JP3422500B2 - Heat treatment method for semiconductor wafer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment technique for a semiconductor wafer, and more particularly to a technique for heating a semiconductor wafer by a point or linear heat source provided in a part of a furnace. The present invention relates to a technique which is effective when used in a method. 2. Description of the Related Art Conventionally, as a heat treatment apparatus of this kind, FIG.
FIG. 8 is a front sectional view showing an example of such a conventional heat treatment apparatus. In the prior art shown in FIG. 8, a furnace body 1 made of a heat-resistant material into a box shape is provided with a main body 1 if necessary.
a and a lid 1b, and an opening 3 is provided on the side wall of the main body 1a to allow the semiconductor wafer 2 to be heat treated to enter and exit. The lid 1b has a semicircular concave portion 1c formed inside, and a lamp 4 (for example, an infrared lamp) is provided in the concave portion 1c. Further, the ceiling of the main body 1a is matched with the recess 1c,
An opening corresponding to the diameter of the concave portion 1c is provided so that heat generated by the lamp 4 can be radiated into the main body 1a.
The semiconductor wafer 2 is placed on a wafer holder 5, and the wafer holder 5 is attached to a support 6 that enters and exits the main body 1a. When heat treatment is performed in the above configuration, the semiconductor wafer 2 is placed on the wafer holder 5 drawn out of the furnace, and then the support 6 is pushed into the main body 1a, and the semiconductor wafer 2 is placed immediately below the lamp 4. Set to. Here, the lamp 4 is turned on, and the main body 1a is moved for a short time (for example, several seconds to 6 seconds).
The semiconductor wafer 2 is heated in a high-temperature atmosphere of several hundred degrees (for example, 800 ° C.) at about 0 second). According to the study of the present inventors, when a semiconductor wafer placed on a wafer holder is heated from the exposed surface (front surface) side, a high temperature is rapidly applied to the semiconductor wafer, Since the heat applied in the wafer surface escapes from the wafer surface to the peripheral portion, a sharp temperature difference between the central portion and the peripheral portion of the wafer (a high temperature in the central portion and a low temperature in the peripheral portion) is generated. However, there is a problem that a slip line is generated. In recent years, there has been a demand for making the channel layer thinner. However, it is impossible to perform heating for a long time in response to this demand, and it is necessary to raise the temperature to 800 to 900 ° C. in a short time. However, this causes the above-described problem. SUMMARY OF THE INVENTION An object of the present invention is to provide a technique capable of reducing a temperature difference between a central portion and a peripheral portion of a semiconductor wafer even when high-temperature heating is performed in a short time. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings. Means for Solving the Problems Of the inventions disclosed in the present application, a typical one will be briefly described.
It is as follows. [0010] That is, on both sides of the top and bottom surfaces of the semiconductor wafer, each provided with a heater for heating the semiconductor wafer, between the respective heaters and the semiconductor wafer, respectively top and bottom surfaces of the buffer member And the buffer material on the lower surface side is the same as the semiconductor wafer.
The thickness of the portion where the semiconductor wafer is placed in contact with and supports the semiconductor wafer is thinner than the other portions ,
A soaking plate between each and the walls of the furnace body outside them
And the semiconductor wafer is indirectly heated by the heat from the heater via the buffer material. According to the above-described means, heat is indirectly applied to the semiconductor wafer to be processed. Therefore, the temperature difference between the peripheral portion and the inside of the object can be reduced,
There is no occurrence of slip lines and the like. FIG. 1 is a front sectional view showing a first embodiment of a heat treatment apparatus used in the present invention. In FIG. 1,
Since the same reference numerals are used for those that are the same as in FIG. 8,
Here, duplicate description is omitted. The furnace body 7 is a box-shaped main body 7 having an opening 7b on its side wall for allowing the semiconductor wafer 2 (workpiece) to enter and exit.
a, and a lid 7c is provided so as to be coupled to the lower part. The lid 7c has a concave portion 7d like the lid 1b, and the lamp 4 as a heat source is disposed in the concave portion 7d. An opening having the same diameter as that of the recess 7 d is formed in the main body 7.
a is provided at the bottom. Further, a small-diameter through hole 7e is provided in the ceiling of the main body 7a, and the support member 8 is inserted into the main body 7a so as to be able to move up and down through the through hole 7e. When viewed from the front, the lower end of the support 8 has an "L" shape, the horizontal portion has a disk shape, and pins 8a (not limited to this, but any projecting object) may be provided at several places on the upper surface. It is erected. A wafer holder 9 (buffer material) on which the semiconductor wafer 2 is placed is placed on the pins 8a. FIG. 2 is a plan view showing details of the wafer holder 9, and FIG. 3 is a front sectional view of the wafer holder 9 of FIG. The wafer holder 9 has a dish shape and is formed at a wafer mounting portion 9a on which the semiconductor wafer 2 is mounted and at a peripheral portion of the wafer mounting portion 9a in order to keep the temperature and prevent the wafer from jumping out. And a guard ring 9b. The wafer holder 9 is made of, for example, graphite or quartz, and has a thickness of several tens μm (for example, 60 μm) on the surface.
To prevent the generation of foreign matter from graphite. An example of the dimensions of the wafer holder 9 is as follows. [Example 1] Materials used: graphite, diameter: 100 mm, thickness: 4.0 mm, guard ring 9b
Width: 15.0mm, guard ring 9b height: 0.5m
m. [Example 2] Material used: graphite, diameter: 130 mm, thickness: 4.0 mm, guard ring 9b
Width: 15.0mm, guard ring 9b height: 0.5m
m. In this embodiment, when heat treatment is performed, the wafer holder 9 on which the semiconductor wafer 2 is placed is placed on the pins 8a of the support 8 in the furnace body 7, and the lamp 4 is turned on. As a result, the inside of the main body 7a suddenly becomes a high-temperature atmosphere of 800 to 900 ° C. At this time, the heating of the semiconductor wafer 2 is indirectly applied from the lower surface through the wafer holder 9 from the lower heat source. Therefore, in the heating state in the semiconductor wafer 2, a temperature difference between locations is reduced, and a slip line or the like is not generated. FIG. 4 is a front sectional view showing a second example of the wafer holder. In this embodiment, a concave portion 9c is provided on the lower surface of the wafer mounting portion 9a so as to enhance the soaking effect on the semiconductor wafer 2 as compared with the configuration shown in FIGS.
That is, since the inside of the semiconductor wafer 2 has a high temperature, the recess 9c is provided in a part of the wafer mounting portion 9a so that the heat inside can be easily released. The other parts are the same as those of the wafer holder 9 of FIGS. 2 and 3, and the description thereof is omitted here. Embodiment 2 FIG. 5 is a front sectional view showing another embodiment of the heat treatment apparatus used in the present invention. This embodiment is an example in which a heater is used as a heat source. The heater 1 is provided on both the ceiling surface and the floor surface of the box-shaped furnace body 10.
The heating power is increased by installing 1a and 11b. further,
Between each of the heaters 11a and 11b and the opposing wall surface, a heat equalizing plate 12a,
12b is provided. Heater 11a and heater 11b
The semiconductor wafer 2 is disposed between the
In order to prevent the heat of the semiconductor wafer 2 from being directly applied to the semiconductor wafer 2, the semiconductor wafer 2 is divided into two wafer holders 13a, 13b each having the same configuration as the wafer holder 9.
And hold it in a sandwich shape. In order to hold the wafer holders 13a, 13b at the center of the furnace body 10, pins 14 are erected through the bottom wall of the furnace body 10, and the wafer holders 13a, 13b are mounted on the upper ends thereof. According to the present embodiment, the heaters 11a and 11b
In either case, heat is applied to the semiconductor wafer 2 indirectly via the wafer holders 13a and 13b, so that the temperature difference between the periphery and the inside of the semiconductor wafer 2 can be reduced as in the previous embodiment, and Lines and the like can be eliminated. Further, by using the heaters 11a and 11b as heat sources, temperature control becomes easy. As described above, the invention made by the inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. Needless to say. For example, in the above embodiment, the guard ring 9b has an example of a square cross section. However, the guard ring 9b has an inclined surface as shown in FIG. 6 or a structure having projections on both upper and lower surfaces as shown in FIG. You can also In the above embodiment, a lamp or a heater is used as a heat source. However, the present invention is not limited to this.
For example, a laser or the like can be used. Further, in the configuration shown in FIG.
Although the concave portion 9c is provided on the lower surface of the wafer, the thickness of the portion of the wafer mounting portion 9a may be changed stepwise or continuously. Further, in the above embodiment, the wafer holder is used alone, but it may be integrated with the support. The effects obtained by the representative inventions among the inventions disclosed in the present application will be briefly described.
It is as follows. [0030] That is, on both sides of the top and bottom surfaces of the semiconductor wafer, each provided with a heater for heating the semiconductor wafer, between the respective heaters and the semiconductor wafer, respectively top and bottom surfaces of the buffer member And the buffer material on the lower surface side is the same as the semiconductor wafer.
The thickness of the portion where the semiconductor wafer is placed in contact with and supports the semiconductor wafer is thinner than the other portions ,
A soaking plate between each and the walls of the furnace body outside them
Since the semiconductor wafer is disposed and indirectly heated by the heat from the heater via the buffer material, heat is applied to the semiconductor wafer to be processed by the semiconductor wafer.
The temperature difference between the peripheral portion and the inside of the semiconductor wafer can be reduced, no slip line or the like is generated , and the buffer material on the lower surface side is reduced by half.
Since it is supported in surface contact with the conductor wafer, local stress
The generation of crystal defects due to the generation can be prevented and
The temperature deviation of the heating part can be reduced,
More uniform heating over the entire body wafer
Thermal effect reduces thermal stress on semiconductor wafers
To reduce the occurrence of crystal defects in the semiconductor wafer.
Can be

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view showing a first embodiment of a heat treatment apparatus used in the present invention. FIG. 2 is a plan view showing details of a wafer holder. FIG. 3 is a front sectional view of the wafer holder of FIG. 2; FIG. 4 is a front sectional view showing a second example of the wafer holder. FIG. 5 is a front sectional view showing a second embodiment of the heat treatment apparatus used in the present invention. FIG. 6 is a sectional view of a main part showing a second example of the guard ring of the wafer holder. FIG. 7 is a sectional view of a main part showing a third example of the guard ring of the wafer holder. FIG. 8 is a front sectional view showing a conventional heat treatment apparatus. [Description of Signs] 1 Furnace body 1a Main body 1b Lid 1c Recess 2 Semiconductor wafer 3 Opening 4 Lamp 5 Wafer holder 6 Support 7 Furnace 7a Main body 7b Opening 7c Lid 7d Recess 7e Through hole 8 Support 8a Pin 9 Wafer holder 9a Wafer mounting portion 9b Guard ring 9c Recess 10 Furnace bodies 11a, 11b Heaters 12a, 12b Heat equalizing plates 13a, 13b Wafer holder 14 pins

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-58822 (JP, A) JP-A-3-108716 (JP, A) JP-A-47-43107 (JP, A) JP-A-60-1985 88432 (JP, A) JP-A-60-173852 (JP, A) JP-A-63-224323 (JP, A) JP-A 64-12229 (JP, A) JP-A 64-8616 (JP, A) JP-A-64-50523 (JP, A) JP-A-64-71118 (JP, A) JP-A-62-37927 (JP, U) Appl. Phys. Vol. 2 (1989-7) p. 663-665 (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/26 L H01L 21/324 D

Claims (1)

(57) on both sides of the Claims 1 a top and bottom surfaces of the semiconductor wafer, each provided with a heater for heating the semiconductor wafer, between the semiconductor wafer wherein the heaters, The buffer material on the upper surface side and the buffer material on the lower surface side are disposed, and the buffer material on the lower surface side is supported in surface contact with the semiconductor wafer.
And the thickness of the portion on which the semiconductor wafer is placed is thinner than the other portions, and the space between each of the heaters and the wall surface of the furnace body outside thereof is reduced.
, The soaking plate is disposed, the heat from the heater, the heat treatment method of a semiconductor wafer, which comprises indirectly heating the semiconductor wafer through the buffer material.