JP7180022B2 - Heat treatment method and heat treatment apparatus - Google Patents

Description

The present invention relates to a heat treatment method and a heat treatment apparatus for heating a thin precision electronic substrate such as a semiconductor wafer (hereinafter simply referred to as "substrate") by irradiating the substrate with flash light.

In the manufacturing process of semiconductor devices, impurity introduction is an essential step for forming a pn junction in a semiconductor wafer. At present, impurity introduction is generally performed by an ion implantation method followed by an annealing method. The ion implantation method is a technique of physically implanting impurities by ionizing impurity elements such as boron (B), arsenic (As), and phosphorus (P) and bombarding a semiconductor wafer at a high acceleration voltage. The implanted impurities are activated by annealing. At this time, if the annealing time is several seconds or longer, the implanted impurities are diffused deeply by heat, and as a result, the junction depth becomes too deep than required, which may hinder the formation of good devices.

Therefore, in recent years, flash lamp annealing (FLA) has attracted attention as an annealing technique for heating a semiconductor wafer in an extremely short time. Flash lamp annealing uses a xenon flash lamp (hereinafter simply referred to as a "flash lamp" to mean a xenon flash lamp) to irradiate the surface of the semiconductor wafer with flash light, thereby removing impurities from the semiconductor wafer. It is a heat treatment technology that raises the temperature of only the surface of the steel in an extremely short time (several milliseconds or less).

The radiation spectral distribution of the xenon flash lamp is from the ultraviolet region to the near-infrared region, the wavelength is shorter than that of the conventional halogen lamp, and it almost matches the fundamental absorption band of the silicon semiconductor wafer. Therefore, when the semiconductor wafer is irradiated with flash light from the xenon flash lamp, it is possible to rapidly raise the temperature of the semiconductor wafer with little transmitted light. In addition, it has been found that only the vicinity of the surface of the semiconductor wafer can be selectively heated by flash light irradiation for a very short period of several milliseconds or less. Therefore, if the xenon flash lamp raises the temperature in an extremely short period of time, only impurity activation can be performed without diffusing impurities deeply.

In a heat treatment apparatus using such a flash lamp, the surface of a semiconductor wafer is instantaneously irradiated with flash light having extremely high energy, so the surface temperature of the semiconductor wafer rises rapidly in an instant, while the back surface temperature decreases. does not rise to that extent. For this reason, rapid thermal expansion occurs only on the surface of the semiconductor wafer, and the semiconductor wafer is deformed such that the upper surface is convex and warped. At the next moment, the semiconductor wafer was warped with its bottom surface convex due to the recoil.

When the semiconductor wafer is deformed to have a convex upper surface, the edge of the wafer collides with the susceptor. Conversely, when the semiconductor wafer is deformed so that the lower surface is convex, the central portion of the wafer collides with the susceptor. As a result, there is a problem that the semiconductor wafer is cracked due to the impact of colliding with the susceptor.

When a wafer crack occurs during flash heating, it is necessary to quickly detect the crack, stop loading subsequent semiconductor wafers, and clean the chamber. In addition, from the viewpoint of preventing adverse effects such as particles generated by wafer cracking scattering outside the chamber and adhering to subsequent semiconductor wafers, semiconductor wafers are placed in the chamber before opening the loading/unloading port of the chamber immediately after flash heating. It is preferable to detect wafer cracks.

For this reason, Patent Document 1, for example, discloses a technique for judging whether a wafer is cracked by providing a microphone in a chamber in which a flash heat treatment is performed and detecting the sound when a semiconductor wafer is cracked. Further, Patent Document 2 discloses a technique of receiving reflected light from a semiconductor wafer with a light guide rod and detecting wafer cracks from the intensity of the reflected light.

JP 2009-231697 A JP 2015-130423 A

However, the technique disclosed in Patent Document 1 has a problem that it is difficult to perform filtering for extracting only the sound of a cracked semiconductor wafer. Further, in the technique disclosed in Patent Document 2, the step of rotating the light guide rod is required twice before and after flash light irradiation, so there is a problem of deterioration in throughput.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat treatment method and a heat treatment apparatus capable of detecting cracks in a substrate during flash light irradiation with a simple configuration.

In order to solve the above-mentioned problems, the invention of claim 1 provides a heat treatment method for heating a substrate by irradiating the substrate with flash light, wherein the substrate is heated to a preheating temperature by irradiating light from a continuously lit lamp. a heating step, a flash light irradiation step of irradiating the surface of the substrate with flash light from a flash lamp, a temperature measurement step of measuring the temperature of the substrate at predetermined sampling intervals to obtain a plurality of temperature measurement values, and an accumulating step of calculating an integrated temperature value by accumulating a set number of temperature measurement values obtained from a time point corresponding to the start of irradiation of the flash light among the plurality of temperature measurement values, and calculating the integrated temperature value based on the integrated temperature value; and a determination step of determining cracks in the substrate.

According to a second aspect of the invention, in the heat treatment method according to the first aspect of the invention, the time point that coincides with the start of irradiation with the flash light includes a time point when the temperature of the substrate is at the preheating temperature. and

According to a third aspect of the invention, in the heat treatment method according to the first or second aspect of the invention, the temperature of the back surface of the substrate is measured in the temperature measuring step.

According to a fourth aspect of the present invention, there is provided a heat treatment method for heating a substrate by irradiating the substrate with flash light, wherein the substrate held by the susceptor is irradiated with light from a continuously lit lamp to heat the substrate to a preheating temperature. a preheating step of heating; a flash light irradiation step of irradiating the surface of the substrate with flash light from a flash lamp; and a temperature measurement step of measuring the temperature of the susceptor at predetermined sampling intervals to obtain a plurality of temperature measurement values. an accumulating step of calculating a temperature integrated value by accumulating a set number of temperature measurement values acquired from a point in time corresponding to the start of irradiation of the flash light among the plurality of temperature measurement values; and a determination step of determining cracks in the substrate based on the above.

Further, according to the invention of claim 5, in the heat treatment method according to the invention of claim 4, the time point coincident with the irradiation start time of the flash light includes a time point when the temperature of the substrate is the preheating temperature. and

The invention of claim 6 is the heat treatment method according to any one of claims 1 to 5, wherein, in the determination step, the integrated temperature value is out of the preset upper limit value and lower limit value range. It is determined that the substrate is cracked when the substrate is broken.

According to a seventh aspect of the present invention, the heat treatment method according to the sixth aspect of the invention further comprises a setting step of setting the upper limit value and the lower limit value.

According to an eighth aspect of the invention, there is provided a heat treatment apparatus for heating a substrate by irradiating the substrate with flash light, comprising: a chamber for housing the substrate; a susceptor for holding the substrate in the chamber; a continuously lit lamp for irradiating light onto the substrate thus heated to a preheating temperature; a flash lamp for irradiating the surface of the substrate with flash light; A radiation thermometer that acquires temperature measurement values and a set number of temperature measurement values acquired from a time point that coincides with the start of irradiation of the flash light among the plurality of temperature measurement values are integrated to calculate a temperature integrated value. It is characterized by comprising an accumulator and a determination unit that determines cracks in the substrate based on the temperature integrated value.

According to a ninth aspect of the invention, there is provided the heat treatment apparatus according to the eighth aspect of the invention, wherein the point of time coinciding with the start of irradiation of the flash light includes a point of time when the temperature of the substrate is at the preheating temperature. and

According to a tenth aspect of the invention, in the heat treatment apparatus according to the eighth or ninth aspect of the invention, the radiation thermometer measures the temperature of the back surface of the substrate.

According to an eleventh aspect of the invention, there is provided a heat treatment apparatus for heating a substrate by irradiating the substrate with flash light, comprising: a chamber for housing the substrate; a susceptor for holding the substrate in the chamber; a continuously lit lamp that irradiates light onto the substrate thus heated to a preheating temperature; a flash lamp that irradiates the surface of the substrate with flash light; A radiation thermometer that acquires temperature measurement values and a set number of temperature measurement values acquired from a time point that coincides with the start of irradiation of the flash light among the plurality of temperature measurement values are integrated to calculate a temperature integrated value. It is characterized by comprising an accumulator and a determination unit that determines cracks in the substrate based on the temperature integrated value.

According to a twelfth aspect of the invention, in the heat treatment apparatus according to the eleventh aspect of the invention, the time point that coincides with the start of irradiation with the flash light includes a time point when the temperature of the substrate is at the preheating temperature. and

According to a thirteenth aspect of the present invention, there is provided the heat treatment apparatus according to any one of the eighth to twelfth aspects of the invention, wherein the determination unit determines that the integrated temperature value is out of a preset upper limit value and lower limit value range. It is determined that the substrate is cracked when the substrate is broken.

According to a fourteenth aspect of the invention, the heat treatment apparatus according to the thirteenth aspect of the invention is characterized by further comprising a setting unit for setting the upper limit value and the lower limit value.

According to the invention of claims 1 to 7, among a plurality of temperature measurement values obtained by measuring the temperature of the substrate or the susceptor at a predetermined sampling interval, the temperature measurement values are obtained from the time that coincides with the start of flash light irradiation. Since cracking of the substrate is determined based on the integrated temperature value obtained by accumulating the set number of temperature measurement values, cracking of the substrate during flash light irradiation can be detected with a simple configuration.

According to the eighth to fourteenth aspects of the invention, among the plurality of temperature measurement values obtained by measuring the temperature of the substrate or susceptor at predetermined sampling intervals, the Since cracking of the substrate is determined based on the integrated temperature value obtained by accumulating the set number of temperature measurement values, cracking of the substrate during flash light irradiation can be detected with a simple configuration.

1 is a vertical cross-sectional view showing the configuration of a heat treatment apparatus according to the present invention; FIG. It is a perspective view which shows the whole external appearance of a holding|maintenance part. 4 is a plan view of the susceptor; FIG. 4 is a cross-sectional view of the susceptor; FIG. It is a top view of a transfer mechanism. It is a side view of a transfer mechanism. FIG. 4 is a plan view showing the arrangement of a plurality of halogen lamps; It is a functional block diagram of a radiation thermometer and a control unit. 4 is a flow chart showing a procedure for processing a semiconductor wafer; It is a figure which shows the change of the back surface temperature of a semiconductor wafer measured with a radiation thermometer. It is a figure which shows an example of the setting screen of an upper limit and a lower limit.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First embodiment>
FIG. 1 is a vertical cross-sectional view showing the configuration of a heat treatment apparatus 1 according to the present invention. The heat treatment apparatus 1 of FIG. 1 is a flash lamp annealing apparatus that heats a disk-shaped semiconductor wafer W as a substrate by irradiating the semiconductor wafer W with flash light. Although the size of the semiconductor wafer W to be processed is not particularly limited, it is, for example, φ300 mm or φ450 mm (φ300 mm in this embodiment). Impurities are implanted into the semiconductor wafer W before it is carried into the heat treatment apparatus 1 , and activation processing of the implanted impurities is performed by heat treatment by the heat treatment apparatus 1 . In addition, in FIG. 1 and subsequent figures, the dimensions and numbers of each part are exaggerated or simplified as necessary for easy understanding.

The heat treatment apparatus 1 includes a chamber 6 containing a semiconductor wafer W, a flash heating section 5 containing a plurality of flash lamps FL, and a halogen heating section 4 containing a plurality of halogen lamps HL. A flash heating section 5 is provided on the upper side of the chamber 6, and a halogen heating section 4 is provided on the lower side. The heat treatment apparatus 1 also includes a holding unit 7 that holds the semiconductor wafer W in a horizontal posture inside the chamber 6, a transfer mechanism 10 that transfers the semiconductor wafer W between the holding unit 7 and the outside of the apparatus, Prepare. Further, the heat treatment apparatus 1 includes a control section 3 that controls each operation mechanism provided in the halogen heating section 4, the flash heating section 5, and the chamber 6 to perform the heat treatment of the semiconductor wafer W. As shown in FIG.

The chamber 6 is configured by mounting chamber windows made of quartz on the upper and lower sides of a cylindrical chamber side portion 61 . The chamber side part 61 has a substantially cylindrical shape with upper and lower openings, the upper opening being closed by an upper chamber window 63, and the lower opening being closed by a lower chamber window 64. ing. The upper chamber window 63 forming the ceiling of the chamber 6 is a disc-shaped member made of quartz and functions as a quartz window through which the flash light emitted from the flash heating unit 5 is transmitted into the chamber 6 . A lower chamber window 64 forming the floor of the chamber 6 is also a disk-shaped member made of quartz and functions as a quartz window through which the light from the halogen heating unit 4 is transmitted into the chamber 6 .

A reflecting ring 68 is attached to the upper portion of the inner wall surface of the chamber side portion 61, and a reflecting ring 69 is attached to the lower portion thereof. Both the reflecting rings 68 and 69 are formed in an annular shape. The upper reflector ring 68 is attached by fitting from the upper side of the chamber side 61 . On the other hand, the lower reflecting ring 69 is attached by fitting from the lower side of the chamber side portion 61 and fastening with screws (not shown). That is, both the reflecting rings 68 and 69 are detachably attached to the chamber side portion 61 . A space inside the chamber 6 , that is, a space surrounded by the upper chamber window 63 , the lower chamber window 64 , the chamber side portion 61 and the reflective rings 68 and 69 is defined as a thermal processing space 65 .

A concave portion 62 is formed in the inner wall surface of the chamber 6 by attaching the reflecting rings 68 and 69 to the chamber side portion 61 . That is, the recess 62 is formed by the central portion of the inner wall surface of the chamber side portion 61 where the reflecting rings 68 and 69 are not attached, the lower end surface of the reflecting ring 68, and the upper end surface of the reflecting ring 69. . The concave portion 62 is formed in an annular shape along the horizontal direction on the inner wall surface of the chamber 6 and surrounds the holding portion 7 that holds the semiconductor wafer W. As shown in FIG. The chamber side portion 61 and the reflecting rings 68, 69 are made of a metallic material (for example, stainless steel) having excellent strength and heat resistance.

A transfer opening (furnace port) 66 for transferring the semiconductor wafer W into and out of the chamber 6 is formed in the chamber side portion 61 . The transport opening 66 can be opened and closed by a gate valve 185 . The conveying opening 66 is communicated with the outer peripheral surface of the recess 62 . Therefore, when the gate valve 185 opens the transfer opening 66 , the semiconductor wafer W can be transferred from the transfer opening 66 to the heat treatment space 65 through the recess 62 and transferred from the heat treatment space 65 . It can be performed. Further, when the gate valve 185 closes the transfer opening 66, the heat treatment space 65 in the chamber 6 becomes a closed space.

A gas supply hole 81 for supplying a processing gas to the heat treatment space 65 is formed in the upper portion of the inner wall of the chamber 6 . The gas supply hole 81 is formed above the recess 62 and may be provided in the reflection ring 68 . The gas supply hole 81 is communicated with a gas supply pipe 83 through an annular buffer space 82 formed inside the side wall of the chamber 6 . The gas supply pipe 83 is connected to a process gas supply source 85 . A valve 84 is inserted in the middle of the path of the gas supply pipe 83 . When valve 84 is opened, process gas is delivered from process gas supply 85 to buffer space 82 . The processing gas that has flowed into the buffer space 82 flows so as to expand in the buffer space 82 , which has a smaller fluid resistance than the gas supply hole 81 , and is supplied from the gas supply hole 81 into the heat treatment space 65 . As the processing gas, for example, an inert gas such as nitrogen (N ₂ ), a reactive gas such as hydrogen (H ₂ ) or ammonia (NH ₃ ), or a mixed gas thereof can be used (this Nitrogen gas in embodiments).

On the other hand, a gas exhaust hole 86 for exhausting the gas in the heat treatment space 65 is formed in the lower part of the inner wall of the chamber 6 . The gas exhaust hole 86 is formed below the recess 62 and may be provided in the reflecting ring 69 . The gas exhaust hole 86 is communicated with a gas exhaust pipe 88 through an annular buffer space 87 formed inside the side wall of the chamber 6 . The gas exhaust pipe 88 is connected to the exhaust section 190 . A valve 89 is inserted in the middle of the path of the gas exhaust pipe 88 . When the valve 89 is opened, the gas in the heat treatment space 65 is discharged from the gas exhaust hole 86 to the gas exhaust pipe 88 through the buffer space 87 . A plurality of gas supply holes 81 and gas exhaust holes 86 may be provided along the circumferential direction of the chamber 6, or may be slit-shaped.

A gas exhaust pipe 191 for exhausting the gas in the heat treatment space 65 is also connected to the tip of the transfer opening 66 . A gas exhaust pipe 191 is connected to an exhaust section 190 via a valve 192 . By opening the valve 192 , the gas within the chamber 6 is evacuated through the transfer opening 66 .

FIG. 2 is a perspective view showing the overall appearance of the holding portion 7. As shown in FIG. The holding portion 7 includes a base ring 71 , a connecting portion 72 and a susceptor 74 . The base ring 71, the connecting portion 72 and the susceptor 74 are all made of quartz. That is, the entire holding portion 7 is made of quartz.

The base ring 71 is an arc-shaped quartz member that is partly missing from an annular ring. This missing portion is provided to prevent interference between the transfer arm 11 of the transfer mechanism 10 and the base ring 71, which will be described later. The base ring 71 is supported by the wall surface of the chamber 6 by being placed on the bottom surface of the recess 62 (see FIG. 1). A plurality of connecting portions 72 (four in this embodiment) are erected on the upper surface of the base ring 71 along the circumferential direction of the annular shape. The connecting portion 72 is also a quartz member and is fixed to the base ring 71 by welding.

The susceptor 74 is supported by four connecting portions 72 provided on the base ring 71 . 3 is a plan view of the susceptor 74. FIG. 4 is a cross-sectional view of the susceptor 74. FIG. The susceptor 74 comprises a retaining plate 75 , a guide ring 76 and a plurality of substrate support pins 77 . The holding plate 75 is a substantially circular flat member made of quartz. The diameter of the holding plate 75 is larger than the diameter of the semiconductor wafer W. That is, the holding plate 75 has a planar size larger than the semiconductor wafer W. As shown in FIG.

A guide ring 76 is installed on the peripheral edge of the upper surface of the holding plate 75 . The guide ring 76 is an annular member having an inner diameter larger than the diameter of the semiconductor wafer W. As shown in FIG. For example, when the diameter of the semiconductor wafer W is φ300 mm, the inner diameter of the guide ring 76 is φ320 mm. The inner circumference of the guide ring 76 is tapered such that it widens upward from the holding plate 75 . The guide ring 76 is made of quartz similar to the holding plate 75 . The guide ring 76 may be welded to the upper surface of the holding plate 75, or may be fixed to the holding plate 75 by a separately processed pin or the like. Alternatively, the holding plate 75 and the guide ring 76 may be processed as an integral member.

A region of the upper surface of the holding plate 75 inside the guide ring 76 serves as a planar holding surface 75a for holding the semiconductor wafer W. As shown in FIG. A plurality of substrate support pins 77 are erected on the holding surface 75 a of the holding plate 75 . In this embodiment, a total of 12 substrate support pins 77 are erected at 30° intervals along a circle concentric with the outer circumference of the holding surface 75a (the inner circumference of the guide ring 76). The diameter of the circle in which the 12 substrate support pins 77 are arranged (the distance between the opposing substrate support pins 77) is smaller than the diameter of the semiconductor wafer W. 270 mm in shape). Each substrate support pin 77 is made of quartz. The plurality of substrate support pins 77 may be provided on the upper surface of the holding plate 75 by welding, or may be processed integrally with the holding plate 75 .

Returning to FIG. 2, the four connecting portions 72 erected on the base ring 71 and the peripheral portion of the holding plate 75 of the susceptor 74 are fixed by welding. That is, the susceptor 74 and the base ring 71 are fixedly connected by the connecting portion 72 . The holder 7 is attached to the chamber 6 by supporting the base ring 71 of the holder 7 on the wall surface of the chamber 6 . When the holding portion 7 is attached to the chamber 6, the holding plate 75 of the susceptor 74 assumes a horizontal posture (a posture in which the normal line coincides with the vertical direction). That is, the holding surface 75a of the holding plate 75 becomes a horizontal surface.

The semiconductor wafer W carried into the chamber 6 is placed and held in a horizontal posture on the susceptor 74 of the holding part 7 mounted in the chamber 6 . At this time, the semiconductor wafer W is held by the susceptor 74 while being supported by twelve substrate supporting pins 77 erected on the holding plate 75 . More strictly, the upper ends of the 12 substrate support pins 77 are in contact with the lower surface of the semiconductor wafer W to support the semiconductor wafer W. As shown in FIG. Since the height of the 12 substrate support pins 77 (the distance from the upper end of the substrate support pin 77 to the holding surface 75a of the holding plate 75) is uniform, the semiconductor wafer W can be held in a horizontal posture by the 12 substrate support pins 77. can support.

Also, the semiconductor wafer W is supported by a plurality of substrate support pins 77 at a predetermined distance from the holding surface 75a of the holding plate 75. As shown in FIG. The thickness of the guide ring 76 is greater than the height of the board support pins 77 . Accordingly, the guide ring 76 prevents the semiconductor wafer W supported by the plurality of substrate support pins 77 from being displaced in the horizontal direction.

Further, as shown in FIGS. 2 and 3, the holding plate 75 of the susceptor 74 is formed with an opening 78 penetrating vertically. The opening 78 is provided so that the radiation thermometer 120 (see FIG. 1) receives radiation light (infrared light) emitted from the lower surface of the semiconductor wafer W. As shown in FIG. That is, the radiation thermometer 120 measures the temperature of the semiconductor wafer W by receiving light emitted from the lower surface of the semiconductor wafer W through the opening 78 . Further, the holding plate 75 of the susceptor 74 is formed with four through holes 79 through which the lift pins 12 of the transfer mechanism 10 (to be described later) penetrate to transfer the semiconductor wafer W. As shown in FIG.

FIG. 5 is a plan view of the transfer mechanism 10. FIG. 6 is a side view of the transfer mechanism 10. FIG. The transfer mechanism 10 includes two transfer arms 11 . The transfer arm 11 has an arc shape along the generally annular concave portion 62 . Two lift pins 12 are erected on each transfer arm 11 . The transfer arm 11 and lift pins 12 are made of quartz. Each transfer arm 11 is rotatable by a horizontal movement mechanism 13 . The horizontal movement mechanism 13 moves the pair of transfer arms 11 to the transfer operation position (solid line position in FIG. It is horizontally moved to and from the retracted position (the two-dot chain line position in FIG. 5) that does not overlap in plan view. As the horizontal movement mechanism 13, each transfer arm 11 may be rotated by an individual motor. It may be something that moves.

Also, the pair of transfer arms 11 is vertically moved together with the horizontal movement mechanism 13 by the lifting mechanism 14 . When the lifting mechanism 14 raises the pair of transfer arms 11 to the transfer operation position, a total of four lift pins 12 pass through the through holes 79 (see FIGS. 2 and 3) drilled in the susceptor 74, and the lift pins 12 protrudes from the upper surface of the susceptor 74 . On the other hand, when the lifting mechanism 14 lowers the pair of transfer arms 11 to the transfer operation position and removes the lift pins 12 from the through-holes 79, the horizontal movement mechanism 13 moves the pair of transfer arms 11 so as to open them. The transfer arm 11 moves to the retracted position. The retracted position of the pair of transfer arms 11 is directly above the base ring 71 of the holding section 7 . Since the base ring 71 is placed on the bottom surface of the recess 62 , the retracted position of the transfer arm 11 is inside the recess 62 . An exhaust mechanism (not shown) is also provided in the vicinity of the portion where the drive section (horizontal movement mechanism 13 and lifting mechanism 14) of the transfer mechanism 10 is provided, and the atmosphere around the drive section of the transfer mechanism 10 is is discharged to the outside of the chamber 6.

As shown in FIG. 1, the heat treatment apparatus 1 is provided with three radiation thermometers 120, 130 and 140. As shown in FIG. As described above, radiation thermometer 120 measures the temperature of the lower surface of semiconductor wafer W through opening 78 provided in susceptor 74 . The radiation thermometer 130 detects infrared light emitted from the central portion of the susceptor 74 and measures the temperature of the central portion. On the other hand, the radiation thermometer 140 detects infrared light emitted from the upper surface of the semiconductor wafer W to measure the temperature of the upper surface of the wafer. As the radiation thermometer 140, it is preferable to employ a high-speed radiation thermometer capable of following a rapid temperature change of the upper surface of the semiconductor wafer W at the moment when flash light is emitted from the flash lamp FL. The heat treatment apparatus 1 is also provided with a temperature sensor 150 . A temperature sensor 150 measures the ambient temperature of the heat treatment space 65 inside the chamber 6 .

The flash heating unit 5 provided above the chamber 6 includes a light source composed of a plurality of (30 in this embodiment) xenon flash lamps FL inside a housing 51, and a light source provided so as to cover the upper side of the light source. and a reflector 52 . A lamp light emission window 53 is attached to the bottom of the housing 51 of the flash heating unit 5 . The lamp light emission window 53 forming the floor of the flash heating unit 5 is a plate-shaped quartz window made of quartz. By installing the flash heating unit 5 above the chamber 6 , the lamp light emission window 53 faces the upper chamber window 63 . The flash lamp FL irradiates the heat treatment space 65 with flash light from above the chamber 6 through the lamp light emission window 53 and the upper chamber window 63 .

Each of the plurality of flash lamps FL is a rod-shaped lamp having an elongated cylindrical shape, and the longitudinal direction of each flash lamp FL is along the main surface of the semiconductor wafer W held by the holding portion 7 (that is, along the horizontal direction). They are arranged in a plane so as to be parallel to each other. Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane.

The xenon flash lamp FL is composed of a rod-shaped glass tube (discharge tube) in which xenon gas is filled and an anode and a cathode connected to a condenser are arranged at both ends of the tube (discharge tube), and an outer peripheral surface of the glass tube is provided. and a trigger electrode. Since xenon gas is an electrical insulator, electricity does not flow in the glass tube under normal conditions even if electric charges are accumulated in the capacitor. However, when a high voltage is applied to the trigger electrode to break down the insulation, the electricity stored in the capacitor instantly flows into the glass tube, and the xenon atoms or molecules are excited at that time to emit light. In such a xenon flash lamp FL, the electrostatic energy previously stored in the capacitor is converted into an extremely short light pulse of 0.1 millisecond to 100 milliseconds. It has the characteristic of being able to irradiate extremely strong light compared to the light source. That is, the flash lamp FL is a pulsed light emitting lamp that instantaneously emits light in an extremely short time of less than 1 second. The light emission time of the flash lamp FL can be adjusted by the coil constant of the lamp power source that supplies power to the flash lamp FL.

Moreover, the reflector 52 is provided above the plurality of flash lamps FL so as to cover them as a whole. The basic function of the reflector 52 is to reflect the flash light emitted from the plurality of flash lamps FL to the heat treatment space 65 side. The reflector 52 is made of an aluminum alloy plate, and its surface (the surface facing the flash lamp FL) is roughened by blasting.

The halogen heating unit 4 provided below the chamber 6 incorporates a plurality of (40 in this embodiment) halogen lamps HL inside a housing 41 . The halogen heating unit 4 heats the semiconductor wafer W by irradiating the heat treatment space 65 with light from the lower side of the chamber 6 through the lower chamber window 64 using a plurality of halogen lamps HL.

FIG. 7 is a plan view showing the arrangement of multiple halogen lamps HL. The 40 halogen lamps HL are arranged in two upper and lower stages. Twenty halogen lamps HL are arranged in the upper stage near the holding part 7, and twenty halogen lamps HL are arranged in the lower stage farther from the holding part 7 than the upper stage. Each halogen lamp HL is a rod-shaped lamp having an elongated cylindrical shape. The 20 halogen lamps HL in both the upper stage and the lower stage are arranged so that their longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holding portion 7 (that is, along the horizontal direction). there is Therefore, the plane formed by the arrangement of the halogen lamps HL in both the upper stage and the lower stage is a horizontal plane.

Further, as shown in FIG. 7, the arrangement density of the halogen lamps HL in both the upper and lower stages is higher in the region facing the peripheral portion than in the region facing the central portion of the semiconductor wafer W held by the holding portion 7. there is That is, in both the upper and lower stages, the arrangement pitch of the halogen lamps HL is shorter in the peripheral portion than in the central portion of the lamp arrangement. Therefore, it is possible to irradiate a larger amount of light to the peripheral portion of the semiconductor wafer W, which tends to cause a temperature drop during heating by light irradiation from the halogen heating unit 4 .

A group of halogen lamps HL in the upper stage and a group of halogen lamps HL in the lower stage are arranged so as to cross each other in a grid pattern. That is, a total of 40 halogen lamps HL are arranged such that the longitudinal direction of the 20 halogen lamps HL arranged in the upper stage and the longitudinal direction of the 20 halogen lamps HL arranged in the lower stage are perpendicular to each other. there is

The halogen lamp HL is a filament-type light source that emits light by turning the filament incandescent by energizing the filament arranged inside the glass tube. Inside the glass tube, a gas obtained by introducing a small amount of a halogen element (iodine, bromine, etc.) into an inert gas such as nitrogen or argon is sealed. By introducing a halogen element, it becomes possible to set the temperature of the filament to a high temperature while suppressing breakage of the filament. Therefore, the halogen lamp HL has characteristics that it has a longer life than a normal incandescent lamp and can continuously irradiate strong light. That is, the halogen lamp HL is a continuous lighting lamp that continuously emits light for at least one second. Further, since the halogen lamp HL is a rod-shaped lamp, it has a long life. By arranging the halogen lamp HL along the horizontal direction, the radiation efficiency to the semiconductor wafer W above is excellent.

In addition, a reflector 43 is provided below the two-stage halogen lamp HL in the housing 41 of the halogen heating unit 4 (FIG. 1). The reflector 43 reflects the light emitted from the plurality of halogen lamps HL to the heat treatment space 65 side.

The control unit 3 controls the various operating mechanisms provided in the heat treatment apparatus 1 . The hardware configuration of the control unit 3 is the same as that of a general computer. That is, the control unit 3 includes a CPU that is a circuit that performs various arithmetic processing, a ROM that is a read-only memory that stores basic programs, a RAM that is a readable and writable memory that stores various information, and control software and data. Equipped with a magnetic disk for storage. The processing in the heat treatment apparatus 1 proceeds as the CPU of the control unit 3 executes a predetermined processing program.

FIG. 8 is a functional block diagram of the radiation thermometer 120 and the controller 3. As shown in FIG. A radiation thermometer 120 that measures the temperature of the lower surface of the semiconductor wafer W includes an infrared sensor 121 and a temperature measurement unit 122 . The infrared sensor 121 receives infrared light emitted through the opening 78 from the lower surface of the semiconductor wafer W held by the susceptor 74 . Infrared sensor 121 is electrically connected to temperature measurement unit 122 and transmits a signal generated in response to light reception to temperature measurement unit 122 . The temperature measurement unit 122 includes an amplifier circuit, an A/D converter, a temperature conversion circuit, etc. (not shown), and converts a signal indicating the intensity of infrared light output from the infrared sensor 121 into temperature. The temperature obtained by the temperature measurement unit 122 is the temperature of the lower surface of the semiconductor wafer W. FIG. A radiation thermometer 130 that measures the temperature of the susceptor 74 and a radiation thermometer 140 that measures the temperature of the upper surface of the semiconductor wafer W have substantially the same configuration as the radiation thermometer 120 .

Radiation thermometer 120 is electrically connected to control unit 3 which is a controller of the entire heat treatment apparatus 1 , and the temperature of the lower surface of semiconductor wafer W measured by radiation thermometer 120 is transmitted to control unit 3 . The control unit 3 includes an integration unit 31 and a crack determination unit 32 . The integration unit 31 and the crack determination unit 32 are functional processing units realized by the CPU of the control unit 3 executing a predetermined processing program. The processing contents of the integration unit 31 and the crack determination unit 32 will be further described later.

A display unit 33 and an input unit 34 are also connected to the control unit 3 . The control unit 3 displays various information on the display unit 33 . The input section 34 is a device for the operator of the heat treatment apparatus 1 to input various commands and parameters to the control section 3 . While confirming the display contents of the display unit 33 , the operator can set the conditions of the processing recipe describing the processing procedure and processing conditions of the semiconductor wafer W from the input unit 34 . A touch panel having both functions can be used as the display unit 33 and the input unit 34, and in this embodiment, a liquid crystal touch panel provided on the outer wall of the heat treatment apparatus 1 is adopted.

In addition to the above configuration, the heat treatment apparatus 1 prevents excessive temperature rise of the halogen heating section 4, the flash heating section 5, and the chamber 6 due to thermal energy generated from the halogen lamps HL and the flash lamps FL during the heat treatment of the semiconductor wafer W. Therefore, it has various cooling structures. For example, the walls of the chamber 6 are provided with water cooling pipes (not shown). The halogen heating unit 4 and the flash heating unit 5 have an air-cooling structure in which heat is exhausted by forming a gas flow inside. Air is also supplied to the gap between the upper chamber window 63 and the lamp light emission window 53 to cool the flash heating part 5 and the upper chamber window 63 .

Next, a procedure for processing the semiconductor wafer W in the heat treatment apparatus 1 will be described. FIG. 9 is a flow chart showing the processing procedure of the semiconductor wafer W. As shown in FIG. The semiconductor wafer W to be processed here is a semiconductor substrate to which impurities (ions) are added by an ion implantation method. Activation of the impurities is performed by flash light irradiation heat treatment (annealing) by the heat treatment apparatus 1 . The processing procedure of the heat treatment apparatus 1 described below proceeds as the control unit 3 controls each operating mechanism of the heat treatment apparatus 1 .

First, the valve 84 for air supply is opened, and the valves 89 and 192 for exhaust are opened to start supplying and exhausting air to and from the chamber 6 . When the valve 84 is opened, nitrogen gas is supplied from the gas supply hole 81 to the heat treatment space 65 . Further, when the valve 89 is opened, the gas inside the chamber 6 is exhausted from the gas exhaust hole 86 . As a result, the nitrogen gas supplied from the upper portion of the heat treatment space 65 inside the chamber 6 flows downward and is exhausted from the lower portion of the heat treatment space 65 .

Further, the gas in the chamber 6 is exhausted from the transfer opening 66 by opening the valve 192 . Furthermore, the atmosphere around the drive section of the transfer mechanism 10 is also exhausted by an exhaust mechanism (not shown). Nitrogen gas is continuously supplied to the heat treatment space 65 during the heat treatment of the semiconductor wafer W in the heat treatment apparatus 1, and the supply amount is appropriately changed according to the treatment process.

Subsequently, the gate valve 185 is opened to open the transfer opening 66, and the semiconductor wafer W to be processed is carried into the heat treatment space 65 in the chamber 6 through the transfer opening 66 by the transfer robot outside the apparatus ( step S1). At this time, there is a risk that the atmosphere outside the apparatus will be involved as the semiconductor wafer W is loaded. Involvement of the external atmosphere can be minimized.

The semiconductor wafer W carried in by the transfer robot advances to a position directly above the holding part 7 and stops there. When the pair of transfer arms 11 of the transfer mechanism 10 moves horizontally from the retracted position to the transfer operation position and rises, the lift pins 12 protrude from the upper surface of the holding plate 75 of the susceptor 74 through the through holes 79 . receives the semiconductor wafer W. At this time, the lift pins 12 rise above the upper ends of the substrate support pins 77 .

After the semiconductor wafer W is placed on the lift pins 12 , the transfer robot leaves the heat treatment space 65 and the transfer opening 66 is closed by the gate valve 185 . As the pair of transfer arms 11 descends, the semiconductor wafer W is transferred from the transfer mechanism 10 to the susceptor 74 of the holding section 7 and held from below in a horizontal posture. The semiconductor wafer W is held by the susceptor 74 while being supported by a plurality of substrate support pins 77 erected on a holding plate 75 . Further, the semiconductor wafer W is held by the holding portion 7 with the surface having the pattern formed and the impurity implanted as the upper surface. A predetermined gap is formed between the back surface (main surface opposite to the front surface) of the semiconductor wafer W supported by the plurality of substrate support pins 77 and the holding surface 75 a of the holding plate 75 . The pair of transfer arms 11 that have descended below the susceptor 74 are retracted by the horizontal movement mechanism 13 to the retracted position, that is, to the inside of the recess 62 .

When the semiconductor wafer W is held from below in a horizontal posture by the susceptor 74 of the holding portion 7 made of quartz, the temperature measurement by the radiation thermometer 120 is started. That is, the radiation thermometer 120 receives infrared light emitted from the lower surface (back surface) of the semiconductor wafer W held by the susceptor 74 through the opening 78 to measure the temperature of the back surface of the semiconductor wafer W. FIG. FIG. 10 is a diagram showing changes in the rear surface temperature of the semiconductor wafer W measured by the radiation thermometer 120. As shown in FIG.

After the semiconductor wafer W is carried into the chamber 6 and held by the susceptor 74, at time t1, the 40 halogen lamps HL of the halogen heating unit 4 are turned on simultaneously to start preheating (assist heating) ( step S2). Halogen light emitted from the halogen lamps HL passes through the lower chamber window 64 and the susceptor 74 made of quartz, and irradiates the lower surface of the semiconductor wafer W. As shown in FIG. The semiconductor wafer W is preheated by being irradiated with light from the halogen lamp HL, and the temperature rises. Since the transfer arm 11 of the transfer mechanism 10 is retracted inside the recess 62, it does not interfere with the heating by the halogen lamp HL.

A radiation thermometer 120 measures the temperature of the semiconductor wafer W, which is heated by light irradiation from the halogen lamp HL. The measured temperature of the semiconductor wafer W is transmitted to the controller 3 . The control unit 3 controls the output of the halogen lamps HL while monitoring whether the temperature of the semiconductor wafer W, which is heated by light irradiation from the halogen lamps HL, has reached a predetermined preheating temperature T1. That is, the control unit 3 feedback-controls the output of the halogen lamp HL based on the measured value by the radiation thermometer 120 so that the temperature of the semiconductor wafer W reaches the preheating temperature T1. The preheating temperature T1 is about 200° C. to 800° C., preferably about 350° C. to 600° C. (600° C. in this embodiment), at which there is no risk of thermal diffusion of impurities added to the semiconductor wafer W. . Thus, the radiation thermometer 120 is a sensor for controlling the output of the halogen lamp HL during the preheating stage. Although the radiation thermometer 120 measures the temperature of the back surface of the semiconductor wafer W, there is no temperature difference between the front and back surfaces of the semiconductor wafer W during preheating by the halogen lamp HL. The measured rear surface temperature can be regarded as the temperature of the semiconductor wafer W as a whole.

After the temperature of the semiconductor wafer W reaches the preheating temperature T1, the controller 3 temporarily maintains the semiconductor wafer W at the preheating temperature T1. Specifically, when the temperature of the semiconductor wafer W measured by the radiation thermometer 120 reaches the preheating temperature T1, the control unit 3 adjusts the output of the halogen lamp HL to bring the temperature of the semiconductor wafer W almost to the preliminary temperature. The heating temperature is maintained at T1.

By performing such preheating using the halogen lamps HL, the temperature of the entire semiconductor wafer W is uniformly raised to the preheating temperature T1. In the stage of preheating by the halogen lamps HL, the temperature of the peripheral portion of the semiconductor wafer W, where heat is more likely to be released, tends to be lower than that of the central portion. The region facing the peripheral portion of the substrate W is higher than the region facing the central portion. For this reason, the amount of light irradiated to the peripheral portion of the semiconductor wafer W, which tends to cause heat dissipation, is increased, and the in-plane temperature distribution of the semiconductor wafer W in the preheating stage can be made uniform.

At time t2 when the temperature of the semiconductor wafer W reaches the preheating temperature T1 and a predetermined time has elapsed, the flash lamps FL of the flash heating unit 5 irradiate the surface of the semiconductor wafer W held by the susceptor 74 with flash light (step S3). At this time, part of the flash light emitted from the flash lamp FL goes directly into the chamber 6, and the other part is once reflected by the reflector 52 and then goes into the chamber 6. Flash heating of the semiconductor wafer W is effected by irradiation.

Since the flash heating is performed by irradiating flash light (flash light) from the flash lamps FL, the surface temperature of the semiconductor wafer W can be raised in a short time. That is, the flash light emitted from the flash lamp FL has an extremely short irradiation time of about 0.1 millisecond or more and 100 millisecond or less, in which the electrostatic energy previously stored in the capacitor is converted into an extremely short light pulse. A strong flash. Then, the surface temperature of the semiconductor wafer W flash-heated by flash light irradiation from the flash lamps FL instantaneously rises to the processing temperature T2 of 1000° C. or higher, and the impurities implanted into the semiconductor wafer W are activated. After that, the surface temperature drops rapidly. As described above, in the heat treatment apparatus 1, the surface temperature of the semiconductor wafer W can be raised and lowered in an extremely short time. Therefore, the impurities implanted into the semiconductor wafer W can be activated while suppressing the thermal diffusion of the impurities. can be done. Since the time required for the activation of the impurity is extremely short compared to the time required for the thermal diffusion of the impurity, even in a short time of 0.1 milliseconds to 100 milliseconds in which diffusion does not occur, the activation will not occur. complete.

In flash heating in which the temperature of the surface of the semiconductor wafer W is rapidly raised by irradiating flash light with an extremely short irradiation time, a temperature difference occurs between the front and back surfaces of the semiconductor wafer W. FIG. That is, the temperature of the front surface of the semiconductor wafer W irradiated with the flash light rises first, and the temperature of the rear surface rises later due to heat conduction from the front surface. Further, the maximum temperature T3 reached by the back surface of the semiconductor wafer W during flash heating is lower than the maximum temperature reached by the front surface (processing temperature T2). Therefore, the temperature change on the back surface of the semiconductor wafer W during flash heating is moderate compared to the temperature change on the front surface.

The temperature of the back surface of the semiconductor wafer W is measured by the radiation thermometer 120 even after the time t2 when the flash light irradiation is started. A sampling interval of the radiation thermometer 120 is, for example, 10 milliseconds. As described above, the irradiation time of the flash light is extremely short, but the temperature change of the back surface of the semiconductor wafer W during flash heating is moderate over a relatively long period of time. It can follow temperature changes. After time t2, the temperature profile as shown in FIG. 10 can be obtained by measuring the back surface temperature of the semiconductor wafer W with the radiation thermometer 120 at sampling intervals of 10 milliseconds.

In the present embodiment, among the plurality of temperature measurement values obtained by measuring the back surface temperature of the semiconductor wafer W with the radiation thermometer 120 at sampling intervals of 10 milliseconds, The integration unit 31 (FIG. 8) integrates a set number of temperature measurement values to calculate an integrated temperature value (step S4). Time t3, which is the integration start point, is the point at which the temperature of the semiconductor wafer W during flash heating reaches an integration start trigger temperature T4, which is higher than the preheating temperature T1 by a set temperature ΔT. Therefore, the integration start time (time t3) is inevitably after the flash light irradiation start time (time t2). The set temperature ΔT is an apparatus parameter of the heat treatment apparatus 1 set in advance. An apparatus parameter is a control parameter set for the control unit 3 of the heat treatment apparatus 1 . It is also possible to set 0° C. as the set temperature ΔT. When the set temperature ΔT is 0° C., the integration start time coincides with the flash light irradiation start time.

In addition, the integration unit 31 integrates the set number N of temperature measurement values acquired after the integration start time. That is, the set number N is the number of integrated temperature integrated values. This set number N is also an apparatus parameter of the heat treatment apparatus 1 that is set in advance. In this embodiment, 300 is set as the set number N. Integrating 300 temperature measurement values obtained at sampling intervals of 10 milliseconds means accumulating the temperature measurement values of the semiconductor wafer W for 3 seconds from the start of integration. In addition to the set temperature ΔT and the set number N, the sampling interval of the radiation thermometer 120 is also a value set in advance as an apparatus parameter.

The integration of temperature measurement values by the integration unit 31 is represented by the following equation (1). In equation (1), S is the temperature integrated value, and Ti is the temperature measurement value of the semiconductor wafer W by the radiation thermometer 120 . That is, the integrator 31 obtains the temperature integrated value S by sequentially adding N (300 in this embodiment) temperature measurement values after the start of integration.

Next, the crack determination unit 32 determines cracks in the semiconductor wafer W based on the integrated temperature value S (step S5). If the semiconductor wafer W is cracked during flash light irradiation, the temperature measurement by the radiation thermometer 120 will be hindered and an abnormal temperature measurement value will be obtained. Then, the integrated temperature value S obtained by integrating such abnormal temperature measurement values also becomes an abnormal value. Therefore, cracking of the semiconductor wafer W can be determined by determining whether or not the integrated temperature value S is within an appropriate range. Specifically, the crack determining unit 32 determines whether the semiconductor wafer W is cracked by the following equation (2). In Equation (2), LL and UL are the lower limit and upper limit, respectively, for crack determination. The crack determining unit 32 determines that the semiconductor wafer W is not cracked when the formula (2) is satisfied, and determines that the semiconductor wafer W is cracked when the formula (2) is not satisfied. That is, the crack determination unit 32 determines that the semiconductor wafer W is cracked when the integrated temperature value S is out of the range between the preset upper limit value UL and lower limit value LL.

While the set temperature ΔT, the set number N, and the sampling interval are set as apparatus parameters, the upper limit UL and lower limit LL are values set as recipe parameters. A recipe parameter is a parameter set in a processing recipe describing a processing procedure and processing conditions of the semiconductor wafer W. FIG. Since the processing recipe is transferred to the control unit 3 for each semiconductor wafer W to be processed, recipe parameters can also be set for each semiconductor wafer W. FIG.

FIG. 11 is a diagram showing an example of a screen for setting the upper limit value UL and the lower limit value LL. The setting screen of FIG. 11 is a screen displayed on the touch panel of the control section 3 that functions as the display section 33 and the input section 34 . The operator of the heat treatment apparatus 1 can input the numerical value of the upper limit value UL from the text box 35a of the setting screen shown in FIG. 11 and the numerical value of the lower limit value LL from the text box 35b. As the upper limit value UL and the lower limit value LL, values obtained by adding and subtracting a predetermined threshold value to and from the standard value, for example, the integrated temperature value obtained by the formula (1) when no crack occurs are adopted. preferably. The narrower the range between the upper limit value UL and the lower limit value LL, the more severe the crack determination.

Returning to FIG. 9, when the crack determination unit 32 determines that the semiconductor wafer W is cracked after the start of flash light irradiation, the process proceeds from step S6 to step S7, the control unit 3 interrupts the processing in the heat treatment apparatus 1, and the chamber 6 The operation of the transport system for loading and unloading the semiconductor wafer W is also stopped. Alternatively, the control unit 3 may issue a warning to the display unit 33 that a wafer crack has occurred. When the semiconductor wafer W cracks, particles are generated in the chamber 6, so the chamber 6 is opened and cleaning work is performed.

On the other hand, when the crack determination unit 32 determines that the semiconductor wafer W is not cracked after the flash light irradiation is started, the process proceeds from step S6 to step S8, and the semiconductor wafer W is unloaded. Specifically, the halogen lamp HL is extinguished after a predetermined time has elapsed after the flash heating process is finished. As a result, the temperature of the semiconductor wafer W is rapidly lowered from the preheating temperature T1. The temperature of semiconductor wafer W during cooling is measured by radiation thermometer 120 , and the measurement result is transmitted to controller 3 . The control unit 3 monitors whether the temperature of the semiconductor wafer W has decreased to a predetermined temperature based on the measurement result of the radiation thermometer 120 . After the temperature of the semiconductor wafer W is lowered to a predetermined level or less, the pair of transfer arms 11 of the transfer mechanism 10 moves horizontally again from the retracted position to the transfer operation position, thereby moving the lift pins 12 to the susceptor. It protrudes from the upper surface of 74 and receives the semiconductor wafer W after heat treatment from the susceptor 74 . Subsequently, the transfer opening 66 closed by the gate valve 185 is opened, the semiconductor wafer W placed on the lift pins 12 is transferred out by the transfer robot outside the apparatus, and the semiconductor wafer W is heat-treated in the heat treatment apparatus 1. is completed.

In this embodiment, the radiation thermometer 120 measures the back surface temperature of the semiconductor wafer W at sampling intervals of 10 milliseconds to acquire a plurality of temperature measurement values. The integration unit 31 integrates a set number N of temperature measurement values acquired after the integration start time among the plurality of temperature measurement values to calculate a temperature integration value S, and based on the temperature integration value S, crack determination is performed. A section 32 determines cracks in the semiconductor wafer W after the start of flash light irradiation. The radiation thermometer 120 is originally configured to control the output of the halogen lamp HL in the preheating stage. That is, the radiation thermometer 120 for controlling the output of the halogen lamp HL is also used for crack determination, and without adding a special hardware configuration for wafer crack detection to the heat treatment apparatus 1, the semiconductor during flash light irradiation can be used. A crack in the wafer W is detected with a simple configuration. In addition, since cracks in the semiconductor wafer W are detected by simple arithmetic processing, there is no concern that the throughput will be lowered.

Further, in the present embodiment, the temperature integrated value S is calculated by integrating the temperature integrated values acquired from the time of starting the integration after the start of irradiation of the flash light. Therefore, when a crack occurs in the semiconductor wafer W during flash light irradiation, the abnormal integrated temperature value is accumulated and the integrated temperature value S becomes an abnormal value, so that the crack in the semiconductor wafer W can be accurately detected. can be done.

<Second embodiment>
Next, a second embodiment of the invention will be described. The configuration of the heat treatment apparatus 1 of the second embodiment is exactly the same as that of the first embodiment. Further, the processing procedure of the semiconductor wafer W in the heat treatment apparatus 1 of the second embodiment is also substantially the same as that of the first embodiment. The difference between the second embodiment and the first embodiment is that the measured temperature values of the susceptor 74 are integrated to calculate the integrated temperature value S for crack determination.

In the second embodiment, the radiation thermometer 130 measures the temperature of the central portion of the susceptor 74 at predetermined sampling intervals (eg, 10 milliseconds). Of the plurality of temperature measurement values obtained by measuring the temperature of the quartz susceptor 74 at predetermined sampling intervals by the radiation thermometer 130, the set number N of temperatures obtained from the start of integration after the start of flash light irradiation. The integrated unit 31 integrates the measured values to calculate the integrated temperature value S. As shown in FIG. The crack determining unit 32 determines whether the semiconductor wafer W is cracked by determining whether the integrated temperature value S of the susceptor 74 is within an appropriate range. Arithmetic processing relating to crack determination is the same as equations (1) and (2) in the first embodiment.

Although the transparent susceptor 74 is hardly heated by light irradiation from the halogen lamp HL, the susceptor 74 is also heated by heat conduction and heat radiation from the semiconductor wafer W whose temperature is rising. Therefore, when the semiconductor wafer W breaks during flash light irradiation, the heating of the susceptor 74 by the semiconductor wafer W is interrupted, and the temperature change of the susceptor 74 also exhibits abnormal behavior. As a result of acquiring an abnormal temperature measurement value of the susceptor 74, the integrated temperature value S also becomes an abnormal value. Therefore, cracking of the semiconductor wafer W can be determined by determining whether or not the integrated temperature value S of the susceptor 74 is within an appropriate range.

<Modification>
Although the embodiments of the present invention have been described above, the present invention can be modified in various ways other than those described above without departing from the scope of the invention. For example, cracking of the semiconductor wafer W was determined based on the integrated temperature value of the back surface of the semiconductor wafer W in the first embodiment, and based on the integrated temperature value of the susceptor 74 in the second embodiment. The crack determination of the semiconductor wafer W may be performed based on the integrated temperature value obtained by integrating the measured values. For example, cracks in the semiconductor wafer W may be determined based on a temperature integrated value obtained by integrating the surface temperature of the semiconductor wafer W measured by the radiation thermometer 140 . Alternatively, cracking of the semiconductor wafer W may be determined based on a temperature integrated value obtained by integrating the ambient temperature in the chamber 6 measured by the temperature sensor 150 . When the semiconductor wafer W is cracked during flash light irradiation, the atmospheric temperature in the chamber 6 also exhibits abnormal behavior due to the influence thereof, so cracking can be determined based on the temperature integrated value of the atmospheric temperature. In short, when the semiconductor wafer W is cracked during flash light irradiation, cracking of the semiconductor wafer W can be determined based on the integrated temperature value obtained by integrating the temperatures of the elements exhibiting abnormal temperature changes different from normal. .

Further, the crack determination based on the integrated temperature value of the semiconductor wafer W in the first embodiment and the crack determination based on the integrated temperature value of the susceptor 74 in the second embodiment may be "OR-determined". That is, the crack determining unit 32 determines that the semiconductor wafer W is cracked when the integrated temperature value of the semiconductor wafer W is not within an appropriate range, or when the integrated temperature value of the susceptor 74 is not within an appropriate range. You may make it determine. By doing so, it becomes possible to determine whether the semiconductor wafer W is cracked more reliably. Alternatively, the crack determination based on the temperature integrated value of the semiconductor wafer W and the crack determination based on the temperature integrated value of the susceptor 74 may be determined using other logical operations (for example, AND, XOR, etc.). .

Further, in the above embodiment, the flash heating unit 5 is provided with 30 flash lamps FL, but the present invention is not limited to this, and the number of flash lamps FL can be any number. . Also, the flash lamp FL is not limited to a xenon flash lamp, and may be a krypton flash lamp. Also, the number of halogen lamps HL provided in the halogen heating unit 4 is not limited to 40, and may be an arbitrary number.

Further, in the above embodiment, the semiconductor wafer W is preheated by using the filament type halogen lamp HL as the continuous lighting lamp that continuously emits light for one second or longer. Preheating may be performed by using a discharge type arc lamp (for example, a xenon arc lamp) as a continuous lighting lamp instead of the halogen lamp HL.

Further, substrates to be processed by the heat treatment apparatus 1 are not limited to semiconductor wafers, and may be glass substrates used for flat panel displays such as liquid crystal display devices or substrates for solar cells. Further, the technique according to the present invention may be applied to heat treatment of a high-dielectric-constant gate insulating film (High-k film), bonding of metal and silicon, or crystallization of polysilicon.

1 heat treatment apparatus 3 control unit 4 halogen heating unit 5 flash heating unit 6 chamber 7 holding unit 10 transfer mechanism 31 integration unit 32 crack determination unit 33 display unit 34 input unit 63 upper chamber window 64 lower chamber window 65 heat treatment space 74 susceptor 75 holding plate 77 substrate supporting pin 120, 130, 140 radiation thermometer 150 temperature sensor FL flash lamp HL halogen lamp W semiconductor wafer

Claims (14)

A heat treatment method for heating a substrate by irradiating the substrate with flash light,
a preheating step of heating the substrate to a preheating temperature by irradiating light from a continuously lit lamp;
a flash light irradiation step of irradiating the surface of the substrate with flash light from a flash lamp;
a temperature measurement step of measuring the temperature of the substrate at predetermined sampling intervals to obtain a plurality of temperature measurements;
an accumulating step of calculating a temperature integrated value by accumulating a set number of temperature measurement values acquired from a point in time corresponding to the start of irradiation of the flash light among the plurality of temperature measurement values;
a determination step of determining cracks in the substrate based on the integrated temperature value;
A heat treatment method, comprising: In the heat treatment method according to claim 1,
The heat treatment method, wherein the point of time corresponding to the start of irradiation of the flash light includes a point of time when the temperature of the substrate is the preheating temperature. In the heat treatment method according to claim 1 or claim 2,
The heat treatment method, wherein in the temperature measuring step, the temperature of the back surface of the substrate is measured. A heat treatment method for heating a substrate by irradiating the substrate with flash light,
a preheating step of irradiating the substrate held by the susceptor with light from a continuously lit lamp to heat the substrate to a preheating temperature;
a flash light irradiation step of irradiating the surface of the substrate with flash light from a flash lamp;
a temperature measurement step of measuring the temperature of the susceptor at predetermined sampling intervals to obtain a plurality of temperature measurements;
an accumulating step of calculating a temperature integrated value by accumulating a set number of temperature measurement values acquired from a point in time corresponding to the start of irradiation of the flash light among the plurality of temperature measurement values;
a determination step of determining cracks in the substrate based on the integrated temperature value;
A heat treatment method, comprising: In the heat treatment method according to claim 4,
The heat treatment method, wherein the point of time corresponding to the start of irradiation of the flash light includes a point of time when the temperature of the substrate is the preheating temperature. In the heat treatment method according to any one of claims 1 to 5,
The heat treatment method, wherein, in the determining step, it is determined that the substrate is cracked when the integrated temperature value is out of a range between a preset upper limit value and a lower limit value. In the heat treatment method according to claim 6,
A heat treatment method, further comprising a setting step of setting the upper limit value and the lower limit value. A heat treatment apparatus for heating a substrate by irradiating the substrate with flash light,
a chamber containing the substrate;
a susceptor that holds the substrate in the chamber;
a continuous lighting lamp that irradiates the substrate held by the susceptor with light to heat it to a preheating temperature;
a flash lamp for irradiating the surface of the substrate with flash light;
a radiation thermometer that measures the temperature of the substrate at predetermined sampling intervals to obtain a plurality of temperature measurements;
an integrator for calculating a temperature integrated value by accumulating a set number of temperature measurement values acquired from a point in time corresponding to the start of irradiation of the flash light among the plurality of temperature measurement values;
a determination unit that determines cracking of the substrate based on the integrated temperature value;
A heat treatment apparatus comprising: In the heat treatment apparatus according to claim 8,
The heat treatment apparatus, wherein the point of time that coincides with the start of irradiation of the flash light includes a point of time when the temperature of the substrate is the preheating temperature. In the heat treatment apparatus according to claim 8 or 9,
The heat treatment apparatus, wherein the radiation thermometer measures the temperature of the back surface of the substrate. A heat treatment apparatus for heating a substrate by irradiating the substrate with flash light,
a chamber containing the substrate;
a susceptor that holds the substrate in the chamber;
a continuous lighting lamp that irradiates the substrate held by the susceptor with light to heat it to a preheating temperature;
a flash lamp for irradiating the surface of the substrate with flash light;
a radiation thermometer that measures the temperature of the susceptor at predetermined sampling intervals to obtain a plurality of temperature measurements;
an integrator for calculating a temperature integrated value by accumulating a set number of temperature measurement values acquired from a point in time corresponding to the start of irradiation of the flash light among the plurality of temperature measurement values;
a determination unit that determines cracking of the substrate based on the integrated temperature value;
A heat treatment apparatus comprising: In the heat treatment apparatus according to claim 11,
The heat treatment apparatus, wherein the point of time that coincides with the start of irradiation of the flash light includes a point of time when the temperature of the substrate is the preheating temperature. In the heat treatment apparatus according to any one of claims 8 to 12,
The heat treatment apparatus, wherein the determination unit determines that the substrate is cracked when the integrated temperature value is out of a preset upper limit value and lower limit value range. In the heat treatment apparatus according to claim 13,
A heat treatment apparatus, further comprising a setting unit that sets the upper limit value and the lower limit value.

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