JP2004179510A - Heat treatment apparatus and susceptor therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a susceptor for heat treatment and a heat treatment apparatus in which a wafer may be prevented from being cracked during heat treatment. <P>SOLUTION: In a susceptor 73, a recess 97 having a tapered surface 95 and a placing surface 99 is formed. A gradient α of the tapered surface 95 to the placing surface 99 is made ≥5°and <30°. Thus, when the susceptor 73 receives a semiconductor wafer W, the semiconductor wafer W may be positioned on the placing surface 99 by the tapered surface 95. Even when a wafer surface is rapidly thermally expanded by radiation with flashing light, excessive stress is suppressed from being imparted to the semiconductor wafer W, such that the semiconductor wafer W may be prevented from being cracked during the heat treatment. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat treatment susceptor that holds a substrate to be treated when a substrate such as a semiconductor wafer is heat treated, and a heat treatment apparatus including the heat treatment susceptor.
[0002]
[Prior art]
Conventionally, in an ion activation process of a semiconductor wafer after ion implantation, a heat treatment apparatus such as a lamp annealing apparatus using a halogen lamp has been used. In such a heat treatment apparatus, the semiconductor wafer is ion-activated by heating (annealing) the semiconductor wafer to a temperature of about 1000 ° C. to 1100 ° C., for example. In such a heat treatment apparatus, the temperature of the substrate is raised at a rate of several hundred degrees per second by using the energy of light irradiated from the halogen lamp.
[0003]
However, even when ion activation of a semiconductor wafer is performed using a heat treatment apparatus that raises the temperature of the substrate at a speed of several hundred degrees per second, the profile of ions implanted into the semiconductor wafer is reduced, that is, due to heat It has been found that a phenomenon occurs in which ions diffuse. When such a phenomenon occurs, even if ions are implanted at a high concentration on the surface of the semiconductor wafer, the ions after implantation are diffused, so that ions must be implanted more than necessary. Has occurred.
[0004]
In order to solve the above-mentioned problems, the surface of the semiconductor wafer is irradiated with flash light using a xenon flash lamp or the like, so that only the surface of the semiconductor wafer into which ions are implanted is raised in a very short time (several milliseconds or less). Techniques for heating have been proposed (see, for example, Patent Documents 1 and 2). If the temperature is raised for a very short time with a xenon flash lamp, there is not enough time for ions to diffuse, so only ion activation is performed without the profile of the ions implanted in the semiconductor wafer being distorted. Can do it.
[0005]
In addition, the heat treatment is not limited to the heating method by light irradiation. Generally, in a heat treatment apparatus, heat treatment is often performed in a state where a substrate is held by a susceptor having excellent heat resistance (see, for example, Patent Documents 3 and 4).
[0006]
[Patent Document 1]
JP 59-169125 A
[Patent Document 2]
JP 63-166219 A
[Patent Document 3]
JP-A-10-74705
[Patent Document 4]
JP 2000-355766 A
[0007]
[Problems to be solved by the invention]
By the way, since the xenon flash lamp instantaneously irradiates the semiconductor wafer with light having extremely high energy, the surface temperature of the semiconductor wafer rapidly rises instantaneously, and when the energy of the irradiating light exceeds a certain threshold value, the surface rapidly changes. Due to the thermal expansion of the semiconductor wafer, the semiconductor wafer is cracked with high probability. For this reason, when the heat treatment is actually performed, light of energy having a certain margin (process margin) less than the above threshold is irradiated.
[0008]
However, when the wafer is heated by flash irradiation from a xenon flash lamp in a state where the semiconductor wafer is held on the susceptor, the semiconductor wafer may be broken even if flash light having an energy less than the above threshold is irradiated. This is because when the wafer surface suddenly thermally expands due to flash exposure and the semiconductor wafer tries to warp convexly, if the wafer edge is in contact with the pocket edge of the susceptor or positioning pins, This is because there is no time for the wafer to slide on the susceptor to relieve such stress while a large force is applied to the substrate. As a result, even when a flash of energy less than the above threshold is irradiated, if the edge of the semiconductor wafer is in contact with something, the wafer will be cracked by the stress received from it during instantaneous thermal expansion. It was.
[0009]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a heat treatment susceptor and a heat treatment apparatus capable of preventing the substrate from cracking during heat treatment.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention of claim 1 is a heat treatment susceptor for holding a substrate to be processed when performing heat treatment, a flat mounting surface having a region larger than the planar size of the substrate, A taper surface surrounding the peripheral portion of the placement surface to define the placement surface, and connecting the lower end portion of the tapered surface to the peripheral portion of the placement surface and raising the tapered surface upward The inclination of the tapered surface with respect to the mounting surface is 5 ° or more and less than 30 °.
[0011]
According to a second aspect of the present invention, in the heat treatment susceptor according to the first aspect of the present invention, the surface average roughness of the tapered surface is 1.6 μm or less.
[0012]
According to a third aspect of the present invention, there is provided a heat treatment susceptor for holding a substrate to be processed when heat treatment is performed, the heat treatment susceptor including a recess for accommodating the substrate at the time of heat treatment, and a flat bottom surface and a peripheral edge of the bottom surface. An inclined surface surrounding the portion is provided, and the gradient of the inclined surface with respect to the bottom surface is set to 5 ° or more and less than 30 °.
[0013]
According to a fourth aspect of the present invention, in a heat treatment apparatus that heats a substrate by irradiating the substrate with light, the light source having a plurality of lamps is provided below the light source and emitted from the light source. 4. A chamber having an upper chamber window that transmits light, and a holding unit that holds the substrate in a substantially horizontal position in the chamber, wherein the holding unit includes any one of claims 1 to 3. The susceptor for heat treatment according to the invention is provided.
[0014]
The invention of claim 5 is the heat treatment apparatus according to claim 4, wherein each of the plurality of lamps is a xenon flash lamp, and the holding means further includes an assist heating means for preheating the substrate to be held. I am letting.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
1 and 2 are side sectional views showing the structure of a heat treatment apparatus according to the present invention. This heat treatment apparatus is an apparatus for performing heat treatment of a substrate such as a circular semiconductor wafer by flash light from a xenon flash lamp.
[0017]
This heat treatment apparatus includes a light transmitting plate 61, a bottom plate 62, and a pair of side plates 63 and 64, and includes a chamber 65 for housing the semiconductor wafer W and heat-treating it. The translucent plate 61 constituting the upper part of the chamber 65 is made of, for example, a material having infrared transparency such as quartz, and functions as a chamber window that transmits light emitted from the light source 5 and guides it into the chamber 65. doing. The bottom plate 62 constituting the chamber 65 is provided with support pins 70 that pass through a susceptor 73 and a heating plate 74 described later and support the semiconductor wafer W from the lower surface thereof.
[0018]
Further, an opening 66 for carrying in and out the semiconductor wafer W is formed in the side plate 64 constituting the chamber 65. The opening 66 can be opened and closed by a gate valve 68 that rotates about a shaft 67. The semiconductor wafer W is loaded into the chamber 65 by a transfer robot (not shown) with the opening 66 released. Further, when the semiconductor wafer W is heat-treated in the chamber 65, the opening 66 is closed by the gate valve 68.
[0019]
The chamber 65 is provided below the light source 5. The light source 5 includes a plurality (27 in the present embodiment) of xenon flash lamps 69 (hereinafter also simply referred to as “flash lamps 69”) and a reflector 71. The plurality of flash lamps 69 are rod-shaped lamps each having a long cylindrical shape, and are arranged in parallel with each other such that the longitudinal direction thereof is along the horizontal direction. The reflector 71 is disposed above the plurality of flash lamps 69 so as to cover them entirely.
[0020]
The xenon flash lamp 69 includes a glass tube in which xenon gas is sealed and an anode and a cathode connected to a capacitor at both ends thereof, and a trigger electrode wound around an external portion of the glass tube. Is provided. Since xenon gas is an electrical insulator, electricity does not flow into the glass tube under normal conditions. However, if the insulation is broken by applying a high voltage to the trigger electrode, the electricity stored in the capacitor instantaneously flows into the glass tube, and the xenon gas is heated by Joule heat at that time, and light is emitted. . In the xenon flash lamp 69, the electrostatic energy stored in advance is converted into an extremely short light pulse of 0.1 millisecond to 10 millisecond. It has the feature that it can.
[0021]
A light diffusing plate 72 is disposed between the light source 5 and the translucent plate 61. As the light diffusion plate 72, a surface of quartz glass as an infrared transmitting material subjected to light diffusion processing is used.
[0022]
Part of the light emitted from the flash lamp 69 passes directly through the light diffusing plate 72 and the light transmitting plate 61 toward the chamber 65. Further, another part of the light emitted from the flash lamp 69 is once reflected by the reflector 71, then passes through the light diffusing plate 72 and the light transmitting plate 61 and goes into the chamber 65.
[0023]
A heating plate 74 and a susceptor 73 are provided in the chamber 65. The susceptor 73 is attached to the upper surface of the heating plate 74. The heating plate 74 and the susceptor 73 constitute holding means for holding the semiconductor wafer W in the chamber 65 in a substantially horizontal posture.
[0024]
The heating plate 74 is for preheating (assist heating) the semiconductor wafer W. The heating plate 74 is made of aluminum nitride and has a configuration in which a heater and a sensor for controlling the heater are housed. On the other hand, the susceptor 73 is for positioning and holding the semiconductor wafer W, and for preheating the semiconductor wafer W uniformly by diffusing the thermal energy from the heating plate 74. As the material of the susceptor 73, a material having a relatively low thermal conductivity such as aluminum nitride or quartz is employed. Details of the susceptor 73 will be described later.
[0025]
The susceptor 73 and the heating plate 74 are configured to move up and down between the loading / unloading position of the semiconductor wafer W shown in FIG. 1 and the heat treatment position of the semiconductor wafer W shown in FIG.
[0026]
That is, the heating plate 74 is connected to the moving plate 42 via the cylindrical body 41. The moving plate 42 can be moved up and down by being guided by a guide member 43 supported by a bottom plate 62 of the chamber 65. A fixed plate 44 is fixed to the lower end portion of the guide member 43, and a motor 40 that rotationally drives a ball screw 45 is disposed at the central portion of the fixed plate 44. The ball screw 45 is screwed with a nut 48 connected to the moving plate 42 via connecting members 46 and 47. For this reason, the susceptor 73 and the heating plate 74 can be moved up and down between the loading / unloading position of the semiconductor wafer W shown in FIG. 1 and the heat treatment position of the semiconductor wafer W shown in FIG.
[0027]
The loading / unloading position of the semiconductor wafer W shown in FIG. 1 is placed on the support pin 70 by placing the semiconductor wafer W loaded from the opening 66 using a transfer robot (not shown). The susceptor 73 and the heating plate 74 are lowered so that the semiconductor wafer W can be carried out from the opening 66. In this state, the upper end of the support pin 70 passes through a through hole formed in the susceptor 73 and the heating plate 74 and protrudes upward from the surface of the susceptor 73.
[0028]
On the other hand, the heat treatment position of the semiconductor wafer W shown in FIG. 2 is a position where the susceptor 73 and the heating plate 74 are raised above the upper ends of the support pins 70 in order to perform heat treatment on the semiconductor wafer W. In the process in which the susceptor 73 and the heating plate 74 are raised from the loading / unloading position in FIG. 1 to the heat treatment position in FIG. 2, the semiconductor wafer W placed on the support pins 70 is received by the susceptor 73. It rises while being supported by the surface, and is held in a horizontal position at a position close to the translucent plate 61 in the chamber 65. Conversely, in the process in which the susceptor 73 and the heating plate 74 are lowered from the heat treatment position to the carry-in / carry-out position, the semiconductor wafer W supported by the susceptor 73 is transferred to the support pins 70.
[0029]
In a state where the susceptor 73 and the heating plate 74 that support the semiconductor wafer W are raised to the heat treatment position, the translucent plate 61 is located between the semiconductor wafer W held by them and the light source 5. Note that the distance between the susceptor 73 and the light source 5 at this time can be adjusted to an arbitrary value by controlling the rotation amount of the motor 40.
[0030]
Further, between the bottom plate 62 of the chamber 65 and the moving plate 42, a telescopic bellows 77 is disposed so as to surround the cylindrical body 41 and maintain the chamber 65 in an airtight body. When the susceptor 73 and the heating plate 74 are raised to the heat treatment position, the bellows 77 contracts, and when the susceptor 73 and the heating plate 74 are lowered to the loading / unloading position, the bellows 77 is extended, and the atmosphere in the chamber 65 and the external atmosphere are increased. Cut off.
[0031]
In the side plate 63 opposite to the opening 66 in the chamber 65, an introduction path 78 connected to the on-off valve 80 is formed. The introduction path 78 is for introducing a gas necessary for processing, for example, an inert nitrogen gas, into the chamber 65. On the other hand, a discharge passage 79 connected to the on-off valve 81 is formed in the opening 66 in the side plate 64. The discharge path 79 is for discharging the gas in the chamber 65, and is connected to an exhaust means (not shown) via the on-off valve 81.
[0032]
Further description of the susceptor 73 will be continued. 3 and 4 are a side sectional view and a plan view of the susceptor 73, respectively. The susceptor 73 of this embodiment is configured by forming a concave portion 97 having a circular shape when viewed from above on a disk-shaped member. The recess 97 functions to position and hold the semiconductor wafer W on the susceptor 73.
[0033]
The mounting surface 99 of the susceptor 73 is the bottom surface of the recess 97. The mounting surface 99 is a circular plane having a diameter slightly larger than the diameter of the semiconductor wafer W, that is, a flat surface having a region equal to or larger than the plane size of the semiconductor wafer W. A tapered surface 95 is formed so as to surround the peripheral portion of the mounting surface 99 which is the bottom surface of the recess 97. The tapered surface 95 is also an inclined surface for forming the recess 97. The lower end portion 95a of the taper surface 95 is connected to the peripheral edge portion of the placement surface 99, and the placement surface 99 is defined by the taper surface 95 if the way of viewing is changed.
[0034]
On the other hand, the upper end portion 95 b of the tapered surface 95 is connected to the peripheral surface 91 of the susceptor 73. The peripheral surface 91 is an annular plane and is parallel to the placement surface 99. The inner diameter of the peripheral surface 91 is larger than the diameter of the mounting surface 99. That is, the tapered surface 95 is formed so as to widen upward.
[0035]
The gradient α of the tapered surface 95, which is an inclined surface for forming the recess 97, with respect to the mounting surface 99 is 5 ° or more and less than 30 °, for example, 15 ° (see FIG. 5). Further, the surface average roughness (Ra) of the tapered surface 95 is set to 1.6 μm or less.
[0036]
Next, the heat treatment operation of the semiconductor wafer W by the heat treatment apparatus according to the present invention will be described. A semiconductor wafer W to be processed in this heat treatment apparatus is a semiconductor wafer after ion implantation.
[0037]
In this heat treatment apparatus, the semiconductor wafer W is loaded through the opening 66 by a transfer robot (not shown) in a state where the susceptor 73 and the heating plate 74 are arranged at the loading / unloading position of the semiconductor wafer W shown in FIG. , Placed on the support pin 70. When the loading of the semiconductor wafer W is completed, the opening 66 is closed by the gate valve 68. Thereafter, the susceptor 73 and the heating plate 74 are raised to the heat treatment position of the semiconductor wafer W shown in FIG. 2 by driving the motor 40, and the semiconductor wafer W is held in a horizontal posture. Further, the on-off valve 80 and the on-off valve 81 are opened to form a nitrogen gas flow in the chamber 65.
[0038]
Here, in the process in which the susceptor 73 and the heating plate 74 are raised, the susceptor 73 receives the semiconductor wafer W placed on the support pins 70. At this time, a thin air layer is sandwiched between the susceptor 73 and the semiconductor wafer W for several seconds after the semiconductor wafer W is transferred from the support pins 70 to the susceptor 73, and the semiconductor wafer W is removed from the susceptor 73 by the air layer. Slightly floated. In such a state, the phenomenon that the semiconductor wafer W moves so as to slide in the recess 97 due to some cause (for example, a slight inclination) and the wafer end is rebounded by the tapered surface 95 is repeated for several seconds. Thereafter, the air layer is eventually removed, so that the semiconductor wafer W is stably held in the recess 97 of the susceptor 73. That is, the slightly floating semiconductor wafer W is positioned by the taper surface 95 and is held on the lowest position of the recess 97, that is, on the mounting surface 99 without providing a special positioning pin or the like. . The diameter of the mounting surface 99 is slightly larger than the diameter of the semiconductor wafer W, and the semiconductor wafer W is normally positioned and held eccentrically on the mounting surface 99. It will be stably held in contact with the
[0039]
The susceptor 73 and the heating plate 74 are preheated to a predetermined temperature by the action of a heater built in the heating plate 74. For this reason, in a state where the susceptor 73 and the heating plate 74 are raised to the heat treatment position of the semiconductor wafer W, the semiconductor wafer W is preliminarily heated by coming into contact with the heated susceptor 73, and the temperature of the semiconductor wafer W gradually increases. To do.
[0040]
In this state, the semiconductor wafer W is continuously heated by the susceptor 73. When the temperature of the semiconductor wafer W rises, a temperature sensor (not shown) always monitors whether or not the surface temperature of the semiconductor wafer W has reached the preheating temperature T1.
[0041]
The preheating temperature T1 is, for example, about 200 ° C. to 600 ° C. Even if the semiconductor wafer W is heated to such a preheating temperature T1, ions implanted into the semiconductor wafer W will not diffuse.
[0042]
Eventually, when the surface temperature of the semiconductor wafer W reaches the preheating temperature T1, the flash lamp 69 is turned on to perform flash heating. The lighting time of the flash lamp 69 in this flash heating process is a time of about 0.1 to 10 milliseconds. Thus, in the flash lamp 69, the electrostatic energy stored in advance is converted into such an extremely short light pulse, so that an extremely strong flash light is irradiated.
[0043]
By such flash heating, the surface temperature of the semiconductor wafer W instantaneously reaches the temperature T2. This temperature T2 is a temperature necessary for the ion activation treatment of the semiconductor wafer W at about 1000 ° C. to 1100 ° C. When the surface of the semiconductor wafer W is heated to such a processing temperature T2, ions implanted into the semiconductor wafer W are activated.
[0044]
At this time, since the surface temperature of the semiconductor wafer W is raised to the processing temperature T2 in an extremely short time of about 0.1 to 10 milliseconds, ion activation in the semiconductor wafer W is completed in a short time. . Therefore, the ions implanted into the semiconductor wafer W do not diffuse, and it is possible to prevent the phenomenon that the profile of the ions implanted into the semiconductor wafer W is lost. Since the time required for ion activation is extremely short compared with the time required for ion diffusion, the ion activation is performed even for a short time in which no diffusion of about 0.1 millisecond to 10 millisecond occurs. Complete.
[0045]
Further, before the flash lamp 69 is turned on to heat the semiconductor wafer W, the surface temperature of the semiconductor wafer W is heated to the preheating temperature T1 of about 200 ° C. to 600 ° C. using the heating plate 74. The flash lamp 69 makes it possible to quickly raise the temperature of the semiconductor wafer W to the processing temperature T2 of about 1000 ° C. to 1100 ° C.
[0046]
After the flash heating process is completed, the susceptor 73 and the heating plate 74 are lowered to the loading / unloading position of the semiconductor wafer W shown in FIG. 1 by driving the motor 40 and the opening 66 closed by the gate valve 68 is released. Is done. As the susceptor 73 and the heating plate 74 are lowered, the semiconductor wafer W is transferred from the susceptor 73 to the support pins 70. Then, the semiconductor wafer W placed on the support pins 70 is carried out by a transfer robot (not shown). As described above, a series of heat treatment operations is completed.
[0047]
By the way, when the semiconductor wafer W is heated by turning on the flash lamp 69, the surface of the wafer is suddenly thermally expanded by the flash irradiation, and the semiconductor wafer W tends to warp in a convex shape. At this time, if the end portion of the semiconductor wafer W is in contact with the positioning pins or the like, the semiconductor wafer W may be cracked by the stress received from it during instantaneous thermal expansion as described above.
[0048]
In the present embodiment, the gradient α of the tapered surface 95 with respect to the mounting surface 99 is 15 °. As described above, the semiconductor wafer W is normally stably held in a state where one point of the peripheral end portion is in contact with the tapered surface 95. Here, if the slope α of the taper surface 95 is less than 30 °, as shown in FIG. 5, even when the semiconductor wafer W is instantaneously thermally expanded, as shown by the arrow AR5 in the figure, the semiconductor wafer The end of W (the end in contact with the tapered surface 95) can slide with respect to the tapered surface 95. That is, by setting the slope α of the tapered surface 95 to less than 30 °, the end of the semiconductor wafer W is not restrained by the tapered surface 95, so that the semiconductor wafer W expands freely when the flash lamp 69 is turned on. It can be done. As a result, even if the wafer surface undergoes rapid thermal expansion due to instantaneous flash irradiation, the semiconductor wafer W is not subjected to a large stress from the tapered surface 95, and cracking of the semiconductor wafer W during flash irradiation can be prevented.
[0049]
In order for the end portion of the semiconductor wafer W to slide with respect to the tapered surface 95 during such instantaneous thermal expansion, the gradient α of the tapered surface 95 with respect to the mounting surface 99 must be less than 30 °. When the gradient α of the taper surface 95 is 30 ° or more, the static frictional force between the end portion of the semiconductor wafer W and the taper surface 95 increases, and the end portion of the semiconductor wafer W (contacts with the taper surface 95 during instantaneous thermal expansion). This is because the semiconductor wafer W may break due to the restraining stress from the tapered surface 95 as a result. If the slope α of the taper surface 95 is less than 30 °, the end of the semiconductor wafer W can slide with respect to the taper surface 95. Particularly, if the slope α is less than 20 °, the end of the semiconductor wafer W and the taper surface 95, the frictional force between the semiconductor wafer W and the semiconductor wafer W is very small even when the wafer surface undergoes rapid thermal expansion due to flash irradiation. Can be more reliably prevented.
[0050]
On the other hand, when the gradient α of the tapered surface 95 with respect to the mounting surface 99 is less than 5 °, the positioning effect of the semiconductor wafer W by the tapered surface 95 as described above can hardly be obtained, and the susceptor 73 receives the semiconductor wafer W. In addition, the semiconductor wafer W may run on the peripheral surface 91. For this reason, the gradient α of the tapered surface 95 with respect to the mounting surface 99 needs to be 5 ° or more. In order to obtain a particularly stable positioning effect of the semiconductor wafer W, the gradient α is preferably 10 ° or more.
[0051]
Further, in order to reduce the frictional force between the end portion of the semiconductor wafer W and the tapered surface 95 so that the end portion can freely slide, the surface property of the tapered surface 95 is also important. In other words, when the coefficient of friction between the end portion of the semiconductor wafer W and the tapered surface 95 is small, the end portion easily slides with respect to the tapered surface 95. For this reason, the surface average roughness (Ra) of the tapered surface 95 is set to 1.6 μm or less, and within this range, the frictional force between the end portion of the semiconductor wafer W and the tapered surface 95 becomes smaller, and the flash irradiation is performed. As a result, even if the wafer surface undergoes rapid thermal expansion, the stress that the semiconductor wafer W receives from the tapered surface 95 becomes smaller, so that the cracking of the semiconductor wafer W during flash irradiation can be prevented more reliably. In this embodiment, Ra = 1.6 μm.
[0052]
In summary, the tapered surface 95 of the susceptor 73 according to the present invention is provided with two functions of positioning the semiconductor wafer W and preventing cracking of the semiconductor wafer W during flash irradiation. And in order to make these two functions compatible, gradient (alpha) of the taper surface 95 with respect to the mounting surface 99 is 5 degrees or more and less than 30 degrees. If the slope α is 5 ° or more, the semiconductor wafer W can be positioned on the mounting surface 99 by the tapered surface 95 when the susceptor 73 receives the semiconductor wafer W, and if it is less than 30 °, the wafer surface is irradiated by flash light irradiation. It is possible to suppress an excessive stress from being applied to the semiconductor wafer W even when the thermal expansion of the semiconductor wafer rapidly increases. In order to obtain these two functions more effectively, it is preferable that the gradient α of the tapered surface 95 with respect to the mounting surface 99 is 10 ° or more and less than 20 °. Further, if the surface average roughness (Ra) of the tapered surface 95 is set to 1.6 μm or less, the frictional force between the end of the semiconductor wafer W and the tapered surface 95 becomes smaller, and the wafer surface is sharply exposed by flash irradiation. Even when the thermal expansion occurs, it is possible to more reliably suppress an excessive stress from being applied to the semiconductor wafer W.
[0053]
While the embodiments of the present invention have been described above, the present invention is not limited to the above examples. For example, in the above embodiment, the light source 5 is provided with 27 flash lamps 69, but the present invention is not limited to this, and the number of flash lamps 69 may be arbitrary.
[0054]
In the above embodiment, the support pins 70 are fixed and the susceptor 73 and the heating plate 74 are moved up and down to transfer the semiconductor wafer W between them. 74 may be fixed and the support pins 70 moved up and down to deliver the semiconductor wafer W between them. That is, any configuration may be used as long as the susceptor 73 and the heating plate 74 and the support pin 70 are moved up and down relatively.
[0055]
In the above embodiment, the semiconductor wafer is irradiated with light to perform the ion activation process. However, the substrate to be processed by the heat treatment apparatus according to the present invention is not limited to the semiconductor wafer. . For example, the glass substrate on which various silicon films such as a silicon nitride film and a polycrystalline silicon film are formed may be processed by the heat treatment apparatus according to the present invention.
[0056]
【The invention's effect】
As described above, according to the invention of claim 1, since the gradient of the tapered surface with respect to the mounting surface is 5 ° or more and less than 30 °, the substrate can be appropriately positioned on the mounting surface, Even when the substrate surface undergoes rapid thermal expansion during heat treatment, it is possible to prevent excessive stress from acting on the substrate and to prevent cracking of the substrate during heat treatment.
[0057]
According to the invention of claim 2, since the surface average roughness of the tapered surface is 1.6 μm or less, the frictional force between the substrate and the tapered surface becomes smaller, and the substrate surface is heated rapidly during the heat treatment. Even when the substrate expands, it is possible to more reliably suppress an excessive stress from acting on the substrate.
[0058]
According to the invention of claim 3, since the slope of the inclined surface with respect to the bottom surface of the recess is set to 5 ° or more and less than 30 °, the substrate can be properly positioned in the recess and the substrate surface is sharpened during the heat treatment. Even when the substrate is thermally expanded, it is possible to prevent the substrate from being cracked during the heat treatment by suppressing the excessive stress from acting on the substrate.
[0059]
According to the invention of claim 4, since the holding means of the heat treatment apparatus has the susceptor for heat treatment according to any one of claims 1 to 3, the heat treatment is performed by light irradiation in the heat treatment apparatus. It is possible to prevent the substrate from cracking when performing.
[0060]
According to the invention of claim 5, since each of the plurality of lamps is a xenon flash lamp and the holding means has an assist heating means for preheating the substrate, the heat treatment is performed by light irradiation from the xenon flash lamp. In addition, the substrate can be prevented from cracking.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a configuration of a heat treatment apparatus according to the present invention.
FIG. 2 is a side sectional view showing a configuration of a heat treatment apparatus according to the present invention.
FIG. 3 is a side sectional view of a susceptor of the heat treatment apparatus of FIG.
4 is a plan view of a susceptor of the heat treatment apparatus of FIG. 1. FIG.
FIG. 5 is a diagram showing the behavior of a semiconductor wafer during flash irradiation.
[Explanation of symbols]
5 Light source
40 motor
65 chambers
69 Flash lamp
70 Support pin
71 reflector
73 Susceptor
74 Heating plate
91 Peripheral surface
95 Tapered surface
99 Placement surface
W Semiconductor wafer

Claims (5)

A susceptor for heat treatment that holds a substrate to be processed when performing heat treatment,
A flat mounting surface having a region equal to or larger than the planar size of the substrate;
A tapered surface surrounding the peripheral edge of the mounting surface and defining the mounting surface;
With
The lower end portion of the tapered surface is connected to the peripheral edge portion of the mounting surface, and the tapered surface is formed so as to widen upward, and the gradient of the tapered surface with respect to the mounting surface is 5 ° or more. A susceptor for heat treatment, characterized by being less than 30 °. The susceptor for heat treatment according to claim 1,
A heat treatment susceptor, wherein the taper surface has a surface average roughness of 1.6 μm or less. A susceptor for heat treatment that holds a substrate to be processed when performing heat treatment,
A recess for accommodating the substrate during heat treatment;
The concave portion has a flat bottom surface and an inclined surface surrounding a peripheral portion of the bottom surface,
The susceptor for heat treatment, wherein the slope of the inclined surface with respect to the bottom surface is 5 ° or more and less than 30 °. A heat treatment apparatus for heating a substrate by irradiating the substrate with light,
A light source having a plurality of lamps;
A chamber provided below the light source, and provided with a chamber window at the top for transmitting light emitted from the light source;
Holding means for holding the substrate in a substantially horizontal posture in the chamber;
With
The said holding | maintenance means has the susceptor for heat processing in any one of Claims 1-3, The heat processing apparatus characterized by the above-mentioned. The heat treatment apparatus according to claim 4, wherein
Each of the plurality of lamps is a xenon flash lamp,
The heat treatment apparatus, wherein the holding means further includes assist heating means for preheating the substrate to be held.

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