JP2002184683A - Wafer-heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve the problem of damage in uniformity in film formation such as resist, which is caused by a large difference in the temperature distribution of a wafer surface in a transient state of installing a wafer on a soaking plate and heating it, since a space between a wafer and a soaking plate is irregular, due to warpage of a soaking plate in the conventional wafer heating device. SOLUTION: In a wafer-heating device, one main surface of a soaking plate consisting of ceramic is made a mounting surface of a wafer, and heat generation resistor is provided to the other main surface or an inside, and the other main surface is provided with a feed part electrically connected to the heat generation resistor. A fixing metal part is installed in a recessed part provided to a wafer mounting surface, and a guide for carrying out positioning of a wafer is fixed to the fixing metallic part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer heating apparatus mainly used for heating a wafer, for example, a method of forming a semiconductor thin film on a wafer such as a semiconductor wafer, a liquid crystal substrate or a circuit substrate. Alternatively, it is suitable for forming a resist film by drying and baking a resist solution applied on the wafer.

[0002]

2. Description of the Related Art For example, in a semiconductor thin film forming process, an etching process, a resist film baking process, etc. in a manufacturing process of a semiconductor manufacturing apparatus, a semiconductor wafer (hereinafter abbreviated as "wafer") is heated to heat a semiconductor wafer. The device is used.

A conventional semiconductor manufacturing apparatus uses a batch-type apparatus for forming a plurality of wafers at a time. However, as the size of a wafer increases from 8 inches to 12 inches, the processing accuracy increases. In order to increase the quality, a technique called a single-wafer processing that processes one sheet at a time has been implemented in recent years. However, in the case of the single-wafer method, the number of processes per one process is reduced, so that the processing time of the wafer is required to be shortened. For this reason, it has been required for the wafer support member to shorten the heating time of the wafer, speed up the suction and desorption of the wafer, and improve the heating temperature accuracy.

In forming a resist film on a semiconductor wafer, one main surface of a heat equalizing plate 52 made of ceramics such as aluminum nitride or alumina as shown in FIG. A wafer heating device 51 having a structure in which a heating resistor 55 is provided on the other main surface via an insulating layer 54 and a conduction terminal 57 is fixed to the heating resistor 55 by a brazing material layer 56. Was used. The heat equalizing plate 52 is fixed to the support 61 by screws 65, and a thermocouple 60 is inserted into the heat equalizing plate 52 so that the temperature of the heat equalizing plate 52 is maintained at a predetermined temperature. In this case, the power supplied from the conduction terminal 57 to the heating resistor 55 is adjusted.

The mounting surface 53 of the wafer heating device 51
After the wafer W coated with the resist solution is positioned and placed on the wafer positioning guide 64 by the wafer positioning guide 64, the heating resistor 55 is caused to generate heat. Is heated and the resist liquid is dried and baked to form a resist film on the wafer W.

In the above-described wafer heating apparatus 51, the transient characteristics until the temperature is stabilized when the wafer W is replaced on the soaking plate 52, and the temperature variation in the wafer surface are important in drying the resist. It is. This is because the management of the drying greatly affects the etching property when etching the resist, and a uniform pattern cannot be formed.

[0007] As shown in FIG.
Are built in the heat equalizing plate 72, and the heat generating resistors 75
There is also known a wafer heating device 71 having a metallized portion 76 provided on the surface of the device 2, a conductive terminal 77 provided inside the metalized portion 76 via a brazing material, and a support 81 for supporting the heat equalizing plate 52.

Then, for example, as shown in FIG. 6, a mounting surface 53 of a heat equalizing plate 52 is provided in a wafer heating device 51 shown in FIG.
A positioning guide 64 is provided on the mounting surface 53 to thereby position and fix the wafer W on the mounting surface 53.
Specifically, a hole 63 is formed in the heat equalizing plate 52 and the hole 63 is formed.
A screw 65 is inserted into the hole, and a nut 66 is fixed so as to sandwich the heat equalizing plate 52 and the guide 64.

[0009]

However, the conventional wafer heating apparatus 51 shown in FIG. 6 has a structure in which the positioning guide 64 is fixed with the screw 65 so as to sandwich the heat equalizing plate 52. This causes a problem in that the heat equalizing plate 52 is warped, and the warp causes an uneven spacing between the wafer W and the heat equalizing plate 52. Particularly, in a transient state in which the wafer W is placed on the heat equalizing plate 52 and heated, the temperature distribution on the surface of the wafer W is greatly different, and the uniformity is deteriorated in the formation of a film such as a resist.

[0010]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems, the present inventors have found that one main surface of a ceramic soaking plate is used as a mounting surface for a wafer, and the other main surface or inside is provided. In a wafer heating apparatus having a heating element and a power supply section electrically connected to the heating element on the other main surface, a fixture is installed in a recess provided on a wafer mounting surface. The problem has been solved by fixing a guide for positioning the wafer to the fixing bracket.

[0011]

Embodiments of the present invention will be described below.

FIG. 1 is a sectional view showing an example of a wafer heating apparatus according to the present invention, in which one main surface of a heat equalizing plate 2 made of ceramics containing silicon carbide, alumina or aluminum nitride as a main component is attached to a wafer W. And a heating resistor 5 formed on the other main surface thereof via an insulating layer 4 made of glass, resin or the like.

A guide 14 for positioning the wafer is mounted on the mounting surface 3 on which the wafer W is mounted. When the wafer W is mounted on the mounting surface 3, the positioning is performed along the guide 14. It has become.

Further, a method of attaching the guide 14 for positioning the wafer will be described with reference to FIG. A recess 13 is formed in the heat equalizing plate 2 made of ceramic, and a fixing bracket 17 having an outer diameter larger than the inner diameter of the recess 13 is embedded in the recess 13 by press fitting or the like. As shown in FIG. 3, the fixing bracket 17 has a screw portion 19 formed in the inner peripheral portion and a slit 20 partially formed in the ring portion.
0 is inserted into the recess 13 in a state where
Of the recess 1 due to the elastic force of the slit
3.

Further, a wafer positioning guide 14 made of ceramics is placed thereon, and
The guide 14 is fixed by passing a screw 15 through a through hole 14 a formed in the screw 4 and tightening the screw 15 into a screw portion 19.

By adopting such a structure, it is not necessary to sandwich the heat equalizing plate 2 with bolts and nuts to fix the guide 14, so that the heat equalizing plate 2 can be prevented from warping. Become. In addition, the fixing bracket 1 is
By elastically fixing the fixing member 7, the fixing bracket 17 and the like can be reduced in size and the heat capacity can be reduced, so that the occurrence of temperature distribution on the surface of the wafer W can be suppressed.

The fixing member 17 is made of a material having a coefficient of thermal expansion close to that of the nitride ceramic or carbide ceramic used for the heat equalizing plate 2, and has a coefficient of thermal expansion of 3.9 to 8.
It is preferable to ^{0 × 10 -6 / ℃ (30~400} ℃). This is because if the coefficient of thermal expansion is smaller than that range, the difference in the thermal expansion when the soaking plate 2 is heated causes
This is because the problem that the heat sink 7 comes off from the heat equalizing plate 2 easily occurs. On the contrary, if it is too large, a crack may be generated in the heat equalizing plate 2 due to a difference in thermal expansion. Specifically, it is preferable to use an oxidation-resistant metal such as Invar, Fe-Co-Ni alloy, 42 alloy, Ni, or SUS304, or a material subjected to oxidation-resistant surface treatment.

The outer diameter of the fixture 17 is 0.01 to 0.1 m larger than the diameter of the recess 13 formed in the heat equalizing plate 2.
It is preferable to increase m. If it is smaller than 0.01 mm, the holding force of the fixing member 17 to the heat equalizing plate 2 is significantly reduced, and there is a possibility that the fixing member 17 comes off. In addition, there is a high possibility that chipping or cracking may occur from the recess 13. Further, by narrowing the slit 20, the screw portion 19 is formed.
Is narrowed, so that a problem occurs that the screw applied to the guide 14 does not enter. The size of the slit depends on the size of the fixing bracket 17, but may be about 0.2 to 0.8 mm.

Although the method of fixing the guide 14 to the fixing bracket 17 has been described by screwing, it is not necessary to limit the method to screwing, and another method using, for example, metal elasticity may be used.

It is preferable that the corner 17a of the bottom surface of the fixture 17 on the side of the heat equalizing plate 2 be a curved surface having a radius of curvature of 0.05 mm or more or a C surface having a width of 0.05 mm or more. The recess 13 into which the fixing bracket 17 is press-fitted.
Similarly, the radius of curvature of the bottom corner 13a is 0.05 mm.
It is preferable to perform the above-mentioned curved surface processing. By processing each corner 17a in this way, stress concentration on the corner 17a can be prevented, and cracks can be prevented from occurring.

Further, when press-fitting the fixing bracket 17, it is preferable to press-fit the bottom of the recess 13 and the bottom of the fixing bracket 17 so as not to be in contact with each other. Since the thickness of the heat equalizing plate 2 is processed to 2 to 7 mm to increase the heating and cooling rate, the concave portion 1 is formed.
3 has a small bottom thickness, and when the fixing fitting 17 to be press-fitted comes into contact with the bottom surface of the recess 13, the corner 13 a of the recess 13 is pressed by the stress of press-fitting.
Cracks may occur. Therefore, fixing bracket 1
It is preferable that a gap of 0.05 mm or more is left between the bottom of the recess 7 and the bottom of the recess 13.

As a material of the guide 14, it is preferable to use a high-purity ceramic from the viewpoint of preventing contamination of the wafer W. The surface is preferably mirror-polished to prevent wear due to sliding with the wafer W. Specifically, materials such as alumina, mullite, and zirconia can be used.

The number of the guides 14 may be three or more. With two, the position cannot be fixed.
In addition, if the number of guides 14 is extremely increased,
Since the temperature distribution on the mounting surface is worsened, the number is preferably eight or less.

The material of the screw 15 is SUS3
It is preferable to use a heat-resistant stainless steel material such as 04 or SUS316 from the viewpoint of economy.

Further, the wafer heating apparatus 1 of the present invention will be described in detail with reference to FIG.

As the pattern shape of the heating resistor 5, the mounting surface 3 can be uniformly heated, such as a substantially concentric or spiral-shaped one having an arc-shaped electrode portion and a linear electrode portion. Any pattern shape is acceptable. In order to improve heat uniformity, the heating resistor 5 can be divided into a plurality of patterns. Further, as the heating resistor 5, gold, silver,
Palladium, platinum group metals and the like can be used.

Further, a power supply portion 6 made of a material such as gold, silver, palladium, or platinum is formed on the heating resistor 5, and the conductive terminal 7 is pressed against the power supply portion 6 by an elastic body 8 to make contact therewith. Thus, conduction is ensured.

As described above, the connection between the power supply section 6 and the conduction terminal 7 formed on the heat equalizing plate 2 is made to be a contact by pressing, so that the expansion of the heat equalizing plate 2 and the support 11 due to the temperature difference therebetween. Can be mitigated by the sliding of the contact portion, so that it is possible to provide the wafer heating apparatus 1 having good durability against a thermal cycle during use.

The heat equalizing plate 2 is provided on a metal support 11.
It is installed so as to cover the opening. The metal support 11 has a single-layer or multilayer plate-like structure 13. In the plate-like structure portion 12, a conduction terminal 7 for conducting electricity to a power supply portion 6 for supplying power to the heating resistor 5 of the heat equalizing plate 2 is provided via an insulating material 9. The hot plate 2 is pressed against the power supply section 6 on the surface. In addition, thermocouple 1
Numeral 0 is installed near the wafer mounting surface 3 at the center of the heat equalizing plate 2 and adjusts the temperature of the heat equalizing plate 2 based on the temperature of the thermocouple 10. When the heating resistor 5 is divided into a plurality of blocks and the temperature is individually controlled, a thermocouple 10 for temperature measurement is installed in each block of the heating resistor 5.

As the thermocouple 10, it is preferable to use a sheath-type thermocouple 10 having an outer diameter of 1.0 mm or less from the viewpoint of its responsiveness and workability of holding. The middle of the thermocouple 10 is held by the plate-like structure 13 of the support portion 11 so that no force is applied to the tip embedded in the heat equalizing plate 2. The distal end of the thermocouple 10 has a hole formed in the heat equalizing plate 2 and is fixed to the inner wall surface of the cylindrical metal body provided therein by a spring material to improve the reliability of temperature measurement. In addition, operations such as mounting the wafer W on the mounting surface 3 and lifting the wafer W from the mounting surface 3 are performed by lift pins (not shown) installed in the support 11 so as to be able to move up and down. When the wafer W carried above the mounting surface 3 by the transfer arm (not shown) is lowered by the lift pins (not shown), the wafer W is positioned following the guide. Preferably, three or more positioning guides on the heat equalizing plate 2 are installed at equal intervals.

The wafer W is held in a state of being floated from the mounting surface 3 by wafer support pins (not shown) so as to prevent a temperature variation due to a one-sided contact or the like.

Next, the power supply unit 6 is energized to cause the heating resistor 5 to generate heat, and the wafer W on the mounting surface 3 is heated via the insulating layer 4 and the soaking plate 2. When the heat equalizing plate 2 is formed of a silicon carbide-based sintered body or an aluminum nitride-based sintered body, the deformation is small even if heat is applied, and the plate thickness can be reduced, so that the heating time until heating to a predetermined processing temperature is performed. In addition, the cooling time required for cooling from a predetermined processing temperature to around room temperature can be shortened, and productivity can be increased, and at the same time, 50 W / m
-Since it has a thermal conductivity of K or more, the Joule heat of the heating resistor 5 can be quickly transmitted even with a small plate thickness, and the temperature variation of the mounting surface 3 can be extremely reduced.

As the ceramic forming the heat equalizing plate 2, a sintered body containing silicon carbide, boron carbide, boron nitride, silicon nitride or aluminum nitride as a main component is used.

The silicon carbide sintered body forming the heat equalizing plate 2 is
Boron (B) and carbon (C) are added as sintering aids to silicon carbide as a main component, or alumina (Al
₂ O ₃ ) and a metal oxide such as yttria (Y ₂ O ₃ ) are added and mixed well, processed into a plate shape,
It is obtained by firing at 2100 ° C. Silicon carbide may be any of those mainly composed of α-type and those mainly composed of β-type.

Further, the aluminum nitride sintered body forming the heat equalizing plate 2 requires a rare earth element oxide such as Y ₂ O ₃ or Yb ₂ O ₃ as a sintering aid with respect to aluminum nitride as a main component. According to the above, an alkaline earth metal oxide such as CaO is added, mixed well, processed into a plate shape,
It is obtained by firing at 0 to 2100 ° C.

The boron carbide sintered body is obtained by mixing 3 to 10% by weight of carbon as a sintering aid with boron carbide as a main component and sintering the mixture by hot pressing at 2100 to 2200 ° C. You can get the body.

As the boron nitride sintered body forming the heat equalizing plate 2, 30 to 45% by weight of aluminum nitride and 5 to 10% by weight of rare earth are used as sintering aids with respect to boron nitride as a main component. Mix elemental oxides, 1900-2100 ° C
And sintered by hot pressing. As another method for obtaining a sintered body of boron nitride, there is a method in which borosilicate glass is mixed and sintered, but this method is not preferable because the thermal conductivity is significantly reduced.

As the silicon nitride sintered body forming the heat equalizing plate 2, 3 to 12% by weight of a rare earth element oxide and 0.5 to 3 weight%
Of Al ₂ O _3, further mixing SiO ₂ so that 1.5 to 5 wt% as SiO ₂ content in the sintered body, 16
A sintered body can be obtained by performing hot press firing at 50 to 1750 ° C. The amount of SiO ₂ shown here is
Si generated from impurity oxygen contained in silicon nitride raw material
O ₂ and SiO as impurities contained in other additives
₂ and the sum of intentionally added SiO ₂ .

Further, when the wafer heating apparatus 1 is used for forming a resist film, if a material containing nitride as a main component is used for the heat equalizing plate 2, it reacts with moisture in the atmosphere and ammonia gas is used. In this case, it is preferable to use a heat equalizing plate 2 made of a carbide such as silicon carbide or boron carbide. At this time, it is necessary to prevent the sintering aid from containing a nitride which may react with water to form ammonia or an amine. Thus, fine wiring can be formed on the wafer W at a high density.

Further, the main surface of the heat equalizing plate 2 on the side opposite to the mounting surface 3 has a flatness of 20 μm or less and a surface roughness of the center line from the viewpoint of enhancing the adhesion to the insulating layer 4 made of glass or resin. It is preferable to polish to an average roughness (Ra) of 0.1 μm to 0.5 μm.

On the other hand, when a silicon carbide sintered body is used as the heat equalizing plate 2, the insulating layer 4 for maintaining insulation between the heat equalizing plate 2 having semiconductivity and the heat generating resistor 5 is made of glass or glass. It is possible to use a resin. Here, when using glass, if the thickness is less than 100 μm, the withstand voltage is 1.5 k
When the thickness is less than V and the insulating property cannot be maintained, and when the thickness exceeds 600 μm, the thermal expansion difference with the silicon carbide sintered body forming the heat equalizing plate 2 becomes too large, so that cracks are generated and insulation occurs. It no longer functions as layer 4. Therefore, when glass is used as the insulating layer 4, the thickness of the insulating layer 4 is 100 μm to 6 μm.
It is preferably formed in the range of 00 μm, and more preferably in the range of 200 μm to 400 μm.

When the soaking plate 2 is formed of a ceramic sintered body containing aluminum nitride as a main component, the soaking plate 2
The insulating layer 4 made of glass is formed in order to improve the adhesion of the heating resistor 5 to the insulating layer 4. However, when sufficient glass is added to the heat generating resistor 5 and a sufficient adhesion strength can be obtained by this, it can be omitted.

The properties of the glass forming the insulating layer 4 may be either crystalline or amorphous. The glass has a heat resistant temperature of 200 ° C. or higher and a thermal expansion coefficient in a temperature range of 0 ° C. to 200 ° C. It is preferable to appropriately select and use a ceramic having a coefficient of thermal expansion in the range of -5 to + 5 × 10 ⁻⁷ / ° C. with respect to the thermal expansion coefficient of the ceramic constituting the plate 2. In other words, when a glass having a coefficient of thermal expansion outside the above range is used, the difference in thermal expansion between the ceramic forming the soaking plate 2 and the ceramic becomes too large.
This is because defects such as cracks and peeling easily occur during cooling after baking of the glass.

Next, when a resin is used for the insulating layer 4, if the thickness is less than 30 μm, the withstand voltage falls below 1.5 kV, the insulation cannot be maintained, and the heating resistor 5 is trimmed by, for example, laser processing. In this case, the insulating layer 4 is damaged and does not function as the insulating layer 4. Conversely, when the thickness exceeds 150 μm, the amount of evaporation of the solvent and water generated during baking of the resin increases, and a foam-like peeling portion called blister is formed between the heat equalizing plate 2 and the presence of this peeling portion. Since the heat transfer becomes worse, the soaking of the mounting surface 3 is hindered. Therefore, when a resin is used as the insulating layer 4, the thickness of the insulating layer 4 is preferably in the range of 30 μm to 150 μm, and more preferably in the range of 60 μm to 150 μm.

When the insulating layer 4 is formed of a resin, considering the heat resistance of 200 ° C. or more and the adhesion to the heating resistor 5, polyimide resin, polyimide amide resin,
It is preferable to use a polyamide resin or the like.

As a means for applying the insulating layer 4 made of glass or resin on the heat equalizing plate 2, an appropriate amount of the glass paste or resin paste is dropped on the center of the heat equalizing plate 2 and spin coating is performed. Stretch and apply uniformly, or apply evenly by screen printing, dipping, spray coating, etc., then at a temperature of 600 ° C. for glass paste and 3 for resin paste.
What is necessary is just to bake at the temperature of 00 degreeC or more. When glass is used as the insulating layer 4, the heat equalizing plate 2 made of a silicon carbide sintered body or an aluminum nitride sintered body is previously
By heating to a temperature of about 0 ° C. and oxidizing the surface on which the insulating layer 4 is to be adhered, adhesion to the insulating layer 4 made of glass can be increased.

Further, the heating resistor 5 to be deposited on the insulating layer 4 is made of a simple metal such as gold (Au), silver (Ag), copper (Cu), palladium (Pd), formed by vapor deposition or plating. Directly, or the above-mentioned metal simple substance, rhenium oxide (Re ₂ O ₃ ), lanthanum manganate (LaMn)
A conductive metal oxide such as O ₃ ) or a paste obtained by dispersing the above metal material in a resin paste or a glass paste is prepared, printed in a predetermined pattern shape by a screen printing method or the like, and then baked. The materials may be joined by a matrix made of resin or glass. When glass is used as the matrix, either crystallized glass or amorphous glass may be used, but it is preferable to use crystallized glass in order to suppress a change in resistance due to thermal cycling.

However, when silver or copper is used for the heating resistor 5, migration may occur. In such a case, the insulating layer 4 covers the heating resistor 5.
A protective film made of the same material as described above may be coated with a thickness of about 30 μm.

The heating resistor 5 is formed into a disk shape after sufficiently mixing, for example, a raw material containing aluminum nitride as a main component and a sintering aid as appropriate, and pastes W or WC on the surface thereof. , And another aluminum nitride molded body is overlaid thereon and adhered thereto, followed by firing in nitrogen gas at a temperature of 1900 to 2100 ° C. In addition, the heating resistor 5
For conduction from, an electrode may be drawn out to the surface by forming a through hole 19 in an aluminum nitride base material, embedding a paste made of W or WC, and then firing. When the heating temperature of the wafer W is high, the power supply unit 6 applies a paste containing a noble metal as a main component such as Au, Ag, etc.
By baking at 00 ° C., oxidation of the internal heating resistor 5 can be prevented.

[0050]

Embodiments of the present invention will be described below.

Example 1 A silicon carbide sintered body having a thermal conductivity of 80 W / m · K was subjected to grinding to form a disk having a thickness of 4 mm and an outer diameter of 230 mm. For this purpose, as shown in FIG. 2, the heat equalizing plate 2 having a counterbored hole 13 having a diameter of 4 mm and a depth of 2 mm as shown in FIG.
As a comparative example, as shown in FIG. 6, a plurality of heat equalizing plates 52 each having a through hole having a diameter of 2.5 mm were manufactured, and the insulating layer 4 was coated on one main surface of each of the heat equalizing plates 2 and 52. To adhere, a glass paste prepared by kneading glass powder with ethyl cellulose as a binder and terpineol as an organic solvent is formed using a screen printing method.
After heating to 50 ° C to dry the organic solvent, 550 ° C
Degreasing treatment for 30 minutes at 700 to 900 ° C
The insulating layers 4 and 54 made of glass and having a thickness of 200 μm were formed by baking at a temperature of.

Next, on the insulating layers 4 and 54,
In order to adhere 55, a glass paste to which Au powder and Pd powder are added as a conductive material is printed in a predetermined pattern shape by a screen printing method, and then heated to 150 ° C. to dry the organic solvent. After performing degreasing at 30 ° C. for 30 minutes, baking is performed at a temperature of 700 to 900 ° C., so that the heating resistors 5 and 55 having a thickness of 50 μm are formed.
Was formed. The heating resistors 5 and 55 have a five-pattern configuration in which a central portion and an outer peripheral portion are divided into four in the circumferential direction.

After fixing the power supply portions 6 and 56 to the heating resistors 5 and 55 with a conductive adhesive, the heat equalizing plate 2 of the embodiment of the present invention of the type shown in FIG. 05m
m, a thickness of 1.8 mm, and a fitting 17 having a threaded portion 19 of M2 is press-fitted into the concave portion 13 to guide the guide 14 to the threaded portion of the M2 screw 1.
No. 5 fixed in Table 1 4 to 6 heat equalizing plates 2 were produced. As a comparative example, a guide 64 and a through hole 63 are provided.
No. 2 shown in Table 1, in which an M2 screw 65 was passed through 1 to 3 were prepared.

The heat equalizing plates 2 and 52 are provided with a support 11 and
The wafer heating devices 1 and 51 were obtained by assembling the plate-like structure 23, the thermocouple 10, and the conduction terminal 7.

Then, the conduction terminals 7 and 97 of the two types of wafer heating devices 1 and 51 thus obtained are energized and maintained at 250 ° C., and the wafer W placed on the mounting surfaces 3 and 53 After confirming that the temperature at a total of 7 points, that is, 6 points on the circumference of the circumference of the center and 1/2 of the wafer radius, is within 1 ° C., the surface temperature distribution is kept at 150 ° C. for 30 minutes. The transient characteristics of the temperature variation in the wafer surface until the wafer W was held at 150 ° C. with the wafer W placed thereon were examined for five cycles of each sample, and the maximum value was measured.

As evaluation criteria, those having a temperature variation of not more than 10 ° C. when the temperature of the wafer surface rises were determined to be OK, and those having a temperature variation of not less than NG were determined to be NG. Regarding the temperature variation during the temperature holding, OK was set within 1 ° C., and NG was set when it exceeded this. Each result was as shown in Table 1.

[0057]

[Table 1]

As can be seen from Table 1, the comparative example No.
In Nos. 1 to 3, the temperature variation in the wafer surface was as large as 12 to 13 ° C., and the temperature variation in keeping the temperature at 150 ° C. exceeded 1 ° C., which was not preferable.

On the other hand, in the embodiment of the present invention, No. 4
6 to 6 have a temperature variation of 6 to 7 ° C. when the temperature in the wafer surface is raised.
The temperature variation when the temperature of the wafer was maintained at 150 ° C. was also reduced to 0.6 to 0.8 ° C.

Embodiment 2 Here, investigation was made on the proper dimensions in the press-fitting operation of the fixture 17 and the difference in the coefficient of thermal expansion between the fixture 17 and the heat equalizing plate 2 made of ceramic was held by the guide 14 for positioning the wafer. The effect on power was investigated.

A 42 alloy (8.0 × 10 ⁻⁶ / coefficient of thermal expansion) was added to a silicon carbide sintered body having a coefficient of thermal expansion of 3.9 × 10 ⁻⁶ / ° C.
° C), Fe-Ni-Co alloy (thermal expansion coefficient 5.9 × 10 ^-6)
/ ° C), W (thermal expansion coefficient 4.3 × 10 ⁻⁶ / ° C), Ni (thermal expansion coefficient 15 × 10 ⁻⁶ / ° C), SUS304 (thermal expansion coefficient 1)
8.7 × 10 ⁻⁶ / ° C.), amber (coefficient of thermal expansion 0.8 × 1)
0 ^-6 / ° C.) to a fixing bracket 17 outer diameter 4.005mm shown in Fig. 3 that the material, 4.01mm, 4.03mm, 4.0
6mm, 4.09mm, 4.12mm, 4.15mm,
It is manufactured with a thickness of 1.8 mm.
(A hole diameter of 4.00 mm and a depth of 2.0 mm) was embedded by press-fitting, and a guide 14 having a slit 20 having a width of 0.3 mm was set on the screw portion 19 to prepare a sample.
In the case where the slit 20 was not formed, the fixture 17 could not be inserted, or cracks occurred around the concave portion 13 of the heat equalizing plate 2.

These samples were treated at 30-250 ° C. with O
N, while applying a current to OFF, a tensile load was applied to the fixing bracket 17, and the pull-out strength was examined. As evaluation criteria,
Those with a pull-out strength of 100 N or more were rated OK, and those with less than 100 N were rated NG.

The results are as shown in Table 2.

[0064]

[Table 2]

As can be seen from Table 2, in all the samples, when the outer diameter of the fixing bracket 17 became larger than the inner diameter of the concave portion 13 of the heat equalizing plate 2 by more than 0.1 mm, the screws could not be inserted, Problems such as the occurrence of cracks in the plate 2 occurred, and the yield was significantly reduced. Further, the difference between the outer diameter of the fixing bracket 17 and the inner diameter of the recess 13 is 0.0
All of those smaller than 1 mm had a low pull-out strength of 100 N or less.

On the other hand, when the outer diameter of the fixing bracket 17 is larger than the inner diameter of the recess 13 by 0.01 to 0.1 mm,
A good pull-out strength of 100 N or more was exhibited.

Ni and SUS304 having a coefficient of thermal expansion higher than 8.0 × 10 ⁻⁶ / ° C. have cracks due to the difference in the coefficient of thermal expansion with the soaking plate 2 during ON and OFF energization, and are capable of being press-fitted. Was narrow and not very desirable. On the other hand, when the amber has a coefficient of thermal expansion of 3.8 × 10 ⁻⁶ / ° C. or less, the fixture 17 comes off with an extremely low load when the power is turned ON and OFF. It was judged that it was not preferable to select a small material as the fixing bracket 17.

On the other hand, the coefficient of thermal expansion is 4.3 to 8.0 ×
As for W, Fe-Ni-Co alloy, and 42 alloy at 10 ^-6 / ° C, when the outer diameter of the fixing bracket 17 is larger than the inner diameter of the recess 13 by 0.01 to 0.1 mm, cracks are generated. It was found to be good without generation.

Embodiment 3 Here, a preferable range of the radius of curvature of the corner 17a at the bottom of the fixing bracket 17 was investigated. 3m thick
A 30 mm heat equalizing plate 2 was prepared by processing a concave portion 13 having a hole diameter of 4 mm and a depth of 2 mm in a silicon carbide sintered body of m. Then, the radius of curvature of the corner portion 17a of the fixture 17 having an outer diameter of 4.06 mm and a thickness of 1.8 mm is set to 0.03 mm on the heat equalizing plate 2.
After processing so as to be 0.05 mm, 0.1 mm, 0.2 mm, and 0.3 mm, press-fitting was performed to investigate whether or not the heat equalizing plate 2 was affected.

The evaluation criteria were NG when the appearance of the heat equalizing plate 2 was cracked or cracked, and OK when there was no abnormality in the appearance.

The results are as shown in Table 3.

[0072]

[Table 3]

As shown in Table 3, the radius of curvature of the corner 17a of the fixture 17 was 0.03 mm. 1 is
Abnormalities such as cracks and cracks were found near the concave portion 13 of the heat equalizing plate 2. This is because the bottom of the fixture 17 and the heat equalizing plate 2
It is presumed that when the distance from the bottom surface of the hole 13 becomes short, stress is applied to the outer peripheral portion of the bottom surface of the weakest concave portion 13 to cause cracks and cracks. On the other hand, in the case of No. 3 where the radius of curvature was 0.05 mm or more. In Nos. 2 to 6, cracks and cracks did not occur and were good.

[0074]

As described above, according to the present invention, one of the main surfaces of the heat equalizing plate made of ceramic is used as the mounting surface of the wafer, and the other main surface or inside thereof has the heating resistor. In a wafer heating device having a power supply portion electrically connected to a heating resistor on the other main surface, a fixture is installed in a concave portion provided on the wafer mounting surface to position the wafer. By fixing the guide to the fixing jig, the warping of the heat equalizing plate was prevented, and the wafer could be heated with a good temperature distribution.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a wafer heating apparatus according to the present invention.

FIG. 2A is a perspective view of a wafer heating apparatus according to the present invention, and FIG. 2B is a sectional view taken along line XX.

FIG. 3 is a perspective view of a fixture used in the wafer heating device of the present invention.

FIG. 4 is a sectional view showing a conventional wafer heating apparatus.

FIG. 5 is a sectional view showing a conventional wafer heating apparatus.

FIG. 6A is a perspective view showing a conventional wafer heating apparatus, and FIG. 6B is a sectional view taken along line YY of FIG.

[Explanation of symbols]

 1: Wafer heating device 2: Heat equalizing plate 3: Placement surface 4: Insulating layer 5: Heating resistor 6: Power supply unit 7: Conductive terminal 8: Elastic body 9: Insulator 10: Thermocouple 11: Support body 12: Plate-like structure portion 13: concave portion 14: guide 15: bolt 16: nut 17: fixing bracket 18: gap 19: screw portion 20: slit

Claims (5)

[Claims] A power supply electrically connected to one of the main surface of a heat equalizing plate made of ceramics, the main surface being a mounting surface of a wafer, the other main surface or an internal heating resistor and being electrically connected to the heating resistor. In the wafer heating device having a portion on the other main surface, a fixing bracket is installed in a concave portion provided on the wafer mounting surface, and a guide for positioning the wafer is fixed to the fixing bracket. Characteristic wafer heating device. 2. The wafer heating apparatus according to claim 1, wherein said fixture is fixed to a recess of said heat equalizing plate by elastic force. 3. The fixing device according to claim 1, wherein the fixing bracket is located at a distance of 0.01 to 0.01 from the recess.
3. The wafer heating apparatus according to claim 2, wherein the wafer heating apparatus has a diameter larger by 0.1 mm and a slit portion is provided. 4. A fixture having a thermal expansion coefficient of 3.9 to 8.
2. The temperature range of 0 * 10 < ^-6 > / [deg.] C.
A wafer heating apparatus as described in the above. 5. The wafer heating apparatus according to claim 1, wherein the corner of the bottom surface of the fixing bracket is a curved surface or a C surface.