JP2002252180A - Heat treatment apparatus for substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device which can quickly cool a substrate on the high temperature side. SOLUTION: This heat treatment device is equipped with a mobile cooling plate 52, which is supported capably of reciprocating between the cooling position, where it contacts wit or draws near the wafer W retained within a heat treatment furnace 10 and the waiting position, where it contacts with or draws near the reflecting plate 44 constituting the lower furnace wall of the heat treatment furnace, and a mechanism 54 winch raises and lowers its cooling plate, and is further provided with a gas inlet path 56 which introduces gas between the mobile cooling plate and the reflecting plate in the waiting position. The mobile cooling plate is shifted to the cooling position, immediately after heat treatment of the wafer, and also the gas is introduced between the mobile cooling plate and the reflecting plate through the gas inlet path at that time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for a semiconductor wafer, a glass substrate for a liquid crystal display, a glass substrate for a photomask, a substrate for an optical disk, etc. (hereinafter referred to as "substrate"). The present invention relates to a substrate heat treatment apparatus which carries in and heats a substrate by light irradiation.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process,
Various types of single-wafer heat treatment apparatuses, such as a lamp annealing apparatus and a CVD apparatus, which heat a substrate by carrying a substrate, for example, a semiconductor wafer one by one, into a heat treatment furnace and irradiating the substrate with light, etc. Widely used in the process.

By the way, in order to achieve high integration of semiconductor devices, high speed operation as well as miniaturization of devices are important factors. For example, for high-speed operation of a diode, P
Since it is necessary to make the depth of the N junction shallow, it is necessary to electrically activate ions of B, As, P, etc. implanted in the wafer without diffusion. for that purpose,
The temperature of the wafer is rapidly raised to the ion activation temperature (for example, 1
(50 ° C./sec), and a device for rapidly cooling the wafer to a temperature at which ions do not diffuse after the temperature is raised is required.

[0004] The lamp annealing apparatus has been developed from the above-mentioned necessity, and a conventional method for cooling a wafer in this lamp annealing apparatus is to turn off a lamp as a heating source and to cool the wafer naturally. Had been taken. Also, compressed air or nitrogen is blown out from the nozzle of the gas injection device toward the outer wall surface of the heat treatment furnace holding the heat-treated wafer inside, and the furnace wall of the heat treatment furnace is cooled to indirectly connect the wafer in the furnace. There has been a method of cooling down.

[0005]

However, it is difficult to rapidly cool the wafer by the method of naturally cooling the wafer. In addition, the method of indirectly cooling the wafer in the furnace by cooling the furnace wall of the heat treatment furnace improves the throughput by rapidly cooling the wafer to the removal temperature (for example, 300 ° C. to 500 ° C.) from the furnace. In this method, it is difficult to rapidly cool the wafer to such an extent that diffusion of ions is suppressed. That is, in order to form a shallow PN junction on a wafer, a required amount of ions are implanted shallowly into the wafer using a low-voltage ion implanter, and the wafer is subjected to an ion activation temperature (eg, 1000
(° C.) at a high speed, and then it is necessary to cool the wafer to a temperature (about 700 ° C.) in which ion diffusion is suppressed as much as possible. However, in the conventional method of indirectly cooling the wafer, it is possible to increase the cooling rate mainly on the low-temperature side and to shorten the time for cooling the wafer to the removal temperature, but on the high-temperature side, diffusion of ions is minimized. The time for cooling the wafer to a temperature that can be suppressed cannot be shortened.

The present invention has been made in view of the above circumstances, and has as its object to provide a substrate heat treatment apparatus capable of rapidly cooling a substrate on a high temperature side.

[0007]

According to the first aspect of the present invention,
A heat treatment furnace in which at least an upper furnace wall is formed of a light-transmitting material, and a substrate is carried in and held therein; and the heat treatment furnace is disposed so as to face at least an upper surface of the substrate held in the heat treatment furnace; A heating means for irradiating the substrate with light through a furnace wall formed of a transparent material to heat the substrate, wherein a cooling position in contact with or close to the substrate held in the heat treatment furnace; A movable cooling plate supported so as to be able to reciprocate between a lower furnace wall of the heat treatment furnace and a contact position or an adjacent standby position, a driving unit for reciprocating the movable cooling plate, and the movable cooling plate in the standby position. Gas introduction means for introducing a gas between the lower furnace wall of the heat treatment furnace, and the gas introduction means when the movable cooling plate is moved from the standby position to the cooling position by the driving means. And Gosuru control means, and further comprising a.

According to a second aspect of the present invention, in the heat treatment apparatus according to the first aspect, the movable cooling plate is formed of quartz glass.

According to a third aspect of the present invention, in the heat treatment apparatus according to the first or second aspect, the movable cooling plate is provided with five movable cooling plates.
It is characterized by being cooled to a temperature of 0 ° C. or less.

According to a fourth aspect of the present invention, in the heat treatment apparatus according to any one of the first to third aspects, the lower furnace wall of the heat treatment furnace is water-cooled, and the movable cooling is performed on the water-cooled lower furnace wall. The movable cooling plate is cooled by contacting or approaching the plate.

In the heat treatment apparatus according to the first aspect of the present invention, the substrate is heat-treated by irradiating the substrate held in the heat treatment furnace with light by the heating means. Before this heat treatment was performed, the movable cooling plate was
It is stopped and cooled at a standby position in contact with or close to the lower furnace wall of the heat treatment furnace. Immediately after the heat treatment is completed, the heating of the substrate by the heating means is stopped, and the driving means and the gas introduction means are respectively operated by the control means, and the movable cooling plate at the standby position and the heat treatment furnace are operated by the gas introduction means. Gas is introduced between the lower furnace wall and the movable cooling plate is moved from the standby position to the cooling position by the driving means. As described above, when the movable cooling plate is moved from the standby position to the cooling position, gas is introduced between the movable cooling plate and the lower furnace wall of the heat treatment furnace, so that the movable cooling plate moves and the movable cooling plate moves. Due to the vacuum state formed between the plate and the lower furnace wall of the heat treatment furnace, the movable cooling plate does not remain in close contact with the lower furnace wall of the heat treatment furnace, or the movement of the movable cooling plate is not suppressed. Then, the movable cooling plate quickly moves from the standby position to the cooling position, contacts or approaches the substrate, rapidly removes the heat of the substrate, and rapidly cools the substrate on the high temperature side.

In the heat treatment apparatus according to the second aspect of the present invention, since the movable cooling plate is formed of quartz glass, even if the movable cooling plate is interposed between the substrate and the lower furnace wall of the heat treatment furnace, the heat treatment is performed. There is no problem in measuring the temperature of the substrate or the substrate supporting member by the radiation thermometer or the like performed on the lower furnace wall of the furnace.

In the heat treatment apparatus according to the third aspect of the present invention, the movable cooling plate is cooled to a temperature of 50 ° C. or less,
The cooling effect of the substrate by the movable cooling plate is reliably obtained.

In the heat treatment apparatus according to the fourth aspect of the invention, the movable cooling plate is reliably cooled at the standby position by contacting or approaching the water-cooled lower furnace wall.

[0015]

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, in which a schematic configuration of a lamp annealing apparatus, which is one of apparatuses for heat-treating a substrate such as a semiconductor wafer, is shown by a cut end face.

The lamp annealing apparatus includes a heat treatment furnace 10 having an opening 12 for carrying in and carrying out the semiconductor wafer W. The opening 12 of the heat treatment furnace 10
The shutter 14 closes openably and closably. At least an upper furnace wall of the heat treatment furnace 10 serves as a light incident window 16. The light entrance window 16 which is a partition wall between the reaction chamber 18 of the heat treatment furnace 10 and a lamp house 20 (not shown in detail) serving as a heating source is formed of a material having infrared transmittance, for example, quartz glass. The radiant light emitted from the lamp of the house 20 is transmitted efficiently. The light incident window 16 is incorporated in a quartz glass window holder 22 so as to be detachable, sealed by an O-ring 24, and disposed above the reaction chamber 18.

Although not shown, a support arm for supporting the wafer W in a horizontal position is provided on the surface of the heat treatment furnace 10 facing the opening 12, and the wafer W before heat treatment is moved from the alignment unit to the heat treatment furnace 10 A wafer loading / unloading device for loading the wafer W into and out of the heat treatment furnace 10 is provided.

The inside of the heat treatment furnace 10 contains silicon carbide (Si)
A wafer support ring 26 formed by C) or the like is disposed, and the wafer support ring 26 is fixed in a horizontal posture to an upper end portion of a wafer support cylindrical holder 28 formed of quartz glass. The wafer support cylindrical holder 28 holds the wafer W
Is held on a wafer rotating mechanism 32 via an adjuster 30 for adjusting the horizontal state of the device. The wafer W is supported on the wafer support ring 26 and is rotated by the wafer rotation mechanism 32. Further, a plurality of (for example, three) support pins 34 for supporting the wafer W in contact with the lower surface of the wafer W are provided.
Wafer push-up mechanism 36 for vertically reciprocating 4
Is provided.

The wafer W before the heat treatment is carried into the heat treatment furnace 10 while being supported by the support arm of the wafer carry-in / out device.
After being transferred onto the raised support pins 34 of the wafer lifting mechanism 36, the support pins 34 are lowered,
It is placed on the wafer support ring 26 and is supported in a horizontal posture. Further, the wafer W after the heat treatment is lifted from above the wafer support ring 26 by raising the support pins 34 of the wafer push-up mechanism 36, and then is transferred from above the support pins 34 onto the support arm of the wafer loading / unloading device. The wafer is transferred out of the heat treatment furnace 10 by the wafer transfer device.

In the inside of the heat treatment furnace 10, a plurality of gas blowing holes formed of a material having an infrared transmission property, for example, quartz glass, are opposed to the upper surface of the wafer W supported on the wafer support ring 26. Is provided with a shower plate 38 in which is drilled. A space between the shower plate 38 and the light incident window 16 is a gas introduction chamber 40 into which a reaction gas is introduced. The gas introduction chamber 40 is connected to a reaction gas supply source through a gas introduction path 42. I have. Then, the gas is supplied from the reaction gas supply source to the gas introduction chamber 4.
The reaction gas introduced into the chamber 0 is uniformly blown out to the entire upper surface of the wafer W on the wafer support ring 26 through a plurality of gas blowing holes of the shower plate 38.

The lower furnace wall of the heat treatment furnace 10 is constituted by a reflection plate 44. The reflection plate 44 is made of stainless steel, and the surface facing the wafer W is polished to a mirror surface to obtain a high reflectance. The reflector 44 has a cooling water passage 46 formed therein.
Is cooled by flowing cooling water into the passage 46. Two kinds of radiation thermometers, that is, a radiation thermometer 48 for detecting the temperature of the support ring and a radiation thermometer 50 for detecting the temperature of the wafer are attached to the reflection plate 44. The support ring temperature detecting radiation thermometer 48 is installed such that the focal point is at a position on the outer side of the wafer W on the wafer support ring 26 by about 5 mm on the outer side. The radiation thermometers 50 for detecting the wafer temperature are mounted at a plurality of positions, for example, positions substantially corresponding to the center of the wafer W, positions corresponding to the radius of the wafer W, and positions corresponding to the outer periphery of the wafer W.

A movable cooling plate 52 is provided on the surface of the reflection plate 44 facing the wafer W. Movable cooling plate 52
Is formed of, for example, quartz glass. The movable cooling plate 52 is held by a cooling plate raising and lowering mechanism 54 and is moved at high speed in a vertical direction by a driving device such as an air cylinder of the cooling plate raising and lowering mechanism 54, and is brought into contact with the wafer W on the wafer support ring 26. Alternatively, it reciprocates between an adjacent upper cooling position and a standby position in contact with or in proximity to the reflector 44. Further, a gas introduction path 56 for supplying a gas, for example, nitrogen gas, between the reflection plate 44 and the movable cooling plate 52 is provided at a central position of the reflection plate 44,
The gas introduction path 56 is connected to a nitrogen gas supply device (not shown). Further, a controller (not shown) for controlling the cooling plate raising / lowering mechanism 54 and the nitrogen gas supply device is provided, and at the same time or shortly before the lamp of the lamp house 20 is turned off after the heat treatment of the wafer W is completed. Then, the cooling plate up-down mechanism 54 and the nitrogen gas supply device are operated by a control signal from the controller, and the movable cooling plate 52 is moved at high speed from the standby position to the cooling position.

The reflecting plate 44 and the movable cooling plate 5
2 and cooling plate up / down mechanism 54, and wafer rotation mechanism 3
2. The adjuster 30, the wafer support cylindrical holder 28, the wafer support ring 26, and the like are integrally connected to the metal bellows 58, and are driven by an up-down mechanism 60 such as a reflector, thereby changing the volume of the reaction chamber 18. It has a structure that can be made. There are three stages of this change in volume: upper wafer position A, middle wafer position B, and lower wafer position C, depending on the position of wafer W. The upper wafer position A is a position during heat treatment of the wafer W, and the middle wafer position B is
The gas stored between the wafer W and the movable cooling plate 52 is purged, and the lower wafer position C is a position at which the wafer W is taken in and out of the heat treatment furnace 10.

An upper exhaust port 62 for exhausting the wafer W during heat treatment is formed in the upper part of the heat treatment furnace 10. Then, during the heat treatment of the wafer W, the reaction gas is introduced into the gas introduction chamber 40 through the gas introduction passage 42, and the reaction gas of the wafer W on the wafer support ring 26 is introduced through a plurality of gas outlets of the shower plate 38. After being blown out to the entire upper surface, the wafer W is discharged from the outer periphery of the wafer W to the outside of the heat treatment furnace 10 through the upper exhaust port 62 through the upper surface of the wafer support ring 26.

A purge gas for introducing a reaction gas into the heat treatment 10 is provided below the upper exhaust port 62 in order to purge gas accumulated between the wafer W and the movable cooling plate 52 at the wafer middle position B. An inlet 64 is formed. Further, a middle exhaust port 66 is formed below the purge gas inlet 64. The middle exhaust port 66 is connected to the reaction chamber 18.
And the periphery of the wafer rotation mechanism 32 by a gas flow. That is, the gas (sometimes a corrosive gas) in the reaction chamber 18 is prevented from flowing around the wafer rotation mechanism 32 and the gas (including particulate dust) around the wafer rotation mechanism 32 is The gas is exhausted while being adjusted by the middle exhaust to prevent soaring.

The gas purge port 6 is used to quickly exhaust particulate dust that may be discharged from the wafer rotating mechanism 32 or the metal bellows 58 to the outside of the heat treatment furnace 10.
8 and a lower exhaust port 70 are formed. Normally, nitrogen gas is introduced from the gas purge port 68, and the gas in the reaction chamber 18 flows around the wafer rotation mechanism 32 by increasing or decreasing the space volume of the reaction chamber 18 with the vertical movement of the reflection plate 44. Conversely, the reaction chamber 18 is prevented from flowing around the wafer rotation mechanism 32 into the reaction chamber 18.
The flow rate of the introduced gas is adjusted in accordance with the increase or decrease in the space volume of. Further, in order to prevent air from being drawn into the reaction chamber 18 from the wafer loading / unloading opening 12 due to opening and closing of the shutter 14, a purge gas such as nitrogen gas introduced into the heat treatment furnace 10 from the purge gas inlet 64 is supplied to the furnace port. A furnace port exhaust port 72 for flowing in the direction is provided.

Reference numeral 74 in FIG. 1 indicates a vertical mechanism 6 such as a reflector.
This is a stopper for preventing the wafer W moved in the vertical direction by 0 from further rising above the wafer upper position C. Reference numeral 76 denotes a radiation thermometer 48, 5 when the wafer W is being heat-treated at the wafer upper position C.
0 is a light-blocking ring for blocking stray light of the lamp so that the lamp light from the lamp house 20 does not go around to 0;
The light shielding ring 76 is formed in a ring shape using SiC or the like.

In the lamp annealing apparatus having the above-described structure, the heat treatment of the wafer W is performed as usual by irradiating the wafer W with light from the lamp of the lamp house 20 to heat the wafer W. Prior to the heat treatment and throughout the heat treatment, the movable cooling plate 52 is stopped at a standby position in contact with or close to the reflection plate 44 as shown by a solid line in FIG. The movable cooling plate 52 is cooled to substantially the same temperature as the water-cooled reflection plate 44, for example, a temperature of 30 ° C. to 50 ° C.

When the lamp of the lamp house 20 is turned off after the heat treatment of the wafer W is completed, at the same time or shortly before that, the controller moves the cooling plate up and down mechanism 5.
4 and the nitrogen gas supply device are respectively operated to introduce nitrogen gas between the movable cooling plate 52 and the reflecting plate 44 through the gas introduction path 56, and the movable cooling plate 52 moves upward from the standby position. Let me do. And
When nitrogen gas is introduced between the movable cooling plate 52 and the reflecting plate 44, the movable cooling plate 52 is easily separated from the reflecting plate 44, and is quickly raised by the air cylinder of the cooling plate vertical mechanism 54. Quickly move to the cooling position and stop as shown by the dashed line. As described above, the low-temperature movable cooling plate 52 comes into contact with or approaches the wafer W on the wafer support ring 26, so that the movable cooling plate 52
, And the wafer W is rapidly cooled on the high temperature side.

FIG. 3 shows the temperature drop of each wafer W between when the movable cooling plate 52 is brought close to the wafer W immediately after the heat treatment to rapidly cool the wafer W and when the wafer W is naturally cooled. It is the figure which compared a situation. A solid line a indicates a case where the wafer W is cooled by the movable cooling plate 52, and a broken line b indicates a case where the wafer W is naturally cooled. As shown by the solid line a, when the wafer W is cooled by the movable cooling plate 52, the wafer W is heated to a high temperature side (700 ° C to 10 ° C).
(00 ° C.), the cooling rate is increased, and cooling is performed in a short time to a temperature of about 700 ° C., which is a temperature at which diffusion of ions is suppressed as much as possible.

On the low temperature side of about 500 ° C. or lower, cooling the wafer W with the movable cooling plate 52 is slower than cooling it naturally. This is because the temperature of the movable cooling plate 52 rises on the high temperature side due to radiant heat from the wafer W, and thereafter, on the low temperature side, the wafer W and the movable cooling plate 52 are naturally cooled together.
As a result, the time required for cooling the wafer W to the removal temperature from the inside of the furnace becomes longer. However, since the purpose of the apparatus of the present invention is to increase the cooling rate on the high temperature side, there is no problem. Further, the temperature of the wafer W is set to 500 ° C.
When the temperature is lowered to about 700 ° C., the movable cooling plate 52
May be moved downward to return to the original standby position.

[0033]

According to the heat treatment apparatus for a substrate according to the first aspect of the present invention, the substrate can be rapidly cooled on a high temperature side. For example, in a diode manufacturing process, a wafer can be rapidly cooled to an ion activation temperature. After the temperature is raised, the wafer can be rapidly cooled to a temperature at which ions do not diffuse.

In the heat treatment apparatus according to the second aspect of the present invention, even if a movable cooling plate is interposed between the substrate and the lower furnace wall of the heat treatment furnace, the substrate is measured by a radiation thermometer or the like performed on the lower furnace wall of the heat treatment furnace. It does not hinder the measurement of the temperature of the substrate support member.

In the heat treatment apparatus according to the third aspect of the present invention, the substrate can be reliably cooled rapidly on the high temperature side.

In the heat treatment apparatus according to the fourth aspect of the present invention, the movable cooling plate is reliably cooled to a desired temperature.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of the present invention, and is a view showing a schematic configuration of a lamp annealing apparatus as one of heat treatment apparatuses for a substrate by a cut end face.

FIG. 2 is an enlarged longitudinal sectional view of a part of the device shown in FIG.

FIG. 3 is a diagram comparing the temperature drop of each wafer when the wafer immediately after the heat treatment is rapidly cooled using the apparatus according to the present invention and when the wafer is naturally cooled.

[Explanation of symbols]

 W Semiconductor wafer 10 Heat treatment furnace 12 Wafer loading / unloading opening 14 Shutter 16 Light entrance window 18 Reaction chamber 20 Lamp house 26 Wafer support ring 28 Wafer support cylindrical holder 30 Adjuster 32 Wafer rotation mechanism 36 Wafer push-up mechanism 38 Shower plate 40 Gas introduction Chambers 42, 56 Gas introduction path 44 Reflector plate forming lower furnace wall of heat treatment furnace 46 Cooling water passage 48, 50 Radiation thermometer 52 Movable cooling plate 54 Cooling plate vertical mechanism 58 Metal bellows 60 Reflecting plate vertical mechanism 62, 66 , 70 exhaust port 64 purge gas inlet port 68 gas purge port 72 furnace port exhaust port

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kowa Takahashi 4-chome Tenjin Kitamachi 1-chome, Kamimachi-ku, Kyoto 1F, Tenjin Kitamachi, Horikawa-dori Teranouchi, Kamigyo-ku, Tokyo 1 Dainippon Screen Mfg. Co., Ltd. F term (reference) 5F045 AC15 DP03 EB02 EC03 EF05 EM10

Claims (4)

[Claims] At least an upper furnace wall is formed of a light-transmitting material, and a heat treatment furnace in which a substrate is carried in and held therein, and is disposed facing at least an upper surface of the substrate held in the heat treatment furnace. A heating means for irradiating the substrate with light through a furnace wall formed of the light-transmissive material to heat the substrate, wherein the substrate is in contact with or close to the substrate held in the heat treatment furnace. A movable cooling plate supported so as to reciprocate between a cooling position to perform and a standby position in contact with or approaching a lower furnace wall of the heat treatment furnace; driving means for reciprocating the movable cooling plate; Gas introduction means for introducing gas between the movable cooling plate and the lower furnace wall of the heat treatment furnace; controlling the driving means, and the driving means moving the movable cooling plate from a standby position to a cooling position. Heat treatment apparatus of the substrate and control means for controlling to actuate the gas introduction means in which moving, further comprising a said. 2. The apparatus according to claim 1, wherein the movable cooling plate is formed of quartz glass. 3. The substrate heat treatment apparatus according to claim 1, wherein said movable cooling plate is cooled to a temperature of 50 ° C. or lower. 4. The lower furnace wall of the heat treatment furnace is water-cooled, and the movable cooling plate contacts or approaches the water-cooled lower furnace wall to cool the movable cooling plate.
A heat treatment apparatus for a substrate according to any one of the above.