TW201904351A - Ceramic Heater and Method for Manufacturing Thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing a ceramic heater, and the method for manufacturing a ceramic heater of the present invention comprises the steps of: molding, between a first ceramic blocking layer and a second ceramic blocking layer, a stacking structure having a sandwich structure in which a ceramic powder layer having a heating element buried therein is interposed; and sintering a molded body of the stacking structure.

Description

Ceramic heater and manufacturing method thereof

The present invention relates to a ceramic heater and a method of manufacturing the same, and, in particular, to a ceramic heater which improves the local resistance change rate of a heat generating body and a method of manufacturing the same.

The ceramic heater is used for heat-treating a plurality of heat treatment target objects such as a semiconductor wafer, a glass substrate, and a flexible substrate at a predetermined heating temperature. For semiconductor wafer processing, ceramic heaters can also be used in conjunction with the function of electrostatic chucks. In general, a ceramic heater includes a ceramic plate that receives power supply from an external electrode and generates heat. The ceramic plate includes a heat generating body having a predetermined resistance embedded in the ceramic sintered body.

As related related documents, reference may be made to Korean Patent No. 10-0533471 (December 06, 2005) and the like. Japanese Laid-Open Patent Publication No. 10-0533471 discloses a ceramic heater manufacturing method in which a sintered molded body is in contact with one or more metal stacking members selected from elements of Groups 4a, 5a and 6a of the periodic table of elements in the upper and lower portions of the ceramic plate. Therefore, the carbonization of the built-in heating element is suppressed. However, such a conventional metal stacking method of ceramic heater manufacturing has various problems.

First, the ceramic heater manufactured by the metal stacking method has local resistance unevenness depending on the heat generating body portion. Secondly, in the conventional metal stacking method, the metal stacked member needs to be removed after manufacture, and is a disposable consumable member that is difficult to reuse. Further, in the conventional metal stacking method, the carbide formed by the carbonization of the metal stacked member induces a damage on the surface of the ceramic heater sintered body which is in contact therewith, and the ceramic is present as the damaged portion is removed. The thickness of the heater needs to be thicker than necessary.

Technical problem solved

The inventors of the present invention have found that in the method of using the conventional metal stacked member, the metal stacked member exhibits brittleness by reacting with the carbide during sintering, and thus induces cracking. Further, the inventors of the present invention have found that a carbon source that functions as a factor of resistance change of a heating element is caused by an external source, that is, a carbon in a carbon mold or a furnace, compared with a carbon content in a powder. member. Therefore, the crack formed in the introduced metal stack member acts as an inflow passage of carbon from other carbon sources in the furnace, for example, from a carbon mold or a carbon member, and as a result, is not suitable for suppressing carbon derived from the outside of the molded body. Inflow, the carbonization of the heating element cannot be sufficiently suppressed.

The present invention has been made to solve the problem, and an object of the present invention is to provide a method for manufacturing a ceramic heater which is subjected to a sintering treatment by using a ceramic cutting layer which improves a local resistance change rate of a heating element, and a ceramic manufactured according to the method. Heater.

Further, an object of the present invention is to provide a method for producing a ceramic heater using a reusable ceramic cutting layer for carbonization suppression and a ceramic heater produced by the method.

Further, an object of the present invention is to provide a method for producing a ceramic heater capable of appropriately maintaining the thickness of a sintered body and a ceramic heater manufactured according to the method.

Technical solutions

First, if the features of the present invention are summarized, a method of manufacturing a ceramic heater according to an aspect of the present invention for achieving the object includes: embedding a heat between the first ceramic cutting layer and the second ceramic cutting layer a step of molding the laminated structure of the sandwich structure of the bulk ceramic powder layer; and a step of sintering the molded body of the laminated structure.

Preferably, the step of molding the laminated structure comprises: a step of providing a first ceramic cutting layer; a step of providing a ceramic powder layer in which the heating element is embedded on the first ceramic cutting layer; and providing a second ceramic on the ceramic powder layer The step of cutting the layer.

Preferably, the ceramic powder layer providing step includes the steps of: providing a first ceramic powder layer; disposing a heating element on the first ceramic powder layer; and providing a second ceramic on the first ceramic powder layer on which the heating element is disposed The step of the powder layer.

Preferably, in the step of providing the first ceramic powder layer, the first ceramic powder layer may be a molded body.

Preferably, after the step of providing the second ceramic powder layer, the step of press molding the first ceramic powder layer, the heat generating body and the second ceramic powder layer is further included.

Preferably, an inactive layer containing BN (Boron Nitride) is interposed between each of the first and second ceramic cutting layers and the ceramic powder layer.

Preferably, the first and second ceramic cutting layers comprise a rare earth oxide.

Preferably, the first and second ceramic cutting layers comprise a nitride and a rare earth oxide, and the rare earth oxide is 10% by weight or less of the ceramic cutting layer.

Preferably, the first and second ceramic cutting layers are sintered bodies.

Preferably, the first and second ceramic cutting layers reduce the localized formation of carbides in the heating element by the reaction with carbon flowing in from the outside during the sintering process.

Furthermore, a ceramic heater according to another aspect of the present invention includes a ceramic sintered body and a heat generating body embedded in the ceramic sintered body, and the ceramic sintered body is formed between the first ceramic cut layer and the second ceramic cut layer. After forming a molded body of a laminated structure of a sandwich structure in which a ceramic powder layer of a heating element is embedded, the ceramic powder layer is sintered and formed.

Effect of the invention

According to the method for producing a ceramic heater of the present invention, the ceramic green layer is formed up and down along the ceramic powder molded body in which the heat generating body is embedded, whereby the local resistance change rate of the heat generating body can be improved during the sintering process. In other words, since the electric resistance of the local heating element is increased by the use of the ceramic cutting layer, the temperature deviation at each position of the heating target surface such as the wafer is remarkably reduced, and the temperature uniformity of the heating surface can be improved.

Further, in the prior art, in order to suppress the occurrence of damage on the surface of the product, there is a problem that the sintered ceramic powder body needs to be made thicker than necessary. However, in the present invention, the sintered body can be formed by the use of the ceramic cutting layer without cracking. The thickness of the processing is smaller, and has the advantage of reducing the amount of ceramic used.

The invention will now be described in detail with reference to the drawings. In this regard, in the respective drawings, the same constituent elements are represented by the same reference numerals as much as possible. In addition, a detailed description of well-known functions and/or configurations will be omitted. The contents of the following disclosure will be explained with a focus on understanding the operation of the various embodiments, and the description of the elements that may obscure the description will be omitted. In addition, some of the components of the drawings may be exaggerated, omitted, or schematically illustrated. The size of each component does not fully reflect the actual size. Therefore, the content described herein is not limited by the relative size or interval of the components drawn in the respective drawings. Further, in the present invention, "stacking" is used as a meaning for defining the relative positional relationship of each layer. The expression "B layer on layer A" expresses the relative positional relationship between layer A and layer B. It is not required that layer A and layer B must be in contact, or a third layer may be interposed between them. Similarly, the expression "the C layer is interposed between the A layer and the B layer" does not exclude the case where the third layer is interposed between the A layer and the C layer or between the B layer and the C layer.

Fig. 1 is a view for explaining a ceramic heater 100 according to an embodiment of the present invention.

Referring to Fig. 1, a ceramic heater 100 according to an embodiment of the present invention includes a ceramic sintered body (hereinafter referred to as 130') formed by sintering a ceramic powder layer 130, and a heat generating body 140 embedded in the ceramic sintered body 130'. The heat generating body 140 embedded in the ceramic sintered body 130' and the ceramic sintered body 130' corresponds to a ceramic plate.

In the present invention, as shown in Fig. 1, the ceramic sintered body layer 130 is formed on the upper and lower surfaces of the ceramic powder layer 130 in which the heating element 140 is inserted, and after the respective ceramic cutting layers 110 and 150 are formed, the ceramic powder layer 130 is placed on the carbon. The furnace or carbon mold 200 is formed by treatment by a sintering process.

Before the sintering process, each ceramic cutting layer formed on the lower surface of the ceramic powder layer 130, that is, BN (Boron Nitride) is included as the inner side of one or more of the first ceramic cutting layer 110 and the second ceramic cutting layer 150. The inactive layer can be interposed with a BN layer 115/155. The BN layer 115/155 serves as a release agent for suppressing the reaction of the ceramic cutting layers 110, 150 with the ceramic sintered body 130'. The BN layer 115/155 may also be formed in a coating or spray form using a substance containing BN, or subjected to a sintering process, and used in the form of a sintered body.

Next, the manufacturing process of the ceramic heater 100 of one embodiment of the present invention will be described in more detail with reference to the flowchart of Fig. 2.

Fig. 2 is a flow chart for explaining a manufacturing process of the ceramic heater 100 of one embodiment of the present invention.

Referring to Fig. 2, first, a laminated structure of the first and second ceramic cutting layers 110 and 150 is formed on the upper and lower surfaces of the ceramic powder layer 130 in which the heating element 140 is inserted (step S110). In the present invention, the laminated structure and the components constituting the same can be manufactured in various methods.

For example, the first and/or second ceramic cutting layers 110, 150 may be coated in a mold or sprayed by means of a spray method, and may be provided in the form of a molded body or a sintered body. Preferably, the first and/or second ceramic cutting layers 110, 150 are provided in the form of a dense sintered body. The first and/or second ceramic cutting layers 110 and 150 of the dense sintered body having high brittleness and no firing deformation can effectively cut off the inflow of the carbon source from the outside.

The first ceramic cut layer 110 is provided, and then the ceramic powder layer 130 in which the heat generating body 140 is buried is formed on the first ceramic cut layer 110. At this time, the ceramic powder layer 130 may be laminated in various ways. For example, a first ceramic powder layer is formed as a part of the ceramic powder layer 130, and after the heat generating body 140 is disposed on the first ceramic powder layer, the second ceramic powder layer is covered on the first ceramic powder layer on which the heat generating body 140 is disposed. Thus, the ceramic powder layer 130 can be formed. At this time, the first ceramic powder layer can be provided in a form of a molded body which can be pressurized by a predetermined pressure to maintain the shape. Of course, the entire ceramic powder layer 130 can also be provided in the form of a press-formed molded body. On the ceramic powder layer 130, the second ceramic cut layer 150 is laminated.

Each of the ceramic cut layers formed on the upper and lower surfaces of the ceramic powder layer 130, that is, between the first ceramic cut layer 110 and the second ceramic cut layer 150 and the ceramic powder layer 130, serves as a release agent. The inactive layer may be coated or sprayed to form a material comprising BN (Boron Nitride) or a BN layer 115/155 in the form of a sintered body.

When heat is generated in the heating element 140 during use as a heater, the heating element 140 is embedded in the ceramic powder layer 130 having excellent heat resistance and excellent heat transfer characteristics. The heating element 140 may be made of a conductive material, and may be, for example, tungsten (W), molybdenum (Mo), silver (Ag), nickel (Ni), gold (Au), niobium (Nb), or titanium (Ti). The conductive material is combined to form a resistance heating element having an appropriate resistance value.

The ceramic powder layer 130 may be, for example, Al ₂ O ₃ , Y ₂ O ₃ , Al ₂ O ₃ /Y ₂ O ₃ , ZrO ₂ , AlC (Autoclaved lightweight concrete), TiN, AlN, TiC, MgO, CaO, CeO ₂ , TiO ₂ , BxCy, BN, SiO ₂ , SiC, YAG, Mullite (mullite), AlF _{3 ,} etc. or a combination of their various ceramic material powders.

As described above, the heat generating body 140 inserted into the ceramic powder layer 130 reacts with the surrounding carbon during the sintering process to form carbides in the heat generating body 140, which causes an increase in electrical resistance and causes a temperature unevenness of the heating surface.

However, in the present invention, each ceramic cut layer 110/150 is formed above and below the ceramic powder layer 130 before sintering. The ceramic powder layer 130 has a small amount of carbon, and most of the cause of formation of carbides in the heating element 140 is caused by carbon flowing in from the outside.

In the present invention, the first ceramic cut layer 110 underlying the ceramic powder layer 130 and the second ceramic cut layer 150 overlying the ceramic powder layer 130 are covered so that the heat generation body 140 can be suppressed in the sintering process and from the outside. The influent carbon reacts to form carbides.

The first ceramic cut layer 110 and the second ceramic cut layer 150 may include the same material as the ceramic powder layer 130. However, the aforementioned ceramic material has low reactivity with carbon, and therefore it is preferred to add a predetermined amount of rare earth oxide so as to be able to react with carbon. For example, preferably, the first ceramic cutting layer 110 and the second ceramic cutting layer 150 contain a nitride, like the ceramic powder layer 130, and contain 1 to 10% by weight (wt%) of the rare earth oxide. As the rare earth group oxide, for example, various rare earth oxides such as LaAlO ₃ , La ₂ O ₃ , Y ₂ O ₃ , and LaAl ₃ O ₆ can be used.

In this manner, after forming a molded body having a laminated structure in which a ceramic layer 130 in which the heating element 140 is embedded is interposed between the first and second ceramic cutting layers 110 and 150, as shown in FIG. The sintering process is performed in the carbon furnace or the carbon mold 200 so that the ceramic powder layer 130 becomes a ceramic sintered body (step S120).

The sintering process can be achieved by heating the carbon or carbon mold 200 to a predetermined temperature at which the ceramic does not decompose (for example, 1500 ∼ 2500 ° C) for a predetermined time (for example, 10 hours or less). Further, preferably, the sintering process is sintered under a non-oxidizing atmosphere, for example, under a vacuum or a N ₂ atmosphere. In addition, the sintering process can be achieved by means of a usual hot press.

After the sintering process, the ceramic cutting layers 110 and 150 (including the BN layers 115 and 155) are removed, and the ceramic sintered body 130' including the ceramic powder layer 130 and the heating body 140 embedded in the ceramic sintered body 130' are obtained. The ceramic plate of the ceramic heater 100 (step S130). At this time, the ceramic cutting layers 110, 150 can be easily separated from the ceramic powder layer 130 due to the insertion of the inactive layer as described above.

The removed ceramic cutting layers 110, 150 can later be reused as ceramic cutting layers for new ceramic heaters. For example, the ceramic cut layer 110/150 can be reused after being used in one or more sintering processes, and can be reused within 10 times of use.

The heat generating body 140 embedded in the ceramic sintered body generates electric power (for example, RF (Radio Frequency) power) supplied from the outside by an electrode (not shown), and generates heat according to the resistance property. One side of the ceramic plate serves as a heating surface for heating the target object, and may be a surface for placing or heating the target object. An electrode (not shown) for supplying electric power to the heat generating body 140 may be combined by the other side of the ceramic plate.

The ceramic heater 100 including such a ceramic plate can be used for heat treatment of a plurality of heat treatment targets such as a semiconductor wafer, a glass substrate, and a flexible substrate at a predetermined heating temperature. For semiconductor wafer processing, ceramic heaters can also be used in conjunction with the function of electrostatic chucks.

Fig. 3 is a view for comparison of the rate of change in resistance of each of the conventional ceramic heaters and the ceramic heater 100 of one embodiment of the present invention.

In the third drawing, the case where the stacked layer or the cut layer is not performed in the sintering process (Comparative Example #1), the case where the metal stacked layer is used as shown in the past (Comparative Example #2) In the case of using the ceramic cutting layers 110 and 150 of the present invention (Examples #1 to #6), the rate of change in electrical resistance under various conditions such as the number of times of using the ceramic cutting layer and the content of rare earth (wt%) was shown. Among them, AlN was used for the ceramic cut layer 110/150, and a rare earth oxide capable of reacting with carbon was used, and Y ₂ O ₃ was added.

As shown in Fig. 3, first, if the content of the rare earth oxide exceeds 10 wt%, the liquid state on the ceramic cut layer 110/150 rises during sintering, reacts with the carbon furnace or the carbon mold 200, and is sintered. The processed article is difficult to assemble and disassemble. Therefore, preferably, in the ceramic cut layer 110/150, the rare earth oxide is added in an amount of 10% by weight or less. Further, when the content of the rare earth oxide is less than 1% by weight, the effect of suppressing carbonization of the heating element is also weak.

Further, it was confirmed that the rate of change in electric resistance of the heating element 140 due to the carbon content contained in the ceramic powder layer 130 as the raw material substance was not large.

Further, although the ceramic cutting layer 110/150 can be reused for sintering other ceramic powder molded bodies, as shown in Fig. 3, it has been confirmed that the resistance change rate of the heating element 140 starts to rise if the number of uses reaches 10 or more times. .

Further, in the case where the conventionally carried out without the stacked layer or the cut layer (Comparative Example #1), the case where the metal stacked layer is used as shown in the past (Comparative Example #2), and the present invention, it can be confirmed that it is used. In the case of the examples #1, #2, #5, and #6 of the ceramic cutting layers 110 and 150 of the present invention, when the ceramic heater 100 is used when power is supplied, the temperature deviation at different positions of the heating surface of the ceramic plate is obtained. A considerable improvement, as shown in Fig. 3, in the case of manufacturing according to an embodiment of the present invention, it can be considered that this is due to the rate of change of resistance of a hot zone which occurs due to an increase in resistance due to localized carbide formation. Lower than the previous technology.

In the prior art, in order to reduce the resistance change of the heat generating body, a metal stacking member (for example, 4A, 5A, and 6A metal) is used to shield the inflow of carbon from the outside, and the electric resistance of the heat generating body can be reduced to some extent. That is, such a metal stacking member reduces carbon flowing in from the outside, and reduces the area in which the heating element is carbonized, so that the electric resistance of the heating element can be reduced to some extent. However, such a conventional technique can reduce the change in resistance of the entire heat generating body, but it is not possible to prevent the resistance change of the heat generating body from being locally unevenly generated. Further, since the conventional metal stacking member is used at once, it is rapidly carbonized and brittle during the sintering process due to reaction with carbon, so that cracks are induced at the time of use, and the generated crack acts as an inflow path of the carbon source. In addition, the carbonization reaction of the metal stack induces damage on the surface of the article. Therefore, the powder sintered body can only be made thicker than necessary, and then the damaged portion is removed.

However, as described above, according to the ceramic heater 100 of the present invention, the ceramic cut layer 110/150 is formed up and down along the ceramic powder molded body in which the heat generating body is embedded, and the BN layer 115/155 for the release agent is formed, thereby sintering. In the process, the resistance change of the entire heating element 140 can be reduced, and the local resistance change rate can also be improved. That is, by using the ceramic cutting layer 110/150 in the present invention, the formation of brittle carbides and thus the occurrence of cracks can be remarkably reduced during the sintering process. Therefore, the present invention cuts off a considerable portion of the inflowing carbon by the use of the ceramic cutting layer 110/150, so that the resistance change of the entire heating element 140 can be reduced during the sintering process, and the local resistance change rate can also be improved. Further, the BN layer 115/155 for the release agent does not react with the ceramic powder layer 130, thereby being more advantageous in cutting carbon from the ceramic cutting layer 110/150, and also favors the ceramic cutting layer 110/150. Reuse.

Further, in the heat generating body 140, a portion where severe carbonization occurs locally, after the sintering, when operating as a heater, the amount of heat generated in the corresponding portion increases, and a hot region is formed around the portion. According to the present invention, the possibility of increasing the resistance of the heat generating body such as the local position of the hot zone is cut, and thus the temperature deviation at each position of the heating surface of the target object such as the wafer is remarkably reduced, and the temperature uniformity of the heating surface can be improved. . Further, in the prior art, in order to suppress the occurrence of wounds on the surface of the product, there is a problem that it is necessary to make the ceramic powder sintered body thicker than necessary. However, in the present invention, by using the ceramic cutting layer 110/150 having low reactivity, The processing allowance of the thickness of the sintered body can be made smaller, and there is an advantage that the amount of use of the ceramic powder molded body can be reduced.

As described above, the present invention has been described in terms of specific matters, such as specific constituent elements, and the embodiments and the drawings, which are provided to provide a more complete understanding of the present invention, and the present invention is not limited to the embodiment. Various modifications and changes can be made without departing from the spirit and scope of the invention. Therefore, the inventive concept is not limited to the illustrated embodiments, and the scope of the present invention should be construed as not only the scope of the scope of the appended claims. All technical ideas of the deformation.

100‧‧‧Ceramic heater

130‧‧‧Ceramic powder layer

140‧‧‧heating body

110, 150‧‧‧ceramic cutting layer

115, 155‧‧‧BN (Boron Nitride) layer

200‧‧‧Carbon mould

S110~S130‧‧‧Steps

Fig. 1 is a view for explaining a ceramic heater according to an embodiment of the present invention.

Fig. 2 is a flow chart for explaining a manufacturing process of a ceramic heater according to an embodiment of the present invention.

Fig. 3 is a view for explaining the comparison of the rate of change in resistance of the heating element of the conventional ceramic heater and the ceramic heater of one embodiment of the present invention under various conditions.

Claims (11)

A method of manufacturing a ceramic heater, comprising: laminating a sandwich structure in which a ceramic powder layer in which a heat generating body is embedded is interposed between a first ceramic cutting layer and a second ceramic cutting layer a molding step; and a step of sintering the molded body of the laminated structure. The method of manufacturing a ceramic heater according to claim 1, wherein the step of molding the laminated structure comprises: providing the first ceramic cutting layer; and providing the heat on the first ceramic cutting layer a step of the ceramic powder layer; and a step of providing the second ceramic green layer on the ceramic powder layer. The method for manufacturing a ceramic heater according to claim 2, wherein the ceramic powder layer providing step comprises: providing a first ceramic powder layer; and disposing the heat generating body on the first ceramic powder layer a step of providing a second ceramic powder layer on the first ceramic powder layer provided with the heat generating body. The method for producing a ceramic heater according to claim 3, wherein in the step of providing the first ceramic powder layer, the first ceramic powder layer is a molded body. The method of manufacturing a ceramic heater according to claim 3, wherein after the step of providing the second ceramic powder layer, further comprising: the first ceramic powder layer, the heat generating body, and the second ceramic powder The layer is subjected to a step of press molding. The method of manufacturing a ceramic heater according to claim 1, wherein a BN (Boron Nitride) is interposed between each of the first ceramic cutting layer and the second ceramic cutting layer and the ceramic powder layer. An inactive layer). The method for producing a ceramic heater according to the first aspect of the invention, wherein the first ceramic cutting layer and the second ceramic cutting layer comprise a rare earth oxide. The method for manufacturing a ceramic heater according to claim 7, wherein the first ceramic cutting layer and the second ceramic cutting layer comprise a nitride and a rare earth oxide, the rare earth oxide being the first The ceramic cut layer and the second ceramic cut layer are 10% by weight or less. The method for producing a ceramic heater according to the first aspect of the invention, wherein the first ceramic cutting layer and the second ceramic cutting layer are sintered bodies. The method of manufacturing a ceramic heater according to the first aspect of the invention, wherein the first ceramic cutting layer and the second ceramic cutting layer are in the sintering process, by means of inflowing from the outside The reaction of carbon reduces the localized formation of carbides. A ceramic heater comprising: a ceramic sintered body; and a heating element embedded in the ceramic sintered body, the ceramic sintered body being formed between a first ceramic cutting layer and a second ceramic cutting layer A ceramic powder layer of the heat generating body is inserted into a molded body of a laminated structure of a sandwich structure therein, and then formed by sintering the ceramic powder layer.