JP2000269155A - Heat processor and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold in-plane uniformly of high wafer temperature, for example, from increase in temperature to the end of heating in a heating processing of a semiconductor wafer, and radiate heat at a high speed in a processor after the end of heat processing. SOLUTION: There are provided a hole part and a pin 23, moving vertically in a hole part 24 by an electromagnetic coil 22 on an inner wall face of a processing container 21 upwardly of a wafer counterposed to a heating lamp 61, for constituting a reflection part 20. When temperatures of a substrate to be processed W is increased, a pin at a position corresponding to the margin part of the substrate to be processed is recessed to lower the reflectance, and at the heat treatment at a prescribed temperature, reflectance at the center part is lowered conversely, so that the in-plane uniformity of wafer temperatures is enhanced. Furthermore, after the end of the heat processing, all pins of the reflection part 20 are recessed, and the reflectance is minimized, so that the substrate to be processed is radiated of heat at a high rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus and method for performing heat treatment on a substrate to be processed such as a semiconductor wafer by, for example, a heating lamp.

[0002]

2. Description of the Related Art In a process of manufacturing a semiconductor device, for example, a process of converting a semiconductor into an n-type or a p-type is performed by thermal diffusion. As a device for performing such a heat treatment, for example, a device for heating a wafer using a laser or an electron beam, a device using a resistance heater, and a device for heating using lamp heat are known.

[0003] Among them, a lamp annealing apparatus that performs heating by lamp heat is known to be excellent in mass productivity and capable of increasing the temperature at a high speed. A conventional lamp annealing apparatus is shown in FIG.

A mounting table 1 made of quartz is placed in a processing vessel 11.
2 is provided, and an inert gas is supplied by a gas supply pipe 16. Heat rays from the heating lamp 14 are irradiated on the wafer W through the transmission window 13 and the mounting table 12. Wafer W placed on mounting table 12
Is heated by the heating lamp 14 from the back side, and the heat rays transmitted through the wafer W and the mounting table 12 and incident on the inside of the processing vessel 11 are reflected on the inner wall of the processing vessel 11, and the reflected heat rays are also received. Is heated. The temperature of the wafer W is controlled by feeding back, for example, the temperature of the back surface of the wafer detected by a thermometer such as a thermocouple to the lamp power of the heating lamp 14.

[0005]

By the way, in order to secure the in-plane temperature uniformity of the wafer W, for example, a heating lamp or the like capable of controlling heat generation for each concentric circle is used so that the temperature of the wafer W can be adjusted in the radial direction. Although some ideas have been devised,
At the current state, it is difficult to ensure high in-plane uniformity because there is a large difference in the balance between the heat generation amount and the heat release amount between the central portion and the peripheral portion of the wafer.

For example, the temperature rise and fall characteristics of the central portion and the peripheral portion of the wafer W when the temperature of the wafer W is increased, heated, and lowered are shown in FIG. As shown, at the set process temperature, the temperature at the peripheral portion of the wafer is lower than that at the central portion, and it can be seen that there is a temperature difference within the same wafer. on the other hand,
As shown in FIG. 3, in the conventional lamp annealing apparatus, when the temperature is raised to reach a predetermined process temperature (1000 ° C. in FIG. 3), the central portion of the wafer is opposite to the heat treatment at the process temperature. It is lower than the periphery. This is because when the amount of heat generated from the heating lamp is stabilized, the amount of heat radiation at the peripheral portion of the wafer is inevitably increased, and when the temperature rises, the amount of heat absorbed from the peripheral portion is large. Here, with the miniaturization of devices in the future, the in-plane uniformity of the wafer temperature at the time of temperature rise as well as the heat treatment at the process temperature greatly affects the film quality, and a method for solving this problem is required. I have.

In some high-speed heating apparatuses, a heating lamp is provided on the upper side of the wafer in addition to the heating lamp on the lower side of the wafer as shown in the conventional lamp annealing apparatus. Since it is difficult to secure the temperature uniformity, it is necessary to provide, for example, a mechanism for rotating a heating lamp, and there has been a problem that the apparatus becomes large and complicated.

The present invention has been made in view of the above problems and has been made in order to solve the problem effectively, and has as its object a heat treatment apparatus and a heating method capable of improving the in-plane uniformity of the temperature of a substrate to be processed. Is to provide.

[0009]

According to the present invention, there is provided a processing container provided with a mounting table for a substrate to be processed, a heating source for heating the processing substrate mounted on the mounting table, and a processing source. It is an object of the present invention to provide a heat treatment apparatus comprising: a reflecting portion configured to change a reflectance of a heat ray in order to adjust a temperature distribution of a substrate.

The above-mentioned reflecting portion is provided to face the mounting table, and has a plate-like portion forming a reflecting surface, a plurality of holes formed in the plate-like portion, and is exposed and immersed in these holes. A movable member having a reflecting surface provided at a front end surface thereof, wherein the reflectance is variable by changing a position of the movable member in the hole.

[0011] Further, according to the present invention, after the substrate to be processed is placed on the mounting table and the temperature of the substrate to be processed is started by the above apparatus, the heating process is terminated and the temperature of the substrate to be processed is lowered. The present invention provides a heat treatment method characterized in that the reflectance of the heat ray is changed by the reflection portion during the heat treatment.

According to this heat treatment method, first, when the temperature of the substrate to be processed is raised, the reflectance of the portion corresponding to the peripheral portion of the substrate to be processed is made smaller than the reflectance of the portion corresponding to the central portion of the substrate to be processed. Then, while the substrate to be processed reaches a predetermined process temperature and performs the heat treatment, the reflectance of the portion corresponding to the peripheral portion of the substrate to be processed in the reflecting portion is changed to the reflectance of the portion corresponding to the central portion of the substrate to be processed. This is achieved by a series of steps in which the reflectance is set to be higher than the ratio, and after the completion of the heat treatment, the reflectance of the entire reflecting surface is reduced while the temperature of the substrate to be processed is lowered.

[0013]

FIG. 1 is a sectional view showing an embodiment of a heat treatment apparatus used in a heat treatment method of the present invention. Reference numeral 21 denotes a processing container made of aluminum. A mounting table 43 made of, for example, carbon coated with SiC is provided in the processing container 21. The wall of the ceiling of the processing container 21 above the mounting table 43 has, for example, a diameter of 1
A large number of cylindrical holes 24 of about 0 mm are formed.
Here, of the ceiling portion of the processing container 21 facing the wafer W, a portion provided with the hole portion 24 is referred to as a reflection portion 20 for convenience, and the reflection portion 20 is, for example, a dotted line as shown in FIG. The holes 24 are arranged along a large number of concentric circles indicated by a circle, and the outermost concentric circle is a circle somewhat larger than the wafer W.

In each of the holes 24, a pin 23, which is a movable member, is vertically movable by an electromagnetic coil 22 and a spring (not shown), that is, the position where the pin 23 is immersed in the hole and the level of the inner wall surface where the hole is not provided. Is provided movably between an exposure position which is the same level position as that of the control unit 25.
The pin 23 moves up and down in the hole in response to a signal transmitted from the hole. In FIG. 2, the hole 24 and the pin 23 are drawn by a common circle for convenience. To give a specific example of the reflecting section 20,
For example, in an 8-inch wafer, seven concentric circles are formed, and the arrangement interval of the holes along each concentric circle is, for example, about 15 mm. The immersion position of the pin 23 is, for example, about 16 mm. In this example, the wall of the ceiling of the processing container 21 corresponds to a plate-like portion forming a reflection surface.

A wafer lift 4 is provided around the mounting table 43.
The wafer lift 42 is configured to move up and down so that the wafer W can be transferred to a transfer arm (not shown) that carries the wafer W in and out.

A support member 33 is provided above the mounting table 43.
A gas supply unit 34 having a gas ejection hole 35 below is fixed to the mounting table 43 so as to face the mounting table 43, and the valve 31 and the gas supply pipe 30 are connected to the gas supply source 32. Connected through. Mounting table 4
A gas flow plate 44 having a large number of gas holes below 3;
On the lower side, a transmission window 51 is downwardly protruded and hermetically attached so as to close the lower opening of the processing container 21. The gas supply section 34, the gas supply pipe 30, the gas flow plate 44, and the transmission window 51 are made of, for example, quartz.

Inside the transmission window 51, N 2 gas is supplied from a N 2 gas supply source 37 through a valve 36 and a gas supply pipe 38.
A gas is supplied, which is installed together with the gas rectifying plate 44 in consideration of, for example, a case where the present apparatus is used for CVD or the like. On the other hand, below the transmission window 51, a plurality of heating lamps 61 and reflecting portions 62 are provided on a rotary table 63 along concentric circles, and these integrally form a heating means. The reflecting portion 62 has a plurality of mortar-shaped depressions surrounding the periphery and the bottom of each heating lamp 61, and the heating lamp 61 is, for example, a halogen lamp or an arc lamp.

Next, the heating process of the wafer W according to the above embodiment will be described. First, the wafer W is transferred from the gate valve 41 into the processing chamber 21 by the transfer arm (not shown), and is transferred to the wafer lift 42. Then, the wafer lift 42 descends and is mounted on the center of the mounting table 43.
In the processing vessel 21, for example, an inert gas such as N2 gas sent from a gas supply source 32 via a gas supply pipe 30 and a valve 31 to prevent oxidation of the wafer W is provided at a gas ejection hole below the gas supply unit 34. Supplied from 35.

Here, heating by the heating lamp 61 is started. A thermometer (not shown), for example, a thermocouple, is embedded in the mounting table 43 so as to be in contact with the back surface of the wafer. A detection value obtained by this thermocouple is sent to the control unit 25 via a transmission path (not shown), The feedback is performed to adjust the light emission amount of the light 61. Then, the wafer W is heated to a predetermined process temperature, for example, 1000 ° C.
Thereafter, the temperature is maintained at a predetermined process temperature for a predetermined time, and then the temperature is lowered.

Since the above-described temperature control is performed with reference to the central portion of the wafer W, the central portion of the wafer W changes as shown by the solid line in FIG. Further, the peripheral portion of the wafer W changes as shown by a dotted line in FIG. Here, as described in the problem to be solved by the invention, since a temperature difference is generated between the central portion and the peripheral portion of the wafer W, in this embodiment, the inner wall surface of the processing container 21 facing the heating lamp 61 is used. By raising and lowering the pins 23 embedded in the wafer W, the amount of heat energy reflected at each location is adjusted to eliminate the temperature difference on the surface of the wafer W.

When the electromagnetic coil 22 is in the ON state, the pin 23 is immersed in the hole against the restoring force of a spring (not shown), so that the inner wall surface of the processing container 21 is dented, and the heat ray at that location is reflected. The rate decreases. On the other hand, when the electromagnetic coil 22 is OFF, the processing container 21
The lower end of the pin 23 is located at the same level as the inner wall surface, and the pin 23 closes the hole, so that the heat ray reflectance is higher than in the previous state. Here, the control of the electromagnetic coil 22 proceeds as follows.

For example, when the process temperature is set to 1000 ° C., first, in the temperature raising process (the portion indicated by “a” in FIG. 3) from the start of the heating of the wafer W to 1000 ° C., (a) of FIG. As shown in FIG. 4 (a), the pins at the locations facing the peripheral portion of the wafer W are retracted (submerged), and FIG.
As shown in (b), the pin at the location facing the center of the wafer W is exposed (for example, the tip surface of the pin is at the same level as the wall surface other than the hole). Therefore, regarding the amount of heat radiated from the reflecting portion 20 to the wafer W, the peripheral portion is smaller than the central portion of the wafer W, which acts in a direction to offset the temperature distribution shown in FIG. The in-plane temperature uniformity of the wafer W at the time of the temperature is increased.

Thereafter, from t1 to t shown in FIG.
2, the temperature of the peripheral portion of the wafer W is lower than that of the central portion as described above, and therefore, the OFF and ON of the electromagnetic coils 22 disposed at the positions A and B are reversed (FIG. 4).
(B)) The pins at the location facing the peripheral edge of the wafer W are exposed, and the pins at the location facing the center are immersed, thereby offsetting the temperature difference on the surface of the wafer W.

After the elapse of the time t2 shown in FIG. 3 (c), the power supply to the heating lamp 61 is stopped to cool the apparatus at a high speed, and all the pins are immersed as shown in FIG. 4 (c). In this case, the reflectance of the reflection unit 20 is set to be the lowest, so that the temperature is reduced earlier.

According to the above-described embodiment, in the heat treatment of the semiconductor wafer, the temperature control corresponding to each of the temperature raising process, the processing process, and the temperature lowering process is performed by changing the reflectance of the reflector 20. In addition, high uniformity in the temperature plane of the wafer can be maintained consistently from the start of heating to the end of the heat treatment at a predetermined temperature, and an annealing process with high uniformity can be performed. After the heating is completed, the wafer can be cooled at a high speed, and a high throughput can be obtained.

The examples shown in FIGS. 4 (a), (b) and (c) are so-called open control. For example, in the case of a closed loop, a pin exposed according to the surface temperature of the wafer W and a pin immersed are determined. An arrangement pattern may be selected. In addition, the pin is configured not only to take two positions, exposure and immersion, but also to be able to adjust the amount of immersion, and to adjust the amount of immersion of the pin at the stage of setting up the device so that the reflection portion has an appropriate reflectance. Alternatively, the amount of immersion of each pin may be adjusted in real time according to the detected temperature of the wafer.

FIG. 5 shows another embodiment according to the present invention. In this apparatus, a heating means including a heating lamp 61 and the like is provided above the wafer W, and the processing vessel 2 below the mounting table 43 is opposed to the heating means.
The reflecting portion 20 is provided on the inner wall surface of the device. In this embodiment, heat rays radiated from the lower surface of the mounting table 43 are
And the reflectivity is adjusted so that the mounting table 43
, The in-plane temperature uniformity of the wafer W is increased.

In the above-described embodiments, an apparatus using a heating lamp as a heating means has been exemplified. However, the heating source is not limited to the heating lamp. For example, a heating source using a resistance heating element may be employed. It is possible.

Further, the application of the present invention can be applied to, for example, film formation of a wafer by applying the effect of the above-mentioned heating means.

[0030]

According to the present invention, for example, a reflective portion having a variable reflectance is provided so as to face the wafer, so that high in-plane uniformity of the wafer temperature can be maintained. In addition, high-speed heat radiation is performed after the completion of the wafer heat treatment,
Throughput is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention.

FIG. 2 is a plan view of a reflection section used in the embodiment of FIG. 1 as viewed from below.

FIG. 3 is a temperature profile showing a temperature change in a central portion and a peripheral portion of a substrate to be processed.

FIG. 4 is a cross-sectional view of a reflector showing a state in which pins move up and down according to a temperature change of a substrate to be processed.

FIG. 5 is a sectional view illustrating another embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a lamp annealing apparatus according to a conventional invention.

[Explanation of symbols]

 W wafer 20 reflection unit 21 processing container 22 electromagnetic coil 23 pin 24 hole 25 control unit 34 gas supply unit 43 mounting table 44 gas rectifying plate 51 transmission window 61 heating lamp

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobuaki Takahashi 5-3-6 Akasaka, Minato-ku, Tokyo Inside Tokyo Electron Limited (72) Inventor Takashi Shigeoka 1-241 Machiya, Shiroyamacho, Tsukui-gun, Kanagawa Prefecture No. Tokyo Electron Tohoku Co., Ltd. Sagami Business Office

Claims (7)

[Claims] 1. A processing container provided with a mounting table for a substrate to be processed, a heating source for heating the substrate mounted on the mounting table, and a temperature distribution of the substrate to be processed. And a reflector configured to change the reflectance of the heat ray. 2. The heat treatment apparatus according to claim 1, wherein the reflector is provided to face the mounting table. 3. The reflecting section includes: a plate-shaped section forming a reflecting surface;
By changing the position of the movable member in the hole including a plurality of holes formed in the plate-like portion, and a movable member that is exposed and immersed in these holes and has a reflecting surface that forms a reflecting surface, 2. The method according to claim 1, wherein the reflectance is changed.
The heat treatment apparatus according to the above. 4. After the substrate to be processed is mounted on the mounting table and the temperature of the substrate to be processed is started using the apparatus according to claim 1, the heating process is terminated and the temperature of the substrate to be processed is lowered. Between,
A heat treatment method, wherein the reflectance of a heat ray is changed by a reflection part. 5. When the temperature of the substrate to be processed is raised, the reflectance of the portion corresponding to the peripheral portion of the substrate to be processed in the reflection portion is made smaller than the reflectance of the portion corresponding to the central portion of the substrate to be processed. The heat treatment method according to claim 3, wherein 6. While the substrate to be processed reaches a predetermined process temperature and performs a heat treatment, the reflectance of the portion corresponding to the peripheral portion of the substrate to be processed in the reflection section is changed to the portion corresponding to the central portion of the substrate to be processed. The heat treatment method according to claim 4, wherein the reflectance is higher than the reflectance of the heat treatment. 7. The heat treatment method according to claim 4, wherein the reflectance of the entire reflecting surface is reduced while the temperature of the substrate to be processed is lowered after the completion of the heat treatment.