KR100577921B1 - Thermal Processing Method and Thermal Processing for Substrate Employing Photoirradiation - Google Patents

Abstract

Each of the plurality of flash lamps forming the light source is an elongated cylindrical bar lamp. The ratio of the distance between the flash lamp and the semiconductor wafer to the distance between the flash lamp and the reflector is set to 1.8 or less or at least 2.2. Thus, the roughness is weakened at a portion of the major surface of the semiconductor wafer located just below the flash lamp in the vertical direction, and strengthened at a portion located just below the clearance of the adjacent flash lamp in the vertical direction, Roughness nonuniformity on all major surfaces is reduced and in-plane uniformity of temperature distribution on the semiconductor wafer is improved. Therefore, a heat treatment apparatus is provided that can improve in-plane uniformity of temperature distribution on a substrate.

Heat treatment device, heat treatment method, flash lamp, light source, heat diffuser plate, reflector plate

Description

Heat treatment method and heat treatment apparatus for a substrate using light irradiation {Thermal Processing Method and Thermal Processing for Substrate Employing Photoirradiation}

1 and 2 are side cross-sectional views showing a heat treatment apparatus according to a first embodiment of the present invention;

3 is a diagram typically showing a relationship between illuminance of light emitted from a flash lamp onto a surface of a semiconductor wafer and an installation position of the flash lamp;

4 is a diagram typically showing another relationship between the illuminance of light emitted from the flash lamp onto the surface of the semiconductor wafer and the installation position of the flash lamp;

FIG. 5 is a model diagram showing an arrangement relationship between a reflector, a flash lamp and a semiconductor wafer. FIG.

Description of the main parts of the drawing

10 light sources, 40 motors,

65 chambers, 69 xenon flash lamps,

73 heat spreader plate, 74 heating plate,

The present invention relates to a heat treatment method and a heat treatment apparatus for heat treatment by irradiating light onto a substrate such as a semiconductor wafer or a glass substrate (hereinafter simply referred to as a "substrate").

Generally, heat treatment apparatuses, such as lamp annealing apparatus using halogen lamps, are used in the ion activation process of ion-implanted semiconductor wafers. This heat treatment apparatus performs an ion activation process of a semiconductor wafer, for example by heating a semiconductor wafer at the temperature of about 1000 degreeC to 1100 degreeC. This heat treatment apparatus increases the temperature of the substrate at a rate of several hundred degrees every second through the light energy emitted from the halogen lamp.

However, it has been demonstrated that the profile of the ions implanted into the semiconductor wafer is rounded, that is, the ions are thermally diffused when the heat treatment apparatus for heating the substrate at a rate of several hundred degrees per second performs the ion activation process. When this phenomenon occurs, even when a high concentration of ions are injected to the surface of the semiconductor wafer is diffused. Thus, ions are implanted more adversely than necessary.

In order to solve the above-mentioned problem, Japanese Patent Application Publication Nos. 59-169125 (1984), No. 63-166219 (1988), and the like, flash the surface of a semiconductor wafer through xenon flash lamps or the like. By irradiating with, a technique for increasing the temperature of only the surface of an ion-implanted semiconductor wafer in a very short time of several milliseconds (ms) or less is proposed. When heating a semiconductor wafer with a xenon flash lamp for an extremely short time, since the ions do not diffuse due to lack of time, the heat treatment apparatus performs only the ion activation process without rounding the profile of the ions injected into the semiconductor wafer.

However, a conventional heat treatment apparatus having such a structure has the following problems: In a heat treatment apparatus using a xenon flash lamp, a plurality of bar-shaped or similar xenon flash lamps are provided. As the heat treatment apparatus approaches the plurality of xenon flash lamps to the semiconductor wafer, the in-plane uniformity of the temperature distribution is impaired as the roughness is increased at the portion of the wafer surface located directly below the lamp than the rest. However, in the heat treatment apparatus using the xenon flash lamp having an extremely short heating time, unlike the conventional lamp annealing apparatus using a halogen lamp, a method of maintaining the in-plane uniformity of the illuminance distribution by rotating the wafer can be used. none.

In order to effectively utilize the light emitted from the lamp, a reflecting plate is disposed along the lamp, and the illuminance reflected by the reflecting plate also has a light intensity distribution on the wafer surface. When the lamp emits light in which the light intensity distribution of the reflected light and the amplitude of the light intensity distribution of the irradiation supplied directly to the wafer from the lamp substantially coincide with each other, the in-plane uniformity of the temperature distribution is further impaired.

The present invention relates to a heat treatment apparatus for heating a substrate by irradiating light to the substrate.

According to the present invention, a heat treatment apparatus includes a light source having a plurality of lamps, a holding element for substantially keeping the substrate in a chamber installed below the light source, and the holding through the light source to reflect light emitted from the light source. A reflection element opposite the element and shifting the peak of the illumination distribution of the reflected light introduced through the reflection element to the treated surface of the substrate relative to the peak of the illumination distribution of the light introduced directly from the light source to the treated surface of the substrate.

The roughness is weakened at the position of the treated surface of the substrate located directly below the lamp, while by increasing at the position located just below the gap between adjacent lamps, the roughness irregularity is reduced over the entire treated surface of the substrate. In-plane uniformity of the temperature distribution on the substrate can be improved.

According to one aspect of the present invention, a heat treatment apparatus includes a light source having a plurality of lamps, a holding element for substantially keeping the substrate horizontally in a chamber installed below the light source, and the light source for reflecting light emitted from the light source. And a reflecting element opposed to the holding element, wherein the ratio of the distance between the light source and the substrate held by the holding element with respect to the distance between the reflected light and the light source is set to 1.8 or less or at least 2.2.

Since the reflected light from a lamp adjacent to a lamp does not reach a position located just below a lamp through the reflecting element, the roughness irregularity is reduced on the entire processed surface of the substrate, thereby in-plane uniformity of temperature distribution on the substrate. This can be improved.

According to another aspect of the present invention, a heat treatment apparatus includes a light source formed by aligning a plurality of long cylindrical bar lamps in parallel with each other, a holding element for substantially keeping the substrate in a chamber installed under the light source, and At a location on the substrate surface held by a retaining element located directly below each of the plurality of bar lamps, the reflecting element being opposed to the retaining element through the light source to reflect light emitted from the light source. As can be seen, the reflective element is held by the reflective element, the light source and the retaining element such that the reflective element does not reflect the image of each bar lamp and the adjacent bar lamp through the gap between each bar lamp and the adjacent bar lamp. Arrange the substrate.

Since the reflected light from adjacent bar lamps does not reach the position located below each bar lamp through the reflecting element, the roughness irregularities are reduced on the entire processed surface of the substrate so that the in-plane uniformity of the temperature distribution on the substrate is reduced. Can be improved.

Moreover, this invention relates to the heat processing method of heat-processing a board | substrate by irradiating light to a board | substrate.

Accordingly, it is an object of the present invention to provide a heat treatment method and a heat treatment apparatus that can improve in-plane uniformity of temperature distribution on a substrate.

The above and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.

Embodiments of the present invention will now be described in detail with reference to the drawings.

<1. First embodiment>

1 and 2 are side cross-sectional views showing a heat treatment apparatus according to a first embodiment of the present invention. This heat treatment apparatus heat-treats the semiconductor wafer W with the flash emitted from the xenon flash lamp 69.

This heat treatment apparatus includes a chamber 65 composed of a light transmitting plate 61, a bottom plate 62, and a pair of side plates 63 and 64 to store the semiconductor wafer W therein, and to heat-treat it. . The floodlight plate 61 forming the upper portion of the chamber 65 passes through the light emitted from the light source 10 and functions as a chamber window guiding into the chamber 65, for example, infrared rays, such as quartz. It consists of a transmission material. In the bottom plate 62 forming the chamber 65, the support pins 70 passing through the heat diffusion plate 73 and the heating plate 74, which will be described later, for supporting the semiconductor wafer W from below, are upright. It is installed.

In the side plate 64 which forms the chamber 65, the port 66 which carries in and carries out the semiconductor wafer W with respect to the chamber 65 is formed. The port 66 is openable / closed by the gate valve 68 which is rotated about the axis 67. The carrier robot (not shown) carries the semiconductor wafer W into the chamber 65 when the port 66 is opened. When the heat treatment apparatus heat-treats the semiconductor wafer W in the chamber 65, the port 66 is closed.

The chamber 65 is installed below the light source 10. The light source 10 includes a plurality (27 in this embodiment) xenon flash lamps (hereinafter simply referred to as "flash lamps") 69. The plurality of flash lamps 69 are long cylindrical bar lamps, respectively, and are arranged at a predetermined pitch in parallel to each other horizontally. The reflecting plate 71 is arranged on the plurality of flash lamps 69 forming the light source 10 which completely covers the flash lamp 69.

Each xenon flash lamp 69 is filled with a xenon gas, and includes a glass tube in which anodes and cathodes connected to an electric capacitor are provided at both ends, and a trigger electrode wound around the outer circumference of the glass tube. Xenon gas is an electrical insulator, so electricity does not flow into the glass tube under normal conditions. When a high voltage is applied to the trigger electrode for dielectric breakdown, electricity temporarily flows in the glass tube to heat the xenon gas as Joule heat and take out the light. The xenon flash lamp 69 is capable of emitting extremely strong light as compared to a continuous source since the previously accumulated electrostatic energy is transformed into extremely short light pulses of 0.1 milliseconds (ms) to 10 milliseconds (ms). Can be.

Some of the light emitted from the flash lamp 69 passes directly through the floodlight plate 61 and is introduced into the chamber 65. The remainder of the light emitted from the flash lamp 69 is temporarily reflected by the reflecting plate 71 and then passed through the floodlight plate 61 and introduced into the chamber 65.

The heat diffusion plate 73 and the heating plate 74 are arranged in this order in the chamber 65. The heat diffusion plate 73 is fixed to the upper surface of the heating plate 74. Fins 75 are provided on the surface of the heat diffusion plate 73 to prevent misalignment of the semiconductor wafer W.

The heating plate 74 is used to preheat (secondary-heat) the semiconductor wafer W. The heating plate 74 is made of aluminum nitride and stores therein a heater and a sensor for controlling the heater. On the other hand, the heat diffusion plate 73 is used to uniformly preheat the semiconductor wafer W by diffusing heat energy received from the heating plate 74. The heat diffusion plate 73 is made of a material such as sapphire (Al ₂ O ₃ : aluminum oxide) or quartz having a relatively small thermal conductivity.

The motor 40 drives the heat diffusion plate 73 and the heating plate 74 to carry in / out the semiconductor wafer W with respect to the chamber 65 shown in FIG. 1, and as shown in FIG. 2. Vertically move between the heat treatment positions of the semiconductor wafer (W).

The heating plate 74 is connected to the moving plate 42 through the cylindrical body 41. The guide member 43 suspended from the bottom plate 62 of the chamber 65 guides the movable plate 42 to be movable vertically. The fixed plate 44 is fixed to the lower end of the guide member 43, and the motor 40 for rotating / driving the ball screw 45 is arranged at the center of the fixed plate 44. The ball screw 45 is coupled to the nut 48 connected to the moving plate 42 through the connecting members 46 and 47. Therefore, the motor 40 is a heat spreader plate between a position at which the semiconductor wafer W is loaded and unloaded with respect to the chamber 65 shown in FIG. 1 and a heat treatment position of the semiconductor wafer W shown in FIG. 2. 73 and the heating plate 74 can be moved vertically.

The heat treatment apparatus places a semiconductor wafer W carried into the chamber 65 through the port 66 by a transfer robot (not shown) on the support pin 70 or on the support pin 70. In order to allow the semiconductor wafer W to be carried out from the chamber 65 through the port 66, the heat diffusion plate (a) is placed at a position where the semiconductor wafer W is loaded / exported with respect to the chamber 65 shown in FIG. 1. 73 and the heating plate 74 are lowered. In this state, the upper ends of the support pins 70 pass through through-holes formed in the heat spreader plate 73 and the heating plate 74 to be arranged above the surface of the heat spreader plate 73. . For convenience of description, FIG. 1 shows through holes of the heat spreader plate 73 and the heating plate 74 which were not originally shown in the cross-sectional view of the side surface.

On the other hand, to heat-treat the semiconductor wafer W, the heat diffusion plate 73 and the heating plate 74 are raised to the heat treatment position of the semiconductor wafer W above the upper ends of the support pins 70. The heat diffusion plate 73 and the heating plate 74 are moved from the position at which the semiconductor wafer W is loaded / exported with respect to the chamber 65 shown in FIG. 1 to the heat treatment position of the semiconductor wafer W shown in FIG. 2. In the process of raising, the heat diffusion plate 73 receives the semiconductor wafer W positioned on the support pin 70, supports the lower surface to the surface, raises it, and transmits light at a position in the chamber 65. The semiconductor wafer W is held horizontally close to the plate 61. Meanwhile, the heat diffusion plate 73 and the heating plate 74 are moved from the heat treatment position of the semiconductor wafer W shown in FIG. 2 to the position where the semiconductor wafer W is loaded / exported from the chamber 65 shown in FIG. 1. In the process of lowering the heat diffusion plate 73 transfers the semiconductor wafer (W) to the support pin (70).

An elastic bellows 77 which holds the chamber 65 in a closed state is arranged between the bottom plate 62 and the movable plate 42 of the chamber 65 to surround the cylindrical body 41. The bellows 77 is contracted when the heat diffusion plate 73 and the heating plate 74 are raised to the heat treatment position, and the heat diffusion plate 73 and the heating plate 74 carry in / out of the semiconductor wafer W. When it descends, it expands to block the atmosphere in the chamber 65 from the external atmosphere.

An introduction passage 78 connected to the open / close valve 80 is formed in the side plate 63 of the chamber 65 opposite to the port 66. This introduction passage 78 is used to introduce a gas, such as, for example, an inert nitrogen gas, required for processing in the chamber 65. On the other hand, the discharge passage 79 connected to another open / close valve 81 is formed in the port 66 of the side plate 64. The discharge passage 79 is used to discharge gas from the chamber 65 and is connected to discharge means (not shown) through the opening / closing valve 81.

The heat treatment operation of the heat treatment apparatus according to this embodiment with respect to the semiconductor wafer W will now be described. This heat treatment apparatus processes the semiconductor wafer W on which the ion implantation is completed.

In this heat treatment apparatus, a transfer robot (not shown) is arranged while the heat diffusion plate 73 and the heating plate 74 are arranged at positions to carry in / out of the semiconductor wafer W with respect to the chamber 65 shown in FIG. ) Introduces the semiconductor wafer (W) through the port 66 into the chamber 65 and is positioned on the support pin 70. When the transfer robot completely loads the semiconductor wafer W into the chamber 65, the heat treatment apparatus closes the port 66 with the gate valve 68. Thereafter, the motor 40 drives the heat diffusion plate 73 and the heating plate 74 and moves to the heat treatment position of the semiconductor wafer W shown in FIG. 2 to hold the semiconductor wafer W horizontally. The heat treatment device opens the on / off valves 80 and 81 to form a flow of nitrogen gas in the chamber 65.

The heater built in the heating plate 74 heats the heat diffusion plate 73 and the heating plate 74 in advance at a preset temperature. Therefore, when the heat treatment apparatus raises the heat diffusion plate 73 and the heating plate 74 to the heat treatment position of the semiconductor wafer W, the heated heat diffusion plate 73 is in contact with the semiconductor wafer W to be preheated. As a result, the temperature of the semiconductor wafer W gradually rises.

In this state, the heat diffusion plate 73 continues to heat the semiconductor wafer W. When the heat diffusion plate 73 raises the temperature of the semiconductor wafer W, a temperature sensor (not shown) regularly monitors whether the surface temperature of the semiconductor wafer W has reached the preheating temperature T1.

The preheat temperature T1 is about 200 to 600 degreeC, for example. Further, even when the heat diffusion plate 73 heats the semiconductor wafer W to this preheat temperature T1, the ions implanted in the semiconductor wafer W are not diffused.

When the surface of the semiconductor wafer W reaches the preheating temperature T1, the heat treatment apparatus lights up the flash lamp 69 which performs flash heating. In this flash heating step, the heat treatment apparatus turns on the flash lamp 69 for about 0.1 ms to 10 ms. Therefore, the flash lamp 69 which converts the previously accumulated electrostatic energy into extremely short light pulses emits extremely strong flashes.

The surface of the semiconductor wafer W instantaneously reaches the temperature T2 by this flash heating. A temperature T2 of about 1000 ° C to 1100 ° C is required for ion activation of the semiconductor wafer W. The heat treatment apparatus activates the ions implanted into the semiconductor wafer W by raising the surface temperature of the semiconductor wafer W to the level of this processing temperature T2.

At this time, the heat treatment apparatus completes the ion activation process of the semiconductor wafer W in a short time by raising the temperature of the surface of the semiconductor wafer W to a level of the processing temperature T2 in a very short time of about 0.1 ms to 10 ms. . Therefore, the ions implanted in the semiconductor wafer W are not diffused, and the heat treatment apparatus can prevent the profile of the ions implanted in the semiconductor wafer W from being rounded. Since the time required for the ion activation process is extremely short compared to the time required for the diffusion of the ions, the heat treatment apparatus completes the ion activation process in a short time of about 0.1 ms to 10 ms without causing diffusion.

In addition, before turning on the flashing lamp 69 which heats the semiconductor wafer W, the heat processing apparatus which heats the surface of the semiconductor wafer W by the heating plate 74 by the preheat temperature T1 of about 200 degreeC to 600 degreeC is The flash lamp 69 can quickly raise the temperature of the semiconductor wafer W to the level of the processing temperature T2 of about 1000 ° C to 1100 ° C.

After the flash heating process is completed, while the heat treatment apparatus opens the port 66 to the gate valve 68, the motor 40 drives the heat diffusion plate 73 and the heating plate 74, as shown in FIG. With respect to the chamber 65, the semiconductor wafer W is lowered to the position to carry in / out of. The transfer robot (not shown) carries out the semiconductor wafer W positioned on the support pin 70 from the chamber 65. In this way, the heat treatment apparatus completes the heat treatment operation.

When the heat treatment apparatus opposes the surface of the semiconductor wafer W against the flash lamp 69, as described, the illuminance of the portions located immediately below the flash lamp 69 exceeds the remaining portions in the plane of the temperature distribution. The uniformity is compromised. Therefore, according to the first embodiment, the heat treatment apparatus assumes that the distance between each of the flash lamps 69 and the reflecting plate 71 is 1, so that the distance between the surface of the semiconductor wafer W and each of the flash lamps 69 is different. Since the distance is set to 1.8 or less, the semiconductor wafer W can be uniformly heat treated with the plurality of flash lamps 69. Now, the description of this continues.

3 is a graph that typically shows the relationship between the illuminance of light emitted from the flash lamp onto the surface of the semiconductor wafer and the position of the flash lamp.

Referring to this graph, reference sign LA indicates the illuminance distribution of light reflected by the reflecting plate 71 and supplied to the surface of the semiconductor wafer W, and reference sign LB indicates the surface of the semiconductor wafer W from the flash lamp 69. The illuminance distribution of the light directly supplied to the light source is denoted by reference numeral LC, which indicates the total illuminance distribution of the illuminance distribution LA and the illuminance distribution LB on the surface of the semiconductor wafer W.

The flash lamp 69 includes a plurality of lamps 691, 692 arranged at regular intervals. The illuminance distribution LB has a peak at the position W1 of the surface of the semiconductor wafer W positioned just below the lamp 691 due to the irradiation L11 directly from the center L1 of the lamp 691. Also for the lamp 692, the illuminance distribution LB has a peak at a position located directly below the center L2.

As seen at position W1, reflector plate 71 reflects lamp 692 adjacent to lamp 691 through the gap between lamps 691 and 692. In other words, the irradiation L21 emitted from the lamp 692 and reflected by the reflecting plate 71 is introduced into the position W1, as shown in FIG. In this state, the distance Z1 between the center L1 of the lamp 691 and the reflecting plate 71 and the distance Z2 between the center L1 of the lamp 691 and the semiconductor wafer W have a ratio of 1: 2. Is executed when At this time, the irradiation L31 emitted from the flash lamp 69, reflected by the reflecting plate 71, and introduced into the surface of the semiconductor wafer W is located directly below the gap between the lamps 691 and 692. W2 is not reached. Therefore, the reflected light by the reflecting plate 71 obtains the illuminance distribution LA. Assuming that the reflector plate 71 is formed by a member having, for example, a high reflectance of at least 95%, the illuminance distribution LA is relatively lower in intensity than the illuminance distribution LB because of the extension of the irradiation distance of the reflected light. .

As described above, if the distances Z1 and Z2 are in a ratio of 1: 2, the peaks of the illuminance distribution LA and the illuminance distribution LB coincide with the centers L1 and L2 of the respective flash lamps 691 and 692 respectively. do. Therefore, the surface of the semiconductor wafer W represents the total illuminance distribution LC of the illuminance distribution LA and the illuminance distribution LB, and the peaks overlap with each other and end in large dispersion.

Therefore, the heat treatment apparatus according to the present embodiment reduces the dispersion of the total illuminance distribution LC by shifting the peaks of the illuminance distribution LA and the illuminance distribution LB from each other, thereby reducing the dispersion of the total illuminance distribution LC. Reduce roughness irregularities across the surface. In particular, the heat treatment apparatus, as shown in FIG. 4, shows the ratio of the distance between the surface of the semiconductor wafer W and each of the flash lamps 69 to the distance between each of the flash lamps 69 and the reflector plate 71. Is set to less than 2. According to the first embodiment, the heat treatment apparatus uses a distance Z1 between each flash lamp 69 and a reflector plate 71 and a distance Z3 between the surface of the semiconductor wafer W and each flash lamp 69: 1. Since the ratio is set at 1.8, for example, assuming that the distance Z1 is 25 mm, the distance Z3 is 45 mm. The distance Z10 between the lamps 691 and 692 is 2 mm. Therefore, the peaks of the illuminance distribution LB generated from the main heating process using the direct light from the flash lamp 69 and the illuminance distribution LA resulting from the sub-heating process using the reflected light by the reflector 71 are separated from each other. Is moved. Therefore, in the total illuminance distribution LC of the illuminance distribution LA and the illuminance distribution LB on the surface of the semiconductor wafer W, even if the peaks of the illuminance distribution LA and the illuminance distribution LB overlap each other, the dispersion is Is reduced.

As for the ratio Z3 / Z1 mentioned above, 1.8 or less are preferable. The irradiation L21 passing through the gap between the lamps 691 and 692 exhibits a certain width because of the distance Z10 between the lamps 691 and 692. Therefore, if the ratio Z3 / Z1 is slightly smaller than 2, the effect of shifting the peaks of the roughness distribution LA and the roughness distribution LB is not obtained. Therefore, when the ratio Z3 / Z1 is selected in the range of 1.8 or less, an illuminance distribution having a small dispersion in strength is obtained.

If the absolute value of the distance between the center of each flash lamp 69 and the semiconductor wafer W is large, the illuminance distribution of the irradiation light supplied directly from the flash lamp 69 to the semiconductor wafer W is hardly dispersed. In other words, the above-described roughness distribution LB is substantially flat. Also in this case, the ratio of the distance between the lamp center of each flash lamp 69 and the semiconductor wafer W held by the heat diffusion plate 73 to the distance between the lamp center and the reflecting plate 71 is When reaching 2, the surface roughness distribution of the semiconductor wafer W is dispersed for the following reason.

FIG. 5 is a model diagram showing the arrangement relationship between the reflecting plate 71, the flash lamp 69 and the semiconductor wafer W. As shown in FIG. Numeral 695 represents an attention lamp selected arbitrarily from among the plurality of flash lamps 69, and numeral 696 represents an adjacent lamp adjacent to the attention lamp 695.

The reflected light component RL6 is emitted from the adjacent lamp 696 and regularly reflected by the reflecting plate 71, so that the distance between the adjacent lamp 696 and the lamp 669, in particular, the lamp 695 and the lamp 696 adjacent to each other. Passing through the center point between the centers C5 and C6, respectively, when the distance between the lamp center C5 and the semiconductor wafer W reaches the value Z2, ie, the respective flashes for the distance between the lamp center and the reflector 71 When the ratio of the distance between the lamp center of the lamp 69 and the semiconductor wafer W reaches 2, the surface position W5 of the semiconductor wafer W located just below the lamp center C5 is reached. In addition, the reflected light component RL6 reaches the position W5 in such a manner as to overlap from adjacent lamps 696 provided on both sides of the lamp 669 of interest. On the other hand, the reflected light by the reflecting plate 71 reaches the surface position W6 of the semiconductor wafer W positioned just below the center point between the lamp center C5 of the lamp 669 and one lamp center C6 of the adjacent lamp 696. do.

In other words, the reflector 71 is adjacent to the lamp 669, as seen from the surface position W5 of the semiconductor wafer W held by the heat diffusion plate 73 positioned directly below the lamp 695. Reflects an image of the adjacent lamp 696 through the gap between the lamps 696. On the other hand, as shown from the surface position W6 of the semiconductor wafer W located just below the center point between the attention lamp 695 and one of the adjacent lamps 696, the reflecting plate 71 is adjacent to the attention lamp 695. The semiconductor wafer W itself reflects through the gap between one of the lamps 696.

Therefore, regardless of the presence / absence of the dispersion of the light intensity distribution emitted directly from the flash lamp 69, the lamp center and the semiconductor wafer of each flash lamp 69 relative to the distance between the lamp center and the reflector 71 When the distance ratio between W) reaches 2, the roughness distribution on the surface of the semiconductor wafer W is dispersed to impair in-plane uniformity of the temperature distribution.

By setting the distance between the lamp center C5 and the semiconductor wafer W to the value Z3, between the lamp center of each flash lamp 69 and the semiconductor wafer W with respect to the distance between the lamp center and the reflecting plate 71. When the distance ratio of is set to 1.8, in order to prevent the reflected light RL7 from reaching the position W5, the lamp 669 itself is emitted from the other one of the adjacent lamps 696, and is regularly arranged by the reflecting plate 71. Reflected to block the reflected light RL7 reaching the position W5 located just below the lamp center C5. Reflected light component RL6 passing through the gap between the other of the adjacent lamps 696 and the lamp of interest 695 reaches a position other than the position W5 located just below the lamp center C5, and through the lamp of interest 695 the lamp adjacent to it. The reflected light component RL6 does not reach this position from one of the adjacent lamps 696 opposite to the other of 696, so that the reflected light components RL6 overlap with each other from adjacent lamps 696 provided on both sides of the lamp 695 of interest. I do not lose.

In other words, as seen from the surface position of the semiconductor wafer W held by the heat spreader plate 73 positioned directly below each of the plurality of flash lamps 69, the reflector plate 71 is no flash lamp 69. ) So that the image of the adjacent lamp 696 is not reflected from the gap between the adjacent lamp 696 and the adjacent lamp 696, that is, the reflecting plate 71 reflects the image of the heat diffusion plate 73 or the semiconductor wafer W from the gap. The heat treatment apparatus arranges the reflecting plate 71, the plurality of flash lamps 69, and the semiconductor wafer W.

In this way, dispersion in the illuminance distribution is reduced on the surface of the semiconductor wafer W irradiated with the flash from the flash lamp 69, and the heat treatment apparatus can improve the in-plane uniformity of the temperature distribution on the semiconductor wafer W.

As seen from the surface position of the semiconductor wafer W positioned just below each of the plurality of flash lamps 69, the reflector 71 is not separated from the distance between each of the flash lamps 69 and the adjacent lamps 696. In order not to reflect the image of the adjacent lamp 696, the heat treatment apparatus measures the ratio of the distance between the lamp center of each flash lamp 69 and the semiconductor wafer W to the distance between the lamp center and the reflector 71. 1.8 or less. According to the arrangement relationship of the reflector 71, the plurality of flash lamps 69, and the semiconductor wafer W, the heat treatment apparatus improves in-plane uniformity of the temperature distribution on the semiconductor wafer W. In order to achieve this, dispersion of the illuminance distribution on the surface of the semiconductor wafer W irradiated with the flash from the flash lamp 69 can be reduced.

<2. Second Embodiment>

Now, the heat treatment apparatus according to the second embodiment of the present invention will be described. The heat treatment apparatus according to the second embodiment is the same as the structure according to the first embodiment except for the above-described ratio. The heat treatment apparatus according to the second embodiment is the same as the heat treatment operation according to the first embodiment.

In the heat treatment apparatus according to the second embodiment, as shown in FIG. 4, the distance Z1 between each of the flash lamps 69 and the reflecting plate 71, the surface of the semiconductor wafer W, and the respective flash lamps 69. By setting the distance Z4 between them at a ratio of 1: 2.2, for example, assuming that the distance Z1 is 25 mm, the distance Z4 is 55 mm. The distance Z10 between the lamps 691 and 692 is 2 mm. Therefore, the peaks of the illuminance distribution LB generated from the main heating process using direct light from the flash lamp 69 and the subsidiary illuminating distribution LA resulting from the sub-heating process using the light reflected by the reflecting plate 71 are shifted from each other. Therefore, even when the peaks of the illuminance distribution LA and the illuminance distribution LB overlap each other, the dispersion is the total illuminance distribution LC of the illuminance distribution LA and the illuminance distribution LB on the surface of the semiconductor wafer W. Is reduced.

According to the second embodiment, the ratio Z4 / Z1 is preferably at least 2.2. Irradiation L21 passing through the gap between the lamp 691 and another lamp 692 shows a certain width because of the gap Z10 between the lamps 691 and 692. Therefore, when the ratio Z4 / Z1 slightly exceeds 2, the effect of shifting the peaks of the roughness distribution LA and the roughness distribution LB is not obtained. Therefore, the ratio Z4 / Z1 is selected in the range of at least 2.2 to obtain an illuminance distribution having a dispersion with low strength.

As described above, when the absolute value of the distance between the center of each flash lamp 69 and the semiconductor wafer W is large, the illuminance distribution of the irradiation light directly supplied from the flash lamp 69 to the semiconductor wafer W is almost the same. It is not distributed. Regardless of the presence / absence of dispersion of the illuminance distribution of light emitted directly from the flash lamp 69, the lamp center and the semiconductor wafer W of each flash lamp 69 relative to the distance between the lamp center and the reflector plate 71 It has already been described that when the distance ratio between the two reaches 2, the roughness distribution on the surface of the semiconductor wafer W is dispersed such that the in-plane uniformity of the temperature distribution is impaired.

When the heat treatment apparatus sets the distance between the lamp center C5 and the semiconductor wafer W to level Z4 in FIG. 5, that is, the lamp of each flash lamp 69 with respect to the distance between the lamp center and the reflector plate 71. When the ratio of the distance between the center and the semiconductor wafer W is set to 2.2, the adjacent lamp 696 itself is emitted from the adjacent lamp 696 and regularly reflected by the reflector plate 71, immediately following the lamp center C5. The reflected light RL8 reaching the position W5 located below is blocked. The reflected light component RL6 passing through the gap between the spotlight 695 and the adjacent lamp 696 reaches a position other than the position W5 located just below the lamp center C5, and the adjacent lamp 696 is passed through the spotlight 695. The reflected light component RL6 from another adjacent lamp 696 opposite to does not reach this position, and the reflected light components RL6 do not overlap with each other from adjacent lamps 696 provided on both sides of the lamp 695 of interest.

In other words, as seen from the surface position of the semiconductor wafer W held by the heat spreader plate 73 positioned directly below each of the plurality of flash lamps 69, the reflector plate 71 may be provided with any flash lamp 69; ) Does not reflect an image of any adjacent lamp 696 from the gap between the adjacent lamp 696 and the adjacent lamp 696, that is, the reflector 71 reflects the image of the heat diffusion plate 73 or the semiconductor wafer W from the gap. The heat treatment apparatus arranges the reflecting plate 71, the plurality of flash lamps 69, and the semiconductor wafer W.

In this way, dispersion in the illuminance distribution is reduced on the surface of the semiconductor wafer W to which the flash is irradiated from the flash lamp 69, and the heat treatment apparatus can improve the in-plane uniformity of the temperature distribution on the semiconductor wafer W.

As seen from the surface position of the semiconductor wafer W positioned directly below each of the plurality of flash lamps 69, the reflector 71 is not separated from the distance between each of the flash lamps 69 and the adjacent lamps 696. In order not to reflect the image of the adjacent lamp 696, the heat treatment apparatus measures the ratio of the distance between the lamp center of each flash lamp 69 and the semiconductor wafer W to the distance between the lamp center and the reflector 71. Set to at least 2.2. According to such an arrangement relationship of the reflecting plate 71, the plurality of flash lamps 69, and the semiconductor wafer W, the heat treatment apparatus includes a flash lamp (in order to improve in-plane uniformity of the temperature distribution on the semiconductor wafer W). 69, it is possible to reduce the dispersion of the roughness distribution on the surface of the semiconductor wafer W irradiated with the flash.

The present invention is not limited to the above-described embodiments and can be implemented in other modes as follows:

(1) Although the heat treatment apparatus according to the embodiments described above irradiates light to the semiconductor wafer W to perform ion activation, the substrate processed by the heat treatment apparatus of the present invention is limited to the semiconductor wafer W. It doesn't work. For example, the heat treatment apparatus according to the present invention may selectively process a glass substrate formed of a silicon film such as a silicon nitride film or a polycrystalline silicon film. For example, the formation of a silicon oxide film which is ion-implanted into a polycrystalline silicon film formed on a glass substrate by CVD to form an amorphous silicon film and functions as an anti-reflection coating. This follows. In this state, the heat treatment apparatus according to the present invention can irradiate light to the entire surface of the amorphous silicon film in order to form the polycrystalline silicon film by polycrystallizing the amorphous silicon film.

(2) The heat treatment apparatus according to the present invention forms a lower silicon oxide film and a polysilicon film prepared by crystallizing amorphous silicon on a glass substrate in order to activate impurities impregnated into the polysilicon film in the doping step, and Alternatively, light can be irradiated to a TFT substrate having a structure obtained by doping a polysilicon film with an impurity such as boron.

In addition, it is possible to apply various design modifications within the scope of the details described in the claims.

Although the invention has been shown and described in detail, the foregoing description is in all aspects illustrative and not restrictive. Thus, of course, various modifications and variations can be devised without departing from the scope of the invention.

As described above, according to the present invention, it is possible to reduce the irregularity of roughness on the entire processed surface of the substrate, thereby improving in-plane uniformity of the temperature distribution on the substrate.

Claims (11)

In the heat treatment method of heat-treating a substrate by irradiating light to the substrate, A main heating step for introducing light emitted from a plurality of light sources directly into the treated surface of the substrate; And Concurrently with the main heating process, a sub-heating process for reflecting the light emitted from the plurality of light sources by the reflector and for introducing the reflected light to the treated surface of the substrate, And a peak of an illuminance distribution on the treated surface of the substrate resulting from the sub-heating process relative to a peak of an illuminance distribution on the treated surface of the substrate resulting from the main heating process. According to claim 1, By setting the ratio of the distance between the light sources and the substrate to the distance between the reflector and the light sources to be 1.8 or less, at least 2.2, the roughness distribution on the treated surface of the substrate resulting from the main heating process And moving said peak of said roughness distribution on said treated surface of said substrate resulting from said sub-heating step relative to said peak of. In the heat treatment apparatus for heating a substrate by irradiating light to the substrate, A light source having a plurality of lamps; A retaining element for keeping the substrate substantially horizontal in a chamber provided below the light source; And A reflective element opposite the retaining element through the light source to reflect light emitted from the light source, And a peak of an illuminance distribution of reflected light introduced through the reflective element to the treated surface through the reflecting element with respect to a peak of an illuminance distribution of light directly introduced from the light source to the treated surface of the substrate. The method of claim 3, wherein Each of said plurality of lamps is an elongated cylindrical bar lamp, And the plurality of lamps are aligned parallel to the substrate held by the retaining element to define the spacing between the lamps. The method of claim 4, wherein Each of the plurality of lamps is a xenon flash lamp, And the retaining element comprises an auxiliary heating element for preheating the held substrate. In the heat treatment apparatus for heating a substrate by irradiating light to the substrate, A light source having a plurality of lamps; A retaining element for keeping the substrate substantially horizontal in a chamber provided below the light source; And A reflective element opposite the retaining element through the light source to reflect light emitted from the light source, And setting a ratio of the distance between the light source and the substrate held by the retaining element to the distance between the reflective element and the light source to 1.8 or less or at least 2.2. The method of claim 6, Each of said plurality of lamps is an elongated cylindrical bar lamp, The plurality of lamps are aligned in parallel with the substrate held by the retaining element to define a spacing between the lamps, Setting a ratio of the distance between the centers of the plurality of lamps and the substrate held by the retaining element to a distance between the centers of the plurality of lamps and the reflective element to 1.8 or less or at least 2.2 Device. The method of claim 7, wherein Each of the plurality of lamps is a xenon flash lamp, And the retaining element comprises an auxiliary heating element for preheating the held substrate. In the heat treatment apparatus for heating a substrate by irradiating light to the substrate, A light source formed by horizontally aligning a plurality of long cylindrical bar lamps in parallel with each other; A retaining element for keeping the substrate substantially horizontal in a chamber provided below the light source; And A reflective element opposite the retaining element through the light source to reflect light emitted from the light source, As seen from the surface position of the substrate held by the retaining element located directly below each of the plurality of bar lamps, the reflecting element is adapted for each of the respective through the gap between the respective bar lamps and the adjacent bar lamps. Arranging the substrate held by the reflective element, the light source, and the retaining element such that no image of any adjacent bar lamp adjacent to the bar lamp is reflected. The method of claim 9, Setting a ratio of the distance between the centers of the plurality of bar lamps and the substrate held by the retaining element to the distance between the centers of the plurality of bar lamps and the reflective element to 1.8 or less or at least 2.2 , Heat treatment device. The method of claim 10, Each of said plurality of bar lamps is a xenon flash lamp, And the retaining element comprises an auxiliary heating element for preheating the held substrate.

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