JP7058580B2 - Manufacturing method of ceramic parts - Google Patents

Description

The present invention relates to a method for manufacturing a ceramic member.

In semiconductor manufacturing equipment, electrostatic chucks that hold substrates such as wafers on the surface, heaters that heat substrates placed on the surface, susceptors, etc. are equipped with ceramic members that have electrodes built inside the ceramic substrate. There is.

Such ceramic members are often manufactured by firing a ceramic sheet laminate formed by laminating ceramic green sheets, and by printing a conductor paste on the ceramic green sheet, the internal electrodes and throughs are produced. It forms a hole (see, for example, Patent Documents 1 and 2).

Through holes are formed by filling through holes formed in a ceramic green sheet with a conductor paste by printing, laminating a plurality of ceramic green sheets in a positioned state to form a ceramic sheet laminate, and firing this. Will be done.

It should be noted that Patent Document 3 discloses that a ceramics sintered body in which a metal electrode is embedded is subjected to hole processing (recess processing) to expose a part of the metal electrode, and a feeding terminal is connected to the exposed metal electrode. Has been done.

Japanese Unexamined Patent Publication No. 2000-12195 Japanese Unexamined Patent Publication No. 2017-135250 Japanese Unexamined Patent Publication No. 2006-165181

When the ceramic sheet laminate is fired to form a ceramic sintered body having an internal electrode and a feeding terminal is further provided as in the conventional case, a recess is formed in the ceramic sintered body with reference to the disclosure of Patent Document 3. It is conceivable to connect the feeding terminal to the exposed through hole by brazing or the like.

However, since the ceramic sintered body has a high hardness, there is a problem that it is difficult to form a recess in the ceramic sintered body after firing.

It is also possible to form through holes in the ceramic sheet in advance, align the through holes, and fire the ceramic sheet laminate in which the ceramic green sheets are laminated so that the through holes are continuous in the vertical direction to form recesses. Conceivable.

However, there is a problem that the shape accuracy of the concave portion is inferior due to deformation that occurs during normal pressure firing of the ceramic sheet laminate.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for manufacturing a ceramic member capable of maintaining a good shape of a recess after firing and easily providing a recess.

The present invention electrically relates to a plate-shaped substrate having a front surface and a back surface and made of ceramics, an internal electrode embedded in the substrate along the front surface, a recess provided on the back surface, and the internal electrode. Manufacture of a ceramic member comprising a conductor layer arranged at least on the bottom surface of the recess in a connected state, and terminals electrically connected to the conductor layer in a state where at least a part thereof is housed in the recess. The method includes a step of preparing a plurality of ceramic sheets obtained by adding at least a binder to the ceramic powder, a step of laminating the plurality of ceramic sheets to form a ceramic sheet laminate to be the substrate, and the above-mentioned method. A step of forming a recess on the surface of one surface of the ceramic sheet laminate, a step of applying a conductive material to be the conductor layer to at least the bottom surface of the recess of the ceramic sheet laminate, and a ceramic coated with the conductive material. The step of filling the recesses of the sheet laminate with a powder or a molded body of a material having a melting point of the first temperature, and the ceramic sheet laminate filled with the powder or the molded body in the recesses while pressurizing in the stacking direction. The step of forming the ceramic sintered body by heating at a temperature lower than the first temperature, and the step of removing the powder or the molded body from the recess filled with the powder or the molded body of the ceramic sintered body. It is characterized by being prepared.

According to the present invention, the ceramic sheet laminate is heated at a temperature lower than the first temperature while pressurizing the ceramic sheet laminate in the state where the powder or the molded body of the material whose melting point is the first temperature is filled in the recesses, and the ceramics are ceramics. Since the sintered body is formed, in this heating step, the deformation of the shape of the recess is regulated by the powder or the molded body filled therein, and it becomes possible to maintain the shape of the recess well. Further, in this heating step, it is possible to suppress the bending of the embedded internal electrode. Further, since the recess is formed by processing the ceramic sheet before firing instead of the ceramic sintered body, it is possible to easily provide the recess.

In the present invention, in the step of applying the conductive material, it is preferable to apply the conductive material to the wall surface of the recess of the ceramic sheet laminate.

In this case, a conductive material is also provided on the wall surface of the recess, and when a member such as a power feeding terminal is connected to the conductor obtained by firing the conductive material, more reliable and stable connection can be achieved. Will be.

The flowchart which shows the manufacturing method of the ceramics member which concerns on embodiment of this invention. Schematic cross-sectional view showing a plurality of ceramic sheets. Schematic cross-sectional view showing a ceramic sheet laminate. Schematic cross-sectional view showing a ceramic member.

The method for manufacturing the ceramic member 100 according to the embodiment of the present invention will be described with reference to the drawings. It should be noted that each drawing is deformed in order to clarify the ceramic member 100, the constituent elements, and the like, and does not represent the actual ratio, and the directions such as up and down are merely examples.

As shown in FIG. 1, the method for manufacturing a ceramic member according to an embodiment of the present invention includes a ceramic sheet preparation step (STEP1), an internal electrode forming step (STEP2), a through hole forming step (STEP3), and a ceramic sheet laminate forming. Step (STEP4), recess forming step (STEP5), conductor paste coating step (STEP6), degreasing step (STEP7), powder filling step (STEP8), baking step (STEP9), powder removal step (STEP10) and power supply terminal It includes a connection step (STEP 11).

First, as shown in FIG. 2, in the ceramic sheet preparation step (STEP 1), a plurality of ceramic green sheets (hereinafter, simply referred to as ceramic sheets) 10 made of unfired ceramics are prepared.

The ceramic sheet 10 is prepared by mixing ceramic powders such as aluminum nitride ₍ AlN) and yttrium oxide ₍ Y2O3) with a sintering aid, a binder such as an organic binder, and a plasticizer added using a solvent. It is formed into a thin plate using a known method such as the doctor blade method. The thickness of the ceramic sheet is 0.1 mm or more and 2.0 mm or less, preferably 0.3 mm or more and 0.7 mm or less. The thickness and the like of the plurality of ceramic sheets 10 may be different.

In the internal electrode forming step (STEP 2), a conductive material is provided on the front surface or the back surface of the ceramic sheet 10 in order to form the internal electrode 51 (see FIG. 4). Specifically, for example, the conductor paste 21, which is a conductive material, may be applied to the ceramic sheet 10 by printing or the like so that the desired internal electrode 51 is formed. The conductive material may be provided by placing or attaching a thin plate such as a foil made of the conductive material or a mesh material.

Further, in the through hole forming step (STEP 3), in order to form the through hole 52 (see FIG. 4), a through hole 11 is formed in the ceramic sheet 10, and the conductor paste 21 which is an conductive material is formed in the through hole 11. Is filled by printing or the like.

Then, in the ceramic sheet laminate forming step (STEP 4), a plurality of ceramic sheets 10 are laminated in the order shown in FIG. 2 and pressure-bonded in the vertical direction to form the ceramic sheet laminate 30.

Here, the plurality of ceramic sheets 10 include the ceramic sheets 10 that have undergone STEPs 2 and 3. When the ceramic sheet 10 filled with the conductor paste 22 is laminated in STEP 3, the conductor paste 22 filled in the through hole 11 is formed so that the through hole 52 (see FIG. 4) having a desired depth is formed. A plurality of ceramic sheets 10 are laminated by aligning them so as to be continuous in the vertical direction. The ceramic sheet 10 itself functions as an insulating layer.

Then, in the recess forming step (STEP 5), the recess 31 is machined from the back surface (upper surface in FIG. 3), which is one surface of the ceramic sheet laminate 30, until the conductor paste 22 filled in the through hole 11 is reached. It is formed by grinding. That is, the end surface (lower surface in FIG. 3) of the conductor paste 22 is exposed on the bottom surface 31a of the recess 31. In addition, processing such as cutting may be performed in order to appropriately shape the outer shape of the ceramic sheet laminate 30 into a desired shape.

Next, in the conductor paste application step (STEP 6), the conductor paste 23, which is a conductive material, is applied to at least the bottom surface 31a of the recess 31. However, preferably, the conductor paste 23 is applied to at least a part, more preferably the entire wall surface 31b of the recess 31. The conductor pastes 21 to 23 contain, for example, a metal powder such as Mo (molybdenum) or W (tungsten) as a main component.

After completing the conductor paste application step (STEP 6), the degreasing step (STEP 7) is performed. In the degreasing step (STEP7), the ceramic sheet laminate 30 is heated for degreasing. The degreasing step (STEP7) is performed by heating the ceramic sheet laminate 30 at a degreasing temperature T3 lower than the second temperature T2 for a predetermined time using an electric furnace or the like.

Next, in the powder filling step (STEP 8), the recess 31 of the ceramic sheet laminate 30 degreased in STEP 7 is filled with the powder 41 corresponding to the powder of the present invention. Instead of the powder 41, a molded body (not shown) may be inserted into the recess 31 on the wall surface of the recess 31. The powder 41 or the molded product has a melting temperature of the first temperature T1 and is made of a non-conductive material. As the powder 41, for example, a nitride such as carbon powder, BN powder, ZrN powder, TaC powder, _B4C powder, MgO powder or the like having a melting point of 2400 ° C. or higher, carbides or oxides may be used, and a molded product may be used. For example, one made of an isotropic graphite molded body may be used.

The molded body may be composed of a plurality of molded bodies, and further, in consideration of the fact that the concave portion 31 in the firing step (STEP 9) described later shrinks to become the concave portion 54 (see FIG. 4), the concave portion 31 and the concave portion 31 are formed. It is preferable to provide a gap between the two, but the compact may be damaged or damaged due to this shrinkage. Further, a molded body may be inserted into the recess 31 and the gap between the molded body and the recess 31 may be filled with powder.

Further, since the recess 31 shrinks to become the recess 54 (see FIG. 4) in the firing step (STEP 9), it is possible to reduce problems such as the possibility that the recess 54 is damaged by using the powder 41. Become. Then, in order to reduce such a defect, it is also preferable to provide an internal cavity, a notch, or the like when the molded product is used so that it is easily damaged.

Further, the degreasing step (STEP 7) may be performed after the powder filling step (STEP 8). However, since the recess 31 and the ceramic sheet 30 are not easily deformed when the powder 41 or the molded body is filled, it is preferable to perform the powder filling step (STEP 8) after the degreasing step (STEP 7).

Next, in the firing step (STEP 9), the ceramic sheet laminate 30 in which the recess 31 is filled with the powder 41 or the molded body is pressed in the lamination direction at a second temperature T2 which is lower than the first temperature T1 for a predetermined time. The ceramic sintered body 50 is formed by heating only.

In the firing step (STEP 9), it is preferable to fire the ceramic sheet laminate 30 by a hot press in which pressure is applied in the lamination direction. As a result, the recess 31, the internal electrode 51, the through hole 52, and the like do not shift to the left and right, and the shape of the recess 54 (see FIG. 4) after firing can be made good.

By this heating, as shown in FIG. 4, in the ceramic sintered body 50, the conductive substance in the conductor paste 21 filled in the through hole 11 is sintered and solidified, and this continuously becomes a through hole 52. Then, the conductor layer 53 is fixed to the end surface of the through hole 52, and the upper surface of the conductor layer 53 is formed in the recess 54.

Further, in the firing step (STEP 9), even if hot pressing is performed, the powder 41 or the molded body is present in the recess 54, and the deformation of the recess 31 is restricted by these, so that the recess 54 is restricted. The shape is well maintained. As a result, it is possible to eliminate the possibility that the conductor layer 53 is separated from the recess 54 and to suppress the bending of the internal electrode 51 and the like.

The degreasing step (STEP7) and the firing step (STEP9) may be continuously performed by heating to the second temperature T2 via the degreasing temperature T3 using an electric furnace or the like.

After the completion of the firing step (STEP 9), in the powder removing step (STEP 10), the powder 41 or the molded body is removed from the recess 54 of the ceramic sintered body 50 to expose the conductor layer 53.

Finally, in the power supply terminal connection step (STEP 11), the power supply terminal 55 is connected to the exposed surface of the conductor layer 53, which is located in the recess 54 of the ceramic sintered body 50 and is formed by solidifying the conductor paste 22, via a wax 56 or the like. To connect. As a result, the ceramic member 100 is completed.

The completed ceramic member 100 has a ceramic sintered body 50 which has a front surface 100a (lower surface in FIG. 4) and a back surface 100b (upper surface in FIG. 4) and is a plate-shaped substrate made of ceramics, and ceramics are baked along the surface 100a. The internal electrode 51 embedded in the body 50, the recess 54 provided on the back surface 100b, and the conductor layer 53 arranged on the bottom surface 54a and the wall surface 54b of the recess 54 in a state of being electrically connected to the internal electrode 51. A feeding terminal 55, which is a terminal electrically connected to the conductor layer 53 in a state where at least a part thereof is housed in the recess 54, is provided.

Although not shown, the exposed surface of the conductor layer 53 may be plated with Ni or the like to provide a plating layer, and the feeding terminal 55 may be connected to the plating layer by brazing or the like.

Hereinafter, the present invention will be described with reference to FIGS. 1 and the like with specific examples of the present invention.

First, as shown in FIG. 2, as a ceramic sheet preparation step (STEP1), aluminum nitride powder is the main component, yttrium oxide powder is 0.1 to 4.0% by mass, and calcium oxide powder is 0 as a sintering aid. .2% by mass was added, and an organic binder, a solvent, a plasticizer and the like were mixed with the mixture in a predetermined ratio to prepare a slurry. Then, this slurry was formed into a sheet shape by using the doctor blade method to prepare a disk-shaped ceramic sheet having a radius of 170 mm and a thickness of 0.7 mm.

Next, as an internal electrode forming step (STEP2), a conductor paste 21 containing molybdenum powder as a main component was printed on the surface of one ceramic sheet 10 and applied in a circular shape.

Next, as a through hole forming step (STEP 3), four through holes 11 having a diameter of 0.5 mm are formed in five ceramic sheets 10, and the same conductor paste 22 as the conductor paste 21 is printed in these through holes 11. Filled.

Next, as shown in FIG. 3, as a ceramic sheet laminate forming step (STEP 4), 31 ceramic sheets 10 including the ceramic sheets 10 in the above STEPs 2 and 3 are laminated in the vertical direction and crimped in the vertical direction. , The ceramic sheet laminate 30 was formed.

Next, as a recess forming step (STEP 5), the recess 31 was formed by cutting from the upper surface of the ceramic sheet laminate 30 until the conductor paste 22 filled in the through hole 11 was reached. The recess 31 was a cylindrical hole having a diameter of 7 mm and a depth of 15 mm.

Next, as a conductor paste application step (STEP 6), the same conductor paste 23 as the conductor paste 21 was applied by printing over the entire bottom surface 31a and the wall surface 31b of the recess 31.

Next, as a degreasing step (STEP7), the ceramic sheet laminate 30 was heated in an electric furnace at a degreasing temperature T3 of 600 ° C. for 12 hours.

Next, the ceramic sheet laminate 30 was taken out from the electric furnace, and as a powder filling step (STEP 8), a powder 41 made of carbon powder having an average particle size of 50 μm was filled in the recess 31.

Next, as a firing step (STEP 9), the ceramic sheet laminate 30 was heated in a uniaxial hot press furnace at a second temperature T2 of 1800 ° C. and a pressure of 1 MPa at the maximum ultimate temperature for 3 hours.

Next, the ceramic sheet laminate 30 was taken out from the electric furnace, and the powder 41 was removed from the recess 54 of the ceramic sintered body 50 as a powder removing step (STEP 10).

Finally, as a power feeding terminal connecting step (STEP 11), the feeding terminal 55 was connected to the exposed surface of the conductor layer 53 via the wax 56. As a result, the ceramic member 100 was completed.

In the ceramic sintered body 50, the recess 54 is a cylindrical hole, and there is no unintentional deformation in the horizontal direction, and no problems such as peeling of the conductor layer 53 have occurred. The operator visually confirmed it. Further, it was confirmed that the warp of the internal electrode 51 can be suppressed to 100 μm or less, and the ceramic sintered body 50 can function well as the ceramic member 100 for the semiconductor manufacturing apparatus.

Further, it is the same as the above except that instead of filling the carbon powder in the powder filling step (STEP 8), the recess 31 is filled with a cylindrical isotropic high-density graphite molded product having a diameter of 7 mm and a height of 12 mm. It was confirmed that no problem occurred in the case where the ceramic member 100 was manufactured in the process of.

10 ... Ceramic sheet, 11 ... Through hole, 21-23 ... Conductor paste (conductive material), 30 ... Ceramic sheet laminate, 31 ... Recessed, 31a ... Bottom surface, 31b ... Wall surface, 41 ... Powder (powder), 50 ... Ceramic sintered body (base), 51 ... Internal electrode, 52 ... Through hole, 53 ... Conductor layer, 54 ... Recessed, 55 ... Feeding terminal (terminal), 56 ... Wax, 100 ... Ceramic member, 100a ... Surface, 100b … The back side.

Claims (2)

A plate-shaped substrate having a front surface and a back surface and made of ceramics, an internal electrode embedded in the substrate along the front surface, a recess provided on the back surface, and a state of being electrically connected to the internal electrode. A method for manufacturing a ceramic member comprising a conductor layer arranged at least on the bottom surface of the recess and terminals electrically connected to the conductor layer in a state where at least a part thereof is accommodated in the recess. ,
The process of preparing multiple ceramic sheets made by adding at least a binder to the ceramic powder, and
A step of laminating the plurality of ceramic sheets to form a ceramic sheet laminate to be the substrate, and a process of forming the ceramic sheet laminate.
The step of forming a recess on the surface of one of the ceramic sheet laminates,
A step of applying a conductive material to be the conductor layer to at least the bottom surface of the recesses of the ceramic sheet laminate, and
A step of filling the recess of the ceramic sheet laminate coated with the conductive material with a powder or a molded product of a material having a melting point of the first temperature.
A step of forming a ceramic sintered body by heating a ceramic sheet laminate in which the recess is filled with the powder or a molded body at a temperature lower than the first temperature while pressurizing the ceramic sheet laminate in the lamination direction.
A method for manufacturing a ceramic member, comprising: a step of removing the powder or the molded body from a recess filled with the powder or the molded body of the ceramic sintered body. The method for manufacturing a ceramic member according to claim 1, wherein in the step of applying the conductive material, the conductive material is applied to the wall surface of the recess of the ceramic sheet laminate.

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