JP3367995B2 - Multilayer ceramic heater - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer ceramic heater, and more particularly to a multilayer ceramic heater useful for heating a substrate or a wafer when forming a thin film by a chemical vapor deposition method or a sputtering method. is there.

[0002]

2. Description of the Related Art Pyrolytic boron nitride and pyrolytic carbon are considered to be useful as a method for heating a wafer in molecular beam epitaxy or CVD sputtering in the manufacturing process of semiconductor products (JP-A-63- 241921 gazette), this product is easier to install than the conventional tantalum wire heater, there is no trouble of disconnection short circuit, it is easy to use, and since it is a planar heater, it is relatively easy to obtain uniform heating There is also.

[0003]

However, this is difficult to use because it is consumed in an oxidizing atmosphere because the heating portion is carbon, so it is difficult to use this with pyrolytic boron nitride. Supply its power
It has been proposed to coat the electrode terminal part that should be covered with a refractory metal, but in this latter method the electrode terminal part
The contact resistance value becomes high at the connection part, and heat generation, heating, or sparking occurs, and there is a disadvantage that only the electrode terminal portion is consumed.

Further, as will, for example, pyrolytic carbon (PG) electrical resistance 10 ³ to a direction parallel resistor is deposited surface resistance in the vertical direction of the deposition surface, as shown in FIG. 6
Since becomes nearly twice the current through the PG layer flows in a direction parallel to a small deposition surface of normal resistance, the electrode terminal portions
As shown in FIG. 7, the current flows in the direction perpendicular to the deposition surface , so that the resistance is increased in this portion, a potential difference is generated, and heat generation is increased, which causes heating.
Therefore, for this , the electrode terminals that supply power
Although if Re is brought into contact with the stack cross-section of the PG layer such problems is to solve, 100 the thickness of the PG layer in this case 20
This is not realistic because it is on the order of 0 μm.

[0005]

SUMMARY OF THE INVENTION The present invention relates to such a disadvantage, multilayer ceramic heater which solves the problems, which Ri Do from the electrically conductive layer and the insulating layer,
In a multilayer ceramic heater having a pyrolytic carbon layer deposited and laminated as the electric conductive layer as a heater portion and an electrode terminal portion to which power is to be supplied , the electrode terminal portion is
It is more likely that the deposited layered cross section of the pyrolytic carbon layer is exposed.
And characterized in Rukoto, which is also characterized in that it made the size of the surface area of the electrode terminal portions <br/> minute as more than 20 times the cross-sectional area of the heater section. Also, electrode terminals
The peripheral length of the part is the same as the electrical conductive layer.
It is considered to be larger than the width of the rotor part.

That is, the present inventors lowered the contact resistance,
As a result of various studies to develop a multi-layer ceramics heater that solves the problems at the terminal part, for example, pyrolytic boron nitride (PBN) is used as an insulating layer and an electric conductive layer is deposited.
In a multi-layer ceramic heater having a structure of PBN / PG / PBN having a laminated and laminated pyrolytic carbon layer (PG) as a heater portion, the contact resistance becomes high because PG has a high resistance in the deposition and lamination direction. The electrode terminals that should be supplied with electric power are heavily consumed due to heat generation.
The PG surface of this electrode terminal portion is exposed so that the deposited laminated cross section with low resistance is exposed, or the area of the electrode terminal portion is set to a heater.
The present invention has been completed by finding out that when the cross-sectional area is 20 times or more, the consumption of the electrode terminal portion can be prevented and the life of this multilayer ceramic heater can be extended. This will be described in more detail below.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to multilayer ceramic heater, which is Ri Do from the electrically conductive layer and the insulating As described above, the heater section and electrode terminal portions pyrolytic carbon is deposited laminated as an electrical conductive layer in multilayer ceramic heater according to, which is characterized in that deposition stacking section of pyrolytic carbon layer is exposed at its electrode terminal portion, which is also a heater unit electricity amount of surface area of the electrode terminal portions but those characterized by comprising as least 20 times the cross-sectional area of the conductive layer, the electrode end according to this
Since the consumption of the child portion is prevented, there is an advantage that a long-life multilayer ceramic heater can be obtained.

The multi-layer ceramics heater of the present invention comprises an electrically conductive layer and an insulating layer, and the heater portion is electrically conductive.
The layer is composed of a pyrolytic carbon layer (PG) deposited and laminated as a layer , and this one is such that the deposition and lamination section of the PG layer is exposed at the electrode portion thereof. This PG
Exposing the layer stacking layer cross-section, for example , enlarge the electrode terminal
As shown in FIG. 1 which is, by simply tilting the cut ends of the PG layer in the laminated ceramic heater comprising a PG and PBN, the exposed deposited laminated section and the electrode terminal portions
It is also possible to use the PG layer 2 as shown in FIG.
Laminate and stack the PG layer by sloping and laminating the end part with the base material part inclined and cutting the whole so as to have a uniform thickness.
The surface may be exposed , or, as shown in FIG. 3, unevenness is provided on the electrode terminal forming portion of the PBN ,
After PG is vapor-deposited on this , P is cut by cutting it flat.
Exposing the deposited and laminated cross section of the G layer to form the electrode terminal portion
May be that.

Further, regarding this, the surface area of the electrode terminal portion (terminal contact area) is determined by the cross-sectional area of the heater portion electrically conductive layer .
It may be 20 times or more. In this case, if resistance = R, resistivity = f, length = L, and cross-sectional area = A, then R = f L / A, so increasing the surface area of the electrode terminal portion Electrical
Since the equivalent resistance and the heater portion of the conductive layer can be obtained, electrodes
The surface area of the terminal portion may be 20 times or more the cross-sectional area of the heater portion . Further, when the short outer <br/> circumferential length of the electrode terminal portions as shown in FIG. 8, the contact resistance at narrower than the heater section width W electric <br/> air to flow increases, which electrode terminal portions
The minute periphery length may be greater than the heater section width W.

[0010]

EXAMPLES Next, examples and comparative examples of the present invention will be described. Example, Comparative Example Pyrolytic boron nitride (PB processed by 100 mm in diameter, 1 mm in thickness and 10 mm in the peripheral part with an inclination of 0.1 mm / 10 mm)
N) is installed in the CVD reactor and the vacuum is 1 Torr and the temperature is 1,900 ° C.
Then, propylene gas was supplied thereto at a rate of 1 liter / minute for 5 hours to form a pyrolytic carbon (PG) film having a thickness of 150 μm.

Then, the surface of this electrode terminal portion is polished to a maximum thickness of 100 μm so that the entire thickness is uniform, and the PG film is deposited.
Exposing the laminated stack section to form the electrode terminal part,
A heater pattern is formed by machining , and electrode terminals
Except minute overcoated to 20μm thickness using a PBN, 4
The multilayer ceramic heater shown in Fig. 4 was prepared [Fig. 4
(A) is the plan view, (b) is along the line AA '
Is a vertical cross-sectional view of].

As another embodiment, a diameter of 100 mmφ,
P on a flat PBN disk with a thickness of 1 mm by the same method as above.
A G film is provided, a heater pattern having a heater portion width W of 12 mm is formed by machining, and PBN is formed on portions other than the electrode terminal portions.
Overcoating to a thickness of 20 μm, and shown in FIG. 5 [(a) is a plan view, (b) is a vertical cross-sectional view taken along the line AA ′ ] of which the electrode terminal area is 78 mm ² A ceramic heater was created . As a comparative example, a B part having an area of 28 mm ² was also prepared, and these were as shown in Table 1.

Next, the three kinds of multi-layer ceramic heaters thus prepared are placed in a vacuum chamber,
Electrode terminals for each so that power can be supplied
After connecting to the part , heating under nitrogen gas atmosphere at 10 ^-5 Torr, heating up to 1,000 ° C for 2 hours, and then allowing to cool down to 200 ° C, heating and cooling were repeated 50 times. No abnormalities were found in the sample, but in the case of the comparative example, the electrode terminal portion was worn out after repeating 5 times,
It became unusable below.

[0014]

[Table 1]

[0015]

[Effect of the Invention The present invention relates to multilayer ceramic heater, which is Ri Do from the electrically conductive layer and the insulating layer as described above, pyrolytic carbon layer which is deposited laminated as an electrical conductive layer and a heater In the multilayer ceramic heater, the deposition layer cross section of the pyrolytic carbon layer that is the electrode terminal portion is exposed.
This is also characterized in that the surface area of the electrode terminal portion is 20 times or more the cross-sectional area of the electrically conductive layer of the heater portion.
Since the consumption of the electrode terminal portions is prevented, the advantage of a long life is provided.

[Brief description of drawings]

FIG. 1 is an electrode end of a multilayer ceramic heater according to the present invention .
It is a longitudinal cross-sectional view which expands and shows a child part.

FIG. 2 is an electrode end of the multilayer ceramic heater of the present invention .
It is a longitudinal cross-sectional view showing another example of the child portion.

FIG. 3 is a vertical sectional view showing still another example of the multilayer ceramic heater of the present invention .

FIG. 4 (a) is a plan view of a multilayer ceramic heater of the present invention made in an example, and FIG. 4 (b) is a line AA ′ thereof.
FIG. 3 is a vertical cross-sectional view taken along line (c) of FIG.
The terminal part) is shown in an enlarged manner .

FIG. 5 (a) is a plan view of another multilayer ceramic heater of the present invention made in the example, and FIG. 5 (b) is its AA ′.
It is the longitudinal cross-sectional view along a line .

FIG. 6 is a graph showing changes in the resistance value in the cross-sectional direction and the parallel direction of deposition of pyrolytic carbon in a conventionally known multilayer ceramic heater.

FIG. 7 is a vertical cross-sectional view of a conventionally known multilayer ceramic heater.

FIG. 8: An electrode of a conventionally known multilayer ceramic heater
It is a top view of a terminal part .

[Explanation of symbols]

1 ... PBN substrate insulating layer, 2 ... PG electric conduction layer (heater
Part) , 3 ... Electrode terminal part , 4 ... PBN overcoat layer, W ... PG electric conductive layer width (heater part width) .

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) H05B 3/03 H05B 3/02 H05B 3/14 H05B 3/20

Claims (3)

(57) [Claims] 1. A Ri Do an electrically conductive layer and the insulating layer, the electrical
Heater part of pyrolytic carbon layer deposited as a conductive layer
In and multilayer ceramic heater to the electrode terminal portion to be supplied with power, this electrode terminals portions thereof, consists in depositing the laminated section of the pyrolytic carbon layer is exposed
And a multi-layer ceramic heater. 2. An electric conduction layer comprising an electric conduction layer and an insulating layer.
The pyrolyzed carbon layer deposited and laminated as a conducting layer is used for the heater section.
And a multi-layered ceramic which is an electrode terminal portion to be supplied with power.
In the heater, the multilayer ceramic heater is characterized in that the surface area of the electrode terminal portion is 20 times or more the cross-sectional area of the heater portion . Wherein said electrode peripheral length of the terminal portion, multilayer ceramic heater according to claim 1 or 2 is greater than the deposited laminated width of the heater unit as an electric conductive layer.