JP2002110579A - Light irradiation type heat treating apparatus for wafers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus which possibly increases the number of treated substrates for which some treating uniformity is ensured, if a substance evaporated from a substrate during heat treating deposits the inner wall of a heat treating furnace to stain the inner wall, thereby reducing the cleaning work frequency of the furnace to improve the availability of the apparatus. SOLUTION: A light diffusion plate 32a is disposed between the upside of a substrate W held in a heat treating furnace 10 and a light irradiating light source 20 so that diffused lights irradiate the substrate surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light irradiation type heat treatment apparatus for heat treating various substrates such as semiconductor wafers one by one by light irradiation, such as a lamp annealing apparatus.

[0002]

2. Description of the Related Art In recent years, in the manufacturing process of semiconductor devices, a single-wafer type lamp which heats and heat-treats a semiconductor wafer by using light irradiation from a lamp such as a halogen lamp or an arc lamp instead of a batch type electric furnace. Annealing devices are widely used in various processes. The lamp annealing apparatus includes a heat treatment furnace 10 having an opening 12 on the front side for carrying in and carrying out the semiconductor wafer W as shown in FIG. .

[0003] The furnace wall of the heat treatment furnace 10 is formed of a material having infrared transmittance, for example, quartz glass.
On the opening 12 side of the heat treatment furnace 10, a furnace port block 14 connected to the heat treatment furnace 10 is provided. Furnace block 1
4 is closed by a gate valve 16 so that it can be opened and closed. On the inner surface side of the gate valve 16, a wafer W
Is horizontally fixed, and the gate valve 16 reciprocates in the horizontal direction, whereby the wafer W supported by the susceptor 18 is loaded into the heat treatment furnace 10 and the heat treatment furnace 10 is carried out. When the gate valve 16 moves toward the heat treatment furnace 10 and abuts on the furnace opening block 14, the front opening of the furnace opening block 14 is closed and the susceptor 1 is closed.
The wafer W supported by 8 is accommodated in a predetermined position in the heat treatment furnace 10.

In the upward and downward directions of the heat treatment furnace 10, respectively,
A light irradiation light source 20 composed of a lamp group such as a halogen lamp and an arc lamp is disposed facing the upper wall surface and the lower wall surface of the heat treatment furnace 10. Reflectors (reflecting plates) 22a and 22b are arranged behind each light source 20 and on both sides (front and opposite sides of the paper) and rear of the heat treatment furnace 10 so as to surround the heat treatment furnace 10. The inner surfaces of the respective reflectors 22a and 22b are subjected to mirror polishing or the like so that light can be reflected efficiently. The light irradiation light source 20
May be arranged only on the upper side of the heat treatment furnace 10.

[0005] The heat treatment furnace 10 has a gas inlet 2
The gas introduction passage 24 is connected to a processing gas supply source such as nitrogen through a gas introduction hole 26 formed in the rear reflector 22b. On the other hand, a gas exhaust path 28 is formed in the furnace opening block 14. In order to keep the airtightness inside the heat treatment furnace 10 high, O-rings 30 are attached to the furnace opening block 14 and the rear reflector 22b, respectively.

In the lamp annealing apparatus having the above-described structure, when the wafer W supported by the susceptor 18 is inserted into the heat treatment furnace 10 and the opening surface of the furnace port block 14 is closed by the gate valve 16, gas is introduced. A processing gas such as nitrogen is introduced into the heat treatment furnace 10 through a passage 24,
The inside of the heat treatment furnace 10 is purged and exhausted through the gas exhaust passage 28. Then, power is supplied to the upper and lower light irradiation light sources 20 so that the wafer W is heated to a desired temperature programmed in advance by a wafer temperature detection device and a temperature controller (not shown), and the wafer W is heated by the light irradiation. Is done. When the heat treatment is completed, the wafer W is cooled to a desired temperature in the heat treatment furnace 10 and then unloaded from the heat treatment furnace 10.

[0007] By the way, for example, a BPSG film (boron / boron) is used by using the above-described single-plate type lamp annealing apparatus.
When a reflow process of a phosphorus-doped glass film) or a sintering process of an aluminum wiring film is performed, components in the film of the wafer W being heated evaporate, and the evaporated substance is deposited on the inner wall surface of the heat treatment furnace 10. And so on.
Then, as the number of processed wafers increases, the wall surface of the heat treatment furnace 10 becomes clouded, and a part of the light beam from the light source 20 for light irradiation is blocked by the wall surface of the heat treatment furnace 10.
Inconveniences such as a decrease in the amount of light applied to the light source are caused. In particular, the gas in the heat treatment furnace 10 naturally convects due to the heating of the wafer W, and the evaporant from the wafer W rises,
Evaporated substances are remarkably adhered to a portion of the inner wall surface of the heat treatment furnace 10 corresponding to a position directly above the wafer W. As a result, heat treatment furnace 1
0 fogging on the inner wall surface, heat treatment furnace 1
Heat treatment furnace 10 with the complicated flow of gas
Depending on the location of the inner wall surface, the cloudiness may become uneven. As described above, when fogging occurs on the inner wall surface of the heat treatment furnace 10, the amount of light actually irradiated onto the wafer W surface partially decreases,
The temperature uniformity on the surface of the wafer W is impaired, and the heat treatment quality is reduced.

In order to avoid the above-mentioned inconveniences, conventionally, the number of processed wafers is determined in advance by evaluating the results of the heat treatment of the wafer to obtain a level at which the uniformity of the processing becomes unacceptable. When the number reaches the predetermined number, the heat treatment furnace 10 is removed from the apparatus, and the heat treatment furnace 1 is removed.
After the inner wall surface of No. 0 was washed to remove the fogging, the heat treatment furnace 10 was attached to the apparatus again, and the heat treatment operation was restarted.

[0009]

However, according to the conventional method of removing the heat treatment furnace 10 from the apparatus and cleaning it, the upper reflector 22a is opened and the heat treatment furnace 10 is removed.
Is pulled up and removed, and after cleaning the inner wall surface of the heat treatment furnace 10, the heat treatment furnace 10 is mounted again, and a series of operations such as closing the upper reflector 22a takes time. Further, after the heat treatment furnace 10 is attached, it is necessary to perform an operation for confirming the airtightness in the heat treatment furnace 10. For these reasons, the non-operation time of the heat treatment apparatus becomes longer,
There is a problem that the operation efficiency of the device is reduced.

The present invention has been made in view of the above circumstances, and a substance evaporated from a substrate during heat treatment adheres to an inner wall surface of a heat treatment furnace to cause fogging on the inner wall surface. As a result, the evaporation material adheres remarkably to the portion of the inner wall surface just above the substrate, resulting in fogging of the substrate shape on the inner wall surface of the heat treatment furnace and unevenness of the fog depending on the location of the inner wall surface of the heat treatment furnace. Even if the amount of light actually radiated onto the substrate surface is suppressed from changing by position, the uniformity of temperature on the substrate surface is maintained and the processing uniformity of the substrate is ensured. It is an object of the present invention to provide a light irradiation type heat treatment apparatus for a substrate capable of improving the operation efficiency of the apparatus by reducing the frequency of cleaning work of the heat treatment furnace.

[0011]

The invention according to claim 1 is
A heat treatment furnace in which a furnace wall is formed of a light transmissive material, a substrate is carried into the inside, and held in a horizontal position, and light irradiation heating disposed at least at an upper surface of the substrate held in the heat treatment furnace And a light diffusing means disposed between at least the upper surface of the substrate held in the heat treatment furnace and the light irradiation heating means.

According to a second aspect of the present invention, in the light irradiation type heat treatment apparatus of the first aspect, the light diffusing means has a size equal to or larger than a substrate in plan view.

According to a third aspect of the present invention, there is provided the light irradiation type heat treatment apparatus according to the first or second aspect, wherein light diffusion processing is performed between an outer wall surface of the heat treatment furnace and the light irradiation heating means. A plate is interposed, and the plate is used as the light diffusing means.

According to a fourth aspect of the present invention, in the light irradiation type heat treatment apparatus according to the first or second aspect, the furnace wall of the heat treatment furnace facing at least the upper surface of the substrate held therein is light-diffused. The light diffusing means is characterized by being formed from a processed quartz plate.

According to a fifth aspect of the present invention, in the light irradiation type heat treatment apparatus of the first or second aspect, at least an upper surface of the substrate held inside the heat treatment furnace and an inner wall surface of the heat treatment furnace are provided. It is characterized in that a quartz plate subjected to light diffusion processing is interposed, and this is used as the light diffusion means.

In the light irradiation type heat treatment apparatus according to the first aspect of the present invention, the substance evaporated from the substrate during the heat treatment adheres to the inner wall surface of the heat treatment furnace to cause fogging on the inner wall surface. However, as a result of the vaporized substance remarkably adhering to the portion corresponding directly above the substrate, the substrate shape becomes cloudy on the inner wall surface of the heat treatment furnace, or even if the clouding method becomes uneven depending on the location of the inner wall surface of the heat treatment furnace, The light emitted from the light irradiation heating means is diffused in multiple directions by the light diffusion means, and the scattered light is irradiated on the substrate surface, so that the light from the light irradiation heating means is directly irradiated on the substrate surface. Therefore, the influence of the irradiation light amount distribution due to the fogging of the evaporant attached to the inner wall surface of the heat treatment furnace is reduced by half. For this reason, the change in the amount of light actually irradiated on the substrate surface due to the position is suppressed, the uniformity of the temperature on the substrate surface is maintained, and the uniformity of the processing is ensured. The frequency of cleaning work of the heat treatment furnace is reduced.

In the light irradiation type heat treatment apparatus according to the second aspect of the present invention, the light from the light irradiation and heating means does not directly irradiate the substrate surface, and the scattered light diffused by the light diffusion means is applied to the substrate surface. Will be irradiated. Therefore, the above operation of the invention according to claim 1 is optimally performed.

In the light irradiation type heat treatment apparatus according to the third aspect of the present invention, the light radiated from the light irradiation heating means is emitted by a quartz plate interposed between the outer wall surface of the heat treatment furnace and the light irradiation heating means. In the direction, and the scattered light is irradiated on the substrate surface.

In the light irradiation type heat treatment apparatus according to the present invention, the light emitted from the light irradiation heating means is diffused in multiple directions by the quartz plate itself forming the furnace wall of the heat treatment furnace.
The diffused light is applied to the substrate surface.

In the light irradiation type heat treatment apparatus according to the fifth aspect of the present invention, the light emitted from the light irradiation heating means is transmitted between the upper surface of the substrate held inside the heat treatment furnace and the inner wall surface of the heat treatment furnace. The light is diffused in multiple directions by the inserted quartz plate, and the scattered light is applied to the substrate surface.

[0021]

Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an embodiment of the present invention and is a schematic side sectional view of a lamp annealing apparatus which is a light irradiation type heat treatment apparatus. In FIG. 1 (the same applies to FIGS. 3 and 4 to be described later), the portions denoted by the same reference numerals as those used in FIG. 5 have the same functions as the respective constituent elements of the lamp annealing apparatus described based on FIG. , And the description thereof is omitted here.

In the lamp annealing apparatus shown in FIG. 1, a light formed of an infrared transmitting material, for example, quartz glass and subjected to a light diffusion process is provided between the outer wall surface of the heat treatment furnace 10 and the light source 20 for light irradiation. Diffusing plates (diffuse plates) 32a, 32b
Are disposed above and below the heat treatment furnace 10, respectively.
The light diffusing plates 32a and 32b are provided with supports 34a and 3a fixed to the heat treatment furnace 10 and the rear reflector 22b, respectively.
4b, so that it can be easily removed when the heat treatment furnace 10 is washed. The light diffusing plates 32a and 32b are formed, for example, by polishing the surface of a quartz plate to form a rough surface having fine irregularities, or by processing the quartz plate so as to include many fine bubbles. Produced. The sizes of the light diffusion plates 32a and 32b are preferably equal to or larger than the wafer W in plan view, and as shown in a plan view in FIG. It is more preferable that the size is such that it covers. The light diffusion plate 32
The planar shapes of a and 32b are rectangular in the illustrated example.
A circular shape similar to the wafer W may be used. Further, the light diffusion plate 32a may be provided only on the upper side of the heat treatment furnace 10.

Also in the lamp annealing apparatus having the structure shown in FIG. 1, the substance evaporated from the wafer W during the heat treatment adheres to the inner wall surface of the heat treatment furnace 10 and fogs on the inner wall surface, similarly to the conventional apparatus. . Then, the amount of light actually irradiated on the surface of the wafer W decreases as the number of processed wafers W increases. However, in this apparatus, the light emitted from the light irradiation light source 20 is diffused in multiple directions by the light diffusion plates 32a and 32b, and the scattered light is applied to the surface of the wafer W. Therefore, as compared with the conventional apparatus in which the light from the light irradiation light source 20 is directly irradiated onto the surface of the wafer W, the influence of the irradiation light amount distribution due to the fogging of the vaporized substance attached to the inner wall surface of the heat treatment furnace 10 is reduced by half. become. As a result, a change in the amount of light actually irradiated onto the surface of the wafer W depending on the position is suppressed, and the number of processed wafers W reaches a level at which the uniformity of the processing becomes unacceptable. Therefore, it is possible to lengthen the interval at which the cleaning operation of the heat treatment furnace 10 is performed.

FIG. 3 is a schematic side sectional view of a lamp annealing apparatus showing another embodiment of the present invention. In this apparatus, among the furnace walls of the heat treatment furnace 36 formed of a material having infrared transmittance, for example, quartz glass, the heat treatment furnace 3 is used.
The upper and lower furnace walls 38a and 38b interposed between the wafer W accommodated in the inside of the tube 6 and the light source 20 for light irradiation are formed of light diffusion plates subjected to light diffusion processing. In addition, only the upper furnace wall 38a may be configured by a light diffusion plate subjected to light diffusion processing. The device shown in FIG. 3 can provide exactly the same operation and effect as the device shown in FIG.

Next, the lamp annealing apparatus whose schematic side sectional view is shown in FIG. 4 is provided between the wafer W accommodated in the heat treatment furnace 10 and the inner wall surface of the heat treatment furnace 10, that is, inside the heat treatment furnace 10. Light diffusion plates 40a and 40 formed of an infrared transmitting material such as quartz glass and subjected to light diffusion processing.
b are disposed above and below the wafer W, respectively. Each of the light diffusion plates 40a and 40b is supported by a supporting member 42 attached to the inner wall surface of the heat treatment furnace 10, and when the heat treatment furnace 10 is cleaned, the heat treatment furnace 1
0 can be easily taken out. The size of the light diffusion plates 40a and 40b is preferably equal to or larger than the wafer W in plan view,
As in the case of the apparatus shown in FIGS. 1 and 2, it is more preferable that the size be such that the entire surface of the wafer W is completely covered. The planar shape of the light diffusion plates 40a and 40b may be rectangular, or may be a circle similar to the wafer W. Further, the light diffusion plate 40a may be provided only above the wafer W.

The same operation and effect as those of the apparatus shown in FIG. 1 can be obtained by the apparatus shown in FIG. However, in the apparatus shown in FIG. 4, a considerable amount of the substance evaporated from the upper surface (circuit formation surface) of the wafer W during the heat treatment of the wafer W adheres to the lower surface of the upper light diffusion plate 40a, and the heat treatment furnace 10 The amount adhering to the inner wall surface is reduced. Therefore, when cleaning the heat treatment furnace 10, it is necessary to take out the light diffusion plate 40a (40b) from the inside of the heat treatment furnace 10 for cleaning or replacement at the same time.

[0028]

When the light irradiation type heat treatment apparatus according to the first aspect of the present invention is used, the temperature on the substrate surface can be made uniform as compared with a conventional apparatus in which light from the light irradiation heating means is directly irradiated on the substrate surface. Therefore, the number of substrates to be processed and the uniformity of the processing is ensured and the frequency of the cleaning operation of the heat treatment furnace is reduced, so that the operation efficiency of the apparatus can be improved.

In the light irradiation type heat treatment apparatus according to the second aspect of the present invention, only the diffused light is irradiated on the substrate surface, and the light from the light irradiation heating means is not directly irradiated on the substrate surface. The above-mentioned effect of the invention according to the first aspect is maximized.

According to the light irradiation type heat treatment apparatus of each of the inventions according to claims 3 to 5, the effect of the invention according to claim 1 can be reliably obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional side view of a lamp annealing apparatus as a light irradiation type heat treatment apparatus, showing an example of an embodiment of the present invention.

FIG. 2 is a plan view showing the relationship between the shape and size of a light diffusion plate and a wafer, which are one of the components of the lamp annealing apparatus shown in FIG.

FIG. 3 is a schematic sectional side view of a lamp annealing apparatus showing another embodiment of the present invention.

FIG. 4 is a schematic sectional side view of a lamp annealing apparatus showing still another embodiment of the present invention.

FIG. 5 is a schematic side sectional view showing an example of a configuration of a conventional lamp annealing apparatus.

[Explanation of symbols]

 10, 36 heat treatment furnace 12 heat treatment furnace opening 14 furnace port block 16 gate valve 18 susceptor 20 light irradiation light source 22a, 22b reflector (reflector) 24 gas introduction path 26 gas introduction hole 28 gas exhaust path 30 O-ring 32a, 32b, 40a, 40b Light diffusion plates 34a, 34b, 42 Supports 38a, 38b Upper and lower furnace walls of heat treatment furnace W Semiconductor wafer

Claims (5)

[Claims] 1. A heat treatment furnace in which a furnace wall is formed of a light transmissive material and a substrate is carried into the furnace and held in a horizontal posture, and is disposed facing at least an upper surface of the substrate held in the heat treatment furnace. A light irradiation type heat treatment apparatus for a substrate, comprising: a light diffusion heating means provided with a light diffusion heating means between at least an upper surface of the substrate held in the heat treatment furnace and the light irradiation heating means. A light irradiation type heat treatment apparatus for substrates. 2. The heat treatment apparatus for light irradiation of a substrate according to claim 1, wherein said light diffusion means has a size equal to or larger than the substrate in plan view. 3. The light diffusion means is a quartz plate which is interposed between an outer wall surface of the heat treatment furnace and the light irradiation heating means and has been subjected to light diffusion processing. Light irradiation type heat treatment equipment for substrates. 4. A light diffusion process in which a furnace wall of the heat treatment furnace is formed of a quartz plate, and wherein the light diffusion means forms a furnace wall of the heat treatment furnace facing at least an upper surface of a substrate held therein. The light irradiation type heat treatment apparatus for a substrate according to claim 1 or 2, wherein the substrate is a quartz plate to which a heat treatment is applied. 5. The light diffusion means is a quartz plate interposed between at least an upper surface of a substrate held in the heat treatment furnace and an inner wall surface of the heat treatment furnace and subjected to light diffusion processing. The light irradiation type heat treatment apparatus for a substrate according to claim 1.