JP7589112B2 - Ceramic joint and method for producing same - Google Patents

Description

This disclosure relates to a ceramic joint and a method for manufacturing the same.

In the manufacturing process of semiconductor products, vacuum chucks are used to attract and hold objects to be attracted in processes such as film formation, processing, wiring formation, and inspection. As shown in Patent Document 1, for example, a vacuum chuck is formed by joining an attracting part made of a porous body having an attracting surface that attracts and holds an object to be attracted, such as a substrate or element, and a supporting part made of a dense body having a recess for housing the porous body.

If the flatness of the recess is large, the gap between the back surface of the suction part and the suction part when it is inserted will be large, and a space that causes poor bonding will easily occur. Poor bonding will cause a decrease in bonding strength and variations in suction force and temperature distribution. When a vacuum chuck is used in a grinding device or thermocompression bonding device, the suction part will deform due to the load when pressed. This will result in a decrease in processing accuracy and cause poor bonding. To improve the processing accuracy of the wafer or other object to be suctioned, it is better for the bottom surface of the recess to be as flat as possible.

On the other hand, in order to improve the bonding strength, it is preferable that the bottom surface of the recess is moderately rough in the hope of creating an anchor effect. Surfaces that can be lapped, such as the back surface of the suction part, tend to form a moderately rough, flat surface. However, the surface roughness of the bottom surface of the recess tends to decrease with flattening (e.g., grinding). If roughening (e.g., blasting) is performed after flattening, the flatness tends to increase.

JP 2012-140257 A

The objective of this disclosure is to provide a ceramic joint that reduces poor bonding between the back surface of the bonding layer and the recessed portion, firmly bonds the back surface of the bonding layer and the recessed portion, and has excellent thermal conductivity.

The ceramic joint according to the present disclosure includes a first ceramic member having a flat surface and a back surface located opposite the flat surface, a second ceramic member having a recess for accommodating the first ceramic member, and a vitreous joint layer that joins the back surface of the first ceramic member to the bottom surface of the recess of the second ceramic member. The bottom surface of the recess of the second ceramic member includes a groove portion and a flat portion other than the groove portion. The arithmetic mean roughness of the groove portion surface is greater than the arithmetic mean roughness of the flat portion surface. The joint layer joins at least the groove portion to the back surface.

The method for manufacturing a ceramic joint according to the present disclosure includes the steps of: preparing a first ceramic member having a flat surface and a back surface opposite the flat surface; preparing a second ceramic member having a recess for accommodating the first ceramic member; planarizing the bottom surface of the recess of the second ceramic member; forming a groove in the bottom surface of the recess of the second ceramic member by laser processing; and applying glass paste to at least one of the back surface of the first ceramic member and the recess of the second ceramic member, bonding them together and firing them, and bonding at least the groove and the back surface with a glassy bonding layer.

According to the ceramic joint according to the present disclosure, the bottom surface of the recess of the second ceramic member includes a groove portion and a flat portion other than the groove portion, and the arithmetic mean roughness of the groove portion surface is greater than the arithmetic mean roughness of the flat portion surface. Therefore, the ceramic joint according to the present disclosure has reduced bonding failure between the back surface of the bonding layer and the recess, firmly bonds the back surface of the bonding layer and the recess, and has excellent thermal conductivity.

Furthermore, according to the method for manufacturing a ceramic joint according to the present disclosure, poor bonding between the back surface of the bonding layer and the recess is reduced, and the back surface of the bonding layer and the recess are firmly bonded to each other, making it possible to provide a ceramic joint having excellent thermal conductivity.

1A is a perspective view showing a ceramic joined body according to an embodiment of the present disclosure, and FIG. 1B is a perspective view showing a second ceramic member included in the ceramic joined body shown in FIG. 1A is a cross-sectional view taken along line XX in FIG. 1A, and FIG. 1B is an enlarged view of region Y in FIG. 11 is an electron microscope photograph showing a groove formed in a bottom surface of a recess of a second ceramic member in a ceramic joined body according to an embodiment of the present disclosure. Graph (A) is a graph showing the cross-sectional shape, width, and depth of a groove when cut in the direction of arrow A shown in FIG. 3 , and graph (B) is a graph showing the undulations of the bottom surface of the groove when cut in the direction of arrow B shown in FIG. 3 .

As described above, the ceramic joint according to the present disclosure includes a first ceramic member having a flat surface and a back surface located opposite the flat surface, a second ceramic member having a recess for accommodating the first ceramic member, and a glassy joining layer joining the back surface of the first ceramic member to the bottom surface of the recess of the second ceramic member. The ceramic joint according to the present disclosure will be described with reference to Figures 1 and 2.

The ceramic joint 1 according to one embodiment of the present disclosure is a vacuum chuck, and as shown in Figs. 1(A) and 2(A), a first ceramic member 11 is housed in a recess 12a of a second ceramic member 12, and a back surface 11b of the first ceramic member 11 and a bottom surface of the recess 12a of the second ceramic member 12 are joined by a joining layer 13. Fig. 1(A) is a perspective view showing a ceramic joint 1 according to one embodiment. Fig. 2(A) is a cross-sectional view showing a cross section cut along line X-X shown in Fig. 1(A).

The first ceramic member 11 is not limited as long as it is made of ceramic. The first ceramic member 11 is made of, for example, a porous ceramic in which ceramic particles are connected with a binder such as glass. Examples of the ceramic that forms the first ceramic member 11 include carbides such as silicon carbide, nitrides such as silicon nitride, boron nitride, and aluminum nitride, and oxides such as aluminum oxide. In this disclosure, porous means a state in which the area ratio of closed pores in the cross section of the ceramic member is greater than 10%.

The shape and size of the first ceramic member 11 are not limited, and are appropriately set according to the application of the resulting ceramic joint 1 and the shape of the adsorbate. When viewed from above, the first ceramic member 11 has a circular shape as shown in FIG. 1(A). However, the shape of the first ceramic member 11 is not limited to a circular shape, and may be, for example, an elliptical shape or a polygonal shape (triangular, rectangular, pentagonal, hexagonal, etc.). In the case of a polygonal shape, it may be a regular polygon or a scalene polygon.

The size of the first ceramic member 11 is not limited, and may be, for example, a diameter of 10 mm or more and 500 mm or less. If the first ceramic member 11 is elliptical, both the major axis and the minor axis may be within such ranges. If the first ceramic member 11 is polygonal, the length of one side is, for example, 10 mm or more and 500 mm or less. The thickness of the first ceramic member 11 is, for example, 1 mm or more and 50 mm or less.

The first ceramic member 11 has a flat front surface 11a and a back surface 11b located on the opposite side of the front surface 11a. When the first ceramic member 11 is a vacuum chuck as shown in FIG. 1, the front surface 11a serves as an adsorption surface for adsorbing an object to be adsorbed, such as a substrate. On the other hand, the back surface 11b serves as a surface that faces the recess 12a when the first ceramic member 11 is stored in the recess 12a of the second ceramic member 12 described below.

The second ceramic member 12 is a member for housing the first ceramic member 11. The second ceramic member 12 is not limited as long as it is made of ceramic. The second ceramic member 12 is made of, for example, dense ceramic. Dense ceramics are superior in mechanical strength, thermal conductivity, and airtightness compared to porous ceramics, and are suitable for the base that is the main part of the vacuum chuck 1. Examples of ceramics that form the second ceramic member 12 include carbides such as silicon carbide, and nitrides such as silicon nitride, boron nitride, and aluminum nitride. The ceramic that forms the second ceramic member 12 may be the same as or different from the ceramic that forms the first ceramic member 11. In this disclosure, dense refers to a state in which the area ratio of closed pores in the cross section of the ceramic member is less than 10%.

The shape and size of the second ceramic member 12 are not limited, and are appropriately set according to the application of the resulting ceramic joint 1 and the shape of the first ceramic member 11. When viewed from above, the second ceramic member 12 has a circular shape as shown in FIG. 1(A). However, the shape of the second ceramic member 12 is not limited to a circular shape, and may be, for example, an elliptical shape or a polygonal shape (triangular, rectangular, pentagonal, hexagonal, etc.). In the case of a polygonal shape, it may be a regular polygon or a scalene polygon.

The second ceramic member 12 has a recess 12a for accommodating the first ceramic member 11. The recess 12a is formed according to the shape and size of the first ceramic member 11. The bottom surface of the recess 12a, i.e., the surface facing the back surface 11b of the first ceramic member 11, includes a groove portion 12b and a flat portion 12c other than the groove portion 12b, as shown in FIG. 1(B). FIG. 1(B) is a perspective view showing the second ceramic member 12 included in the ceramic joint 1 shown in FIG. 1(A). When the ceramic joint is a vacuum chuck like the ceramic joint 1, a suction groove 14 is provided on the bottom surface of the recess 12a of the second ceramic member 12, and a suction hole (not shown) is provided to connect the suction groove 14 and the lower surface of the second ceramic member 12. The suction groove 14 and the suction hole become a path for sucking air, and the object to be adsorbed is adsorbed and held via the first ceramic member 11.

The grooves 12b are formed in a straight line as shown in FIG. 1(B). However, the grooves 12b are not limited to being straight, and may be formed in a curved shape such as a spiral or serpentine shape. In the case of a straight line, the grooves 12b may intersect as shown in FIG. 1(B), or may be formed parallel to one direction. The pitch of the grooves 12b (the width between the grooves 12b) is set appropriately according to the size of the bottom surface of the recess 12a, and may be, for example, 100 μm or more and 5000 μm or less.

The width and depth of the groove portion 12b are not limited. The groove portion 12b may have a width of, for example, 100 μm or less, or may have a width of 30 μm or more and 50 μm or less. Furthermore, the groove portion 12b may have a depth of, for example, 50 μm or less, or may have a depth of 5 μm or more and 15 μm or less.

It is preferable that the groove 12b is wider than it is deep, and that the surface of the groove 12b has a gentle slope. The shallower and more gentle the groove 12b, the less likely it is that gaps will form with the bonding layer 13, and the less likely it is that poor bonding will occur. For example, it is preferable that the surface of the groove 12b has a slope such that, when the surface of the groove 12b is plotted at 5 μm intervals in the width direction, the angle between a straight line connecting two adjacent points and a plane horizontal to the width direction is 45° or less.

The bottom of the groove 12b may have undulations in the extension direction of the groove 12b. If such undulations are present, a stronger anchor effect is exhibited, and the bonding strength is further improved. The height of the undulations is not limited, and for example, the maximum height of the undulation curve (the difference between the lowest point and the highest point) is 1 μm or more and 6 μm or less. Furthermore, it is preferable that the undulations exist at a period smaller than the width of the groove 12b.

The arithmetic mean roughness of the groove 12b surface (the inner peripheral surface and bottom surface of the groove 12b) is greater than the arithmetic mean roughness of the flat portion 12c surface. In other words, the groove 12b surface is rough, and the flat portion 12c surface is smoother than the groove 12b surface.

In this way, if the arithmetic mean roughness of the groove portion 12b surface is greater than the arithmetic mean roughness of the flat portion 12c surface, the bonding strength of the bonding layer 13 described below is improved. Specifically, if the groove portion 12b surface is rough, the bonding layer 13 that flows into the groove portion 12b is firmly bonded by the anchor effect. On the other hand, if the flat portion 12c surface is smoother than the groove portion 12b surface, gaps are less likely to occur between the flat portion 12c and the back surface of the bonding layer 13. As a result, spaces that cause poor bonding are less likely to occur. Furthermore, the thickness of the bonding layer 13 located on the flat portion 12c is thinner than the thickness of the bonding layer 13 that flows into the groove portion 12b. As a result, the thermal conductivity is improved by the thin bonding layer 13 located on the flat portion 12c.

The arithmetic mean roughness of the groove 12b surface is, for example, 0.4 μm or more, and may be 0.8 μm or more. If the groove 12b surface has such an arithmetic mean roughness, a stronger anchor effect is exerted. The upper limit of the arithmetic mean roughness of the groove 12b surface is, for example, about 3 μm.

The arithmetic mean roughness of the surface of the flat portion 12c is, for example, 0.8 μm or less, and may be 0.4 μm or less. When the surface of the flat portion 12c has such an arithmetic mean roughness, the flatness of the flat portion 12c can be reduced, and gaps are less likely to occur between the flat portion 12c and the back surface of the bonding layer 13. As a result, spaces that cause poor bonding are less likely to occur.

When the second ceramic member 12 is made of carbide or nitride, it is preferable that the surface of the groove portion 12b has a lower proportion of at least one of carbon and nitrogen than the surface of the flat portion 12c at the bottom of the recess 12a. When carbide and nitride are heated and bonded in an oxidizing atmosphere such as air, degassing due to oxidation reaction may occur, and bubbles may be generated in the bonding layer 13. The bubbles may cause a decrease in bonding strength. If the proportion of carbon and nitrogen at the bottom of the recess 12a is low, the generation of degassing during bonding is suppressed, the number of bubbles is reduced, and the bonding strength is improved. If the proportion of at least one of carbon and nitrogen at the surface of the groove portion 12b is low, the number of active dangling bonds increases. As a result, it becomes easier to bond with oxygen contained in the bonding layer 13 described later, and the bonding strength can be further improved.

The first ceramic member 11 and the second ceramic member 12 are bonded to the back surface 11b of the first ceramic member 11 and the bottom surface of the recess 12a of the second ceramic member 12 via a bonding layer 13. The bonding layer 13 only needs to bond at least the groove portion 12b of the recess 12a to the back surface 11 of the first ceramic member 11. Furthermore, the bonding layer 13 may be located on the flat portion 12c of the recess 12a and the side surface of the recess 12a. If the bonding layer 13 is located on the flat portion 12c and the side surface of the recess 12a in addition to the groove portion 12b of the recess 12a, the bonding strength can be further improved.

The bonding layer 13 is not limited as long as it is glassy. There is also no limitation on the thickness of the bonding layer 13, and it is sufficient that the bonding layer 13 has a thickness that can bond the back surface 11b of the first ceramic member 11 and the bottom surface of the recess 12a of the second ceramic member 12. For example, when the bonding layer 13 is present on the flat portion 12c of the recess 12a, the thickness of the bonding layer 13 is preferably greater than the sum of the flatness of the flat portion 12c of the recess 12a and the flatness of the back surface 11b of the first ceramic member 11. Specifically, the thickness of the bonding layer 13 is preferably about 10 μm or more and 30 μm or less.

Next, a method for producing the ceramic joint body according to the present disclosure will be described. The method for producing the ceramic joint body according to the present disclosure includes the following steps (a) to (e).
(a) providing a first ceramic member having a planar front surface and a back surface opposite the front surface;
(b) providing a second ceramic member having a recess for receiving the first ceramic member;
(c) A step of flattening the bottom surface of the recess of the second ceramic member.
(d) forming a groove in the bottom surface of the recess in the second ceramic member;
(e) A step of applying glass paste to at least one of the back surface of the first ceramic member and the recessed portion of the second ceramic member, bonding them together and firing them to bond at least the groove portion and the back surface with a glassy bonding layer.

Step (a) is a step of preparing a first ceramic member having a flat front surface and a back surface located opposite the front surface. The material, shape, and size of the first ceramic member 11 are as described above, and detailed description will be omitted.

Step (b) is a step of preparing a second ceramic member having a recess for accommodating the first ceramic member. The material, shape, and size of the second ceramic member 12 are as described above, and detailed description is omitted.

Step (c) is a step of flattening the bottom surface of the recess in the second ceramic member. The method of flattening the bottom surface of the recess 12a in the second ceramic member 12 is not limited. For example, the bottom surface of the recess 12a in the second ceramic member 12 is flattened by polishing with a grindstone or grinding.

Step (d) is a step of forming a groove on the bottom surface of the recess of the second ceramic member. The area other than the groove 12b on the bottom surface of the recess 12a becomes the flat portion 12c. When the groove 12b is formed on the bottom surface of the recess 12a of the second ceramic member 12 by laser processing, the surface roughness (arithmetic mean roughness) becomes larger than that of the flat portion 12c, and undulations are easily formed on the bottom surface of the groove 12 groove 12b. When undulations are formed on the bottom surface of the groove 12b, a stronger anchor effect is exerted, and a ceramic joint 1 with improved joint strength is obtained. The height of the undulations is not limited, and for example, the maximum height in the undulation curve is 1 μm or more and 6 μm or less. Furthermore, it is preferable that the undulations exist at a period smaller than the width of the groove 12b. The surface roughness and undulations can be adjusted by the spot diameter, scanning pitch, irradiation intensity, etc. of the laser. The grooves 12b may be formed using various processing methods such as electron beam processing, dry etching, and blasting, instead of laser processing, so that the grooves 12b have a greater surface roughness than the flat portion 12c.

Furthermore, if the second ceramic member 12 is formed of a carbide or nitride as described above, when the groove portion 12b is formed by laser processing in an oxidizing atmosphere such as air, the carbon and nitrogen present on the surface of the groove portion 12b are oxidized and vaporized. Therefore, the proportion of at least one of the carbon and nitrogen on the surface of the groove portion 12b is reduced. If the proportion of at least one of the carbon and nitrogen on the surface of the groove portion 12b is low, the number of bubbles in the bonding layer 13 due to degassing from the ceramic is reduced when the bonding layer 13 is formed by heating in an oxidizing atmosphere. As a result, the bonding strength can be further improved as described above.

The grooves 12b may be formed in a straight line as described above, or in a curved line such as a spiral or serpentine line. Furthermore, the grooves 12b may be processed so that the surface has an arithmetic mean roughness of 0.4 μm or more, and may be processed so that the surface has an arithmetic mean roughness of 0.8 μm or more. When the groove 12b surface is processed to have such an arithmetic mean roughness, a ceramic joint 1 that exhibits a stronger anchor effect is obtained. The upper limit of the arithmetic mean roughness of the groove 12b surface is about 3 μm as described above.

As mentioned above, it is preferable that the width of the groove 12b is greater than the depth, and that the slope of the surface of the groove 12b is gentle. The shallower and more gentle the groove 12b, the less likely it is that poor bonding will occur. For example, it is preferable that the groove 12b is formed so that, when the surface of the groove 12b is plotted at intervals of 5 μm in the width direction, the angle between a straight line connecting two adjacent points and a plane horizontal to the width direction is 45° or less.

The bottom surface of the recess 12a of the second ceramic member 12 is a flat portion 12c other than the groove portion 12b. The flat portion 12c is processed so that the surface has an arithmetic mean roughness of 0.8 μm or less, and may be processed so that the surface has an arithmetic mean roughness of 0.4 μm or less. When the surface of the flat portion 12c is processed to have such an arithmetic mean roughness, a ceramic joint 1 is obtained in which gaps are less likely to occur between the flat portion 12c and the back surface of the joining layer 13. As a result, a ceramic joint 1 is obtained in which spaces due to poor joining are less likely to occur. In order to make the surface of the flat portion 12c have an arithmetic mean roughness of 0.8 μm or less, when the bottom surface of the recess 12a is flattened in step (c), it is sufficient to process it so that the arithmetic mean roughness is 0.8 μm or less.

As shown in FIG. 1, when the ceramic joint 1 is used as a vacuum chuck, in any one of steps (b) to (d), a suction groove 14 is formed in the bottom surface of the recess 12a of the second ceramic member 12. The suction groove 14 is formed, for example, by cutting or grinding. In addition, a suction hole (not shown) that connects the suction groove 14 and the bottom surface of the second ceramic member 12 is formed by drilling or the like.

Step (e) is a step in which glass paste is applied to at least one of the back surface of the first ceramic member and the recess of the second ceramic member, and then the members are bonded together and fired to bond at least the groove and the back surface with a glassy bonding layer 13.

Specifically, glass paste is applied to at least one of the back surface 11b of the first ceramic member 11 and the recessed portion 12a of the second ceramic member 12. The bonding surfaces are then pressed together and fired at a temperature between the softening point of the glass and the firing temperature of the ceramic members, forming a bonding layer 13, bonding the back surface 11b of the first ceramic member 11 and at least the groove portion 12b of the recessed portion 12a of the second ceramic member 12. The amount of glass paste applied may be set appropriately, taking into account the thickness of the bonding layer 13 formed after firing.

In this manner, the ceramic joint 1 according to the present disclosure is obtained by steps (a) to (e). The ceramic joint 1 according to the present disclosure obtained in this manner is used, for example, in a vacuum chuck, a gas supply member, etc.

Next, a specific method for manufacturing the ceramic joint 1 according to one embodiment of the present disclosure will be described. First, α-type silicon carbide powder, silicon powder, and a molding aid (phenolic resin) were mixed to obtain a mixture. Next, the obtained mixture was fed into a rolling granulator to form granules, and then a molded body was obtained by dry pressure molding.

Then, the obtained molded body was degreased at 500°C in a nitrogen atmosphere, and then heat-treated at 1420°C in a nitrogen atmosphere to obtain a porous body with a porosity of about 31% and an average pore diameter of 55 μm. This porous body corresponds to the first ceramic member 11.

Next, a second ceramic member 12 is prepared, which is a substantially disk-shaped dense body mainly composed of silicon carbide and has a circular recess 12a in the center. The bottom surface of this recess 12a is flattened with a grindstone or the like so that the flatness is, for example, 50 μm or less and the arithmetic mean roughness is about 0.2 μm. After the flattening process, a groove 12b is formed by laser processing. As shown in FIG. 3, the groove 12b is formed vertically and horizontally so as to intersect. FIG. 3 is an electron microscope photograph showing the groove 11b formed in the bottom surface of the recess 12a of the second ceramic member 12 in the ceramic joint 1 according to one embodiment.

As shown in FIG. 4(A), the width of the groove 12b was about 50 μm, and the depth of the groove 12b was about 6 to 10 μm. FIG. 4(A) is a graph showing the width and depth of the groove when cut in the direction of the arrow A shown in FIG. 3. Furthermore, as shown in FIG. 4(B), at the bottom of the groove 12b, there is a ripple in the extension direction of the groove 12b. FIG. 4(B) is a graph showing the undulations of the bottom surface of the groove when cut in the direction of the arrow B shown in FIG. 3. As shown in FIG. 4(B), the ripple has a maximum height (difference between the bottom and top) of about 5 μm and is formed periodically. In the flat portion 12c other than the groove 12b, the arithmetic mean roughness of the surface was 0.16 μm. On the other hand, the arithmetic mean roughness of the surface of the groove 12b was 0.85 μm.

The ratio (Si/C) of the element counts on the surface of the groove portion 12b and the surface of the flat portion 12c was calculated by energy dispersive X-ray analysis (EDS) on the bottom surface of the recessed portion 12a of the obtained second ceramic member 12. The result was 12 on the surface of the groove portion 12b and 10 on the surface of the flat portion 12c. This result shows that the proportion of carbon is lower on the surface of the groove portion 12b than on the surface of the flat portion 12c.

Then, the obtained first ceramic member 11 and second ceramic member 12 were joined. Specifically, glass paste was applied to the back surface 11b and side surface of the first ceramic member 11, the area other than the suction groove 14 on the bottom surface of the recess 12a of the second ceramic member 12, and the inner peripheral surface of the recess 12a, and the first ceramic member 11 was inserted into the recess 12a of the second ceramic member 12 so that the back surface 11b of the first ceramic member 11 and the bottom surface of the recess 12a of the second ceramic member 12 faced each other. Thereafter, the joining surfaces were fired at about 980°C while applying pressure to form a glassy joining layer 13, and the back surface 11b of the first ceramic member 11 and the bottom surface of the recess 12a of the second ceramic member 12 were joined. In this way, a ceramic joint 1, which is a vacuum chuck, was obtained.

As test samples, a first ceramic member 11 and a plate-shaped second ceramic member 12 without a recess 12a were processed and joined in the same way, and a torsional shear strength test was performed on the obtained ceramic joint. Specifically, the ceramic joint was fixed in a vice and twisted with a torque wrench to break it, and the torque at the time of breakage was measured. Three ceramic joints 1 were prepared and the test was performed three times. There was no break at the joint interface between the first ceramic member 11 and the second ceramic member 12, but rather at the first ceramic member 11 part. Furthermore, the glassy joint layer 13 did not peel off.

As comparative samples, a ceramic joint was obtained by grinding the surface of the plate-like second ceramic member 12 without the recess 12a (corresponding to the bottom surface of the recess 12a) without providing the groove 12b, and a ceramic joint was obtained by lapping and joining the first ceramic member 11. Except for not providing the groove 12b, they were manufactured under the same conditions as the ceramic joint 1. The ceramic joint with the ground surface and the ceramic joint with the lapped surface were subjected to the torsional shear strength test three times, as with the test sample. The average measured shear stress was lower than that of the test sample. Furthermore, both ceramic joints were broken at the joining interface, and the glassy joining layer 13 was peeled off.

1 Ceramic joint (vacuum chuck)
Reference Signs List 11: First ceramic member 11a: Front surface 11b: Back surface 12: Second ceramic member 12a: Recess 12b: Groove 12c: Flat portion 13: Bonding layer 14: Suction groove

Claims (12)

a first ceramic member having a flat front surface and a back surface opposite the front surface;
a second ceramic member having a recess for receiving the first ceramic member;
a glassy bonding layer bonding a rear surface of the first ceramic member and a bottom surface of the recess of the second ceramic member;
Including,
a bottom surface of the recess of the second ceramic member includes a groove portion and a flat portion other than the groove portion,
the arithmetic mean roughness of the groove surface is greater than the arithmetic mean roughness of the flat surface,
the bonding layer bonds at least the groove portion and the flat portion to the rear surface,
a thickness of the bonding layer located in the flat portion is thinner than a thickness of the bonding layer flowing into the groove portion;
Ceramic joints. The ceramic joint according to claim 1, wherein the groove portion includes at least one of a straight groove and a curved groove. The ceramic joint according to claim 1 or 2, wherein the arithmetic mean roughness of the groove surface is 0.4 μm or more. The ceramic joint according to any one of claims 1 to 3, wherein the arithmetic mean roughness of the groove surface is 0.8 μm or more. The ceramic joint according to claim 1, 2 or 4, wherein the arithmetic mean roughness of the flat surface is less than 0.8 μm. The ceramic joint according to any one of claims 1 to 5, wherein the arithmetic mean roughness of the flat surface is less than 0.4 μm. The ceramic joint according to any one of claims 1 to 6, wherein the grooves are wider than they are deep, and when the groove surface is plotted at 5 μm intervals in the width direction, an angle between a straight line connecting two adjacent points and a plane horizontal to the width direction is 45° or less. The ceramic joint according to any one of claims 1 to 7, wherein the groove has a wavy shape at the bottom in the extension direction of the groove. The ceramic joint according to claim 8, wherein the undulations exist at a period smaller than the width of the grooves. The ceramic joint according to any one of claims 1 to 9, wherein the second ceramic member is made of carbide or nitride, and the surface of the groove portion has a smaller proportion of at least one of carbon and nitrogen than the surface of the flat portion. The ceramic joint according to any one of claims 1 to 10, which is a vacuum chuck. Providing a first ceramic member having a planar surface and a back surface opposite the planar surface;
providing a second ceramic member having a recess for receiving the first ceramic member;
a step of flattening a bottom surface of the recess of the second ceramic member;
forming a groove portion on a bottom surface of the recess of the second ceramic member by laser processing;
applying a glass paste to at least one of the rear surface of the first ceramic member and the recessed portion of the second ceramic member, bonding them together and firing them to bond at least the groove portion and a flat portion other than the groove portion to the rear surface with a glassy bonding layer;
Including ,
a thickness of the bonding layer located in the flat portion is thinner than a thickness of the bonding layer flowing into the groove portion;
A method for producing a ceramic joint.

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