JP5331490B2 - Junction structure and semiconductor manufacturing apparatus - Google Patents

Description

  The present invention relates to a junction structure and a semiconductor manufacturing apparatus. More particularly, the present invention relates to a structure for joining a connecting member to a metal terminal embedded in a ceramic member, a joining structure having a connecting member for supplying electric power to an embedded electrode, and a semiconductor manufacturing apparatus having this joining structure.

  In the field of semiconductor manufacturing apparatuses such as etching apparatuses and CVD apparatuses, semiconductor susceptors such as electrostatic checks in which electrodes are embedded in ceramic members are used. For example, a semiconductor susceptor that functions as a discharge electrode for generating plasma by burying an electrode in an aluminum nitride or dense alumina substrate, or a CVD in which a metal resistor (heater) is embedded in an aluminum nitride or alumina substrate A semiconductor susceptor that functions as a ceramic heater for controlling the temperature of a wafer in a heat treatment process such as the above. In semiconductor susceptors that function as an electrostatic chuck for adsorbing and holding semiconductor wafers in film deposition processes such as transport, exposure, CVD, and sputtering, microfabrication, cleaning, etching, and dicing. Some have electrodes embedded.

  In order to supply power to these semiconductor devices from the outside, for example, a semiconductor susceptor has a joint structure including a connection member that supplies power from the outside to a terminal embedded in a ceramic member. (For example, refer to Patent Document 1.) The end of the electrode provided with the spiral groove is screwed into the spiral groove provided inside the connection member, so that power is supplied from the outside to the semiconductor susceptor. There is something.

  However, there is a tendency that the joint structure is damaged due to stress when the end of the electrode is screwed into the groove of the connection member or due to stress applied to the joint structure during use of the semiconductor susceptor. Therefore, the improvement of the torsional breaking strength of the joint structure has been demanded.

Japanese Patent No. 379000

  The present invention provides a junction structure having a high torsional break strength, and a semiconductor manufacturing apparatus having the junction structure, including a metal connection member that is connected to the outside or supplies power from the outside to a metal terminal embedded in a ceramic member. With the goal.

  A first feature of the present invention is a ceramic member having a hole and an exposed surface embedded in the ceramic member and exposed at the bottom of the hole, and has a high melting point substantially the same as that of the ceramic member. A metal terminal, a solder joint layer in contact with the exposed surface of the terminal, a ceramic member inserted into the hole and connected to the terminal through the solder joint layer, and a joint member made of a refractory metal having substantially the same thermal expansion coefficient as the ceramic member The inner diameter of the hole is larger than the outer diameter of the connecting member, and when the connecting member is inserted, a clearance is formed between the side wall of the hole and the connecting member, and a low reservoir space is formed on the side wall of the hole. The solder storage space is formed and has a substantially semicircular shape in a cross section parallel to the main surface of the ceramic member, and at least a part of the solder storage space is filled with a soldering material. Is the gist.

  ADVANTAGE OF THE INVENTION According to this invention, the joining structure with high torsion breaking strength provided with the metal connection member which connects with the exterior to the metal terminal embed | buried in the ceramic member or supplies electric power from the outside, and the semiconductor manufacturing apparatus which has this junction structure are provided. Is done.

FIG. 1A is a schematic cross-sectional view perpendicular to the main surface of the ceramic member of the semiconductor susceptor according to the embodiment, and FIG. 1B is the main surface of the ceramic member of the semiconductor susceptor according to the embodiment. 1 shows a schematic cross-sectional view in parallel. FIG. 2 is a manufacturing process diagram of the semiconductor susceptor according to the embodiment. FIG. 3A and FIG. 3B show manufacturing process diagrams of the semiconductor susceptor according to the embodiment. FIG. 4A and FIG. 4B are manufacturing process diagrams of the semiconductor susceptor according to the embodiment. FIGS. 5A and 5B are manufacturing process diagrams of the semiconductor susceptor according to the embodiment. FIG. 6 is a manufacturing process diagram of the semiconductor susceptor according to the embodiment. 7A is a schematic cross-sectional view perpendicular to the main surface of the ceramic member of the semiconductor susceptor according to the first modification of the embodiment, and FIG. 7B is a diagram for the semiconductor according to the first modification of the embodiment. The cross-sectional schematic diagram parallel to the main surface of the ceramic member of a susceptor is shown. FIG. 8A is a schematic cross-sectional view perpendicular to the main surface of the ceramic member of the semiconductor susceptor according to the second modification of the embodiment, and FIG. 8B is a diagram for the semiconductor according to the second modification of the embodiment. The cross-sectional schematic diagram parallel to the main surface of the ceramic member of a susceptor is shown. FIG. 9A is a schematic cross-sectional view perpendicular to the main surface of the ceramic member of the semiconductor susceptor according to the third modification of the embodiment, and FIG. 9B is a diagram for the semiconductor according to the third modification of the embodiment. A1A2 cross-sectional schematic view parallel to the main surface of the ceramic member of the susceptor is shown, and FIG. 9C shows a cross-sectional schematic view of B1B2 parallel to the main surface of the ceramic member of the semiconductor susceptor according to Modification 3 of the embodiment. . FIG. 10A is a schematic cross-sectional view perpendicular to the main surface of the ceramic member of the semiconductor susceptor without clearance, and FIG. 10B is a schematic cross-sectional view of the main surface of the ceramic member of the semiconductor susceptor without clearance. The figure is shown. FIG. 11A shows a schematic cross-sectional view perpendicular to the main surface of the ceramic member of the semiconductor susceptor provided with a clearance, and FIG. 11B shows the main surface of the ceramic member of the semiconductor susceptor provided with a clearance. 1 shows a schematic cross-sectional view in parallel.

  Hereinafter, the present invention will be described with reference to embodiments, but the present invention is not limited to the following embodiments. Components having the same function or similar functions in the figures are given the same or similar reference numerals and description thereof is omitted.

Embodiment
(Semiconductor susceptor (junction structure))
FIG. 1A is a schematic cross-sectional view perpendicular to the main surface of the ceramic member of the semiconductor susceptor according to the embodiment, and FIG. 1B is the main surface of the ceramic member of the semiconductor susceptor according to the embodiment. 1 shows a schematic cross-sectional view in parallel. In addition, by explaining the semiconductor susceptor 11 according to the embodiment, a junction structure and a semiconductor device having the junction structure will also be explained.

  The semiconductor susceptor 11 according to the embodiment includes a ceramic member 14 in which a heater resistor 2 is embedded as a conductor layer and a hole 14a is provided in the upper portion, and a first main surface is exposed at the bottom of the hole 14a. The solder 3 includes a terminal 3 made of a refractory metal having substantially the same thermal expansion coefficient as that of the ceramic member 4 in electrical contact with the heater resistor 2 and gold (Au) in contact with the first main surface of the terminal 3. The bonding layer 61 and the connecting member 5 made of a refractory metal having substantially the same thermal expansion coefficient as the ceramic member 14 inserted into the hole 14a and connected to the terminal 3 through the solder bonding layer 61 are provided. The heater resistor 2 as a conductor layer is embedded in parallel to the main surface of the ceramic member 14. The inner diameter of the hole 14 a is larger than the outer diameter of the connection member 5. A clearance 14b is formed between the outer diameter of the connecting member 5 so that the connecting member 5 can be inserted into the hole 14a and so that the connecting member 5 can be thermally expanded when inserted. The clearance 14b may extend over the entire circumference of the connection member 5, or a part thereof may be in contact with the hole 14a. The absence of the clearance 14b over the entire circumference does not substantially occur.

  As shown in FIG. 3A and FIG. 4, the solder bonding layer 61 is formed between the main surface of the end portion of the connection member 5 and the bottom surface of the hole 14 a including the first main surface (exposed surface) of the terminal 3. It is provided in between, and fills a substantially cylindrical first space 14c having the main surface at the end of the connection member 5 as the upper surface (bottom surface). When the ceramic member 14 is cut parallel to the main surface of the ceramic member 14, the wax reservoir space 14 d having a substantially semicircular cross-section when viewed from the opening side of the hole 14 a is a part of the side wall of the hole 14 a of the ceramic member 14. And a brazing material 62 constituting a part of the brazing bonding layer 61 fills a part of the brazing reservoir space 14d.

  A spiral groove 5a is cut inside the connecting member 5 and is not shown for easy understanding of the invention, but an electrode having a spiral groove for supplying power to the susceptor 11 in the groove 5a. The end of is screwed.

  The clearance 14b is preferably greater than 0 mm and approximately 0.5 mm or less when the outer diameter of the connecting member 5 is 4 to 6 mm. If it is smaller than the lower limit value, the connecting member 5 cannot be inserted into the hole 14a, which makes the production extremely difficult. This is because if the hole diameter is large, impurities are likely to enter, which may cause contamination of the contamination source and electrode. Of course, the larger the hole in the ceramic, the lower the strength of the ceramic and the role of a guide when the connecting member 5 is inserted. Therefore, it is not necessary to make a hole larger than necessary.

The ceramic member 14 is not particularly limited, and examples thereof include alumina, aluminum nitride (AlN), Si ₃ N ₄ , and boron nitride (BN). These can be formed into a desired shape by a sintering method or the like.

As the material of the terminal 3, since the terminal 3 is fired simultaneously with the ceramic powder such as alumina powder or aluminum nitride powder when the ceramic member 14 is manufactured, the terminal 3 is formed of a high melting point metal having substantially the same thermal expansion coefficient as that of the ceramic. It is preferred that A combination of alumina and niobium or titanium, aluminum nitride and molybdenum or platinum, Si ₃ N ₄ , boron nitride (BN) and tungsten is preferable. Although not limited to these combinations, it is preferable to use aluminum nitride and molybdenum. When aluminum nitride ceramics is used as the ceramic member 14, the thermal expansion coefficient is close to that of the aluminum nitride ceramics, and it can be used as a bulk body having a high melting point and a certain size that can be embedded inside when firing the aluminum nitride ceramics. From the viewpoint, it is preferable to use molybdenum.

  As a material of the connection member 5, it is preferable to use a metal having the same thermal expansion coefficient as that of the terminal 3. This is because when the connecting member 5 and the ceramic member 4 are directly brazed, the bonding strength tends to decrease due to the difference in thermal expansion between them.

  When the connecting member 5 and the terminal 3 are made of the same material, the stress difference between the connecting member 5 and the terminal 3 is eliminated, and the stress on the ceramic member 14 can be relieved. From the above viewpoint, when the ceramic member is aluminum nitride, it is particularly preferable to use molybdenum as the connection member 5 and the terminal 3. Aluminum nitride is an insulating material with high thermal conductivity and high strength, and is an optimal material for use in the semiconductor susceptor 11.

  It is preferable that the diameter of the solder bonding layer 6 is approximately the same as the diameter of the connection member 5. The thickness of the brazing layer 6 is preferably 0.1 mm or more and 0.2 mm or less when the diameter of the brazing layer 6 is 4 mm or more and 6 mm or less. This is because the bonding strength is lowered when it is out of the above range.

  The heater resistor 2 is not particularly limited, but is preferably a planar metal bulk material. As the planar metal bulk material, for example, a metal formed as an integral planar shape, but in addition, a bulk material composed of a plate-like body having a large number of small holes (punching metal) or a net-like bulk material Is included.

  The material of the brazing bonding layer 6 is not particularly limited, but it is preferable to use a brazing material made only of gold. By preventing nickel (Ni) from being contained in the solder joint layer 6, no intermetallic compound is generated between the connection member 5 and the terminal 3, resulting in durability against external forces such as thermal cycle and handling. It is because it improves. Further, since the brazing layer 6 made of only gold (Au) is used, a solid solution layer is formed instead of a fragile intermetallic compound, so that it functions as a buffer layer when an external force is applied.

  In addition to the brazing material made only of gold, various brazing materials can be used for the brazing layer 6.

  The solder bonding layer 6 may be a three-layer structure including a first tantalum layer in contact with the first main surface of the terminal 3, a gold layer on the first tantalum layer, and a second tantalum layer on the gold layer. In the case where the first tantalum layer and the second tantalum layer are provided in the solder bonding layer 6 with the gold layer sandwiched therebetween, it is not necessary to provide a particular difference between the first tantalum layer and the second tantalum layer, and the purity and the like of both are substantially the same. Are the same. The diameter of the brazing layer 6 is preferably approximately the same as the diameter of the connection member 5. The thickness of the brazing layer 6 is a gold (Au) layer when the diameter of the brazing layer 6 is 4 mm or more and 6 mm or less, and the thicknesses of the first and second tantalum layers are 0.001 mm, respectively. The thickness is preferably more than 0.05 mm and less than 0.3 mm. This is because the bonding strength decreases when the thickness of the gold (Au) layer is out of the above range. Further, when the diameter of the brazing layer 6 is 4 mm or more and 6 mm or less and the thickness of the gold (Au) layer is 0.15 mm, the thicknesses of the first tantalum layer and the second tantalum layer are 0.001 mm or more and 0, respectively. 0.07 mm or less is preferable. This is because if the thicknesses of the first tantalum layer and the second tantalum layer are out of the above ranges, the bonding strength is lowered.

  An example of a conventional joining structure is shown in FIGS. 10A and 10B as a comparative example. In the comparative example, in the case of the semiconductor susceptor 101 having no clearance, the portion excluding the space occupied by the connection member 5 in the hole 4a of the ceramic member 4 is filled and the semiconductor susceptor 101 without clearance is fixed without clearance. Alternatively, stress is generated due to the difference in thermal expansion between the connecting member 5 and the ceramics during the temperature cycle during use, and the ceramic member 4 around the connecting member 5 tends to be damaged. On the other hand, since the semiconductor susceptor 11 according to the embodiment includes the clearance 4b, when the connection member 5 is thermally expanded, thermal stress is hardly generated by the clearance 14b, so that the ceramic member 14 is not damaged. Further, the semiconductor susceptor according to the embodiment includes a low reservoir space 14d in a part of the clearance 14b. Since the wax-reservoir space 14d and the brazing material 62 serve as keys (hereinafter referred to as “key effect”), the torsional breaking strength with respect to the force of turning around the axis of the connecting member 5 is far greater than in the case where the wax reservoir space 14d is not provided. Very expensive.

  According to the embodiment, since only a part of the clearance 14b is filled with the brazing material 62, the connection member 5 and the ceramic member 14 are firmly restrained only at a part of the side surface of the hole 14a. A clearance 14b is formed in most of the area. Therefore, the destruction of the ceramic member 4 that occurs when the entire clearance 4b as shown in FIG. 10 is filled with the brazing layer 106 does not occur in the embodiment.

  That is, the embodiment has a much higher torsional breaking strength than that including the connecting member 5 having the same cross-sectional shape as the hole 4a as shown in FIG. As shown in FIG. 10, when the connecting member 5 having the same cross-sectional shape as the hole 4 a is inserted, a clearance 4 b is generated between the hole 4 a and the connecting member 5. Although a circular shape is shown in FIG. 10, the clearance 4b is generated even in a connection member having a shape with a protrusion in part. Although the connecting member 5 may be in contact with a part of the hole 4a, there is always a clearance 4b depending on the direction in which the connecting member 5 is twisted. On the other hand, in the embodiment, even when the screw screwed into the groove 5a of the connection member 5 is tightened or loosened, the solder reservoir space 14d has a clearance 14b so that there is no clearance 14b in both twisting directions. Since the material 62 is filled, a high strength torsional breaking strength is exhibited by the key effect.

  The wax reservoir space 14d may be provided at one place, but a plurality of wax reservoir spaces 14d may be provided. This is because, for example, the torsion breaking strength is further increased by arranging the wax reservoir spaces 14d so as to be symmetrical with each other at two or four locations. However, if the number is increased to, for example, 5 or more, the amount of the necessary brazing material increases, and the possibility of breakage in the ceramic increases, which is not preferable. Especially, it is preferable that one or two sets of the wax reservoir space 14d are provided at positions facing each other on the side wall of the hole 14a, and one set is provided at a position facing each other on the side wall of the hole 14a. Most preferred.

  According to the embodiment, there is provided a highly reliable joint structure that can be used even at a high temperature and a semiconductor manufacturing apparatus having the joint structure that is highly reliable even when the external spiral is screwed and removed.

(Manufacturing method of semiconductor susceptor (junction structure))
(A) A ceramic member 14 in which a heater resistor 2 is embedded in parallel to the main surface of the ceramic member 14 as shown in FIG. 2 and terminals 3 are embedded in electrical contact with the heater resistor 2 is prepared.

(B) As shown in FIGS. 3A and 3B, when the connecting member 5 is inserted, a clearance 14b is formed between the connecting member 5 and the outer diameter of the connecting member 5 so that the connecting member 5 can be thermally expanded. The hole 14a having an inner diameter larger than the outer diameter of the connecting member 5 is provided. In addition, the brazing layer 61 is filled in the first space 14c (6) indicated by the phantom line in FIG.

(C) As shown in FIGS. 4A and 4B, a solder reservoir space 14d is formed in a part of the outer periphery of the hole 14a of the ceramic member 14 using a drill or the like. In this case, the wax reservoir space 14d may be formed simultaneously with the hole 14a.

(D) As shown in FIGS. 5A and 5B, the seal member 10 is disposed on the ceramic member 14 except for the wax reservoir space 14d, and metallization is performed. Further, it is preferable to perform the metallization process on the connection member 5 except for the portion where the solder bonding layer 6 is desired to be raised. By performing the metallization process, it is easy to climb up to the wax storage space 14d when the brazing material is melted, but this is not always necessary. The connection member 5 is preferably subjected to surface oxidation treatment except for a portion where the solder bonding layer 6 is desired to rise. Since the brazing material does not crawl up by the surface oxidation treatment, it is possible to prevent the entire clearance from being filled with the brazing material. Not only the surface oxidation treatment but also a substance having poor wettability may be applied. If either or both of the metallization process for ceramics and the surface oxidation process for the connection member 5 are performed, the brazing material can be scooped up only in the solder reservoir space 14d.

(E) As shown in FIG. 6, the row bonding layer 6 is disposed in the first space 14 c on the first main surface (exposed surface) of the terminal 3. Then, the connecting member 5 is disposed in the hole 14 a of the ceramic member 14 through the brazing bonding layer 6. The first space 14 c defined between the bottom surface of the hole 14 a including the connection member 5 and the first main surface of the terminal 3 is filled with the brazing bonding layer 6. Thereafter, the brazing layer 6 is melted by heating. The heating temperature is preferably about 20 ° C. higher than the melting point of gold. After confirming the melting of the brazing layer 6, it is left at that temperature for about 5 minutes.

(F) As shown in FIG. 1, the brazing layer 6 is filled with the brazing layer 6 by selectively climbing up the side surface of the connecting member 5 and the side surface of the brazing space 14d. Then, heating is stopped and natural cooling is performed. The connecting member 5 is connected to the terminal 3 through the solder bonding layer 6.

  As described above, the semiconductor susceptor 11 shown in FIGS. 1A and 1B is manufactured.

(Modification of the embodiment)
As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. Specifically, in order to increase the torsion breaking strength, the following configuration may be used.

  Modification 1: The wax reservoir space 14d having a substantially semicircular cross section parallel to the main surface of the ceramic member 14 shown in FIG. 7A is formed in the hole 14a of the ceramic member 14 as shown in FIG. 7B. Provided on a part of the side wall, the connecting member 5 includes a convex portion 5b on a part of the outer peripheral surface of the connecting member 5 so as to fill a part of the wax reservoir space 14d. The convex portion 5 b has a substantially semicircular shape in a cross section parallel to the main surface of the ceramic member 14. The brazing material 62 may be configured so as to fill a part of the wax storage space 14d continuously with the first space 14c. Here, the wax reservoir space 14d and the convex portion 5b constitute a key portion by fitting. In FIG. 7, the surface of the side surface of the connecting member 5 other than the convex portion 5b is oxidized to deteriorate the wettability of the brazing material so that the brazing material does not crawl up to the side surface other than the convex portion 5b of the connecting member. It has become.

  Modification 2: As shown in FIGS. 8A and 8B, the connecting member 5 includes a notch 5 c cut inwardly at a part of the outer peripheral surface of the connecting member 5, and is attached to the ceramic member 34. In this case, the brazing material 62 constituting a part of the brazing bonding layer 61 may be configured so as to continuously fill a part of the notch 5c in the first space 34c.

  Modification 3: As shown in FIG. 9C, a groove 43 a may be cut in a cross shape on the surface of the first main surface of the terminal 43. This is because when the brazing layer 6a enters the groove 43a, an anchor effect is obtained and the torsion breaking strength is increased.

  In addition, a semiconductor manufacturing apparatus is provided in which a semiconductor substrate is mounted on the susceptor (bonding structure) according to the embodiment, and the semiconductor substrate is processed. As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

(Torsion breaking test)
According to the description of the embodiment, the semiconductor susceptor shown in FIGS. 1 and 7 to 11 was manufactured under the conditions shown in Table 1. Then, the connecting member 5 was twisted with a torque wrench, the torque was increased by 0.1 N · m, and the torsional breaking torque was measured. Thereafter, each semiconductor susceptor was heated at 200 ° C. and heated at 700 ° C. for 100 cycles. The torsional breaking torque was measured in the same manner as described above. The results obtained are summarized in Table 1.

  From Reference Example 1 and Reference Example 2, it was found that the torsional breaking torque was somewhat improved by providing the clearance. In Reference Example 1, the torsional break torque after the durability test was remarkably reduced, and cracks were found in the ceramic because there was no clearance. Further, from Examples 1 to 4, it was found that the torsion breaking torque is remarkably improved by providing the wax reservoir space and the anchor in addition to the clearance due to the key effect and the anchor effect. There was no decrease in torsional break torque after the durability test. Further, from Examples 2 and 3, it was found that the torsional breaking torque was further improved by providing a key part and a notch part in addition to the wax reservoir space.

1: Semiconductor susceptor 2: Heater resistor 3: Terminal 4: Hole 5: Connection member 5a: Groove 5b: Convex portion 5c: Notch 6: Brazing layer

Claims (7)

A ceramic member provided with a hole;
A terminal made of a refractory metal embedded in the ceramic member and having an exposed surface exposed at the bottom of the hole, the thermal expansion coefficient of which is substantially the same as that of the ceramic member;
A solder bonding layer in contact with the exposed surface of the terminal;
Inserted into the hole and connected to the terminal via the solder bonding layer, and comprising a connecting member made of a refractory metal having substantially the same thermal expansion coefficient as the ceramic member,
The inner diameter of the hole is larger than the outer diameter of the connecting member,
When the connecting member is inserted, a clearance is formed between the side wall of the hole and the connecting member ,
A wax reservoir space is formed on the side wall of the hole,
The wax storage space has a substantially semicircular shape in a cross section parallel to the main surface of the ceramic member,
A joining structure, wherein at least a part of the brazing reservoir space is filled with a brazing material. The connection member has a convex portion disposed in the wax reservoir space;
The convex portion, in a cross section parallel to the main surface of the ceramic member has a substantially semicircular shape,
The joining structure according to claim 1, wherein the wax storage space and the convex part form a key part by fitting. A part of the outer peripheral surface of the connection member is formed with a notch that is recessed inside the connection member,
The joining structure according to claim 1 or 2, wherein at least a part of the notch is filled with a brazing material. A groove filled with brazing material is formed on the exposed surface of the terminal,
The joining structure according to claim 1, wherein the brazing material filled in the groove constitutes an anchor.   5. The joining structure according to claim 1, wherein two to four wax reservoir spaces are formed on the sidewalls of the holes as the wax reservoir spaces.   6. The joining structure according to claim 5, wherein one or two sets of wax storage spaces facing each other are formed on the side wall of the hole as the wax storage space.   The bonding structure according to claim 1, wherein the ceramic member is made of aluminum nitride, and the refractory metal having substantially the same thermal expansion coefficient as the ceramic member is molybdenum. A semiconductor manufacturing apparatus comprising:

Images