JP2003031517A - Heat treatment apparatus for substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus which can equalize the powers to be supplied to a plurality of lamps which constitute a light source for heating, and which can drive all the lamps near the rated output. SOLUTION: Between the lamps 28 and a light-incident window 14 of a heat treatment furnace 10, a group of lenses 44 which consists of a plurality of lenses 46 arranged two-dimensionally in parallel is interposed. Among the group of lenses, those disposed near the center are concave lenses, and a condensing degree of a plurality of lenses disposed around those near the center is made higher as gradually approaching toward the periphery.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a semiconductor wafer, a glass substrate for a liquid display device, a glass substrate for a photomask, a substrate for an optical disk, etc., which are brought into a heat treatment furnace one by one and heated by light irradiation. The present invention relates to a heat treatment apparatus for a substrate that is heat-treated.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process,
A substrate such as a semiconductor wafer is carried into a heat treatment furnace one by one like a lamp annealing device or CVD, and the substrate is irradiated with light to heat the wafer, thereby thermally diffusing impurity atoms and performing pn junction. 2. Description of the Related Art A single-wafer type heat treatment apparatus for forming a film, forming a thermal oxide film on a wafer surface, and performing various annealing treatments is widely used in various processes. FIG. 3 shows an example of the configuration of a lamp annealing device which is one of the heat treatment devices.

The lamp annealing apparatus whose schematic side sectional view is shown in FIG. 3 includes a heat treatment furnace 10 having an opening 12 for loading and unloading a semiconductor wafer W. The upper furnace wall of the heat treatment furnace 10 is made of a material having infrared transparency, for example, quartz glass, and serves as a light incident window 14. The opening 12 of the heat treatment furnace 10 has a gate valve 16
It is closed by opening and closing. Although not shown in the figure, on the side of the surface of the heat treatment furnace 10 that faces the opening 12, the wafer W is supported in a horizontal posture by a support arm, and the wafer W before heat treatment is loaded into the heat treatment furnace 10 and subjected to the heat treatment. Wafer W
A wafer loading / unloading device for unloading the wafer from the heat treatment furnace 10 is provided.

A wafer support ring 18 made of SiC or the like is disposed inside the heat treatment furnace 10, and the wafer support ring 18 is rotatably held in a horizontal posture by a wafer holding / rotating mechanism 20. There is. Wafer W
Are horizontally supported on the wafer support ring 18.
Further, there is provided a wafer transfer mechanism 24 that has a plurality of, for example, three support pins 22 that abut the lower surface of the wafer W to support the wafer W and that reciprocates in the vertical direction.

A lamp house 26 is provided above the heat treatment furnace 10 so as to face the light incident window 14. In the lamp house 26, a plurality of lamps such as halogen lamps and arc lamps, for example, straight tube lamps 28 are lined up in the same plane, and a reflector 30 is provided for each straight tube lamp 28.
Are arranged respectively. And each straight tube lamp 28
The infrared light radiated from each is efficiently condensed by the reflector 30, passes through the light irradiation window 14, and is irradiated into the heat treatment furnace 10. The lamp house 26 is divided into a plurality of heating zones, and the electric power supplied to the straight tube lamps 28 can be adjusted for each heating zone, or each straight tube lamp 28 can control the power supplied thereto. The power supply can be adjusted.

Inside the heat treatment furnace 10, facing the upper surface of the wafer W supported on the wafer support ring 18, a plurality of gas blowing holes formed of a material having infrared transparency, for example, quartz glass. A gas flow distribution plate 32 having holes 34 formed therein is disposed. This gas flow distribution plate 3
A gas introducing chamber 36 into which a processing gas such as nitrogen is introduced is provided between the light incident window 2 and the light incident window 14, and the gas introducing chamber 36 is
It is connected to the processing gas supply source through a gas introduction path (not shown). On the other hand, an annular gas exhaust passage 38 is formed between the wafer holding / rotating mechanism 20 and the inner peripheral wall surface of the heat treatment furnace 10, and the gas exhaust passage 38 is connected to an exhaust port (not shown) for communication. Further, in order to keep the airtightness inside the heat treatment furnace 10 high, O-rings 40 are attached to the contact portion with the gate valve 16 and the joint portion with the light incident window 14, respectively.

A plurality of temperature detectors are provided at the bottom of the heat treatment furnace 10 so as to face the lower surface of the wafer W supported on the wafer support ring 18 and the lower surface side of the wafer support ring 18.
For example, radiation thermometers 42a, 42b, 42c, 42d are installed. These radiation thermometers 42a, 42b, 4
By 2c and 42d, the temperatures of the wafer W at a plurality of positions and the temperature of the wafer support ring 18 during the heat treatment are measured without contact. And the radiation thermometers 42a, 4
A controller (not shown) controls the power supplied to each straight tube lamp 28 based on the temperature of the wafer W measured by 2b, 42c, and 42d.

[0008]

In the lamp annealing apparatus as described above, when the wafer is heated by a plurality of lamps, the amount of heat released from the wafer surface increases as it approaches the peripheral edge of the wafer. In order to obtain temperature uniformity, it is necessary to increase the irradiation intensity as it approaches the periphery of the wafer W. Therefore, conventionally, a large amount of electric power is supplied to the lamp facing the peripheral portion of the wafer, and a relatively small amount of electric power is supplied to the lamp facing the central portion of the wafer W. Therefore, the lamp facing the peripheral portion of the wafer is driven near the rated output, while the lamp facing the central portion of the wafer is always driven below the rated output. This means that the power of the lamp is not being effectively used.
Further, the temperature rise of the wafer is rate-controlled by the electric power that can be supplied to the lamp facing the central portion of the wafer, and the temperature of the wafer is raised at high speed, for example, in the process of forming a pn junction by thermal diffusion. Even in the necessary processing, the temperature rising rate cannot be increased above a certain rate.

The present invention has been made in view of the above circumstances, and it is possible to equalize the electric power supplied to a plurality of lamps constituting a heating light source, and all the lamps are rated. An object of the present invention is to provide a substrate heat treatment apparatus that can be driven near the output.

According to a first aspect of the present invention, at least a heat treatment furnace in which at least an upper furnace wall is formed of a light-transmissive material, and a substrate is loaded and held therein, and at least a substrate held in the heat treatment furnace. A heating light source having a plurality of lamps arranged to face the upper surface and irradiating the substrate with light through a furnace wall formed of the light transmissive material to heat the substrate; A lens group in which a plurality of lenses are two-dimensionally arranged in parallel is interposed between a heating light source and a furnace wall formed of a light transmissive material in the heat treatment furnace, and one lens is provided near the center of the lens group. Alternatively, the plurality of lenses may be concave lenses, and the condensing degree of the plurality of lenses arranged around the concave lens may be increased toward the peripheral position of the lens group, or the condensing degree of the plurality of lenses of the lens group may be increased by the lens. In the group Characterized in that the high toward the peripheral position from the position.

According to a second aspect of the invention, in the heat treatment apparatus according to the first aspect, the lens group is formed by arranging a plurality of lenses in a honeycomb shape.

According to a third aspect of the present invention, in the heat treatment apparatus according to the first or second aspect, a lens rotating mechanism for rotating the lens group in a plane is provided.

According to a fourth aspect of the present invention, in the heat treatment apparatus according to the third aspect, the rotation center of the lens group in the lens rotation mechanism is unevenly distributed in plan view from the center of the substrate held in the heat treatment furnace. It is characterized by that.

According to a fifth aspect of the present invention, in the heat treatment apparatus according to the first or second aspect, a substrate rotating mechanism for rotating the substrate held in the heat treatment furnace in a plane is provided, and the substrate rotating mechanism is provided. It is characterized in that the rotation center of the substrate is deviated from the center of the lens group in plan view.

The invention according to claim 6 is the heat treatment apparatus according to any one of claims 1 to 5, wherein the plurality of lamps of the heating light source are straight tube lamps.

In the substrate heat treatment apparatus according to the first aspect of the present invention, among the light emitted from the plurality of lamps of the heating light source, the light passing through the vicinity of the center of the lens group is diffused by the concave lens, and the concave lens is used. The light passing through the periphery of is condensed at a high degree of converging toward the peripheral position of the lens group. Alternatively, when the light emitted from the plurality of lamps of the heating light source passes through the lens group, the light is condensed with a high degree of condensing from the central position of the lens group toward the peripheral position. Therefore, even if the same power is supplied to the plurality of lamps of the heating light source and the intensity of the light emitted from the plurality of lamps is equalized, the light is transmitted through the furnace wall of the heat treatment furnace formed of the light-transmissive material. Then, the intensity of light applied to the surface of the substrate becomes relatively small in the central portion of the substrate and becomes larger as it approaches the periphery of the substrate. For this reason, the change in the irradiation intensity on the substrate surface and the change in the amount of heat released from the substrate surface are canceled out, and the temperature uniformity in the substrate surface is obtained. Therefore, it becomes possible to drive all the lamps constituting the heating light source in the vicinity of the rated output.

In the heat treatment apparatus according to the second aspect of the invention, the action of the invention according to the first aspect is surely exhibited.

In the heat treatment apparatus according to the third aspect of the present invention, since the lens group is rotated in the plane by the lens rotating mechanism, even if there is a variation in the degree of focusing between the lenses in the circumferential direction in the lens group, The influence of the variation is eliminated.

In the heat treatment apparatus according to the fourth aspect of the present invention, even if the plurality of lenses of the lens group are regularly arranged in the radial direction, the lens rotation mechanism causes the lens group to eccentrically rotate with respect to the substrate in the heat treatment furnace. By doing so, the peaks and valleys of the illuminance distribution in the radial direction of the substrate, which are caused by the regularity in the radial direction of the lens groups, are relaxed. As a result, the fluctuation of the illuminance distribution in the radial direction of the substrate surface is reduced.

In the heat treatment apparatus of the fifth aspect of the present invention, even if the plurality of lenses of the lens group are regularly arranged in the radial direction, the substrate rotating mechanism causes the substrate to be eccentrically rotated with respect to the lens group. , The peaks and valleys of the illuminance distribution in the radial direction of the substrate caused by the regularity in the radial direction of the lens groups are relaxed. As a result, the fluctuation of the illuminance distribution in the radial direction of the substrate surface is reduced.

In the heat treatment apparatus according to the sixth aspect of the present invention, even if the same electric power is supplied to the plurality of straight tube lamps of the heating light source, the irradiation intensity on the surface of the substrate in the heat treatment furnace is at the central portion of the substrate. It becomes relatively small and becomes larger as it gets closer to the periphery of the substrate.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a side sectional view showing an example of an embodiment of the present invention and showing a schematic configuration of a lamp annealing apparatus which is one of heat treatment apparatuses. Since the basic structure of the lamp annealing apparatus is not particularly different from that of the conventional apparatus shown in FIG. 3, the same reference numerals as those used in FIG. 3 are given to the respective members in FIG. Omit it.

In this lamp annealing apparatus, a lens group 44 composed of a plurality of lenses 46 is interposed between the lamp house 26 and the light incident window 14 of the heat treatment furnace 10. The plurality of lenses 46 of the lens group 44 are arranged in a plane parallel to the plane in which the plurality of straight tube lamps 28 of the lamp house 26 are arranged. As shown in the plan view of the straight tube lamp 28 and the lens 46 in FIG.
Are arranged in a honeycomb shape. That is, except for the lens 46 located at the outermost circumference, one lens 46 is provided for each.
The plurality of lenses 46 are two-dimensionally arranged so that the six lenses 46 are arranged around the.

The lens group 44 is not composed of lenses of the same kind all, but is composed of lenses of different kinds concentrically. For example, the lenses 46a and 46b located near the center of the lens group 44 are concave lenses, and the lenses 46 located outside the lenses 46a and 46b.
c to 46e are convex lenses. When it is necessary to distinguish the type of lens, it is described as lenses 46a to 46e, and when the type of lens is not distinguished, it is simply described as the lens 46. Further, in FIG. 2, for the sake of convenience, the difference in lens type is expressed by changing the filling pattern.

Of the seven concave lenses 46a, 46b near the center of the lens group 44, the central lens 46a diffuses light to a higher degree than the surrounding lenses 46b. There is. Also,
The lenses 46c to 46e formed of convex lenses are the lens group 4
The degree of condensing increases toward the periphery of 4 (46c <
46d <46e).

Further, in the apparatus provided with the wafer holding / rotating mechanism 20 for rotating the wafer W in the plane like the lamp annealing apparatus shown in FIG. 1, the center of the lens group 44, that is, the center of the lens group 44 is located. The center of the lens 46a and the center of rotation of the wafer W are located at an appropriate distance in plan view,
For example, it is preferable to shift the lens 46 by about 1/5 to 1/2 of the arrangement interval. It should be noted that, without providing the rotation mechanism for the wafer W, the wafer W is held stationary in the heat treatment furnace 10, and instead, a lens rotation mechanism for rotating the lens group 44 in a plane is provided, and the lens group 44 is heated during the heat treatment. May be rotated. Even with such a configuration, the center of rotation of the lens group 44, that is, the lens group 4
It is preferable to shift the center of the lens 46a located at the center of the lens 4 and the center of the wafer W by an appropriate distance in plan view, for example, about 1/5 to 1/2 of the arrangement interval of the lenses 46.

When the wafer is heat-treated by using the lamp annealing apparatus having the above-mentioned structure, the lens group of the infrared light emitted from the plurality of straight tube lamps 28 of the lamp house 26 and condensed by the reflector 30. Light passing near the center of 44 is diffused by the lenses 46a and 46b formed of concave lenses. On the other hand, the light passing outside the lenses 46a and 46b is a lens 46c formed of a convex lens.
Due to 46e, the light is condensed with a higher degree of convergence toward the peripheral position of the lens group 44. Therefore, the straight tube lamps 28 of the lamp house 26 are supplied with substantially the same rated power to drive all the straight tube lamps 28 near the rated output, and the light emitted from the straight tube lamps 28 is emitted. When the intensities of the wafers W are equalized, the intensity of the light transmitted through the light incident window 14 of the heat treatment furnace 10 and irradiated on the surface of the wafer W is
Is relatively small in the central part of the above, and becomes larger as it is closer to the peripheral edge of the wafer W. On the other hand, since the amount of heat released from the surface of the wafer W increases as it approaches the periphery of the wafer W, the change in the irradiation intensity on the surface of the wafer W and the change in the amount of heat released from the surface of the wafer W are canceled out, and the surface of the wafer W is canceled. Uniformity of internal temperature can be obtained.

The same electric power is not always supplied to the plurality of straight tube lamps 28, but like the conventional apparatus,
Based on the temperature of the wafer W measured by the radiation thermometers 42a, 42b, 42c, 42d, the controller adjusts the electric power supplied to the straight tube lamp 28 for each heating zone of the lamp house 26, or the straight tube lamps. The supply power is adjusted every 28.

Further, in this lamp annealing apparatus, since the wafer W is rotated by the wafer holding / rotating mechanism 20 during the heat treatment, even if there is a variation in the degree of focusing between the lenses 46 in the lens group 44 in the circumferential direction. , The influence of the variation is eliminated. Also, heat treatment furnace 1
Even if the wafer W is held in the zero position without being rotated and the lens group 44 is rotated in the plane by the lens rotating mechanism, the same effect can be obtained.

Further, the center of the lens group 44, that is, the center of the lens 46a located at the center of the lens group 44 and the rotation center of the wafer W are, for example, 1/5 to 1/2 of the arrangement interval of the lenses 46 in a plan view. When the configuration is such that the lenses 46 are displaced by a certain degree, even if the plurality of lenses 46 of the lens group 44 are regularly arranged in a honeycomb shape in the radial direction as shown in FIG. Variations in distribution can be reduced.

That is, the center of the lens group 44 and the wafer W
If the center of rotation of the
Will continue to be positioned immediately above the circumference of the wafer W surface. In other words, the light that has passed through each lens 46 will continue to be irradiated onto the predetermined circumference of the wafer W surface. Therefore, the plurality of lenses 46
Are regularly arranged in the radial direction, the irradiation intensity on the surface of the wafer W is also determined by the regularity of the arrangement.
Since there is regularity in the radial direction of, the illuminance distribution will always have peaks and valleys. On the other hand, when the wafer W is eccentrically rotated with respect to the lens group 44, the illuminance distribution peaks in the radial direction of the wafer W caused by the regularity of the lens group 44 in the radial direction.
The valley will be relaxed. As a result, the wafer W
The fluctuation of the illuminance distribution in the radial direction of the surface is reduced.

When the wafer W is held in the heat treatment furnace 10 without being rotated and the lens group 44 is rotated in the plane by the lens rotating mechanism, the center of rotation of the lens group 44 and the center of the wafer W are set. Even when the lenses 46 are displaced by about 1/5 to 1/2 of the arrangement interval of the lenses 46 in a plan view, the variation in the illuminance distribution in the radial direction of the wafer W surface can be reduced in the same manner as described above.

Although it is most preferable to arrange the plurality of lenses 46 in a honeycomb shape to form the lens group 44 as in the above-described embodiment, the plurality of lenses 46 are two-dimensionally arranged in a shape other than the honeycomb shape. The lens groups 44 may be arranged in parallel with each other. Further, in the above-described embodiment, the lenses 46a and 46b near the center of the lens group 44 are concave lenses, but all the lenses 46 are convex lenses, and the lenses 4a and 4b move toward the peripheral position from the central position of the lens group 44.
The light collection degree of 6 may be increased. Further, in the above embodiment, the plurality of straight tube lamps 28 are arranged in parallel in the horizontal direction and in parallel with each other to form the heating light source, but the structure of the heating light source is not particularly limited, and may be, for example, a tube shape. The present invention can also be applied to a heat treatment apparatus provided with a heating light source in which the above lamps are arranged two-dimensionally in parallel.

[0035]

When the substrate heat treatment apparatus according to the first aspect of the present invention is used, the electric power supplied to the plurality of lamps constituting the heating light source can be made equal, and all the lamps are close to the rated output. Can be driven with. Therefore,
The ability of the lamp can be effectively used, and the temperature of the substrate can be raised at the maximum speed.

With the heat treatment apparatus according to the second aspect of the present invention, it is possible to reliably obtain the above effects of the first aspect of the invention.

In the heat treatment apparatus according to the third aspect of the present invention, even if there is a variation in the degree of light condensing between the lenses in the circumferential direction in the lens group, the influence of that variation can be eliminated.

In the heat treatment apparatus according to the fourth aspect of the present invention, even if the plurality of lenses of the lens group are regularly arranged in the radial direction, the peak of the illuminance distribution in the radial direction of the substrate caused by the regularity of the arrangement. -Variations in the illuminance distribution in the radial direction of the substrate surface can be reduced by relaxing the valley portion.

In the heat treatment apparatus according to the fifth aspect of the present invention, even if the plurality of lenses in the lens group are regularly arranged in the radial direction, the peak of the illuminance distribution in the radial direction of the substrate caused by the regularity of the arrangement. -Variations in the illuminance distribution in the radial direction of the substrate surface can be reduced by relaxing the valley portion.

In the heat treatment apparatus of the invention according to claim 6, it is possible to equalize the power supplied to the plurality of straight tube lamps,
All straight tube lamps can be driven near their rated output.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an example of an embodiment of the present invention and showing a schematic configuration of a lamp annealing apparatus which is one of heat treatment apparatuses.

FIG. 2 is a plan view showing only a straight tube lamp and a lens of the lamp annealing apparatus shown in FIG.

FIG. 3 is a schematic side sectional view showing an example of the configuration of a conventional lamp annealing apparatus.

[Explanation of symbols]

10 heat treatment furnace 14 Light incident window 18 Wafer support ring 20 Wafer holding / rotating mechanism 26 Lamp House 28 lamps 44 lens group 46, 46a to 46e lenses W wafer

Claims (6)

[Claims] 1. A heat treatment furnace in which at least an upper furnace wall is formed of a light-transmissive material, and a substrate is carried in and held therein, and a heat treatment furnace arranged to face at least an upper surface of the substrate held in the heat treatment furnace. A heating light source having a plurality of lamps that are provided to heat the substrate by irradiating the substrate with light through a furnace wall formed of the light transmissive material, and the heating light source and the heat treatment. A lens group, in which a plurality of lenses are two-dimensionally arranged in parallel, is interposed between the furnace and a furnace wall made of a light-transmissive material, and a lens group 1 near the center of the lens group is provided.
One or a plurality of lenses as a concave lens, the light collecting degree of the plurality of lenses arranged around the concave lens is increased toward the peripheral position of the lens group, or the light collecting degree of the plurality of lenses of the lens group, A substrate heat treatment apparatus characterized in that the height is increased from the central position of the lens group toward the peripheral position. 2. The substrate heat treatment apparatus according to claim 1, wherein the lens group is configured by arranging a plurality of lenses in a honeycomb shape. 3. The substrate heat treatment apparatus according to claim 1, further comprising a lens rotation mechanism that rotates the lens group in a plane. 4. The heat treatment apparatus for a substrate according to claim 3, wherein a rotation center of the lens group in the lens rotation mechanism is eccentrically located from a center of the substrate held in the heat treatment furnace in a plan view. 5. A substrate rotating mechanism for rotating a substrate held in the heat treatment furnace in a plane, wherein the rotation center of the substrate in the substrate rotating mechanism is unevenly distributed in plan view from the center of the lens group. The heat treatment apparatus for a substrate according to claim 1 or 2. 6. The substrate heat treatment apparatus according to claim 1, wherein the plurality of lamps of the heating light source are straight tube lamps.