阅读说明：本技术 一种多层复合陶瓷盘及其制造方法 (Multilayer composite ceramic disc and manufacturing method thereof ) 是由 张巨先 于 2020-03-27 设计创作，主要内容包括：一种多层复合陶瓷盘及其制造方法,涉及半导体和材料科学领域。所述复合陶瓷盘包括至少一个基础三明治结构,包括：用陶瓷粉体制备一个片状陶瓷素坯；把陶瓷素坯在低于烧结温度的预烧结温度下,进行预烧结,得到具有一定强度的预烧结陶瓷件；在预烧结陶瓷件的上表面上形成一金属电极层；将预烧结陶瓷件放入模具中,且覆有金属电极层的上表面朝上；在预烧结陶瓷件上表面提供一陶瓷前体层；沿着预烧结陶瓷件轴向方向在烧结温度下加压烧结成一体,所述预烧结陶瓷件经加压烧结形成第二陶瓷层,所述陶瓷前体层经加压烧结形成第一陶瓷层,其中,所述金属电极层位于所述第一陶瓷层和第二陶瓷层之间并与第一陶瓷层和第二陶瓷层形成一基础三明治结构。(A multilayer composite ceramic disc and a manufacturing method thereof relate to the field of semiconductor and material science. The composite ceramic disk comprises at least one basic sandwich structure, comprising: preparing a flaky ceramic biscuit by using ceramic powder; pre-sintering the ceramic biscuit at a pre-sintering temperature lower than the sintering temperature to obtain a pre-sintered ceramic part with certain strength; forming a metal electrode layer on the upper surface of the pre-sintered ceramic piece; placing the pre-sintered ceramic piece into a mold, wherein the upper surface covered with the metal electrode layer faces upwards; providing a ceramic precursor layer on the upper surface of the pre-sintered ceramic piece; along presintering pottery spare axial direction pressurization sintering as an organic whole under sintering temperature, presintering pottery spare forms the second ceramic layer through the pressurization sintering, ceramic precursor layer forms first ceramic layer through the pressurization sintering, wherein, metal electrode layer is located between first ceramic layer and the second ceramic layer and form a basic sandwich structure with first ceramic layer and second ceramic layer.)

1. A preparation method of a multilayer composite ceramic disk is characterized in that a mold is adopted for pressure sintering, the mold is a graphite hot-pressing mold, namely, two independent and coaxial graphite cylinders are arranged in an outer graphite cylinder barrel, a graphite mold base is arranged at the lower part, and a graphite mold gland is arranged at the upper part;

the multilayer composite ceramic disc comprises at least one basic sandwich structure, wherein the basic sandwich structure comprises a first ceramic layer, a second ceramic layer and a metal electrode layer which is positioned between the first ceramic layer and the second ceramic layer and is positioned between the first ceramic layer and the second ceramic layer; the preparation method specifically comprises the following steps:

(1) preparing a flaky ceramic biscuit by using ceramic powder; pre-sintering the ceramic biscuit at a pre-sintering temperature lower than the sintering temperature to obtain a pre-sintered ceramic part with certain strength;

(2) preparing a metal electrode layer on the upper surface of the pre-sintered ceramic piece;

(3) placing the pre-sintered ceramic piece into a graphite mold base in a mold, wherein the upper surface covered with the metal electrode layer faces upwards, providing a ceramic precursor layer on the upper surface of the pre-sintered ceramic piece, and pressurizing and sintering the pre-sintered ceramic piece into a whole at a sintering temperature along the axial direction of the pre-sintered ceramic piece; the pre-sintered ceramic piece is pressed and sintered to form a second ceramic layer, the ceramic precursor layer is pressed and sintered to form a first ceramic layer, and the metal electrode layer is positioned between the first ceramic layer and the second ceramic layer and integrated with the first ceramic layer and the second ceramic layer to obtain a basic sandwich structure;

or further preferably, the composite ceramic disc comprises two basic sandwich structures, wherein a metal electrode layer and a first ceramic layer are further formed on the lower surface of the second ceramic layer, two basic sandwich structure five-layer composite ceramic discs are formed, and the five-layer structures are a first ceramic layer/a metal electrode layer/a second ceramic layer/a metal electrode layer/a first ceramic layer in sequence; the preparation method comprises the following steps:

(1) preparing a flaky ceramic biscuit by using ceramic powder; pre-sintering the ceramic biscuit at a pre-sintering temperature lower than the sintering temperature to obtain a pre-sintered ceramic part with certain strength;

(2) respectively preparing a metal electrode layer on the upper surface and the lower surface of the pre-sintered ceramic piece to obtain the pre-sintered ceramic piece with the bimetallic electrode layer;

(3) sequentially arranging a ceramic precursor layer and a pre-sintered ceramic piece with a bimetallic electrode layer according to the following upper-lower layer relation: the ceramic precursor layer/the pre-sintered ceramic piece with the bimetallic electrode layer/the ceramic precursor layer are coaxially arranged on a graphite mould base support in a mould, and then are pressed and sintered into a whole at a sintering temperature along the axial direction of the pre-sintered ceramic piece; the presintering ceramic piece is subjected to pressure sintering to form a second ceramic layer, and the ceramic precursor layer is subjected to pressure sintering to form a first ceramic layer; the two ceramic precursor layers in the preparation of the five-layer composite ceramic disc with the two basic sandwich structures are the same or different, and the corresponding first ceramic layer materials are the same or different.

2. The method of claim 1, wherein said pre-sintered ceramic part of step (1) is resistant to water immersion and capable of being turned, milled, and ground to a precision of within 0.03mm of dimensional tolerance; the forming method of the flaky ceramic biscuit in the step (1) is isostatic pressing.

3. The method of claim 1, further comprising finishing said pre-sintered ceramic part to provide better planarity and more uniform thickness prior to said step (2) of forming a metal electrode layer on the upper surface of said pre-sintered ceramic part. And processing the pre-sintered ceramic piece to the flatness of not more than 0.03 mm.

4. The method of claim 1, wherein the metal electrode layer of step (2) is formed on the pre-sintered ceramic part by a screen printing process or a plating process; the flatness of the metal electrode layer is not more than 0.03 mm.

5. The method of claim 1, wherein the ceramic precursor layer of step (3) is a uniformly distributed ceramic powder or a pre-formed green sheet ceramic body.

6. The method of claim 6, wherein the green sheet is pre-pressed in a mold using ceramic powder.

7. The method for preparing a multilayer composite ceramic disk according to claim 1, wherein the pre-sintering temperature of the pre-sintered ceramic piece in the step (1) is 20 ℃ to 600 ℃, preferably 100 ℃ to 400 ℃ lower than the sintering temperature in the step (3); and (4) the sintering temperature in the step (3) is a densification sintering temperature.

8. The method for preparing a multilayer composite ceramic disk according to claim 1, wherein the ceramic powder in step (1) and the ceramic precursor layer in step (3) are made of one or more materials selected from the group consisting of oxides and nonoxides, wherein the oxides are selected from one or two of aluminum oxide, zirconium oxide, magnesium aluminate spinel, and the nonoxides are selected from one or two of aluminum nitride, silicon carbide, and the like. After sintering, the second ceramic layer and the first ceramic layer correspond to one or more of oxide ceramic and non-oxide ceramic, wherein the oxide ceramic is selected from one or two of alumina ceramic, zirconia ceramic, magnesia alumina spinel and the like, and the non-oxide ceramic is selected from one or two of aluminum nitride, silicon carbide and the like.

9. The method of claim 1, wherein the first ceramic layer and the second ceramic layer have an area larger than that of the metal electrode layer, the metal electrode layer is sandwiched between the first ceramic layer and the second ceramic layer, and outer edge portions of the first ceramic layer and the second ceramic layer are in contact with each other and are sintered into a single body by pressing.

10. A multilayer composite ceramic disk produced according to the method of any one of claims 1 to 9.

Technical Field

The invention relates to the field of semiconductor and material science, in particular to a multilayer composite ceramic plate and a manufacturing method thereof in a semiconductor manufacturing process, and especially relates to an Electrostatic chuck (ESC for short) and a ceramic heating plate and a manufacturing method thereof.

Background

The multilayer composite ceramic plate is widely applied to semiconductor processing equipment, and comprises an electrostatic chuck and a ceramic heating plate according to the difference of specific functions and structures, wherein some electrostatic chucks have the function of the heating plate. In a semiconductor processing apparatus, an electrostatic chuck is used to achieve smooth clamping of a silicon wafer (wafer) by electrostatic attraction, and a ceramic heating plate is used to heat the silicon wafer clamped on the electrostatic chuck to maintain it at a specific temperature. The multilayer composite ceramic disk is widely applied to plasma and vacuum environments, such as etching, PVD, CVD, ion implantation and other semiconductor process processes. The conventional multilayer composite ceramic plate, including an electrostatic chuck and a ceramic heating plate, generally adopts a multilayer composite ceramic plate structure including one or more metal electrode layers, and its base structure is a sandwich structure formed by two ceramic dielectric layers and a metal electrode layer sandwiched between the two ceramic dielectric layers. Composite ceramic disks, particularly for use in semiconductor processing equipment, may include multiple ceramic dielectric layers and metal electrode layers respectively located between adjacent ceramic dielectric layers.

The semiconductor processing technology has extremely high requirements on parameters of surface roughness and flatness of a polished silicon wafer, so that the requirements on the surface roughness and the flatness of a composite ceramic disc contacted with the silicon wafer are extremely high. In addition, for the electrostatic chuck, the uniformity of the thickness of the surface insulating medium layer also determines the uniformity of the electrostatic attraction of each part of the electrostatic chuck. In addition, in the etching process, due to the slight temperature difference of the surface temperature of the silicon wafer, a large etching deviation can be caused, and the etching effect of the wafer is further influenced. Similarly, whether the thickness of the ceramic heater plate is uniform between the layers directly affects the temperature distribution on the surface of the silicon wafer and further affects the precision of the semiconductor processing technology. Therefore, the technological requirements for the composite ceramic plate including the electrostatic chuck and the ceramic heating plate are that the thickness of each layer of the basic sandwich structure is uniform, and the surface flatness of the ceramic composite plate is good.

In order to prepare a multilayer composite ceramic disk with good flatness and uniform thickness, which comprises an electrostatic chuck and a ceramic heating disk, two methods are commonly used at present: one is a layered sintering method, in which an upper ceramic layer and a lower ceramic layer are separately fired and processed, and then an electrode layer is sintered on one of the ceramic layer substrates. Then, each layer is packaged and connected to form the basic sandwich structure and ensure the functions of each layer. However, in the basic sandwich structure formed in this way, the two ceramic layers are in hard contact to clamp the metal electrode layer therebetween, so that the ceramic disc after being packaged and connected has poor performance stability and reliability; the other is an integral sintering method, namely, the three-layer structure of the sandwich structure is formed step by step and then is superposed together, and then the sandwich structure is sintered together to manufacture. Because the integral sintering process is adopted, the two ceramic layers of the formed basic sandwich structure are sintered into a whole, so that the advantages are that the combination of each layer is firm and reliable, but the integral sintering process is difficult to ensure, and the requirement of high flatness of each layer is difficult to ensure.

Therefore, it is desirable to provide a multilayer composite ceramic disk with good flatness and uniform thickness of each layer, which is suitable for the semiconductor processing field, and a preparation method thereof.

Disclosure of Invention

The invention aims to provide a multilayer composite ceramic disc which is good in flatness and uniform in thickness of each layer and is suitable for the field of semiconductor processing and a preparation method thereof.

Therefore, the invention provides the preparation method of the composite ceramic disk, which has the advantages of simple and convenient process, easy realization, easy industrial production, high production efficiency, high yield and good reliability.

In one aspect of the present invention, there is provided a multi-layered composite ceramic plate having good flatness and uniform thickness, which is suitable for use as an electrostatic chuck and/or a ceramic heating plate in a semiconductor process, and a method for preparing the same.

The invention relates to a preparation method of a multilayer composite ceramic disk, which is characterized in that a mold is adopted for pressure sintering, the mold is a graphite hot-pressing mold, namely, two independent and coaxial graphite cylinders are arranged in a graphite cylinder outer barrel, the lower part is a graphite mold base, and the upper part is a graphite mold gland (not shown in the figure).

The multilayer composite ceramic disc comprises at least one basic sandwich structure, wherein the basic sandwich structure comprises a first ceramic layer, a second ceramic layer and a metal electrode layer which is positioned between the first ceramic layer and the second ceramic layer and is positioned between the first ceramic layer and the second ceramic layer; the preparation method specifically comprises the following steps:

(1) preparing a flaky ceramic biscuit by using ceramic powder; pre-sintering the ceramic biscuit at a pre-sintering temperature lower than the sintering temperature to obtain a pre-sintered ceramic part with certain strength;

(2) preparing a metal electrode layer on the upper surface of the pre-sintered ceramic piece;

(3) placing the pre-sintered ceramic piece into a graphite mold base in a mold, wherein the upper surface covered with the metal electrode layer faces upwards, providing a ceramic precursor layer on the upper surface of the pre-sintered ceramic piece, and pressurizing and sintering the pre-sintered ceramic piece into a whole at a sintering temperature along the axial direction of the pre-sintered ceramic piece; the pre-sintered ceramic piece is pressed and sintered to form a second ceramic layer, the ceramic precursor layer is pressed and sintered to form a first ceramic layer, and the metal electrode layer is located between the first ceramic layer and the second ceramic layer and integrated with the first ceramic layer and the second ceramic layer to obtain the basic sandwich structure.

Or further preferably, the composite ceramic disc comprises two basic sandwich structures, wherein a metal electrode layer and a first ceramic layer are further formed on the lower surface of the second ceramic layer, two basic sandwich structure five-layer composite ceramic discs are formed, and the five-layer structures are a first ceramic layer/a metal electrode layer/a second ceramic layer/a metal electrode layer/a first ceramic layer in sequence; the preparation method comprises the following steps:

(1) preparing a flaky ceramic biscuit by using ceramic powder; pre-sintering the ceramic biscuit at a pre-sintering temperature lower than the sintering temperature to obtain a pre-sintered ceramic part with certain strength;

(2) respectively preparing a metal electrode layer on the upper surface and the lower surface of the pre-sintered ceramic piece to obtain the pre-sintered ceramic piece with the bimetallic electrode layer;

(3) sequentially arranging a ceramic precursor layer and a pre-sintered ceramic piece with a bimetallic electrode layer according to the following upper-lower layer relation: the ceramic precursor layer/the pre-sintered ceramic piece with the bimetallic electrode layer/the ceramic precursor layer are coaxially arranged on a graphite mould base support in a mould, and then are pressed and sintered into a whole at a sintering temperature along the axial direction of the pre-sintered ceramic piece; the presintering ceramic piece is subjected to pressure sintering to form a second ceramic layer, and the ceramic precursor layer is subjected to pressure sintering to form a first ceramic layer;

the two ceramic precursor layers in the preparation of the five-layer composite ceramic disc with the two basic sandwich structures are the same or different, and the corresponding first ceramic layer materials are the same or different.

The pre-sintered ceramic part in the step (1) can resist water soaking, and can be subjected to finish machining of turning, milling and grinding with dimensional tolerance precision within 0.03 mm. The forming method of the flaky ceramic biscuit in the step (1) is isostatic pressing.

Further preferably, the method further comprises the step of performing finish machining on the pre-sintered ceramic piece before the step (2) of preparing the metal electrode layer on the upper surface of the pre-sintered ceramic piece, so that the pre-sintered ceramic piece has better flatness and more uniform thickness. And processing the pre-sintered ceramic piece to the flatness of not more than 0.03 mm.

Further preferably, the metal electrode layer in the step (2) is formed on the pre-sintered ceramic piece through a screen printing process or a coating process. It is further preferable that the flatness of the metal electrode layer is not more than 0.03 mm.

Further preferably, the ceramic precursor layer in step (3) is uniformly distributed ceramic powder or a pre-formed unsintered flaky ceramic blank. Preferably, the unsintered ceramic sheet blank is formed by pre-pressing ceramic powder in a die.

Further preferably, the pre-sintering temperature of the pre-sintered ceramic piece in the step (1) is 20-600 ℃ lower than the sintering temperature in the step (3), and preferably 100-400 ℃ lower; and (4) the sintering temperature in the step (3) is a densification sintering temperature, and different materials have different densification sintering temperatures.

Further preferably, the material components of the ceramic powder in the step (1) and the ceramic precursor layer in the step (3) are both selected from one or more of oxides and non-oxides, wherein the oxides are selected from one or two of alumina, zirconia, magnesium aluminate spinel and the like, and the non-oxides are selected from one or two of aluminum nitride, silicon carbide and the like. After sintering, the second ceramic layer and the first ceramic layer correspond to one or more of oxide ceramic and non-oxide ceramic, wherein the oxide ceramic is selected from one or two of alumina ceramic, zirconia ceramic, magnesia alumina spinel and the like, and the non-oxide ceramic is selected from one or two of aluminum nitride, silicon carbide and the like.

The area of the first ceramic layer and the area of the second ceramic layer are larger than that of the metal electrode layer, the metal electrode layer is coated between the first ceramic layer and the second ceramic layer, and the outer edge parts of the first ceramic layer and the second ceramic layer are mutually contacted and are pressed and sintered into a whole.

The invention provides a preparation method of a composite ceramic disk, in particular to a preparation method of a multilayer composite ceramic disk which is suitable for a semiconductor processing technology. The composite ceramic disks are suitable for use as electrostatic chucks and/or heating disks in semiconductor processing. According to the embodiment of the invention, the composite ceramic disc has good flatness and uniform thickness. Compared with the traditional preparation method of the composite ceramic disc, the preparation method has the advantages of high precision, simple process, high yield, simple and convenient processing and the like.

Drawings

FIG. 1 is a schematic view of a basic sandwich structure of a multi-layer composite ceramic disk according to the present invention;

FIG. 2 is a schematic diagram of a process for preparing a multi-layer composite ceramic disk based sandwich structure according to the present invention;

FIG. 3 is a schematic view of a five-layer composite ceramic disk structure with two basic sandwich structures;

FIG. 4 is a schematic diagram of a process for making the five-layer composite ceramic disk of FIG. 3;

reference numerals:

1. a second ceramic layer; 2. a metal electrode layer; 3. a first ceramic layer; 4. a graphite die base; 5. an outer cylinder of the graphite mold; 6. pre-sintering the ceramic piece; 7. a ceramic precursor layer.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

The electrostatic chuck and the heating plate used in the semiconductor processing technology belong to multilayer composite ceramic plates, and the functional structures of the electrostatic chuck and the heating plate have typical basic sandwich structures. The invention provides a multilayer composite ceramic disk suitable for being used as an electrostatic chuck and a heating disk used in a semiconductor processing technology and a preparation method thereof. FIG. 1 is a schematic view of a basic sandwich structure of the multi-layered composite ceramic disk of the present invention, and FIG. 2 is a schematic view of a process for preparing the basic sandwich structure of the multi-layered composite ceramic disk of the present invention. The method comprises the following steps:

1. carrying out cold isostatic pressing on the sprayed and granulated alumina powder to form a flaky ceramic biscuit with the diameter of 300mm and the thickness of 5mm, wherein the forming pressure is 200 MPa;

2. a flaky ceramic biscuit with the diameter of 300mm and the thickness of 5mm is subjected to heat preservation for 1 hour at 1200 ℃ in an oxidizing atmosphere, and is presintered to obtain a flaky alumina presintered ceramic part 6, wherein in the embodiment, the presintering temperature is set to 1200 ℃, the presintering temperature is set to be related to the sintering temperature of subsequent pressure sintering, and the presintering temperature is generally 20 ℃ to 600 ℃ lower than the sintering temperature of the pressure sintering, and is preferably 100 ℃ to 400 ℃ lower than the sintering temperature of the pressure sintering;

3. carrying out flat grinding processing on the plane of the alumina pre-sintered ceramic piece 6 by using a numerical control plane grinder to ensure that the flatness of the plane is not more than 0.03mm, and ideally not more than 0.008 mm;

4. printing a metal tungsten paste on one plane of a precisely processed alumina pre-sintered ceramic piece 6 by using a screen printing method to obtain a metal electrode layer 2, wherein the flatness of the metal electrode layer 2 is not more than 0.03mm, in other embodiments, a coating process or other film forming processes can be selected to form the metal electrode layer 2 on the pre-sintered ceramic piece, in the embodiment, the material of the metal electrode layer is tungsten, but is not limited to tungsten, and other metal materials suitable for being used as metal electrodes can be selected;

5. as shown in fig. 2, in a first step, an alumina pre-sintered ceramic piece 6 coated with a metal electrode layer 2 is smoothly placed on a graphite mold base 4, and then a graphite mold outer cylinder 5 is fitted over, with the upper surface of the pre-sintered ceramic piece 1 coated with the metal electrode layer 2 facing upward. In a second step, a ceramic precursor layer 7 is provided on the pre-sintered ceramic piece 6, in this embodiment, the ceramic precursor layer is alumina powder distributed uniformly, and in other embodiments, the ceramic precursor layer 7 may also be a pre-formed green sheet ceramic body. And thirdly, carrying out pressure sintering along the axial direction of the alumina pre-sintered ceramic part 6, wherein the sintering temperature is set to 1600 ℃, the temperature is kept for 30 minutes, and the pressure is 20 MPa.

Through the pressure sintering, presintering ceramic piece 6 forms second ceramic layer 1, ceramic precursor layer form 7 forms first ceramic layer 3, metal electrode layer 2 corresponds the metal electrode layer 2 of figure 1, and is located between first ceramic layer 3 and the second ceramic layer 1 and with first ceramic layer and second ceramic layer formation basic sandwich structure.

In this embodiment, the ceramic precursor layer 7 and the pre-sintered ceramic member 6 are made of alumina, and both of them are alumina ceramics after pressure sintering. In other embodiments, the material of the ceramic precursor layer 7 and the pre-sintered ceramic piece 6 may also be one or several of the following materials: alumina, zirconia, magnesia alumina spinel, aluminum nitride, silicon carbide. In other embodiments, the first ceramic layer and the second ceramic layer are one or more of alumina, zirconia, magnesium aluminate spinel, and other oxide ceramics. In other embodiments, one or more of the first ceramic layer and the second ceramic layer is one or more of non-oxide ceramics such as aluminum nitride, silicon carbide, and the like. In other embodiments, one or more of the first ceramic layer and the second ceramic layer is a complex phase ceramic.

As shown in fig. 1, the first ceramic layer and the second ceramic layer have an area larger than that of the metal electrode layer, and outer edge portions thereof are in contact with each other and are integrally sintered by pressure, and thus the metal electrode layer is completely encapsulated