiment, the diameter of the cooling plate 30 is the same as the diameter of the lower surface of the ceramic plate 20. The refrigerant flowing in the refrigerant flow path 32 is preferably a liquid and preferably electrically insulating. Examples of electrically insulating liquids include fluorine-based inactive liquids. The cooling plate 30 is made of a conductive material containing, for example, a metal. Examples of conductive materials include metals and composite materials. Examples of metals include Al, Ti, Mo, or alloys thereof. Examples of composite materials include metal matrix composites (MMC) and ceramic matrix composites (CMC). Specific examples of such composite materials include materials containing Si, SiC, and Ti, and materials obtained by impregnating Al and / or Si into a porous SiC body. Materials containing Si, SiC, and Ti are referred to as SiSiCTi; materials obtained by impregnating Al in porous SiC are referred to as AlSiC; and materials obtained by impregnating Si in porous SiC are referred to as SiSiC. As the material for the cooling plate 30, a material with a coefficient of thermal expansion similar to that of the ceramic plate 20 is preferred. The cooling plate 30 also serves as an RF electrode. A protective film made of an insulating material (e.g., alumina, yttrium oxide) can be formed on the outer peripheral surface of the cooling plate 30. The bonding layer 40 bonds the lower surface of the ceramic plate 20 and the upper surface of the cooling plate 30. In this embodiment, the bonding layer 40 is an organic adhesive layer. Acrylic resin, silicone resin, epoxy resin, and other resins can be used as the organic adhesive layer. In addition to resin, it can also contain fillers. FR60 is an annular component placed on the FR placement surface 24a, and is formed, for example, from silicon. A step 62 is provided along the circumferential direction on the upper part of the inner circumferential surface of FR60. The purpose of providing the step 62 is to prevent interference between the wafer W and FR60. The portion 63 of the inner circumferential surface of FR60 opposite the conical surface 23a is the side surface (conical surface) of a frustum of a cone whose diameter increases from top to bottom. This portion 63 does not contact the conical surface 23a. That is, a gap is formed between this portion 63 and the conical surface 23a. Therefore, FR60 is less susceptible to the thermal effects of the frustum of a cone portion 22 of the ceramic plate 20. In this embodiment, the angle β of portion 63 relative to the FR placement surface 24a (refer to...) Figure 3 The angle α between the conical surface 23a and the FR loading surface 24a is the same. Next, use Figure 1The following describes an example of the use of component 10 for a semiconductor manufacturing apparatus. A chamber 80 has a spray head 82 on its top surface. Component 10 for the semiconductor manufacturing apparatus is fixed to a mounting plate 84 disposed inside the chamber 80. Specifically, an O-ring 88 with a diameter approximately the same as that of the cooling plate 30 is disposed between the lower surface of the cooling plate 30 and the upper surface of the mounting plate 84. In this state, the mounting plate 84 and the cooling plate 30 are fastened with multiple bolts 90, thereby fixing component 10 for the semiconductor manufacturing apparatus to the mounting plate 84. Each bolt 90 has a head and a foot. The bolt 90 is inserted from below into a stepped bolt insertion hole 86 that extends vertically through the mounting plate 84, and the foot is screwed into a screw hole 34 provided on the lower surface of the cooling plate 30. At this time, the head of the bolt 90 engages with the stepped portion of the bolt insertion hole 86. The O-ring 88 is compressed in the vertical direction to achieve a seal. If there are other parts where a seal is required, an O-ring is also provided at those parts. An FR60 is placed on the FR mounting surface 24a of the semiconductor manufacturing apparatus component 10, and a disk-shaped wafer W is placed on the wafer mounting surface 22a. In this state, a DC voltage is applied to the wafer adsorption electrode 25, causing the wafer W to be adsorbed onto the wafer mounting surface 22a, and a DC voltage is applied to the FR adsorption electrode 26, causing the FR60 to be adsorbed onto the FR mounting surface 24a. Then, the interior of the chamber 80 is set to a predetermined vacuum atmosphere (or reduced pressure atmosphere), and while process gas is supplied from the spray head 82, a high-frequency voltage is applied between the spray head 82 and the cooling plate 30. Plasma is then generated between the cooling plate 30 and the spray head 82. The wafer W is then processed using this plasma. It should be noted that FR60 is also consumed during plasma treatment of wafer W. However, FR60 is thicker than wafer W, so FR60 is replaced after multiple wafers W have been treated. When the wafer W is processed using the component 10 of the semiconductor manufacturing apparatus, heat is input from the plasma into the wafer W; however, the wafer W is cooled by the cooling plate 30. Since the diameter of the wafer W is larger than the diameter of the wafer mounting surface 22a, the outer periphery of the wafer W is suspended from the wafer mounting surface 22a. Therefore, the outer periphery of the wafer W is less likely to lose heat through the cooling plate 30 and easily becomes hot. However, in this embodiment, the connecting portion (frustum-shaped portion 22) connecting the wafer mounting surface 22a and the FR mounting surface 24a has a truncated cone-shaped side surface (conical surface 23a) whose diameter increases from the wafer mounting surface 22a towards the FR mounting surface 24a. Therefore, compared to the case where the side surface of the connecting portion is perpendicular to the wafer mounting surface 22a, the heat path from the outer periphery of the wafer mounting surface 22a towards the cooling plate 30 is increased. The following will explain this point in detail. Figure 4This is a partial enlarged view of the comparison method (the prior art method disclosed in Patent Document 1). Figure 4 In this ceramic plate 20, a shape is formed by stacking flat, small-diameter cylindrical portions 122 on the upper surface of a flat cylindrical portion 24. The upper surface of the cylindrical portion 122 in the ceramic plate 20 is a wafer mounting surface 22a. The cylindrical portion 122 also serves as a connecting portion connecting the wafer mounting surface 22a and the FR mounting surface 24a. The connecting portion has a side surface (vertical surface 123a) of the cylindrical portion 122. Additionally, the portion 163 of the inner peripheral surface of the FR60 opposite to the vertical surface 123a is also a vertical surface. It should be noted that... Figure 4 In this embodiment, the same symbols are used to mark the same constituent elements as in this embodiment. Figure 4 The conical surface 23a and portion 63 of this embodiment are shown in dashed lines. In this embodiment, the connecting portion (frustum-shaped portion 22) has a side surface (conical surface 23a) of a frustum-shaped cone whose diameter increases as it approaches the wafer mounting surface 22a towards the FR mounting surface 24a. Therefore, compared to the case where the connecting portion (cylindrical portion 122) has a vertical side surface (vertical surface 123a) as in the comparative embodiment, the heat path from the outer periphery of the wafer mounting surface 22a towards the cooling plate 30 is increased. Specifically, Figure 4 The area represented by the right-angled triangle of the cross-section filled with points is the increased path. Accordingly, in this embodiment, the overhanging outer periphery of the wafer W is easier to dissipate heat compared to the comparison method. Furthermore, the wafer W placed on the wafer mounting surface 22a is configured to cover the inner periphery of the FR60 from above. In this case, Figure 4 In the comparison method, since the heat input of the plasma is blocked by the wafer W, the inner periphery of the FR60 covered by the wafer W cools down more easily than other parts. However, in this embodiment, the inner periphery of the FR60 covered by the wafer W is a shape obtained by obliquely cutting off a portion of the inner periphery of the FR60 in the comparison method, therefore, less heat is removed by the cooling plate 30. As a result, it is possible to suppress excessive cooling of the inner periphery of the FR60, which is normally prone to cooling. According to the semiconductor manufacturing apparatus component 10 described above, the connecting portion (frustum-shaped portion 22) has a frustum-shaped side surface whose diameter increases as it approaches the wafer mounting surface 22a and the FR mounting surface 24a. Therefore, the connecting portion has a side surface (vertical surface 123a) perpendicular to it. Figure 4 Compared to the previous method, the thermal path from the outer periphery of the wafer mounting surface 22a to the cooling plate 30 is increased. Therefore, the ability to cool the outer periphery of the wafer W is improved. Furthermore, the diameter of the wafer mounting surface 22a is smaller than the diameter of the wafer W being mounted. In this case, the outer periphery of the wafer W is particularly prone to reaching high temperatures, therefore, the application of this invention is of great significance. Furthermore, the angle α between the conical surface 23a and the FR mounting surface 24a is preferably 70° or less. This sufficiently increases the heat path from the outer periphery of the wafer mounting surface 22a toward the cooling plate 30. Furthermore, the portion 63 of the inner circumferential surface of FR60 opposite the conical surface 23a is a lateral surface of a truncated cone whose diameter increases from top to bottom. Therefore, it is possible to suppress excessive cooling of the inner circumference of FR60, which is usually prone to cooling. In addition, the side surface of the connecting part (frustum portion 22) of the ceramic plate 20 and the inner peripheral surface portion 63 of the FR60 are both conical surfaces. Therefore, when the FR60 is placed on the FR placement surface 24a, the positioning accuracy of the FR60 is improved due to the self-alignment effect. It should be noted that the present invention is not limited to any of the above embodiments. Of course, any implementation can be carried out in various ways as long as it falls within the technical scope of the present invention. In the above embodiments, the angle α of the conical surface 23a relative to the FR loading surface 24a and the angle β of the portion 63 (conical surface) relative to the FR loading surface 24a are the same, but it is not particularly limited to this. For example, it can be used... Figure 5 , Figure 6 The composition of. Figure 5 and Figure 6 In this document, the same symbols are used to mark the same constituent elements as in the above embodiments. Figure 5 In the middle, the angle β of part 63 (conical surface) relative to the FR placement surface 24a is greater than the angle α of conical surface 23a relative to the FR placement surface 24a (that is, β > α). Accordingly, the gap between part 63 (conical surface) of FR60 and the conical surface 23a of ceramic plate 20 tends to be larger towards the top, thus making it easier to prevent part 63 (conical surface) of FR60 from contacting ceramic plate 20. Figure 6 In this case, the angle β of part 63 (conical surface) relative to the FR mounting surface 24a is smaller than the angle α of conical surface 23a relative to the FR mounting surface 24a (i.e., β < α). Accordingly, the contact area between the lower surface of the inner peripheral side of FR60 and the FR mounting surface 24a can be sufficiently reduced, thus more effectively suppressing excessive cooling of the inner peripheral part of FR60, which is usually prone to cooling. Figure 5 and Figure 6 In this configuration, the angle difference between α and β is preferably 30° or less, and more preferably 15° or less. This reduces concerns about excessive space between the portion 63 of FR60 and the conical surface 23a of the ceramic plate 20, which could lead to discharge. In the above embodiment, the portion 63 of the inner circumferential surface of the ceramic plate 20 opposite to the conical surface 23a is strictly defined as the side surface of a frustum, but it is not particularly limited to this. For example, instead of a strictly frustum side surface, the side surface of the frustum can be convex or concave. The same applies to portion 63. In the above embodiments, a wafer heating heater electrode can be embedded in the frustum-shaped portion 22 of the ceramic plate 20. Accordingly, when it is necessary to raise the temperature of the wafer W placed on the wafer mounting surface 22a, the wafer heating heater electrode can be energized to raise the wafer W to the desired high temperature. Alternatively, an FR heating heater electrode can be embedded in the cylindrical portion 24 of the ceramic plate 20 at a position opposite to the FR mounting surface 24a. Accordingly, when it is necessary to raise the temperature of the FR60 placed on the FR mounting surface 24a, the FR heating heater electrode can be energized to raise the FR60 to the desired high temperature. When both the wafer heating heater electrode and the FR heating heater electrode are embedded in the ceramic plate 20, it is preferable that the temperature of each heater electrode can be adjusted separately. In the above embodiment, an organic adhesive layer is used as the bonding layer 40, but it is not particularly limited to this. For example, the bonding layer 40 can be an inorganic bonding layer such as a metal. The inorganic bonding layer can be a metal bonding layer formed by solder or metal solder (e.g., aluminum, titanium, etc.). The metal bonding layer can also be formed using, for example, TCB (Thermal Compression Bonding). TCB refers to a known method in which a metal bonding material is sandwiched between two components to be bonded, and the two components are pressure-bonded while heated to a temperature below the solidus temperature of the metal bonding material. Industrial availability This invention can be used in components used in semiconductor manufacturing equipment, such as electrostatic chuck heaters, electrostatic chucks, ceramic heaters, etc. Symbol Explanation 10 Components for semiconductor manufacturing apparatus, 20 Ceramic plate, 22 Frustum conical section, 22a Wafer placement surface, 23a Conical surface, 24 Cylindrical section, 24a FR placement surface, 25 Wafer adsorption electrode, 26 FR adsorption electrode, 30 Cooling plate, 32 Refrigerant flow path, 34 Screw hole, 40 Bonding layer, 60 Focusing ring (FR), 62 Step, 63 Section, 80 Chamber, 82 Spray head, 84 Mounting plate, 86 Bolt insertion hole, 88 O-ring, 90 Bolt, 122 Cylindrical section, 123a Vertical surface, 163 Section.

Claims

1. A component for a semiconductor manufacturing apparatus, wherein, have: A ceramic plate having a circular wafer mounting surface and an annular focusing ring mounting surface disposed on the outer periphery of the wafer mounting surface at a position one level lower than the wafer mounting surface; as well as A cooling plate is disposed on the lower surface of the ceramic plate. The connecting portion that connects the wafer mounting surface and the focusing ring mounting surface has a truncated cone side surface whose diameter increases as it moves from the wafer mounting surface toward the focusing ring mounting surface.

2. The component for a semiconductor manufacturing apparatus according to claim 1, wherein, The diameter of the wafer mounting surface is smaller than the diameter of the wafer being mounted.

3. The component for a semiconductor manufacturing apparatus according to claim 1 or 2, wherein, The angle between the side of the connecting part and the focusing ring mounting surface is less than 70°.

4. The component for a semiconductor manufacturing apparatus according to claim 1 or 2, wherein, It includes: a focusing ring placed on the focusing ring mounting surface. The portion of the inner circumferential surface of the focusing ring that faces the side of the connecting part is the side of a frustum of cones whose diameter increases from top to bottom.

5. The component for a semiconductor manufacturing apparatus according to claim 4, wherein, The angle of the portion relative to the focusing ring mounting surface is greater than the angle of the side of the connecting portion relative to the focusing ring mounting surface.

6. The component for a semiconductor manufacturing apparatus according to claim 4, wherein, The angle of the portion relative to the focusing ring mounting surface is smaller than the angle of the side of the connecting portion relative to the focusing ring mounting surface.

Images