JP2912613B1 - Plate heating device - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To heat a large-area thin plate-shaped heating object such as a 12-inch silicon wafer stably without causing bending, and to heat it at a high temperature and with a uniform temperature distribution. I do. SOLUTION: A plate heating device is provided in a heat-resistant heating object support member 1 having a flat heating portion 2 on which a heating object a is placed, and in a space portion of the heating object support member 1 behind the heating portion 2. A heating means for heating the heated object support member 1; and a heating means arranged concentrically with the heated object support member 1 and located outside the peripheral surface of the heated object support member 1 and protruding from the heating portion 2. It has a ring-shaped quartz lift ring 13 that holds the peripheral portion of the heating object a from below and moves it up and down.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate heating apparatus for heating a thin flat heating object such as a semiconductor wafer to a high temperature, and more particularly to a heating apparatus for placing or picking up a heating object on a heating section on which the heating object is placed. The present invention relates to a plate heating device provided with an object carrier.

[0002]

BACKGROUND OF THE INVENTION At present, there are 200 semiconductor manufacturers.
The company is aiming for a mass production system for 12-inch wafers with a target of 0 years. The supply of silicon wafers has become almost uncertain, and now we are moving to semiconductor manufacturing technology using it, for example, development of manufacturing equipment and its evaluation. The technology that forms the basis of the process technology is a substrate heater, and (a) thermal uniformity, (b) cleanness, and (c) reliability are required.

Conventionally used plate heating means include electric resistance heating, induction heating and lamp heating.
Two measures have been used. From the viewpoint of (a) thermal uniformity, (b) cleanliness, and (c) reliability, the heating means that can cope with a 12-inch large area wafer has been developed with improved electric resistance heating and lamp heating. Is underway.

A conventional hot plate used for heating a plate is placed in a tray called a susceptor for holding a wafer and then held on the hot plate in order to maintain thermal uniformity and cleanness. Was taken. For this reason, the heat elevating response and the heat conduction efficiency are poor, and the temperature of the hot plate itself needs to be set at a considerably high temperature. In order to cope with this problem, a technique in which a wafer is directly placed on a hot plate and heated is effective.

Conventionally, as a means for transferring a semiconductor wafer for directly placing the wafer on a hot plate, two opposing portions are supported from below by a fork-shaped lift made of quartz and having a flat U-shape, and transferred vertically. Is used. 2 and 3 show examples of a conventional plate heating device. The upper surface of the stage heater 15 is flat, and a heating object a such as a silicon wafer is placed thereon. Stage heater 1
5 has a built-in heater section 16 for heating the stage heater 15.

The outer diameter of the stage heater 15 is basically a disk shape. As shown in FIG. 3, a pair of planes 18 parallel to each other is formed on a part of the peripheral wall facing each other. Is smaller than the diameter of the other part of the stage heater 15 and the diameter of the heating object a. As shown in FIG. 3, a plane U-shaped fork-shaped lifter 19 having an inner space wider than the space between the pair of planes 18 is provided. As shown in FIG. Are inserted on both sides of the flat surface 18, thereby being inserted below the periphery of the heating object a. In this state, the lifter 19
As shown by the arrow in FIG. 2,
The heating object a can be placed on the lifter 19 and lifted. Conversely, from the position shown by the arrow in FIG.
Is lowered so that the heating object a is moved to the stage heater 1.
5 can be placed on the upper surface.

[0007]

However, as described above, in order to place a heated object a such as a semiconductor wafer on the stage heater 15, a fork-shaped lifter 19 is used to face the heated object a. Since only two sides are held, bending or the like is likely to occur particularly in a thin flat plate-like heating object a such as a 12-inch semiconductor wafer. Further, a part of the peripheral surface of the stage heater 15 into which the lifter 19 is inserted must be flattened, so that the stage heater 15 becomes non-circular and heats a circular heating object a such as a semiconductor wafer to a uniform temperature. There was a problem that it became difficult to do.

The present invention has been made in view of the above-mentioned problems of the conventional plate heating apparatus, and is capable of stably moving up and down a large-area thin plate-like heating object such as a 12-inch silicon wafer without causing bending. It is still another object of the present invention to provide a plate heating device capable of heating at a high temperature with a uniform temperature distribution.

[0009]

According to the present invention, in order to achieve the above object, the lifter is a ring-shaped lift ring 13 having a diameter larger than the diameter of the peripheral surface of the heated object support member 1, and the lifter 13 is provided with a lifter. Thin plate-shaped heating object a larger than the diameter of the peripheral surface of
Is supported by a lift ring 13 at the periphery thereof, and is moved up and down so that the heated object a is placed on the flat heating portion a of the heated object support member 1.

That is, the plate heating apparatus according to the present invention comprises:
A heat-resistant heating object support member 1 having a flat heating section 2 on which a heating object a is placed, and the heating section 2 of the heating object support member 1
And a heating means for heating the heated object support member 1, which can be inserted concentrically outside the peripheral surface of the heated object support member 1, and a heating unit 2 of the heated object support member 1.
Ring-shaped lift ring 1 that holds a peripheral portion of a heating object a protruding from below and moves vertically and horizontally.
3 is provided.

In such a plate heating device, the ring-shaped lift ring 13 raises and lowers the heated object a while supporting the entire peripheral portion of the heated object a from below, and the flat heating of the heated object support member 1 is performed. In order to mount the portion 2, even if the heating object a is a thin flat plate having a large diameter, the heating object a is held without causing the heating object a to be bent, and the heating object a is placed on the heating unit 2. Or can be picked up. further,
Since the heating unit 2 of the heating object support member 1 can be made circular in accordance with the shape of the heating object a such as a silicon wafer,
There is no deviation in the heating temperature of the heating object a, and the heating object a can be uniformly heated.

Further, by forming the lift ring 13 from quartz, it is possible to perform heating in a chemically stable state without mixing impurities of the heated object a during heating of the heated object a such as a silicon wafer. become able to.

[0013]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings.
FIG. 1 shows an example of a plate heating apparatus according to the present invention. In FIG. 1, the depressurizing vessel is not shown, and only the stage 17 is shown. However, in practice, the depressurizing vessel is surrounded from both sides of the stage 17 over the stage.

A cooling liquid passage 7 is formed in the wall of the stage portion 17, and the stage portion 17 can be cooled by passing a cooling liquid such as water through the cooling liquid passage 7. On the stage section 17, a heat-resistant heated object support member 1 having a flat heating section 2 on which a thin-plate-shaped heated object such as a silicon wafer is placed is installed. Has a space that is air-tightly separated from the space outside the space. More specifically, the heating object support member 1
The upper surface has a cylindrical shape closed by the heating unit 2 and the lower surface side is open. The flat upper surface of the heating unit 2 is wider than a thin plate-shaped heating object such as a silicon wafer. The lower edge portion of the heated object support member 1 is fixed to the upper surface of the stage section 7 by being applied thereto, and is hermetically sealed by a vacuum seal material 8.

The heating member support member 1 as a whole or at least the heating portion 2 is made of silicon-impregnated silicon carbide, ceramic such as alumina, silicon nitride or the like. As will be described later, when heating a heated object by electron impact, if the heated object support member 1 is made of an insulator such as ceramic, a conductor film is formed on the inner surface of the heating portion 2 and this conductor film is formed. It is grounded via the stage 17.

The outer diameter of the heating object support member 1, that is, the diameter of the heating section 2 is smaller than the diameter of the heating object a such as a silicon wafer. An exhaust passage 4 is formed in the stage section 17, and a space inside the heated object support member 1 is evacuated and evacuated by a vacuum pump 5 connected to the exhaust passage 4. Further, inside the heated object support member 1, a filament 9 and a reflector 3 as heating means are provided.

The filaments 9a and 9b are provided behind the heating section 2 of the heating object support member 1, and the filaments 9a and 9b
The filament heating power supplies 10a and 10b are connected to the a and 9b via an insulating seal terminal 16. further,
The acceleration voltage of the electron acceleration power supply 11 is applied between the filaments 9 a and 9 b and the heating unit 2 via the stage unit 17 and the heated object support member 1. The heating unit 2
It is grounded via the heated object support member 1 and the stage 17, and is maintained at a positive potential with respect to the filaments 9a, 9a.

Here, the filaments 9a and 9b include a circular main filament 9a disposed below and near the periphery of the heating section 2, and a subfilament 9b disposed at the center of the main filament 9a. The main filament 9a is arranged near the lower surface of the heating unit 2, and the sub-filament 9b is arranged below the main filament 9a, that is, farther from the lower surface of the heating unit 2. These main filaments 9a and sub-filaments 9b have filament heating power supplies 10a, 10a, respectively.
b is connected.

The reflector 3 is provided behind the filaments 9a and 9b with respect to the heating section 2 of the heating object support member 1. The reflector 3 is made of a metal having a high reflectance such as gold or silver or a metal having a high melting point such as molybdenum, and at least a surface of the heated object support member 1 facing the heating section 2 is a mirror surface. Reflects infrared light. The reflectors 3 can be multiplexed. On the flat upper surface of the heating section 2 of the heating object support member 1, a thin flat heating object such as a silicon wafer is placed.

A ring-shaped lift ring 13 having an inner diameter larger than the outer circumference of the heated object support member 1 is inserted into the outer peripheral side of the heated object support member 1. The lift ring 13 is moved up and down by a lifting mechanism (not shown) so as to be able to move up and down to a position below the upper surface of the heating unit 2 and a position above the upper surface of the heating object 2. Further, the lift ring 13
Can also move in the horizontal direction and move up and down at any position.

In such a plate heating apparatus, first, the internal space of the heated object support member 1 is depressurized to a vacuum. At the same time, the peripheral portion of the heating object a such as a silicon wafer is placed on the lift ring 13, and the lift ring 13 is moved right above the heating section 2 of the heating object support member 1. Further, the lift ring 13 is lowered below the upper surface of the heating unit 2. As a result, the heating object a is mounted on the upper surface of the heating section 2 of the heating section object support member 1 except for its peripheral portion.

Next, the filaments 9a, which are heating means,
Thermions are emitted from 9b and collide with the heating section 2 of the heated object support member 1 by the acceleration voltage applied by the electron acceleration power supply 11. Due to the electron impact, the heating section 2 of the heating object support member 1 is heated, and the heating object placed on the upper surface of the heating section 2 is heated.

At this time, since the inside of the heated object support member 1 is a vacuum space, heat is not released from the heating portion 2 of the heated object support member 1 to the back thereof by convection, but heat is not emitted by radiation. Only release occurs. The radiant heat radiated to the rear of the heating unit 2 is reflected by the reflector 3 toward the heating unit 2 of the heating object support member 1, so that the release of heat to the rear surface of the reflector 3 is prevented, and Heating can be performed efficiently. Thereby, the heating object can be heated to a high temperature in a short time.

Since the main filament 9a is arranged near the periphery of the lower surface of the heating unit 2, the heating unit 2
Is heated, and the periphery of the heated object is heated. Especially,
In this plate heating device, since the peripheral portion of the heating object a is not placed on the heating section 2, the peripheral portion of the heating object radiates heat to the surroundings, and the temperature tends to decrease. Therefore, by heating the periphery of the heating object a to a high temperature by the main filament 9a, the entire heating object can be heated to a uniform temperature.

However, if only the main filament 9a is arranged, the temperature of the central portion of the heated object will drop. Therefore, by arranging the sub-filament 9b below the center position of the heating unit 2 which corresponds to the center of the heating object,
It is possible to prevent a decrease in the temperature at the center of the heated object. The sub-filament 9b is disposed slightly away from the lower surface of the heating unit 2, or the current of the sub-filament power supply 10b is reduced to slightly suppress the heating energy.
Prevents excessive rise in temperature at the center of the heating object.

In the state where the heated object is heated as described above,
For example, a process gas such as silane is introduced into a reduced-pressure container surrounding the stage section 17, a silicon thin film is deposited on the surface of the heated object, and semiconductor processing can be performed on the surface of the heated object.
After removing the heated object a from the heating unit 2 after processing the heated object a through these steps, the lift ring 13 is raised as shown by an arrow in FIG. Then, the periphery of the workpiece a is placed on the lift ring 13, and the heated object a is raised as it is. Thereafter, the lift ring 13 is moved in the horizontal direction, the workpiece a is moved to a predetermined position, and the next step is performed.

In the above example, an example in which the electron impact method is used as the heating means of the heating object a is shown. However, the present invention is similarly applied to a plate heating apparatus using resistance heating, lamp heating, or the like. Of course, it can be applied.

[0028]

As described above, according to the present invention, a heated object can be stably moved up and down without causing bending, and can be heated to a high temperature with a uniform temperature distribution. A plate heating device that can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a plate heating apparatus and a plate processing apparatus using the same according to the present invention.

FIG. 2 is a longitudinal sectional side view showing a conventional example of a plate heating device.

FIG. 3 is a cross-sectional plan view showing a conventional example of the plate heating apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heated member support member 2 Heated member of heated member support member 3 Reflector 9a Main filament 9b Subfilament 13 Lift ring

Claims (3)

(57) [Claims] 1. A plate heating apparatus for heating a thin flat plate-shaped heating object (a) placed on a heating section (2) for heating the heating object (a) from the back side thereof. ), A heat-resistant heating object support member (1) having a flat heating portion (2), and a heating object provided in a space behind the heating portion (2) of the heating object support member (1). Heating means for heating the support member (1); and a heating means for heating the support member (1), which can be inserted concentrically outside the peripheral surface of the support member (1) and protrude from the heating portion (2) of the support member (1). Heated material (a)
A plate-shaped heating device, comprising: a ring-shaped lift ring (13) that moves vertically and horizontally while holding a peripheral portion of the plate from below. 2. The heating object supporting member (1) has an outer diameter smaller than an outer diameter of the heating object (a).
A plate heating device according to claim 1. 3. The plate heating apparatus according to claim 1, wherein the lift ring is made of quartz.