JPH0330323A - Lamp heating apparatus - Google Patents

Abstract

PURPOSE:To perform uniform temperature increase, heat retaining and temperature decrease by relatively turning two light scattering patterns, and adjusting the relative amounts of radiations at the central part and the peripheral part based on whether the light scattering patterns are made to agree or made different. CONSTITUTION:At least two sheets of heat-resisting light transmitting substrates 3 and 4 which are in parallel and are relatively turned are provided between a lamp 1 and a heated sample 2. Said heat resisting light transmitting substrates 3 and 4 have light scattering patterns 5 and 6 whose light scattering degrees with respect to the relative turning directions are changed. The heat-resisting light transmitting substrates 3 and 4 are relatively turned, and the light scattering patterns 5 and 6 are made to agree or made different. Thus the relative amounts of radiations at the central part and the peripheral part of the wafer 2 can be adjusted. In this way, uniform temperature increase, heat retaining and temperature decrease can be performed at the optimum state all the time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lamp heating device used for various annealing processes such as heat treatment for forming an oxide film or activation treatment of impurities in the manufacturing process of semiconductor devices, for example.

[Summary of the Invention] The present invention relates to a lamp heating device, in which at least two heat-resistant, light-transmitting substrates are provided between the lamp and a sample to be heated, and which rotate relative to each other while maintaining a parallel state. A pattern in which the degree of light scattering changes in the direction of relative rotation is formed on at least two of these heat-resistant light-transmitting substrates, and by selecting the relative rotational position of these heat-resistant light-transmitting substrates, the sample to be heated can be heated. The amount of irradiation from the lamp applied to the heating distribution is controlled to substantially raise the temperature of the sample to be heated, to maintain a predetermined heating temperature, to lower the temperature, and to make it uniform in each part of the sample to be heated.

[Prior Art] In the manufacturing process of various semiconductor devices, various heat treatments such as thermal oxidation or impurity activation treatment are often accompanied by annealing treatment, that is, heat treatment.

In this type of heat treatment, there is a heating device RT that can perform rapid heat treatment compared to heating devices that use an electric furnace that directly irradiates the semiconductor wafer with light from a halogen lamp or the like. P (Rapid
Thermal Process) devices are widely used.

Various types of such RTP devices have been proposed, and various devices have been devised to obtain a uniform temperature distribution for the heated object (for example, Japanese Patent Laid-Open No. 59-201
410 or Japanese Patent Application Laid-Open No. 62-250633).

This type of RTP device is different from a heating device using an electric furnace,
The furnace body is basically a cold wall.
ll), and its temperature is raised by a light absorption stage of a heated sample, for example a semiconductor wafer. Therefore, in this type of RTP device, the actual amount of light irradiated onto the wafer, that is, the amount of light irradiated from the light source (lamp) and the scene that comes from the reflection of light from the surroundings, conversely, the amount of light irradiated from the semiconductor wafer, The actual temperature changes due to heat conduction from the support part in contact with the support part, or radiation heat to the furnace wall adjacent to the support part, and these factors are taken into account. Only then can the temperature uniformity of the heated sample be measured. In other words, even if the sample to be heated is irradiated with uniform light, the degree of heat dissipation will differ between the center and the periphery of the wafer due to the various conditions mentioned above, and the temperature within the wafer surface will change. It is not guaranteed that each part will be uniform. Furthermore, in normal heat treatment, the heating profile consists of a heating process in which the wafer is heated to a predetermined temperature, a process in which the wafer is heated to a predetermined temperature and held at a constant temperature, and a cooling process. For example, when the light irradiation in the heating state is set to 100%, the light intensity is reduced to, for example, 50% in the state of maintaining a constant/closedness,
If, for example, slow cooling is to be performed in the cooled state, a method is used in which the temperature is reduced to about 10 to 20%. In this case, the balance between the amount of reflection from the surroundings to the wafer and the radiation to other parts changes, especially when the temperature is raised, when the predetermined temperature is maintained, and when the temperature is lowered. It becomes necessary to control the amount of light irradiated at the periphery and center of the sample to be heated, that is, the wafer, during crystallization and during temperature cooling, respectively.

In this way, in order to equalize the heating temperature at the center and periphery of the sample to be heated, a device that individually controls the intensity of the lamps facing the periphery and the lamps facing the center of the sample to be heated. has also been proposed, but in this case there are problems in that it complicates the device and makes it difficult to make delicate adjustments.

[Problem to be solved by the invention]

The present invention provides a lamp heating device that has a simple configuration and arbitrarily selects the amount of light irradiated on the sample to be heated, especially at the periphery and center, in each state, for example, when the temperature is rising, when keeping the temperature, and when the temperature is falling. It is an object of the present invention to provide a lamp heating device that can substantially uniformize the heating state of each lamp.

[Means for Solving the Problems] The present invention is such that, for example, FIG. 1 shows a partially cross-sectional plan view of the route, and FIG. 2 shows a partially cross-sectional side view. Between the lamp (1) and the sample to be heated (2), there are at least two heat-resistant light-transmitting substrates (3) and (4) that rotate relative to each other while maintaining a parallel state.
will be established. These heat-resistant light-transmitting substrates (3) and (4) have a light scattering pattern in which the degree of light scattering changes with respect to the direction of relative rotation thereof, as shown in plan views in FIGS. 3 and 4, respectively. (5) and (6) are formed.

[Function] In such a configuration, by relatively rotating the heat-resistant light-transmitting substrates (3) and (4), the light scattering patterns (5) and (6) whose respective light scattering degrees change are mutually rotated. Both light transmitting substrates (
By being able to adjust the overall degree of scattering of light in (3) and (4), that is, the amount of light transmission, the sample to be heated (2)
The effective amount of light irradiation and therefore the amount of light absorbed can be adjusted. That is, by making these light scattering patterns (5) and (6) patterns in which the degree of light scattering changes with respect to the rotating direction in the peripheral areas of the substrates (3) and (4), for example, both light transmission in the peripheral areas can be achieved. The amount of light transmitted through the substrates (3) and (4) can be adjusted, and the relative irradiation between the center and peripheral parts of the wafer (2) can be adjusted. By changing the actual light irradiation stage between the center and the periphery at different times, it is possible to uniformly raise and retain the temperature and lower the temperature at all times in an optimal state.

[Example] An example of a lamp heating device according to the present invention will be described in detail with reference to the drawings. (The power indicates the heating chamber of the lamp heating device, that is, the so-called cold wall type body, and the heating chamber (7
) is placed above the lamp (1). This lamp (
1) consists of a halogen lamp, for example, and is directed in one direction? ! Several of them are arranged in parallel, for example, on a - plane. These lamps (1) are connected to the sample to be heated (
2) For example, the number and position of the semiconductor wafers are selected so that the entire surface of the semiconductor wafer is sufficiently irradiated with light.

Between the lamp (1) and the sample to be heated (2), two light-transmitting substrates (3) and (4) are placed between each lamp (1) and the sample to be heated (2), which rotate relative to each other while maintaining a parallel state. ) and the sample surface of the heated sample (2). These heat-resistant, light-transmitting substrates (3) and (4) are each made of a heat-resistant quartz glass plate or sapphire that is transparent to light, particularly heat rays from the lamp (1), for example, a circular plate. As shown in FIGS. 3 and 4, light scattering patterns (5) and (6) are formed. These light scattering patterns (5) and (6) can be formed by, for example, mechanical processing or (and) By chemical etching etc., for example, in each center -
A roughened central light scattering part (5c) with various light scattering degrees
) and (6c) are formed, and on its outer periphery, similar roughnesses in the shape of a swirling fan, for example, widening outward from the center, are arranged at the same pitch along the circumferential direction, that is, the direction of relative rotation. The pattern is such that the peripheral light scattering portions (5p) and (6p) and the non-light scattering portions (5n) and (6n) are alternately repeated to change the degree of light scattering. When these patterns (5) and (6) are formed into the same pattern, for example, and the respective light scattering parts (5p) and (6ρ) match so as to overlap, the amount of transmission is the largest, and the light scattering part (5ρ) and (6p) are mutually M
M and one non-light scattering part (5n) or (6n)
When the light scattering part (6p) or (5p) matches, the degree of light scattering is the highest overall, and the sample to be heated (2)
The amount of light irradiated to the outer periphery of the area is set to the lowest level.

These heat-resistant light-transmitting substrates (3) and (4) are, for example, -
One plate, for example, the substrate (3), may be fixed, and only the other substrate, for example, the substrate (4), may be configured to rotate, or it may be possible to configure a structure in which the two plates, for example, the substrate (4), are fixed. If necessary, the side substrates (3) and (4) may be rotated together at a required rotational speed to change the relative amount of light irradiation between the center and peripheral areas of the heated object (2). Light scattering patterns (5) and (6) by global rotation
) can also be used to avoid uneven light irradiation. In this case, for example, the side substrates (3) and (4) are arranged on a common rotating shaft (9) rotationally driven by a motor or the like so that they rotate as a whole, and one side is relatively rotated from the outside. For example, the substrate (4) can be rotated to change its position. This relative rotation from the outside is
For example, the base plate (4) may be a spur gear, and the rack (11) that meshes with the spur gear may be operated from the outside, so that only the base plate (4) can be slid and rotated about the rotation axis (9). .

In addition, the light scattering patterns (5) and (6) include light scattering parts (5ρ) and (6p) along one circumferential line as described above.
This is a case where the non-light scattering parts (5n) and (6n) are arranged alternately, and this pattern is applied to each substrate (3) and (4).
It is possible to further prevent unevenness of light by providing patterns concentrically on a plurality of circumferential lines with respect to the center thereof and alternately so that patterns on adjacent circumferential lines are +tl1M apart from each other. In addition, in the above example, the light scattering part (
5p) and non-light-scattering parts (5n) are arranged alternately, but with such a slightly divided pattern, each substrate (3) and (4) A pattern in which the degree of light scattering gradually changes in the direction of relative rotation can also be used.

In the above example, two heat-resistant light-transmitting substrates (3
) and (4), but it is also possible to have a structure in which two or more heat-resistant light-transmitting substrates each having a pattern in which the degree of light scattering changes is stacked. Deformation changes can be made.

〔Effect of the invention〕

According to the device of the present invention, the heat-resistant light-transmitting substrates (3) and (4)
), the light scattering patterns (5) and (6) whose degree of light scattering changes by relatively rotating the M! The overall light scattering degree, that is, the amount of light transmission, of both light passing substrates (3) and (4) is adjusted by adjusting the amount of light passing through the substrates (3) and (4). By being able to do this, it is possible to adjust the substantial amount of light irradiation and therefore the amount of light absorption of the sample to be heated (2). That is, these light scattering patterns (5) and (6)
For example, by forming a pattern in which the degree of light scattering changes with respect to the rotating direction at the peripheral portions of the substrates (3) and (4), for example, the light transmission that passes through both the light transmitting substrates (3) and (4) at the peripheral portions can be reduced. i! II can be adjusted, and the relative irradiation amount between the center and the periphery of the wafer (2) can be adjusted, and it is possible to adjust the relative irradiation amount between the center and the periphery of the wafer (2). By changing the amount of light irradiation, it is possible to uniformly raise, retain, and lower the temperature in an optimal state at all times.

[Brief explanation of drawings]

Fig. 1 is a partially cross-sectional plan view of an example of the device of the present invention, Fig. 2 is a partially cross-sectional side view, and Figs. (This is a diagram of the opposite light scattering part pattern. (1) is the lamp, (2) is the sample to be heated, (3) and (4)
) is a durable, external light transmitting substrate.

Claims (1)

[Scope of Claims] At least two heat-resistant, light-transmitting substrates are provided between the lamp and the sample to be heated and rotated relative to each other while maintaining a parallel state; A lamp heating device characterized in that a light transmitting substrate is formed with a pattern in which the degree of light scattering changes in the direction of relative rotation thereof.