JP3131009B2 - Heating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating apparatus used for plasma CVD, low pressure CVD, plasma etching, optical etching, and the like.

[0002]

2. Description of the Related Art In a semiconductor manufacturing apparatus requiring a super clean state, a corrosive gas such as a chlorine-based gas or a fluorine-based gas is used as a corrosive gas, an etching gas, or a cleaning gas. For this reason, the surface of the resistance heating element is made of stainless steel, as a heating device for heating the wafer in contact with these corrosive gases.
When a conventional heater coated with a metal such as Inconel is used, undesired particles having a particle size of several μm such as chlorides, oxides and fluorides are generated by exposure to these gases. Further, a so-called indirect heating type semiconductor wafer heating apparatus has been developed. However, this type has a large heat loss compared to the direct heating type, takes a long time to raise the temperature, and has a C
There is a problem that the transmission of infrared rays is gradually hindered by the adhesion of the VD film, and heat absorption occurs in the infrared ray transmitting window to overheat the window.

[0003]

In order to solve the above-mentioned problems, the present inventors embed a resistance heating element in a disk-shaped dense ceramic, and hold the ceramic heater in a graphite case. Was considered. As a result, it has been found that this heating device is an extremely excellent device that has further improved the problems described above.

However, such a ceramic heater has the following difficult problems in connecting the terminals of the resistance heating element to the power supply leads. FIG. 6 is an enlarged sectional view of a main part of a heating device developed by the present inventors. A resistance heating element 2 is embedded in a disk-shaped base 1 made of dense ceramics, and the end of the resistance heating element 2 is connected to, for example, a columnar terminal 3. Disc-shaped part 39a of heat insulator 39
A support flange 39c and a cylindrical portion 39d are formed on the side periphery of the support flange 39c. The periphery of the back surface 1c of the disc-shaped base 1 is
c Supported on A through hole 39b is provided in the disc-shaped portion 39a, and the lead member 27 is inserted through the through hole 39b. The male screw 27b of the lead member 27 is fitted to the female screw 3a of the terminal 3.
The lead wire 8 is connected to the end 27a of the lead member 27.

Here, the reason why the base 1 is formed into a simple shape such as a disk shape is that it is necessary to integrally form the base 1 by hot pressing or the like and that processing after firing is easy. Also,
The diameter of the terminal 3 is considerably larger than the diameter of the resistance heating element 2, the diameter of the lead member 27 is adjusted to the size of the terminal 3, the contact area between them is increased, and the terminal 3 is connected to the lead member.
27 was screwed. This is because various corrosive gases flow into the back surface 1c and are exposed to high temperatures, so that a strong heat and corrosion resistant bond must be formed. Further, the heat insulator 39 is necessary to suppress heat transfer, heat dissipation, and the like from the heater back surface 1c and the side circumference, and to reduce energy loss.

However, a new problem has arisen. That is,
The resistance heating element 2 and the terminal 3 are buried in ceramic powder and are integrally molded, and the molded body is subjected to hot press sintering.
In this sintering step, since the terminals 3 are also buried in the sintered body, it is necessary to grind the back surface of the heater to expose the surface of the terminals 3. However, at the stage of press molding and hot press sintering, the terminal 3 slightly moves,
Naturally, the mounting position of the lead member 27 differs for each product. Therefore, the through hole 39b is, for example,
In consideration of the positional tolerance of about ± 6 mm, the hole diameter must be set large so that the lead member 27 passes.

However, the through holes 39 through which the lead members 27 pass are provided.
Since b is large, radiant heat from the back surface 1c of the disc-shaped base 1 cannot be blocked by the through holes 39b. Further, when an inert gas is caused to flow toward the heater back surface 1c, thermal convection is generated from the gap 29 through the through hole 39b to the inner space 19 of the heat insulator 39 as shown by an arrow A. For this reason, the heat of the heater is taken away around the through hole 39b, and
A cold spot with a lower temperature than the surroundings results. In this part, the temperature of the semiconductor wafer is lowered, so that the thickness of the semiconductor film becomes small or the semiconductor becomes defective.

An object of the present invention is to further prevent the occurrence of cold spots on the heating surface under the above-mentioned premise.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a heating disk-shaped substrate made of dense ceramics, in which a metal material is embedded and connected to the metal material. Board-like substrate having terminals exposed to the back surface; a heat insulator provided so as to cover the back surface of the board-like substrate and having a through-hole; coupled to the terminal, the board-like substrate and the heat insulator And a heating device comprising a lead member inserted through the through-hole and coupled to the metal fitting, and configured to select a coupling position of the lead member to the metal fitting. It is.

[0010]

1 is a schematic sectional view showing a state in which a heating device according to an embodiment of the present invention is mounted on a flange portion 14, FIG. 2 is a partially enlarged sectional view of FIG. 1, and FIG. 5 is a plan view, and FIG. 3B is a sectional view taken along line IIIb-IIIb in FIG. 3A.
The substantially disc-shaped ceramic heater 38 includes a substantially disc-shaped base 1 and a resistance heating element 2 embedded inside the disc-shaped base 1. The disk-shaped substrate 1 is made of a dense and gas-tight ceramic. The resistance heating element 2 is embedded in a spiral shape, for example, and both ends of the resistance heating element 2 are connected to terminals 3 respectively.
It is connected to. The surface of each terminal 3 is the rear surface 1c of the base 1.
Exposed to the side.

The wafer heating surface 1a of the disc-shaped substrate 1 is, for example, circular, and an annular step 1b surrounds the wafer heating surface 1a.
Are formed, concentrically annular steps 1d surrounding the steps 1b
Are formed. The flat flange portion 14 is to be attached to a semiconductor manufacturing apparatus (not shown).
In this example, two lead through holes 14a are formed, and the lead member 13 is inserted into each through hole 14a. Each through hole 14d
The insulator 15 is installed so as to cover the insulator 15 and the insulator 15 and the flange portion 14 are sealed with an O-ring. An annular metal body 16 is provided below the insulator 15, and a cylindrical insulating tube 17 is provided inside the metal body 16. Each lead member 13 is further inserted inside the insulator 15 and the insulating tube 17. A power supply cable is connected to a lower end (not shown) of the lead member 13, and a lead wire 8 is connected to an upper end 13a. Cooling jacket on flange 14
18 are installed.

The heat insulator 9 is integrally formed of a heat insulating material such as quartz. A disk-shaped portion 9a is provided substantially in parallel with the heater in opposition to the back surface 1c, an annular support flange 9c is formed on the upper peripheral edge of the disk-shaped portion 9a, and the peripheral back surface of the ceramic heater 1 is supported. I have. A cylindrical portion 9d extends around the periphery of the lower surface of the disk-shaped portion 9a. A regulating plate 22 protrudes from an upper wall surface of the flange portion 14, and the regulating plate 22 is a cylindrical portion.
The heat insulating body 9 is prevented from shifting in the horizontal direction by abutting on the outer periphery of the lower part of 9d. A support leg 9e protrudes from the lower end surface of the cylindrical portion 9d, and the tip of the support leg 9e is inserted into a blind hole 14b of the flange portion 14. The spring coil 20 is installed so as to surround the side peripheral surface of the support leg 9e, and the lower end of the spring coil 20 contacts the flange portion 14 and the upper end contacts the lower end surface of the cylindrical portion 9d.

The tubular body 10 is made of a heat-resistant metal. Cylindrical body 10
The main body 10a has a cylindrical shape, and the main body 10a surrounds the side peripheral surface of the heat insulator 9 and the position of the side peripheral surface of the disk-shaped substrate 1.
An annular mounting portion 10b is formed on the outer periphery of the lower end of the main body 10a, the mounting portion 10b abuts on the flange portion 14, and the space therebetween is sealed by an O-ring. An annular projecting portion 10c is formed on the inner periphery of the upper end of the main body 10a. The annular projecting portion 10c and the step portion 1d face each other, and an annular seal member 21 is sandwiched between the two.

The disc-shaped portion 9a has two through holes 9b, for example.
Are provided in each through hole 9b.
Is inserted. The lead wire 8 is connected to the lower end 7 a of the lead member 7. In the heat-resistant metal fitting 5,
A cylindrical recess 5b and a circular through hole 5c are formed in the head 5a. A pair of elongated locking portions 5d extend parallel to each other from the head 5a to the left in FIG. 3, and a gap 5e is formed between the pair of locking portions 5d. Locking part 5d is head 5a
And a step surface 5f is formed between them.

After sintering the disk-shaped substrate 1, the back surface is subjected to surface grinding to expose, for example, a columnar terminal 3 to the back surface 1c. Next, the metal fitting 5 is set on the back surface 1c, and the circular through hole 5c is formed.
And the female screw 3a are aligned. The male screw of the bolt 4 is fitted with the female screw 3a, the head of the bolt 4 is housed in the recess 5b, and the metal fitting 5 is fixed. Before installing the heat insulator 9, the lead member 7 is arranged at the position of the through hole 9b, and the male screw 7b is inserted into the gap 5e.
And the bolt 6 is fitted into the male screw 7b and fixed. Then, the lead member 7 is inserted into the through hole 9b, and the heat insulator 9 is installed.

According to the present embodiment, the metal fitting 5 is connected to the terminal 3, and the male screw 7b is fixed between the pair of locking portions 5d. Then, the position of the male screw 7b can be changed and selected according to the position of the through hole 9b. Therefore, even if the burying position of the terminal 3 in the sintered body changes, the mounting position of the lead member 7 can be changed accordingly, so that the size of the through hole 9b is more than necessary than the size of the lead member 7. It is not necessary to absorb the tolerance by making it large. Therefore, the size of the through hole 9b only needs to be made larger than the size of the lead member 7 by an amount corresponding to the processing error, and the gap between the two can be substantially eliminated.

Therefore, there is no possibility that the amount of heat of the heater is locally taken away by heat radiation or heat convection around the through hole 9b, and no cold spot is generated on the wafer heating surface 1a, so that the heat uniformity is improved. Defects in film formation due to such cold spots do not occur.

Further, since the terminal 3 and the metal fitting 5 and the metal fitting 5 and the lead member 7 are screwed together, the durability against heat and corrosive gas is high. In addition, since the heater back surface 1c is covered with the heat insulator 9, heat conduction, heat radiation, and heat convection from the ceramic heater toward the flange portion 14 can be prevented. Therefore, the energy loss is small, the temperature rise rate of the heater is increased, and the uniformity of the entire heater is improved.

The annular projection 10c of the cylindrical body 10 is urged against the step 1d via the annular seal member 21. This urging force is provided by the coil spring 20. Thereby, the space between the inner space 19 and the space where the semiconductor wafer is installed can be sealed, and the inner space 19 can be filled with an inert gas such as a nitrogen gas or an argon gas. Therefore, it is possible to prevent the corrosive gas in the semiconductor manufacturing apparatus from corroding metal members such as the lead members 13, 7 and the terminals 3. Further, formation of a conductive film on the back surface 1c by CVD gas or the like in the apparatus can be prevented.

In a process such as low-pressure CVD, the inside of the apparatus is evacuated to a high vacuum state, so that a considerable pressure is applied to the cylindrical body 10. However, the cylindrical body 10 is made of a heat-resistant metal and can sufficiently withstand the pressure of the inert gas in the inner space 19. If the cylindrical body 10 is formed of quartz or ceramics, the annular protruding portion 10c of the cylindrical body 10 is pressed against the step 1d to apply a tensile stress, and if the gas pressure is further applied, the cylindrical body 10 may be broken.

However, if the cylindrical body 10 is made of a heat-resistant metal, when the ceramic heater 38 generates heat, the cylindrical body 10 expands in the vertical direction, and the annular projection 10c moves away from the step 1d. I do. However, in this example, the heat insulator 9 follows this.
Rises and absorbs the rise of the annular projection 10c,
The sealing state is maintained even at high temperatures.

When the tubular body 10 is formed of a heat-resistant metal,
There is a possibility that heat on the side peripheral surface of the ceramic heater will be transmitted through the tubular body 10 and escaped. In this regard, in this embodiment, the cylindrical main body 10a is made thinner to reduce heat transfer. In order to achieve this effect, it is preferable that the thickness of the main body 10a is about 0.5 to 5 mm. It is more preferable that the thickness is increased as the distance from the heater increases.

When the annular seal member 21 is formed of a soft metal, the airtightness can be maximized. As such a soft metal, platinum having high corrosion resistance and high melting point is most preferable. In addition, nickel, silver, and gold are preferable in terms of corrosion resistance. Copper can adversely affect semiconductors.

As the material of the disk-shaped substrate 1, silicon nitride, sialon, aluminum nitride and the like are preferable, and silicon nitride and sialon are more preferable in terms of thermal shock resistance. Aluminum nitride is most preferable in terms of corrosion resistance to halogen-based corrosive gases.
The material of the resistance heating element 2 is preferably tungsten, molybdenum, platinum or the like. As the heat insulating material constituting the heat insulating body 9, quartz, quartz, silicon oxide glass or the like is preferable. As the heat-resistant metal constituting the tubular body 10, Inconel, Hastelloy, stainless steel, nickel, or the like is preferable.

The shape and dimensions of the metal fitting 5 can be variously changed. For example, metal fittings as shown in FIGS. 4 (a) to 4 (c) can be used.
In the metal fitting 25, a cylindrical concave portion 25b and a circular through hole 25c are formed concentrically on a head portion 25a, and the concave portion 25b and the circular through hole 25c are fixed with bolts 4. From the head 25a, FIG.
A thin engaging portion 25d is formed toward the left in the above, and a gap 25e is formed inside the engaging portion 25d. Gap 25
Select the bolt fixing position in e. 25f is a step surface.

In the metal fitting 35, a cylindrical concave portion 35b and a circular through hole 35c are formed concentrically on the head portion 35a, and the concave portion 35b and the circular through hole 35c are fixed with bolts 4. Head 35
A thin locking portion 35d is formed from a to the left,
A plurality of circular through holes 35e are formed in the locking portion 35d. A mounting position of the lead member is selected from the plurality of circular through holes 35e. 35f is a step surface. Hardware 45
Is a thick U-shaped head 45a and a thin U-shaped tail
The head 45a and the tail 45d are closed in a plan view. 45f is a step surface. Head 45a and tail 45
A locking portion 45b is formed inside d. The bolt 4 and the lead member 7 are fixed at appropriate places in the locking portion 45b.

FIG. 5 is a sectional view of an essential part similar to FIG. 2, showing an example in which the metal fitting 35 is used. The same members as those shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. Circular through hole
Align the 35c with the female screw 3a, and attach the bolt 4 to the female screw 3a.
And the head 35a is fixed to the terminal 3. The mounting position of the lead member 7 is selected from the plurality of circular through holes 35e, the male screw 7b is inserted into the predetermined circular through hole 35e, and the bolt 6 is fitted to the male screw 7b.

However, in this example, the circular through holes 35e are slightly apart from each other, and there are only four types of mounting positions of the lead members 7 (the example in FIG. 5). Therefore, in some cases, the diameter of the through hole 9b is made slightly larger than in the example of FIG.
A concave portion 41 is provided in the disk-shaped portion 9a, and a ring 40 made of a heat insulating material is installed in the concave portion 41. The diameter of the circular through hole 40a of the ring 40 is made equal to the diameter of the through hole 9b in FIG. Then, the lead member 7 is inserted into the through holes 9b and 40a. As described above, in this embodiment, the mounting position of the lead member 7 is first selected and adjusted from among the circular through holes 35e.
In addition, the deviation caused by the limited selection position of the circular through hole 35e can be finely adjusted by the ring 40.

The planar shape of the disk-shaped substrate 1 can be variously changed. In the above example, the present invention was applied to a ceramic heater in which a resistance heating element was embedded as a metal material. But,
The present invention can be applied to a ceramic electrostatic chuck in which a film-like electrode is embedded inside a disk-shaped substrate. In this case, for example, a cylindrical terminal is in contact with the membrane electrode, and this terminal is exposed on the back surface of the base. Then, the semiconductor wafer is sucked by the electrostatic chuck, and the disk-shaped substrate is irradiated by the infrared lamp to heat the semiconductor wafer. Connect a DC power supply to the terminals.

In the above example, the terminal 3 and the metal fitting 5, and the metal fitting 5 and the lead member 7 are screwed. However, a high heat and corrosion resistant bond can be formed by caulking, press fitting, diffusion bonding, or friction welding. be able to.

[0031]

According to the present invention, the terminal exposed on the back surface of the board-like base is connected to the metal fitting, and the lead member is connected to the metal fitting. Then, the coupling position of the lead member to the metal fitting can be selected according to the position of the through hole of the heat insulator. Therefore, even if the embedding position of the terminal in the sintered body changes, the mounting position of the lead member can be selected in accordance with this, so that the size of the through hole is made larger than the size of the lead member and the tolerance is increased. No need to absorb. Therefore, the size of the through hole need only be made larger than the size of the lead member by the amount of the processing error, and the gap between the two can be substantially eliminated. Therefore, there is no possibility that the heat of the disk-shaped substrate is locally taken away by heat radiation or thermal convection around the through hole, and no cold spot is generated on the heated surface, and the heat uniformity is improved.

Furthermore, since the back side of the board-shaped base is covered with the heat insulator, heat conduction, heat radiation, and heat convection from the board-shaped base toward the back can be prevented. Therefore, the energy loss is small, the temperature rise rate of the heated surface is increased, and the uniformity of the entire heated surface is improved.

[Brief description of the drawings]

FIG. 1 shows a heating device according to an embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view showing a state in which the device is attached to the device.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3A is a plan view of a metal fitting 5; (b) is II of (a)
It is Ib-IIIb line sectional drawing.

FIGS. 4 (a), (b), and (c) are plan views showing metal fittings of respective examples.

FIG. 5 is a cross-sectional view of a main part showing a periphery of a fitting 35 in another embodiment.

FIG. 6 shows a heat insulator 39 on the back 1c side of the ceramic heater.
FIG. 9 is a cross-sectional view of a main part showing a state where a lead member 27 is installed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc-shaped base 1c Back surface 2 Resistance heating element (an example of a metal material) 3 Terminal 4 Bolt 5, 25, 35, 45 Hardware 6 Nut 7, 13, 27 Lead member 9, 39 Heat insulator 9b, 39b Through hole 10 Cylindrical Body 29 Gap 38 Ceramic heater 40 Ring A Thermal convection

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/205 H01L 21/3065

Claims (1)

(57) [Claims] 1. A board for heating made of dense ceramics, wherein a metal material is buried inside the board-shaped substrate and terminals connected to the metal material are exposed on the back surface. A heat-insulating body provided to cover the back surface of the board-shaped substrate and provided with a through-hole; a metal fitting fixed to a gap between the board-shaped substrate and the heat-insulated body; A heating device including a lead member inserted into the through hole and coupled to the metal fitting, and configured to select a coupling position of the lead member to the metal fitting;