JP2003208964A - Ceramic heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic heater which can make the temperature of heated things, such as a silicon wafer, or the like, equalize, can prevent breakage of the silicon wafer, and even when the unexpected temperature change arises, can recover it to the setting temperature in a short time. <P>SOLUTION: The ceramic heater is constituted with a temperature measuring means, which measures the temperature of a ceramic board or a heated thing while a heating element is formed in the surface or the inside of the ceramic board, a control part, which supplies electric power to the above heating element, a memory part, which memorizes the temperature data measured by the above temperature measuring means, and a calculating part, which calculates electric power required for the above heating element from the above temperature data. And, the above heating element is divided into at least two or more circuits, and is constituted so that different electric power may be supplied to the each circuit. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic heater mainly used in the semiconductor industry for drying, sputtering, etc., and particularly to a ceramic heater which is easy to control in temperature and has excellent temperature uniformity on a heating surface.

[0002]

2. Description of the Related Art Semiconductor products are manufactured through a process of forming a photosensitive resin as an etching resist on a silicon wafer and etching the silicon wafer. This photosensitive resin is in liquid form and is applied to the surface of the silicon wafer using a spin coater, etc., but it must be dried after application, and the applied silicon wafer should be placed on a heater and heated. become. Conventionally, as a metal heater used for such an application, a heater in which a heating element is arranged on the back surface of an aluminum plate has been adopted.

However, such a metal heater is
There were the following problems. First of all, because it is made of metal,
The thickness of the heater plate should be as thick as about 15 mm. This is because, in a thin metal plate, thermal expansion caused by heating causes warping and distortion, and the silicon wafer placed on the metal plate is damaged or tilted. However, if the thickness of the heater plate is increased, the weight of the heater becomes heavier and bulky.

Further, the heating temperature is controlled by changing the voltage and the amount of current applied to the heating element. However, since the metal plate is thick, the temperature of the heater plate can be quickly changed with respect to the change in the voltage and the amount of current. There was also a problem that it was difficult to control the temperature because it did not follow.

Therefore, as proposed in Japanese Examined Patent Publication No. 8-8247, there is proposed a technique for controlling the temperature by using a nitride ceramic in which a heating element is formed and measuring the temperature in the vicinity of the heating element. Has been done.

[0006]

However, when attempting to heat a silicon wafer by using such a technique, there arises a problem that the silicon wafer is damaged by thermal shock due to the temperature difference on the heater surface. .

Therefore, as a result of intensive studies on the cause of damage to the silicon wafer, the inventors of the present invention found that the silicon wafer is damaged even though the temperature control is performed even if the single temperature control is performed. The heating surface does not have a uniform temperature,
We identified the fact that the temperature difference in the silicon wafer caused by location caused damage. Further, the fact that such non-uniformity of temperature is more remarkable as the heat conductivity of nitride ceramics or carbide ceramics is higher is newly found.

Incidentally, Japanese Patent Application Laid-Open No. 6-252055 discloses a control technique for controlling the temperature of the central portion to be higher than the temperature of the peripheral portion.
Each of the technologies for dividing and controlling the heating element circuit has been proposed, but each is a technology for controlling the temperature after previously determining a temperature schedule. However, in the actual heating of a silicon wafer, there is a disturbance such as when a low-temperature silicon wafer is suddenly placed, and when there is an unplanned temperature change in the control technique for predetermining the above temperature schedule. The temperature cannot be controlled.

[0009]

Therefore, the inventors of the present invention have made further studies, divided the heating element into two or more circuits, and applied different electric power to each circuit based on the result of the temperature measurement. By controlling and heating, the temperature difference of the surface of the heater plate that heats the silicon wafer, etc. (hereinafter referred to as the wafer heating surface) is made small, so that the temperature of the entire object to be heated, such as the semiconductor wafer, is made uniform. It is possible to prevent the damage of the silicon wafer and to control the temperature even if there is an unexpected temperature change.
The present invention having the following contents as the gist composition has been completed.

That is, in the ceramic heater of the first aspect of the present invention, a heating element is formed on the surface or inside of the ceramic substrate, and the temperature measuring means for measuring the temperature of the ceramic substrate or the object to be heated, and the heating element. And a storage unit for storing temperature data measured by the temperature measuring means, and an arithmetic unit for calculating electric power required for the heating element from the temperature data. The body is characterized by being divided into at least two circuits, each circuit being configured to be supplied with different power.

Further, in the ceramic heater of the second aspect of the present invention, a heating element is formed on the surface or inside of the ceramic substrate, and a temperature measuring means for measuring the temperature of the ceramic substrate or the object to be heated, and the heating element. A power supply for supplying electric power to the device, a control unit for controlling the power supply, a storage unit for storing the temperature data measured by the temperature measuring means, and a calculation unit for calculating the power necessary for the heating element from the temperature data. And the heating element is divided into at least two or more circuits, and each circuit is configured to be supplied with different electric power.

In the ceramic heater according to the first aspect of the present invention and the ceramic heater according to the second aspect of the present invention, the temperature measuring means is preferably a temperature measuring element or a thermoviewer.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION First, a ceramic heater according to the first aspect of the present invention will be described. In the ceramic heater of the first aspect of the present invention, a heating element is formed on the surface or inside of the ceramic substrate, and a temperature measuring means for measuring the temperature of the ceramic substrate or the object to be heated, and power is supplied to the heating element. The heating unit includes a control unit, a storage unit that stores temperature data measured by the temperature measuring unit, and a calculation unit that calculates the electric power required for the heating element from the temperature data. The circuit is divided into the above circuits, and each circuit is configured to be supplied with different power.

According to the ceramic heater of the first aspect of the present invention, the heater is put into the circuit of the heating element divided into two or more based on the measurement result of the temperature of the wafer heating surface or the temperature of the object to be heated such as a semiconductor wafer. Since the temperature can be controlled by changing the electric power, the temperature of the wafer heating surface can be made uniform and the temperature of the whole object to be heated can be made uniform.
It is possible to prevent damage to the silicon wafer.

FIG. 1A is a block diagram showing an outline of an example of the ceramic heater according to the first aspect of the present invention, and FIG.
[FIG. 7] is a partially enlarged cross-sectional view showing a part thereof. Further, FIG. 2 is a plan view schematically showing a heater portion which constitutes the ceramic heater shown in FIG.

The heater plate 11 is formed in a disk shape, and the heating elements 12 (12x, 12y) heat the wafer heating surface 11a of the heater plate 11 so that the temperature of the entire wafer heating surface 11a becomes uniform. It is formed in a concentric pattern inside the plate 11. Further, these heating elements 12 are connected so that a pair of double concentric circles that are close to each other form one line, and terminal pins 13 serving as input / output terminals are provided at both ends thereof through through holes 18. It is connected. Further, the socket 20 is attached to the terminal pin 13,
The socket 20 is connected to a control unit 23 having a power source. Also, lifter pin 1 should be placed near the center.
A through hole 15 for inserting 6 is formed, and bottomed holes 14a to 14i for inserting a thermocouple 17 as a temperature measuring means (temperature measuring element) are also formed.

Further, as shown in FIG. 1, in this ceramic heater 10, a lifter pin 16 is inserted into the through hole 15, and a silicon wafer 19 is placed on the lifter pin 16.
Are to be placed. Further, by moving the lifter pins 16 up and down, the silicon wafer 19 can be delivered to the carrier (not shown) or the silicon wafer 19 can be received from the carrier. Further, by supporting the silicon wafer by the support pins 560 (see FIG. 6), it is possible to heat the silicon wafer in a state of being separated from the wafer heating surface. The separation distance is 50 to 50
00 μm is desirable.

Further, the heater plate 11 is provided with a bottomed hole 14 from the bottom surface 11b side, and a thermocouple 17 as a temperature measuring means is fixed to the bottom of the bottomed hole 14. The thermocouple 17 is connected to the storage unit 21, and the temperature of each thermocouple 17 can be measured at regular intervals and the data can be stored. The storage unit 21 is connected to the control unit 23 and also to the calculation unit 22, and based on the data stored in the storage unit 21, the calculation unit 2
The voltage value controlled by 2 is calculated, and based on this, a predetermined voltage is applied from the control unit 23 to each heating element 12 so that the temperature of the wafer heating surface 11a can be made uniform. ing.

Next, the operation of the ceramic heater 10 of the present invention will be described. First, when power is applied to the ceramic heater 10 by operating the control unit 23,
Although the temperature of the heater plate 11 itself starts to rise, the surface temperature of the outer peripheral portion becomes slightly lower.

The data measured by the thermocouple 17 is stored in the storage unit 2
1 is temporarily stored. Next, this temperature data is calculated by the calculation unit 2
2, the calculation unit 22 calculates the temperature difference at each measurement point or the difference ΔT from the predetermined temperature, and further calculates the data ΔW necessary for uniformizing the temperature of the wafer heating surface 11a.

For example, if there is a temperature difference ΔT between the heating element 12x and the heating element 12y and the heating element 12x is lower,
Electric power data ΔW that makes ΔT zero is calculated, and this is transmitted to the control unit 23, and the electric power based on the calculated electric power data ΔW is generated.
It is put into 2x to raise the temperature.

Regarding the calculation algorithm of electric power, the most convenient method is to calculate the electric power required to raise the temperature from the specific heat of the heater plate 11 and the weight of the heating area, and the correction coefficient due to the heating element pattern is added to this. May be. It is also possible to perform a temperature rise test on a specific heating element pattern in advance, obtain a function of the temperature measurement position, input power, and temperature in advance, and calculate the input power from this function. Then, the control unit 2 calculates the applied voltage and the time corresponding to the power calculated by the calculation unit 22.
3 to each heating element 1 based on the value transmitted by the control unit 23.
2 will be powered. That is, in the ceramic heater of the first aspect of the present invention, since the calculation unit 22 is provided, even if an unexpected temperature change occurs, the power for equalizing the temperature can be calculated and a practical temperature control can be realized. be able to.

Next, each member constituting the ceramic heater of the first aspect of the present invention will be described. In this ceramic heater 10, the heater plate 11 has a thickness of 0.5 to 5
mm is preferred. When the thickness is less than 0.5 mm, the strength is lowered and the material is easily damaged. On the other hand, when the thickness is more than 5 mm, it is difficult for heat to propagate and the heating efficiency is deteriorated.

The ceramic constituting the ceramic heater 10 is preferably a nitride ceramic or a carbide ceramic. Nitride ceramics and carbide ceramics have a thermal expansion coefficient smaller than that of metal and a mechanical strength much higher than that of metal. Therefore, even if the thickness of the heater plate 11 is thinned, the heater plate 11 may warp or distort due to heating. do not do. Therefore, the heater plate 11 can be made thin and light. Furthermore, since the heat conductivity of the heater plate 11 is high and the heater plate itself is thin, the surface temperature of the heater plate quickly follows the temperature change of the heating element. That is, the surface temperature of the heater plate (temperature of the wafer heating surface) can be controlled by changing the temperature of the heating element 12 by changing the voltage and current values.

The above-mentioned nitride ceramic is, for example,
Examples thereof include aluminum nitride, silicon nitride, boron nitride, titanium nitride and the like. These may be used alone or 2
You may use together 1 or more types.

Examples of the carbide ceramics include silicon carbide, zirconium carbide, titanium carbide, tantalum carbide, tungsten carbide and the like. These may be used alone or in combination of two or more.

Of these, aluminum nitride is most preferred. The highest thermal conductivity of 180 W / mK,
This is because the temperature followability is excellent, but the temperature distribution is likely to be non-uniform, and it is necessary to use the temperature measuring means as in the present invention.

In the ceramic heater 10 of the present invention,
The heater plate 11 has a wafer heating surface 1 on which an object to be heated is placed.
The bottomed holes 14a to 14i (hereinafter also simply referred to as the bottomed holes 14) are provided from the opposite side (bottom surface) of the la to the wafer heating surface 11a, and the bottoms of the bottomed holes 14 are arranged relative to the heating element 12. It is desirable to form the wafer near the wafer heating surface 11a and to provide a temperature measuring means in the bottomed hole 14 (see FIG. 1). The distance L between the bottom of the bottomed hole 14 and the wafer heating surface 11a is 0.1 mm to 1/2 of the thickness of the ceramic substrate.
Is desirable (see FIG. 1 (b)).

As a result, the temperature measurement location is closer to the wafer heating surface 11a than the heating element 12, and the temperature of the silicon wafer can be measured more accurately. Then, this accurate temperature measurement result is stored in the storage unit 21, and based on the temperature data stored in the storage unit 21, the heating element 1 for uniform heating.
The voltage applied to 2 is calculated by the calculation unit 22, and the control voltage is applied to the heating element 12 by the control unit 23 based on the calculation result. Therefore, the temperature of the wafer heating surface is made uniform, and the object to be heated such as a silicon wafer is heated. It becomes possible to uniformly heat the whole.

If the distance between the bottom of the bottomed hole 14 and the wafer heating surface 11a is less than 0.1 mm, heat is dissipated and a temperature distribution is formed on the wafer heating surface 11a, and if it exceeds ½ of the thickness. This is because the temperature of the heating element is apt to be influenced, the temperature cannot be controlled, and the temperature distribution is formed on the wafer heating surface 11a.

The diameter of the bottomed hole 14 is 0.3 mm to 5 mm.
Is desirable. This is because if it is too large, heat dissipation becomes large, and if it is too small, workability deteriorates and it becomes impossible to make the distance to the wafer heating surface 11a uniform.

As shown in FIG. 2, the bottomed holes 14a to 14i are preferably arranged symmetrically with respect to the center of the heater plate 11 and forming a cross. This is because the temperature of the entire wafer heating surface can be measured.

As the temperature measuring means, for example, a thermocouple,
Examples include platinum temperature measuring resistors, temperature measuring elements such as thermistors, and temperature measuring means using optical means such as thermoviewers.

When the above-mentioned thermoviewer is used, not only the temperature of the surface of the ceramic substrate can be measured but also the temperature of the surface of the object to be heated such as a semiconductor wafer can be directly measured. The accuracy of is improved.
The temperature control using the thermoviewer will be described in detail in the description of the ceramic heater according to the second aspect of the present invention.

The thermocouple may be, for example, JI
K, as listed in S-C-1602 (1980).
Type, R type, B type, S type, E type, J type, T type thermocouple and the like, and among these, K type thermocouple is preferable.

The size of the joint portion of the thermocouple is preferably equal to or larger than the diameter of the wire, and is 0.5 mm or less. This is because if the joint is large, the heat capacity becomes large and the responsiveness deteriorates. It is difficult to make the diameter smaller than the diameter of the strand.

When the above temperature measuring element is used, gold solder,
It may be adhered to the bottom of the bottomed hole 14 using silver solder or the like, or may be inserted into the bottomed hole 14 and then sealed with a heat resistant resin, or both may be used together. Examples of the heat resistant resin include thermosetting resins, particularly epoxy resins, polyimide resins, bismaleimide-triazine resins, and the like. These resins may be used alone or in combination of two or more.

As the above-mentioned gold braze, 37 to 80.5 wt% Au-63 to 19.5 wt% Cu alloy, 81.5 to 8
At least one selected from 2.5 wt% Au-18.5 to 17.5 wt% Ni alloy is desirable. These are because the melting temperature is 900 ° C. or higher and it is difficult to melt even in a high temperature region. Examples of silver solder include Ag-Cu
A system can be used.

The heating element 12 is preferably divided into at least two circuits as shown in FIG.
More preferably, it is divided into 2 to 10 circuits.
By dividing the circuit, the amount of heat generated can be changed by controlling the electric power supplied to each circuit.
This is because the temperature of can be adjusted.

As the pattern of the heating element 12, in addition to the concentric circles shown in FIG. 2, for example, a spiral, an eccentric circle, a bent line and the like can be cited.

In the present invention, the heating element may be formed on the surface (bottom surface) of the heater plate, or the heating element may be embedded inside the heater plate. When the heating element is formed on the surface of the heater plate 11, a conductive paste containing metal particles is applied to the surface of the heater plate 11 to form a conductor paste layer having a predetermined pattern, which is then baked to form a conductive paste layer on the heater plate 11. A method of sintering the metal particles on the surface is preferable. In addition, the sintering of the metal is sufficient if the metal particles are fused to each other and the metal particles and the ceramic are fused.

When a heating element is formed on the surface of the heater plate 11, the thickness of the heating element is preferably 1 to 30 μm, more preferably 1 to 10 μm. Also, the heater plate 11
When a heating element is formed inside the
50 μm is preferable.

When a heating element is formed on the surface of the heater plate 11, the width of the heating element is preferably 0.1 to 20 mm, more preferably 0.1 to 5 mm. When a heating element is formed inside the heater plate 11, the width of the heating element is preferably 5 to 20 μm.

The resistance value of the heating element can be changed depending on its width and thickness, but the above range is most practical. The resistance value becomes thinner and becomes thinner as it becomes thinner. When the heating element is formed inside the heater plate 11, both the thickness and the width are larger. However, when the heating element is provided inside, the distance between the wafer heating surface and the heating element is shortened, and the temperature of the surface is reduced. Since the uniformity decreases, it is necessary to widen the width of the heating element itself, and it is not necessary to consider the adhesion with the nitride ceramic or the like in order to provide the heating element inside,
Refractory metals such as tungsten and molybdenum and carbides such as tungsten and molybdenum can be used.
Since the resistance value can be increased, the thickness itself may be increased for the purpose of preventing disconnection or the like. Therefore, it is desirable that the heating element has the above-mentioned thickness and width.

By setting the formation position of the heating element in this way, while the heat generated from the heating element propagates, the heat is diffused over the entire heater plate and the surface to be heated (silicon wafer) is heated. The temperature distribution is made uniform, and as a result,
The temperature in each part of the object to be heated is made uniform.

The heating element may have a rectangular or elliptical cross section, but it is preferably flat. This is because the flat surface is more likely to dissipate heat toward the wafer heating surface, so that the temperature distribution on the wafer heating surface is less likely to occur. The cross-sectional aspect ratio (width of heating element / thickness of heating element) is 10 to 5,000.
Is desirable. By adjusting to this range, the resistance value of the heating element can be increased and the uniformity of the temperature of the wafer heating surface can be ensured.

When the thickness of the heating element is constant, if the aspect ratio is smaller than the above range, the amount of heat propagation in the direction of the wafer heating surface of the heater plate 11 becomes small, and the heat distribution approximates the pattern of the heating element. Is generated on the wafer heating surface,
On the other hand, if the aspect ratio is too large, the temperature directly above the center of the heating element will become high, and eventually a heat distribution similar to the pattern of the heating element will occur on the wafer heating surface. Therefore, considering the temperature distribution, the aspect ratio of the cross section is 1
It is preferably 0 to 5000.

When the heating element is formed on the surface of the heater plate 11, the aspect ratio is 10 to 200, and when the heating element is formed inside the heater plate 11, the aspect ratio is 200 to 200.
It is desirable to set it to 5000.

When the heating element is formed inside the heater plate 11, the aspect ratio becomes larger. However, when the heating element is provided inside, the distance between the wafer heating surface and the heating element becomes shorter. This is because the temperature uniformity on the surface is reduced and the heating element itself needs to be flat.

When the heating element of the present invention is formed eccentrically inside the heater plate 11, the position is close to the bottom surface 11b of the heater plate 11 facing the wafer heating surface 11a, and the bottom surface from the wafer heating surface 11a. 50% for the distance to 11b
It is desirable to set the position above 99% and up to 99%. Fifty
If it is less than 100%, it is too close to the wafer heating surface and a temperature distribution is generated. Conversely, if it exceeds 99%, the heater plate 11 itself warps and the silicon wafer is damaged. .

When the heating element is formed inside the heater plate 11, a plurality of heating element forming layers may be provided. In this case, it is desirable that a heating element is formed in some layer so that the patterns of the respective layers complement each other, and that the pattern is formed in any region when viewed from above the wafer heating surface. As such a structure, for example, a structure in which staggered arrangement is provided.

The conductive paste is not particularly limited, but it is preferable that the conductive paste contains metal particles or conductive ceramics for ensuring conductivity, and also contains resin, solvent, thickener and the like.

As the metal particles, for example, noble metals (gold, silver, platinum, palladium), lead, tungsten, molybdenum, nickel and the like are preferable. These may be used alone or in combination of two or more. This is because these metals are relatively difficult to oxidize and have a resistance value sufficient to generate heat. Examples of the conductive ceramics include carbides of tungsten and molybdenum. These may be used alone or in combination of two or more.

The particle size of these metal particles or conductive ceramic particles is preferably 0.1 to 100 μm. 0.1μ
If it is less than m and too fine, it is easily oxidized, while 100
This is because if it exceeds μm, it becomes difficult to sinter and the resistance value increases.

Even if the shape of the metal particles is spherical,
It may be flaky. When these metal particles are used, they may be a mixture of the above-mentioned spherical material and the above-mentioned scaly material. When the metal particles are flakes, or a mixture of spheres and flakes, it becomes easier to hold the metal oxide between the metal particles, and the adhesion between the heating element and the nitride ceramic, etc. This is advantageous because it can be ensured and the resistance value can be increased.

The resin used for the conductor paste is
For example, an epoxy resin, a phenol resin, etc. are mentioned. Examples of the solvent include isopropyl alcohol and the like. Examples of the thickener include cellulose and the like.

As described above, it is desirable that the conductor paste contains a metal oxide added to the metal particles and the heating element is formed by sintering the metal particles and the metal oxide. As described above, by sintering the metal oxide together with the metal particles, the nitride ceramic or the carbide ceramic, which is the heater plate, can be brought into close contact with the metal particles.

Although it is not clear why the adhesion of the metal oxide to the nitride ceramic or the carbide ceramic is improved, the surface of the metal particles or the surface of the nitride ceramic or the carbide ceramic is slightly oxidized. It is considered that the oxide film is formed by sintering and the oxide film is sintered through the metal oxide to be integrated with each other, and the metal particles and the nitride ceramic or the carbide ceramic adhere to each other.

The metal oxide is preferably at least one selected from the group consisting of lead oxide, zinc oxide, silica, boron oxide (B ₂ O ₃ ), alumina, yttria and titania.

This is because these oxides can improve the adhesion between the metal particles and the nitride ceramic or the carbide ceramic without increasing the resistance value of the heating element.

The proportions of lead oxide, zinc oxide, silica, boron oxide (B ₂ O ₃ ), alumina, yttria and titania are such that, when the total amount of metal oxide is 100 parts by weight, lead oxide is 1-10, silica 1-30, boron oxide 5-50, zinc oxide 20-70, alumina 1
-10, yttria is 1-50, and titania is 1-50, and it is desirable that the total is adjusted not to exceed 100 parts by weight. By adjusting the amounts of these oxides within these ranges, it is possible to improve the adhesion, particularly with the nitride ceramics.

The amount of the above metal oxide added to the metal particles is preferably 0.1% by weight or more and less than 10% by weight. Further, the area resistivity when the heating element is formed using the conductor paste having such a configuration is preferably 1 to 45 mΩ / □.

When the sheet resistivity exceeds 45 mΩ / □, the amount of heat generated becomes too large with respect to the applied voltage amount, and it is difficult to control the amount of heat generated by the heater plate 11 having the heating element provided on the surface of the heater plate. Because. When the amount of the metal oxide added is 10% by weight or more, the sheet resistivity is 50 mΩ / □.
And the amount of heat generation becomes too large, which makes it difficult to control the temperature and reduces the uniformity of temperature distribution.

When the heating element is formed on the surface of the heater plate 11, it is desirable that a metal coating layer (see FIG. 3) 38 is formed on the surface portion of the heating element. This is to prevent the internal metal sintered body from being oxidized and changing its resistance value. The thickness of the metal coating layer to be formed is 0.1 to 10 μm.
m is preferred.

The metal used for forming the metal coating layer is not particularly limited as long as it is a non-oxidizing metal, and specific examples thereof include gold, silver, palladium, platinum and nickel. . These may be used alone or 2
You may use together 1 or more types. Of these, nickel is preferred.

This is because the heating element needs a terminal for connecting to the power source, and this terminal is attached to the heating element via solder, but nickel prevents heat diffusion of the solder. Examples of the connection terminal include a Kovar terminal pin 13.

When the heating element is formed inside the heater plate 11, the surface of the heating element is not oxidized and therefore the coating is unnecessary. When the heating element is formed inside the heater plate 11, a part of the heating element may be exposed on the surface, a through hole for connecting the heating element is provided in the terminal portion, and the terminal is connected to this through hole. , May be fixed.

When connecting the connection terminals, as solder,
Alloys such as silver-lead, lead-tin, bismuth-tin can be used. The thickness of the solder layer is 0.1 to 50.
μm is preferred. This is because the range is sufficient to secure the solder connection.

Next, a method for manufacturing the ceramic heater according to the first aspect of the present invention will be described. Here, a ceramic heater 10 (FIGS. 1 and 2) in which a heating element is formed inside a heater plate is used.
The manufacturing method of the reference) will be described. (1) Step of Manufacturing Heater Plate First, a powder of nitride ceramic or a carbide ceramic is mixed with a binder, a solvent, etc. to prepare a paste, and a green sheet is manufactured using the paste.

As the above-mentioned ceramic powder, aluminum nitride, silicon carbide, etc. can be used, and if necessary, a sintering aid such as yttria may be added.
Further, the binder is preferably at least one selected from acrylic binders, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol.

Further, the solvent is preferably at least one selected from α-terpineol and glycol. The paste obtained by mixing these is molded into a sheet by the doctor blade method to produce a green sheet. The thickness of the green sheet is preferably 0.1 to 5 mm.

Next, in the obtained green sheet, if necessary, a portion to be a through hole into which a lifter pin for supporting a silicon wafer is inserted, and a bottomed hole for embedding a temperature measuring element such as a thermocouple. And a through hole for connecting the heating element to an external end pin. The above-mentioned processing may be performed after forming a green sheet laminate described below.

(2) Step of printing conductor paste on the green sheet A conductive paste containing a metal paste or a conductive ceramic is printed on the green sheet. These conductive pastes contain metal particles or conductive ceramic particles.

The average particle diameter of the tungsten particles or molybdenum particles is preferably 0.1 to 5 μm. If the average particle size is less than 0.1 μm or exceeds 5 μm, it is difficult to print the conductor paste. Examples of such a conductor paste include, for example, 85 to 87 parts by weight of metal particles or conductive ceramic particles; 1.5 to 10 parts by weight of at least one binder selected from acrylic, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol; and Examples thereof include a composition (paste) in which 1.5 to 10 parts by weight of at least one solvent selected from α-terpineol and glycol is mixed.

(3) Laminating Step of Green Sheet The green sheet on which the conductor paste is not printed is laminated above and below the green sheet on which the conductor paste is printed.
At this time, the number of green sheets stacked on the upper side is set to be larger than the number of green sheets stacked on the lower side, and the formation position of the heating element is eccentric in the direction of the bottom surface. Specifically, the number of stacked green sheets on the upper side is preferably 20 to 50, and the number of stacked green sheets on the lower side is preferably 5 to 20.

(4) Firing step of green sheet laminate The green sheet laminate is heated and pressed to sinter the green sheet and the conductor paste inside. The heating temperature is preferably 1000 to 2000 ° C., and the pressure applied is
1 × 10 ^{5 to} 2 × 10 ⁵ Pa is preferable. The heating is performed in an inert gas atmosphere. As the inert gas, for example,
Argon, nitrogen and the like can be used.

After firing, a bottomed hole 14 for inserting the temperature measuring element may be provided. Bottomed hole 14
Can be formed by performing blasting treatment such as sandblasting after surface polishing. In addition, the terminal pin 13 is connected to a through hole for connecting with an internal heating element, heated and reflowed. The heating temperature is 200 ~
500 ° C. is preferred. Further, a thermocouple or the like as a temperature measuring element is attached with silver solder, gold solder or the like, sealed with a heat resistant resin such as polyimide, wiring from the thermocouple 17 is connected to the storage unit 21, wiring from the socket 20. Control unit 23
The production of the ceramic heater is completed by connecting to.

FIG. 3 is a block diagram showing the outline of another example of the ceramic heater of the present invention. In the ceramic heater 30 shown in FIG. 3, the heating element 32 (32x, 32y) is formed on the bottom surface 31b of the heater plate 31, and the heating element 32 is formed.
A metal coating layer 38 is formed around the metal. Further, the terminal pin 33 is connected to the heating element 32 via the metal coating layer 38,
It is fixed and the socket 40 is attached to the terminal pin 33. The socket 40 is connected to a control unit 43 having a power source, and the rest is configured in the same manner as the ceramic heater shown in FIG. That is, the shape of the heater plate 31 is a disk shape similar to the heater plate 11 shown in FIG. 1, and the pattern of the heating element 32 formed on the heater plate 11 in plan view, the formation position, and the bottomed shape. The shape and formation position of the hole 34 are the same as those of the ceramic heater 10 shown in FIG.

Next, the ceramic heater 30 shown in FIG.
The operation of will be described. The operation of the ceramic heater 30 shown in FIG. 3 is the same as that of the ceramic heater 1 shown in FIGS.
Similar to 0, the temperatures of the thermocouples 32x and 32y are measured at regular intervals and stored in the storage unit 41, and the voltage value and the like controlled by the calculation unit 42 is calculated from this data, and the control is performed based on this. By applying a predetermined voltage from the portion 43 to the heating elements 32x and 32y, the temperature of the entire wafer heating surface 31a of the ceramic heater 30 can be made uniform.

Next, the ceramic heater 30 shown in FIG.
The manufacturing method of will be described. (1) Manufacturing process of heater plate After preparing a slurry by adding a sintering aid such as yttria or a binder to the powder of the above-described nitride ceramic or carbide ceramic such as aluminum nitride, etc., this slurry is prepared. Granules are formed by a method such as spray drying, and the granules are put into a mold or the like and pressed to form a plate or the like to produce a green body (green).

Next, if necessary, a portion to be a through hole 35 for inserting a lifter pin for supporting a silicon wafer and a bottomed hole 34 for embedding a temperature measuring element such as a thermocouple are formed in the formed body. To be formed.

Next, this green body is heated and fired to be sintered to produce a ceramic plate-like body. After that, the heater plate 31 is manufactured by processing it into a predetermined shape, but it may have a shape that can be used as it is after firing. By performing heating and firing while applying pressure, it is possible to manufacture the heater plate 31 having no pores. The heating and firing may be performed at a sintering temperature or higher, but in the case of a nitride ceramic or a carbide ceramic, it is 1000 to 250.
It is 0 ° C.

(2) Step of printing the conductor paste on the heater plate The conductor paste is generally a highly viscous fluid consisting of metal particles, resin and solvent. The conductor paste layer is formed by printing the conductor paste on the portion where the heating element is to be provided by screen printing or the like. Since it is necessary for the heating element to have a uniform temperature over the entire heater plate, it is desirable to print it in a concentric pattern as shown in FIG. The conductor paste layer is preferably formed so that the cross section of the heating element 32 after firing has a rectangular shape and a flat shape.

(3) Firing of Conductor Paste The conductor paste layer printed on the bottom surface of the heater plate 31 is heated and fired to remove the resin and the solvent, and the metal particles are sintered and baked on the bottom surface of the heater plate 31. The heating element 32 is formed. The heating and firing temperature is preferably 500 to 1000 ° C. When the above-mentioned metal oxide is added to the conductor paste, the metal particles, the heater plate and the metal oxide are sintered and integrated, so that the adhesion between the heating element 32 and the heater plate 31 is improved.

(4) Formation of metal coating layer It is desirable to provide a metal coating layer on the surface of the heating element 32. The metal coating layer can be formed by electrolytic plating, electroless plating, sputtering, etc., but in consideration of mass productivity, electroless plating is most suitable.

(5) Attachment of terminals and the like Terminals (terminal pins 33) for connection with a power source are attached to the ends of the pattern of the heating element 32 by soldering. Further, a thermocouple is fixed to the bottomed hole 34 with silver solder, gold solder or the like, and sealed with a heat resistant resin such as polyimide, and the manufacturing of the ceramic heater 30 is completed. In the ceramic heater of the present invention, an electrostatic electrode may be provided to serve as an electrostatic chuck, or a chap top conductor layer may be provided to serve as a wafer prober.

Next, the ceramic heater according to the second aspect of the present invention will be described. The ceramic heater of the second invention is
A heating element is formed on the surface or inside of the ceramic substrate, and a temperature measuring means for measuring the temperature of the ceramic substrate or the object to be heated, a power source for supplying power to the heating element, and a control section for controlling the power source. And a storage unit for storing the temperature data measured by the temperature measuring means, and a calculation unit for calculating the electric power required for the heating element from the temperature data, wherein the heating element is at least two or more. It is divided into circuits, and each circuit is configured to be supplied with different electric power.

Like the ceramic heater of the first aspect of the present invention described above, according to the ceramic heater of the second aspect of the present invention, the ceramic heater is divided into two or more parts based on the measurement result of the temperature of the wafer heating surface or the temperature of the object to be heated. The temperature can be controlled by changing the electric power supplied to the circuit of the heating element, so that the temperature of the wafer heating surface can be made uniform, and the temperature of the entire object to be heated can be made uniform. It is possible to prevent damage to the silicon wafer.

FIG. 6 is a block diagram showing the outline of an example of the ceramic heater of the second present invention. In the ceramic heater 50 shown in FIG. 6, lifter pins 560 are formed on the heater plate 51 to support the silicon wafer 19 at a certain distance from the wafer heating surface 51 a of the heater plate 51, and in addition, the heater plate 51 has a lifter pin 560. The peripheral portion is configured similarly to the ceramic heater 30 shown in FIG.

Further, in this ceramic heater 50, the thermoviewer 6 for measuring the temperature of the surface of the silicon wafer 19 or the object to be heated is provided above the silicon wafer 19.
00 is provided, and the thermoviewer 600 includes a storage unit 6
10, the storage unit 610 is connected to the calculation unit 620 and the storage unit 61. Further, the control unit 63 and the power supply unit 630 are not integrated but provided separately. The storage unit 61 includes a calculation unit 62 and a control unit 63, similar to the ceramic heater 30 shown in FIG.
Connected with.

The storage unit 610 also stores the image data and the like obtained from the thermoviewer 600, and also temporarily stores the temperature data obtained by performing image processing in the calculation unit 620 based on this image data. There is. In addition, the storage unit 61 receives the temperature measurement data and stores data for performing other control, and the calculation unit 62 performs calculation for control based on the temperature measurement data and the like.

That is, in the ceramic heater shown in FIG. 6, the storage unit has a storage unit 610 that specially stores the image data obtained from the thermoviewer 600 and a storage unit that stores data for controlling temperature measurement data and the like. The calculation unit is also divided into a calculation unit 620 that specializes in calculation of image data obtained from the thermoviewer 600 and a calculation unit 62 that controls the heater. But,
The storage unit 610 and the storage unit 61 may be integrated into one storage unit, or the arithmetic unit 620 and the arithmetic unit 62 may be integrated into one arithmetic unit. Further, the control unit 63 and the power supply unit 630 may be integrated.

Next, the ceramic heater 50 shown in FIG.
The operation of will be described. This ceramic heater 50
Is provided with a thermoviewer 600 as a temperature measuring means. The thermoviewer 600 photographs the surface of the silicon wafer 19 or the heater plate 51 and transmits optical data to the storage unit 610 together with an image. The data stored in the storage unit 610 is sent to the calculation unit 620, and image processing is performed in the calculation unit 620. In the image processing, the engineering-color-coded image data as shown in FIG.
As shown in (b), the pixel is divided into a plurality of pixels, and the color of each pixel is divided into a plurality of stages to be multivalued.

Also in this ceramic heater 50, since the circuit of the heating element is divided into two or more to be controlled, there are a plurality of temperature control regions. For the temperature of each temperature control region, the multivalued value at the specific point A shown in FIG. 7A is used as a representative value, or the multivalued value in each section of the temperature control region is averaged. Then, processing such as setting the temperature of the area is performed, and the temperature T of each temperature control area is set. Then, the temperature of each temperature control region is stored again in the storage unit 610.

The temperature data T of the temperature region stored in the storage unit 610 is transmitted to the storage unit 61 for control, and for example, the difference between the temperature T of the temperature control region and the desired temperature t or the temperature control region of each temperature control region. The temperature difference ΔT is calculated, and the electric power data ΔW that makes ΔT zero is calculated, transmitted to the control unit 63, and the electric power based on this is supplied to the heating element to raise the temperature, and the wafer heating surface is heated. Alternatively, the temperature of the object to be heated is controlled to be uniform. Incidentally, in the second invention,
Needless to say, a temperature measuring element such as a thermocouple may be used as the temperature measuring means.

In the ceramic heater 50 shown in FIG. 6, the heater plate 31 is manufactured in the same manner as in the case of the ceramic heater shown in FIG. 3, and then the heater plate 31 is processed to support pins 560 on the heater plate 51. After installation and installation of a thermoviewer etc. as shown in FIG. 6, the storage units 61, 610,
It is assembled by wiring with the arithmetic units 62, 620 and the like.

In the ceramic heater 50 shown in FIG. 6, since the thermoviewer is used as the temperature measuring means,
The temperature control of the wafer heating surface of the heater plate and the object to be heated can be performed by the surface temperature control, and the accuracy of the temperature control can be improved as compared with the point temperature control using the temperature measuring element. In addition, even if an unexpected temperature change occurs, the temperature can be restored to the original temperature immediately and a practical temperature control can be realized.

Although the ceramic heater of the present invention has been described above, an electrostatic chuck may be provided by providing a resistance heating element on the surface or inside of the ceramic substrate and providing an electrostatic electrode inside the ceramic substrate.

By providing a resistance heating element on the surface of or inside the ceramic substrate, and by providing a chuck top conductor layer on the surface of the ceramic substrate, and by providing a guard electrode or a ground electrode inside the ceramic substrate,
It may be a wafer prober.

[0100]

The present invention will be described in more detail below. (Example 1) Manufacturing of ceramic heater made of aluminum nitride (see FIG. 3) (1) Aluminum nitride powder (average particle size: 1.1 μm) 1
A composition comprising 00 parts by weight, 4 parts by weight of yttria (average particle size: 0.4 μm), 12 parts by weight of an acrylic binder and alcohol was spray-dried to produce a granular powder.

(2) Next, this granular powder was put into a mold and molded into a flat plate to obtain a green molded body. (3) Processed green compact is 1800 ℃, pressure: 2
Hot pressing was performed at × 10 ⁵ Pa to obtain an aluminum nitride plate having a thickness of 3 mm. Next, from this plate,
A 10 mm disc body was cut out to form a ceramic plate body (heater plate) 31.

This molded body is drilled to form a through hole 35 into which a lifter pin of a silicon wafer is inserted, and a bottomed hole 34 for embedding a thermocouple (diameter: 1.1 mm, depth: 2 mm) was formed.

(4) Conductor paste was printed on the heater plate 31 obtained in (3) above by screen printing. The printing pattern was a concentric pattern as shown in FIG. As a conductor paste, Solbest PS manufactured by Tokuriki Kagaku Kenkyusho is used for forming through holes in printed wiring boards.
603D was used. This conductor paste is a silver-lead paste, and based on 100 parts by weight of silver, lead oxide (5% by weight), zinc oxide (55% by weight), silica (10% by weight), boron oxide (25% by weight). And 7.5 parts by weight of a metal oxide composed of alumina (5% by weight). The silver particles had an average particle size of 4.5 μm and were flaky.

(5) Next, the heater plate 31 on which the conductor paste is printed is heated and fired at 780 ° C. to sinter silver and lead in the conductor paste and bake the heater plate 31.
The heating element 32 was formed. The silver-lead heating element 32 had a thickness of 5 μm, a width of 2.4 mm, and an area resistivity of 7.7 mΩ / □.

(6) In an electroless nickel plating bath consisting of an aqueous solution having a concentration of 80 g / l of nickel sulfate, 24 g / l of sodium hypophosphite, 12 g / l of sodium acetate, 8 g / l of boric acid and 6 g / l of ammonium chloride. The heater plate 31 prepared in (5) was dipped to deposit a metal coating layer (nickel layer) 38 having a thickness of 1 μm on the surface of the silver-lead heating element 32.

(7) A silver-lead solder paste (manufactured by Tanaka Kikinzoku Co., Ltd.) was printed by screen printing on the portion where the terminal for securing the connection with the power source was attached to form a solder layer. Next, the Kovar-made terminal pin 33 was placed on the solder layer, and heated at 420 ° C. to rtflow to attach the terminal pin 33 to the surface of the heating element 32.

(8) A thermocouple for temperature control is provided with a bottomed hole 34.
Then, the ceramic heater 30 was obtained by embedding it in a ceramic adhesive (Toron Gosei Aron Ceramic) and fixing it.

Example 2 Production of Ceramic Heater Made of Silicon Carbide Silicon carbide having an average particle size of 1.0 μm was used, the sintering temperature was set to 1900 ° C., and the surface of the obtained heater plate was set to 15 μm.
A ceramic heater made of silicon carbide was manufactured in the same manner as in Example 1 except that a SiO ₂ layer having a thickness of 1 μm was formed on the surface by firing at 00 ° C. for 2 hours.

(Example 3) Production of ceramic heater (FIGS. 1 and 2) having a heating element inside (1) Aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size:
1.1 μm), yttria (average particle size: 0.4 μm) 4
Parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.
A paste obtained by mixing 5 parts by weight and 53 parts by weight of an alcohol composed of 1-butanol and ethanol was molded by the doctor blading method to have a thickness of 0.47 mm.
Got a green sheet of.

(2) Next, this green sheet was dried at 80 ° C. for 5 hours and punched to a diameter of 1.8 m.
m, 3.0 mm, 5.0 mm, a through hole 15 into which a silicon wafer lifter pin is inserted, and a through hole for connecting to a terminal pin are provided.

(3) A conductor obtained by mixing 100 parts by weight of tungsten carbide particles having an average particle diameter of 1 μm, 3.0 parts by weight of an acrylic binder, 3.5 parts by weight of an α-terpineol solvent and 0.3 part by weight of a dispersant. Paste A was prepared.

Tungsten particles 10 having an average particle diameter of 3 μm
A conductor paste B was prepared by mixing 0 part by weight, 1.9 parts by weight of acrylic binder, 3.7 parts by weight of α-terpineol solvent and 0.2 part by weight of a dispersant. This conductive paste A was printed on the green sheet by screen printing to form a conductive paste layer. The print pattern was a concentric circle pattern as shown in FIG. Further, the through holes for through holes for connecting the terminal pins were filled with the conductor paste B. 37 green sheets on which the tungsten paste is not printed are provided on the upper side (wafer heating surface) and 13 are provided on the lower side.
The layers were laminated at 0 ° C. and a pressure of 8 × 10 ⁴ Pa.

(4) Next, the obtained laminate was placed in a nitrogen gas,
Degreasing at 600 ℃ for 5 hours, 1890 ℃, pressure 1.5 × 1
It was hot pressed at 0 ⁵ Pa for 3 hours to obtain an aluminum nitride plate-shaped body having a thickness of 3 mm. This was cut into a 230 mm disk shape to obtain a ceramic heater having a heating element with a thickness of 6 μm and a width of 10 mm inside.

(5) Next, after polishing the plate-shaped body obtained in (4) with a diamond grindstone, a mask is placed and a bottomed hole for a thermocouple is formed on the surface by blasting with SiC or the like. 14
(Diameter: 1.2 mm, depth: 2.0 mm).

(6) Further, a part of the through hole for the through hole is cut out to form a recess, and a gold brazing material made of Ni-Au is used for this recess, and the reflow is performed by heating at 700 ° C. to make the terminal pin 13 made of Kovar. Was connected. The terminal pin 13
It is desirable that the connection be made with a structure in which a tungsten support supports at three points. This is because connection reliability can be secured. (8) Next, a plurality of thermocouples 17 for temperature control were embedded in the bottomed holes 14 to complete the manufacture of the ceramic heater 10.

(Embodiment 4) Temperature Control of Ceramic Heater (1) A temperature controller (E5ZE manufactured by OMRON Corporation) equipped with a control unit having a power supply, a storage unit, and a calculation unit was prepared.
The wiring from the control unit 43 is connected to the ceramic heater 30 (see FIG. 3) manufactured in 1. through the terminal pins 13, and the wiring from the thermocouple 17 is connected to the storage unit 41. Placed on 30. Although not shown in FIG. 3, the bottomed holes 34a to 34c of the ceramic heater 30 are formed at the same positions as the bottomed holes 14a to 14c of the ceramic heater 10 shown in FIG. The heating elements 32a to 32c are also the heating elements 12a in the ceramic heater 10 shown in FIG.
It is formed at the same position as ~ 12c.

(2) Next, a voltage is applied to the ceramic heater 30 to once raise the temperature to 200 ° C., and further to 200 ° C. to 400 ° C., and the bottomed holes 34a to 34
The temperature was measured by the thermocouple installed in c. The measurement results are shown in FIG. Further, the heating elements 32a, 32b, 32c
FIG. 5 shows the profile of the electric power (marked by the current value) applied to the device. Note that in FIG. 4, the vertical axis represents temperature and the horizontal axis represents elapsed time, and in FIG. 5, the vertical axis represents current value and the horizontal axis represents time.

As is apparent from FIG. 4, the temperature of the ceramic heater becomes uniform in a short time after the electric current is applied to the ceramic heater 30, and as a result, the silicon wafer mounted on the ceramic heater 30 is heated. Was heated uniformly without damage during the heating process.

After heating to 140 ° C., a temperature recovery situation near the central portion, the intermediate portion and the outer peripheral portion of the ceramic heater 30 when a 25 ° C. silicon wafer was placed was examined. Indicated. Further, as is clear from the results shown in FIG. 8, even if the ceramic heater 30 is placed at a constant temperature and a low-temperature silicon wafer is suddenly placed to cause disturbance, the ceramic heater 30 can be used in an extremely short time. Three
The temperature of 0 can be controlled to the original temperature. Further, the same temperature control was performed using the ceramic heaters obtained in Examples 2 and 3, but the silicon wafer could be uniformly heated as in the above case.

(Embodiment 5) Temperature control by a thermoviewer (1) Prepare a temperature controller (E5ZE manufactured by OMRON) equipped with a power supply unit 630, a control unit 63, a storage unit 61 and a calculation unit 62, and insert a thermocouple. A heater plate 51 (ceramic heater 50, see FIG. 6) having the same configuration as that of the first embodiment is manufactured except that the bottomed hole is formed, and the wiring from the control unit 63 is connected via the terminal pin 33. In addition, the Thermoviewer 600 (IR-162012-made by Nippon Datum Co., Ltd.
The wiring from (0012) was connected to a personal computer (Fujitsu FM-V) that also serves as a storage unit 610 and a calculation unit 620.

Image processing software (manufactured by Cognex) is installed in this personal computer. This image processing software partitions the screen of the thermoviewer 600 into 10,000 pixels, and multi-values the colors of the partitioned pixels into 0 to 9 levels. If there are multiple colors in the compartment,
Use the average value. In this way, the average value of the temperature control area is calculated from the multivalued values, the temperature is determined from the color corresponding to this average value, and the temperature of each temperature control area thus determined is transferred to the temperature controller. It is supposed to do.

(2) Next, a voltage was applied to the ceramic heater 50 to once raise the temperature to 200 ° C. Heating element 3
The profile of the electric power (marked by the current value) applied to 2a, 32b, and 32c is shown in FIG. Further, the results of temperature measurement are shown in FIG.

As is apparent from FIG. 10, the temperature of the ceramic heater becomes uniform in a short time after the electric current is passed through the ceramic heater 50, and as a result, the silicon wafer mounted on the ceramic heater 50 is heated. Was heated uniformly without damage during the heating process.

[0124]

As described above, according to the ceramic heater of the present invention, the temperature of the object to be heated such as a silicon wafer can be made uniform by making the temperature of the wafer heating surface of the heater plate uniform. It is possible to prevent the silicon wafer from being damaged. In addition, even if an unexpected temperature change occurs, it can be controlled so as to recover to the set temperature in a short time, which is extremely practical.

[Brief description of drawings]

FIG. 1A is a block diagram schematically showing an example of a ceramic heater according to the first aspect of the present invention, and FIG. 1B is a partially enlarged sectional view thereof.

FIG. 2 is a plan view schematically showing an example of a heater portion of the ceramic heater according to the first aspect of the present invention.

FIG. 3A is a block diagram schematically showing another example of the ceramic heater according to the first aspect of the present invention.

FIG. 4 is a graph showing a temperature profile of a ceramic heater according to Example 4.

5 is a graph showing a power (current) profile of the ceramic heater according to Example 4. FIG.

FIG. 6 is a block diagram schematically showing an example of a ceramic heater of the second present invention.

7A is a schematic diagram showing image data obtained by the thermoviewer shown in FIG. 6, and FIG.
It is a schematic diagram which shows the state which divided | segmented the figure of (a) into several pixels, and divided the color of each pixel into several steps, and was multi-valued.

FIG. 8 is a graph showing a temperature recovery state of the ceramic heater when a disturbance occurs on the surface of the ceramic heater according to the fourth embodiment.

FIG. 9 is a graph showing a power (current) profile of the ceramic heater according to Example 5.

FIG. 10 is a graph showing a temperature profile of a ceramic heater according to Example 5.

[Explanation of symbols]

10, 30, 50 Ceramic heater 11, 31, 51 Heater plate 12, 32 heating element 13, 33 Terminal pin 14, 34 Bottomed holes 15,35 through holes 19 Silicon wafer 11a, 31a, 51a Wafer heating surface 11b, 31b, 51b Bottom surface 16 lifter pins 17,37 Thermocouple 18 through holes 21, 41, 61, 610 storage unit 22, 42, 62, 620 Operation unit 23, 43, 63 Control unit 560 Support pin 600 Thermo Viewer 630 power supply

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3K058 AA41 BA19 CA12 CA23                 3K092 PP09 QA05 RF03 RF11 RF22                       RF26 RF27 UA04 VV22                 4K029 CA05 DA08 EA08                 5F046 KA04

Claims (4)

[Claims] 1. A heating element is formed on the surface or inside of a ceramic substrate, and a temperature measuring means for measuring the temperature of the ceramic substrate or an object to be heated; a control unit for supplying electric power to the heating element; A storage unit that stores temperature data measured by the temperature measuring unit; and a calculation unit that calculates electric power required for the heating element from the temperature data,
The ceramic heater is characterized in that the heating element is divided into at least two circuits, and different powers are supplied to the respective circuits. 2. A heating element is formed on the surface or inside of the ceramic substrate, and temperature measuring means for measuring the temperature of the ceramic substrate or the object to be heated, a power source for supplying power to the heating element, and this power source. And a storage unit that stores temperature data measured by the temperature measuring unit, and a calculation unit that calculates the electric power required for the heating element from the temperature data. A ceramic heater characterized in that it is divided into at least two or more circuits, and each circuit is configured to be supplied with different electric power. 3. The ceramic heater according to claim 1, wherein the temperature measuring means is a temperature measuring element. 4. The ceramic heater according to claim 1, wherein the temperature measuring means is a thermoviewer.