JP2020145350A - Heat treatment method and heat treatment apparatus - Google Patents

Abstract

To provide a heat treatment method and a heat treatment apparatus that can easily detect the crack of a substrate in a heat treatment.SOLUTION: A semiconductor wafer delivered into a treatment chamber is preheated by being irradiated with light from a halogen lamp. After the temperature of the semiconductor wafer starts to increase by the preheating, the measurement of the particle concentration in the air in the treatment chamber is started. The semiconductor wafer whose temperature has increased to a predetermined temperature by the preheating is irradiated with flash light, thereby performing flash heating. The particle concentration in the air in the treatment chamber when the semiconductor wafer is heated is measured and when the concentration value has exceeded a predetermined threshold, it is determined that the semiconductor wafer has cracked. The crack is detected with a simple structure that requires only measurement of the particle concentration in the air and comparison between the increase and the threshold; therefore, the crack of the semiconductor wafer in the heat treatment can be easily detected.SELECTED DRAWING: Figure 11

Description

The present invention relates to a heat treatment method and a heat treatment apparatus for performing a heat treatment for heating or cooling a thin plate-shaped precision electronic substrate (hereinafter, simply referred to as “substrate”) such as a semiconductor wafer.

In the semiconductor device manufacturing process, flash lamp annealing (FLA), which heats a semiconductor wafer in an extremely short time, has attracted attention. Flash lamp annealing uses a xenon flash lamp (hereinafter, simply referred to as "flash lamp" to mean a xenon flash lamp) to irradiate the surface of the semiconductor wafer with flash light, so that only the surface of the semiconductor wafer is extremely exposed. This is a heat treatment technique that raises the temperature in a 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, and the wavelength is shorter than that of the conventional halogen lamp, which is almost the same as the basic absorption band of the silicon semiconductor wafer. Therefore, when the semiconductor wafer is irradiated with the flash light from the xenon flash lamp, the transmitted light is small and the temperature of the semiconductor wafer can be rapidly raised. It has also been found that if the flash light is irradiated for an extremely short time of several milliseconds or less, the temperature can be selectively raised only in the vicinity of the surface of the semiconductor wafer.

Such flash lamp annealing is utilized for processes that require heating for a very short time, for example, activation of impurities injected into a semiconductor wafer. By irradiating the surface of a semiconductor wafer into which impurities have been implanted by the ion implantation method with flash light from a flash lamp, the surface of the semiconductor wafer can be raised to the activation temperature for a very short time, and the impurities are deeply diffused. Only impurity activation can be performed without causing it.

In a heat treatment apparatus using such a flash lamp, since the flash light having extremely high energy is instantaneously irradiated to the surface of the semiconductor wafer, the surface temperature of the semiconductor wafer rises rapidly in an instant, while the back surface temperature rises. It doesn't rise that much. Therefore, a rapid thermal expansion occurs only on the surface of the semiconductor wafer, and the semiconductor wafer is deformed so as to have a convex upper surface and warp. Then, at the next moment, the semiconductor wafer was deformed so as to be warped with the lower surface convex due to the reaction.

When the semiconductor wafer is deformed so that the upper surface is convex, the edge portion of the wafer collides with the susceptor. On the contrary, 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 by the impact of collision with the susceptor.

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

For this reason, for example, Patent Document 1 discloses a technique in which a microphone is provided in a chamber for performing flash heat treatment, and a wafer crack is determined by detecting a sound when a semiconductor wafer is cracked. Further, Patent Document 2 discloses a technique of receiving light reflected from a semiconductor wafer by a light guide rod and detecting wafer cracking from the intensity of the reflected light. Further, Patent Document 3 discloses a technique for detecting wafer cracks from the average value or standard deviation of the temperature profile of a semiconductor wafer after flash light irradiation.

Japanese Unexamined Patent Publication No. 2009-231697 JP-A-2015-130423 JP-A-2018-148201

However, the technique disclosed in Patent Document 1 has a problem that it is difficult to perform filtering for extracting only the sound in which the semiconductor wafer is broken. Further, in the technique disclosed in Patent Document 2, there is a problem that the throughput is deteriorated because the step of rotating the light guide rod is required twice before and after the flash light irradiation. Further, in the technique disclosed in Patent Document 3, it is necessary to acquire a temperature profile of a semiconductor wafer and perform complicated arithmetic processing on the temperature profile.

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 method and a heat treatment apparatus capable of easily detecting cracks in a substrate during heat treatment.

In order to solve the above problems, the invention of claim 1 is a heat treatment method for heat-treating a substrate, in which a processing step of heat-treating the substrate housed in the chamber and the inside of the chamber when the heat treatment is performed. It is characterized by including a measurement step of measuring the air particle concentration of the above, and a detection step of detecting cracks in the substrate based on the air particle concentration measured in the measurement step.

The invention of claim 2 is the heat treatment method according to the invention of claim 1, wherein in the detection step, when the increase in the air particle concentration measured in the measurement step exceeds a predetermined threshold value, the invention is described. It is characterized in that it is determined that the substrate is broken.

Further, according to the invention of claim 3, in the heat treatment method according to the invention of claim 1, in the detection step, the actual measurement pattern of the change in the air particle concentration measured in the measurement step was normally heat-treated. It is characterized in that it is determined that the substrate is cracked when it is different from the acquired normal density pattern.

Further, the invention of claim 4 issues a warning and issues a warning when a crack in the substrate is detected in the detection step in the heat treatment method according to any one of claims 1 to 3. The heat treatment is stopped.

The invention of claim 5 is the heat treatment method according to any one of claims 1 to 4, wherein the heat treatment is a heat treatment of irradiating the substrate with flash light from a flash lamp. To do.

The invention of claim 6 is a heat treatment apparatus for heat-treating a substrate, a chamber for accommodating the substrate, a heat treatment unit for heat-treating the substrate housed in the chamber, and air in the chamber. It is provided with a measuring unit for measuring the particle concentration and a detecting unit for detecting cracks in the substrate based on the air particle concentration in the chamber measured by the measuring unit during the heat treatment. It is a feature.

Further, the invention of claim 7 is the heat treatment apparatus according to the invention of claim 6, wherein the detection unit determines an increase in the concentration of air particles measured by the measurement unit during the heat treatment. It is characterized in that it is determined that the substrate is cracked when the threshold value is exceeded.

Further, the invention of claim 8 shows a normal change in the concentration of air particles measured by the measuring unit when the heat treatment is normally performed without cracking the substrate in the heat treatment apparatus according to the invention of claim 6. The detection unit further includes a storage unit for storing the concentration pattern, and the detection unit is used when the actual measurement pattern of the change in the air particle concentration measured by the measurement unit during the heat treatment is different from the normal concentration pattern. It is characterized in that it is determined that the substrate is cracked.

Further, the invention of claim 9 issues a warning and issues a warning when the detection unit detects a crack in the substrate in the heat treatment apparatus according to any one of claims 6 to 8. It is characterized by further including a control unit for stopping the heat treatment.

Further, the invention of claim 10 includes a heat treatment apparatus according to any one of claims 6 to 9, wherein the heat treatment unit includes a flash lamp that irradiates the substrate with flash light to heat the substrate. It is characterized by that.

According to the inventions of claims 1 to 5, since cracks in the substrate are detected based on the air particle concentration in the chamber during the heat treatment, only the air particle concentration is measured during the heat treatment. Cracks in the substrate can be easily detected.

According to the inventions of claims 6 to 10, the air particle concentration is measured in order to detect cracks in the substrate based on the air particle concentration in the chamber measured by the measuring unit during the heat treatment. It is possible to easily detect cracks in the substrate during heat treatment.

It is a top view which shows the heat treatment apparatus which concerns on this invention. It is a front view of the heat treatment apparatus of FIG. It is a vertical cross-sectional view which shows the structure of the heat treatment part. It is a perspective view which shows the whole appearance of the holding part. It is a top view of the susceptor. It is sectional drawing of the susceptor. It is a top view of the transfer mechanism. It is a side view of the transfer mechanism. It is a top view which shows the arrangement of a plurality of halogen lamps. It is a block diagram which shows the structure of a control part. It is a flowchart which shows the processing procedure of the semiconductor wafer in a heat treatment part. It is a figure which shows the change of the air particle density | concentration in the processing chamber.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
First, the overall configuration of the heat treatment apparatus according to the present invention will be described. FIG. 1 is a plan view showing the heat treatment apparatus 100 according to the present invention, and FIG. 2 is a front view thereof. The heat treatment apparatus 100 is a flash lamp annealing apparatus that irradiates a disk-shaped semiconductor wafer W as a substrate with flash light to heat the semiconductor wafer W. The size of the semiconductor wafer W to be processed is not particularly limited, but is, for example, φ300 mm or φ450 mm. In addition, in FIG. 1 and each subsequent drawing, the dimensions and numbers of each part are exaggerated or simplified as necessary for easy understanding. Further, in each of the drawings of FIGS. 1 to 3, an XYZ Cartesian coordinate system is provided in which the Z-axis direction is the vertical direction and the XY plane is the horizontal plane in order to clarify their directional relationships.

As shown in FIGS. 1 and 2, in the heat treatment apparatus 100, the indexer unit 101 for carrying the unprocessed semiconductor wafer W into the apparatus from the outside and carrying out the processed semiconductor wafer W out of the apparatus, untreated. Alignment unit 230 for positioning the semiconductor wafer W, two cooling units 130 and 140 for cooling the semiconductor wafer W after heat treatment, heat treatment unit 160 for performing flash heat treatment on the semiconductor wafer W, and cooling units 130 and 140. A transfer robot 150 that transfers the semiconductor wafer W to the heat treatment unit 160 is provided. Further, the heat treatment apparatus 100 includes a control unit 3 that controls the operation mechanism and the transfer robot 150 provided in each of the above processing units to advance the flash heat treatment of the semiconductor wafer W.

The indexer section 101 takes out a load port 110 on which a plurality of carriers C (two in the present embodiment) are placed side by side, an unprocessed semiconductor wafer W from each carrier C, and a semiconductor wafer that has been processed on each carrier C. It is equipped with a delivery robot 120 that stores W. The carrier C containing the unprocessed semiconductor wafer W is transported by an automatic guided vehicle (AGV, OHT) or the like and mounted on the load port 110, and the carrier C containing the processed semiconductor wafer W is an automatic guided vehicle. Taken away from the load port 110.

Further, in the load port 110, the carrier C is configured to be movable up and down as shown by the arrow CU in FIG. 2 so that the delivery robot 120 can load and unload an arbitrary semiconductor wafer W with respect to the carrier C. ing. As the form of the carrier C, in addition to the FOUP (front opening unified pod) for storing the semiconductor wafer W in a closed space, the SMIF (Standard Mechanical Inter Face) pod and the OC (open) for exposing the stored semiconductor wafer W to the outside air. cassette) may be used.

Further, the delivery robot 120 is capable of sliding movement as shown by arrow 120S in FIG. 1, turning operation and ascending / descending operation as shown by arrow 120R. As a result, the delivery robot 120 transfers the semiconductor wafer W to and from the two carriers C, and transfers the semiconductor wafer W to the alignment unit 230 and the two cooling units 130 and 140. The semiconductor wafer W is moved in and out of the carrier C by the delivery robot 120 by sliding the hand 121 and moving the carrier C up and down. Further, the semiconductor wafer W is delivered between the delivery robot 120 and the alignment unit 230 or the cooling units 130, 140 by the sliding movement of the hand 121 and the raising / lowering operation of the delivery robot 120.

The alignment portion 230 is provided so as to be connected to the side of the indexer portion 101 along the Y-axis direction. The alignment unit 230 is a processing unit that rotates the semiconductor wafer W in a horizontal plane to orient the semiconductor wafer W in an appropriate direction for flash heating. The alignment portion 230 includes a mechanism for supporting and rotating the semiconductor wafer W in a horizontal posture inside the alignment chamber 231 which is a housing made of an aluminum alloy, and a notch, an orientation flat, or the like formed on the peripheral portion of the semiconductor wafer W. It is configured by providing a mechanism for optically detecting.

The delivery of the semiconductor wafer W to the alignment unit 230 is performed by the delivery robot 120. The semiconductor wafer W is delivered from the delivery robot 120 to the alignment chamber 231 so that the center of the wafer is located at a predetermined position. The alignment unit 230 adjusts the orientation of the semiconductor wafer W by rotating the semiconductor wafer W around the vertical axis around the center of the semiconductor wafer W received from the indexer unit 101 and optically detecting a notch or the like. To do. The semiconductor wafer W whose orientation has been adjusted is taken out from the alignment chamber 231 by the delivery robot 120.

A transfer chamber 170 for accommodating the transfer robot 150 is provided as a transfer space for the semiconductor wafer W by the transfer robot 150. The processing chamber 6 of the heat treatment unit 160, the first cool chamber 131 of the cooling unit 130, and the second cool chamber 141 of the cooling unit 140 are connected to each other on three sides of the transfer chamber 170.

The heat treatment unit 160, which is the main part of the heat treatment apparatus 100, is a substrate processing unit that irradiates a preheated semiconductor wafer W with a flash (flash light) from a xenon flash lamp FL to perform a flash heat treatment. The configuration of the heat treatment unit 160 will be further described later.

The two cooling units 130 and 140 have substantially the same configuration. The cooling units 130 and 140 are provided with a metal cooling plate and a quartz plate placed on the upper surface of the first cool chamber 131 and the second cool chamber 141, which are aluminum alloy housings, respectively. (Both are not shown). The cooling plate is temperature-controlled to room temperature (about 23 ° C.) by a Peltier element or a constant temperature water circulation. The semiconductor wafer W that has been subjected to the flash heat treatment by the heat treatment unit 160 is carried into the first cool chamber 131 or the second cool chamber 141, placed on the quartz plate, and cooled.

Both the first cool chamber 131 and the second cool chamber 141 are connected to both of the indexer portion 101 and the transfer chamber 170. The first cool chamber 131 and the second cool chamber 141 are formed with two openings for loading and unloading the semiconductor wafer W. Of the two openings of the first cool chamber 131, the opening connected to the indexer portion 101 can be opened and closed by the gate valve 181. On the other hand, the opening connected to the transfer chamber 170 of the first cool chamber 131 can be opened and closed by the gate valve 183. That is, the first cool chamber 131 and the indexer portion 101 are connected via the gate valve 181, and the first cool chamber 131 and the transfer chamber 170 are connected via the gate valve 183.

When the semiconductor wafer W is transferred between the indexer portion 101 and the first cool chamber 131, the gate valve 181 is opened. Further, when the semiconductor wafer W is transferred between the first cool chamber 131 and the transfer chamber 170, the gate valve 183 is opened. When the gate valve 181 and the gate valve 183 are closed, the inside of the first cool chamber 131 becomes a closed space.

Further, of the two openings of the second cool chamber 141, the opening connected to the indexer portion 101 can be opened and closed by the gate valve 182. On the other hand, the opening connected to the transfer chamber 170 of the second cool chamber 141 can be opened and closed by the gate valve 184. That is, the second cool chamber 141 and the indexer portion 101 are connected via the gate valve 182, and the second cool chamber 141 and the transfer chamber 170 are connected via the gate valve 184.

When the semiconductor wafer W is transferred between the indexer portion 101 and the second cool chamber 141, the gate valve 182 is opened. Further, when the semiconductor wafer W is transferred between the second cool chamber 141 and the transfer chamber 170, the gate valve 184 is opened. When the gate valve 182 and the gate valve 184 are closed, the inside of the second cool chamber 141 becomes a closed space.

The transfer robot 150 provided in the transfer chamber 170 installed adjacent to the processing chamber 6 is capable of turning around an axis along the vertical direction as shown by an arrow 150R. The transfer robot 150 has two link mechanisms composed of a plurality of arm segments, and transfer hands 151a and 151b for holding the semiconductor wafer W are provided at the tips of the two link mechanisms, respectively. These transport hands 151a and 151b are vertically separated by a predetermined pitch, and are independently slidable in the same horizontal direction by a link mechanism. Further, the transfer robot 150 moves the two transfer hands 151a and 151b up and down while keeping them separated by a predetermined pitch by moving the base provided with the two link mechanisms up and down.

When the transfer robot 150 transfers (puts in and out) the semiconductor wafer W as a transfer partner for the first cool chamber 131, the second cool chamber 141, or the processing chamber 6 of the heat treatment unit 160, first, both transfer hands 151a and 151b It turns so as to face the delivery partner, then moves up and down (or while turning), and is located at a height at which one of the transfer hands delivers the semiconductor wafer W to the delivery partner. Then, the transfer hand 151a (151b) is linearly slid and moved in the horizontal direction to transfer the semiconductor wafer W to the transfer partner.

The transfer of the semiconductor wafer W between the transfer robot 150 and the delivery robot 120 can be performed via the cooling units 130 and 140. That is, the first cool chamber 131 of the cooling unit 130 and the second cool chamber 141 of the cooling unit 140 also function as paths for delivering the semiconductor wafer W between the transfer robot 150 and the delivery robot 120. .. Specifically, the semiconductor wafer W is delivered when one of the transfer robot 150 or the delivery robot 120 receives the semiconductor wafer W passed to the first cool chamber 131 or the second cool chamber 141 by the other. The transfer robot 150 and the transfer robot 120 constitute a transfer mechanism for transporting the semiconductor wafer W from the carrier C to the heat treatment unit 160.

As described above, gate valves 181 and 182 are provided between the first cool chamber 131 and the second cool chamber 141 and the indexer portion 101, respectively. Further, gate valves 183 and 184 are provided between the transfer chamber 170 and the first cool chamber 131 and the second cool chamber 141, respectively. Further, a gate valve 185 is provided between the transfer chamber 170 and the processing chamber 6 of the heat treatment unit 160. When the semiconductor wafer W is conveyed in the heat treatment apparatus 100, these gate valves are opened and closed as appropriate.

Next, the configuration of the heat treatment unit 160 will be described. FIG. 3 is a vertical cross-sectional view showing the configuration of the heat treatment unit 160. The heat treatment unit 160 includes a processing chamber 6 that accommodates the semiconductor wafer W and performs heat treatment, a flash lamp house 5 that incorporates a plurality of flash lamps FL, and a halogen lamp house 4 that incorporates a plurality of halogen lamps HL. Be prepared. A flash lamp house 5 is provided on the upper side of the processing chamber 6, and a halogen lamp house 4 is provided on the lower side. Further, the heat treatment unit 160 is a transfer mechanism 10 that transfers the semiconductor wafer W between the holding unit 7 that holds the semiconductor wafer W in a horizontal posture and the holding unit 7 and the transfer robot 150 inside the processing chamber 6. And.

The processing chamber 6 is configured by mounting quartz chamber windows above and below the tubular chamber side portion 61. The chamber side portion 61 has a substantially tubular shape with upper and lower openings, and the upper chamber window 63 is attached to the upper opening and closed, and the lower chamber window 64 is attached to the lower opening and closed. ing. The upper chamber window 63 constituting the ceiling portion of the processing chamber 6 is a disk-shaped member formed of quartz, and functions as a quartz window that transmits the flash light emitted from the flash lamp FL into the processing chamber 6. Further, the lower chamber window 64 constituting the floor portion of the processing chamber 6 is also a disk-shaped member formed of quartz, and functions as a quartz window that transmits light from the halogen lamp HL into the processing chamber 6.

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

By mounting the reflective rings 68 and 69 on the chamber side portion 61, a recess 62 is formed on the inner wall surface of the processing chamber 6. That is, a recess 62 is formed which is surrounded by the central portion of the inner wall surface of the chamber side portion 61 to which the reflection rings 68 and 69 are not mounted, the lower end surface of the reflection ring 68, and the upper end surface of the reflection ring 69. .. The recess 62 is formed in an annular shape along the horizontal direction on the inner wall surface of the processing chamber 6 and surrounds the holding portion 7 that holds the semiconductor wafer W. The chamber side 61 and the reflective rings 68 and 69 are made of a metal material (for example, stainless steel) having excellent strength and heat resistance.

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

Further, a gas supply hole 81 for supplying the processing gas to the heat treatment space 65 is formed in the upper part of the inner wall of the processing chamber 6. The gas supply hole 81 is formed at a position above the recess 62, and may be provided in the reflection ring 68. The gas supply hole 81 is communicatively connected to the gas supply pipe 83 via a buffer space 82 formed in an annular shape inside the side wall of the processing chamber 6. The gas supply pipe 83 is connected to the processing gas supply source 85. Further, a valve 84 is inserted in the middle of the path of the gas supply pipe 83. When the valve 84 is opened, the processing gas is supplied from the processing gas supply source 85 to the buffer space 82. The processing gas that has flowed into the buffer space 82 flows so as to expand in the buffer space 82 having 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 treatment gas, an inert gas such as nitrogen (N ₂ ) or a reactive gas such as hydrogen (H ₂ ) or ammonia (NH ₃ ) can be used (nitrogen in this embodiment).

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 processing chamber 6. The gas exhaust hole 86 is formed at a position below the recess 62, and may be provided in the reflection ring 69. The gas exhaust hole 86 is communicatively connected to the gas exhaust pipe 88 via a buffer space 87 formed in an annular shape inside the side wall of the processing chamber 6. The gas exhaust pipe 88 is connected to the exhaust mechanism 190. Further, 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 via 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 processing chamber 6, or may be slit-shaped. Further, the processing gas supply source 85 and the exhaust mechanism 190 may be a mechanism provided in the heat treatment apparatus 100, or may be a utility of a factory in which the heat treatment apparatus 100 is installed.

Further, an air particle counter 99 is connected in the middle of the path of the gas exhaust pipe 88 from the processing chamber 6. As the air particle counter 99, for example, a light scattering type particle counter that measures the size and number of particles from the scattered light when a gas containing particles is irradiated with laser light is used. The aerial particle counter 99 measures the aerial particle concentration of the gas flowing through the gas exhaust pipe 88. Since the gas flowing through the gas exhaust pipe 88 is the gas existing in the heat treatment space 65 in the processing chamber 6, the aerial particle counter 99 measures the aerial particle concentration in the processing chamber 6.

FIG. 4 is a perspective view showing the overall appearance of the holding portion 7. 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 in which a part is missing from the ring shape. This missing portion is provided to prevent interference between the transfer arm 11 of the transfer mechanism 10 described later and the base ring 71. By placing the base ring 71 on the bottom surface of the recess 62, the base ring 71 is supported on the wall surface of the processing chamber 6 (see FIG. 3). A plurality of connecting portions 72 (four in the present embodiment) are erected on the upper surface of the base ring 71 along the circumferential direction of the ring 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. FIG. 5 is a plan view of the susceptor 74. Further, FIG. 6 is a cross-sectional view of the susceptor 74. The susceptor 74 includes a holding plate 75, a guide ring 76, and a plurality of substrate support pins 77. The holding plate 75 is a substantially circular flat plate-shaped 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 plane size larger than that of the semiconductor wafer W.

A guide ring 76 is installed on the upper peripheral edge of the holding plate 75. The guide ring 76 is a ring-shaped member having an inner diameter larger than the diameter of the semiconductor wafer W. 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 a tapered surface that 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 is a flat holding surface 75a for holding the semiconductor wafer W. A plurality of substrate support pins 77 are erected on the holding surface 75a of the holding plate 75. In the present embodiment, a total of 12 substrate support pins 77 are erected at every 30 ° along the circumference of the outer circumference circle (inner circumference circle of the guide ring 76) of the holding surface 75a and the concentric circle. The diameter of the circle in which the 12 substrate support pins 77 are arranged (distance between the opposing substrate support pins 77) is smaller than the diameter of the semiconductor wafer W, and if the diameter of the semiconductor wafer W is φ300 mm, the diameter is φ270 mm to φ280 mm (this implementation). In the form, it is φ270 mm). 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. 4, the four connecting portions 72 erected on the base ring 71 and the peripheral edge 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 base ring 71 of the holding portion 7 is supported on the wall surface of the processing chamber 6, so that the holding portion 7 is mounted on the processing chamber 6. When the holding portion 7 is mounted on the processing chamber 6, the holding plate 75 of the susceptor 74 is in 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 is a horizontal plane.

The semiconductor wafer W carried into the processing chamber 6 is placed and held in a horizontal posture on the susceptor 74 of the holding portion 7 mounted on the processing chamber 6. At this time, the semiconductor wafer W is supported by the twelve substrate support pins 77 erected on the holding plate 75 and held by the susceptor 74. More precisely, the upper ends of the 12 substrate support pins 77 come into contact with the lower surface of the semiconductor wafer W to support the semiconductor wafer W. Since the heights of the 12 substrate support pins 77 (distance from the upper end of the substrate support pins 77 to the holding surface 75a of the holding plate 75) are uniform, the semiconductor wafer W is placed in a horizontal position by the 12 substrate support pins 77. Can be supported.

Further, the semiconductor wafer W is supported by a plurality of substrate support pins 77 from the holding surface 75a of the holding plate 75 at a predetermined interval. The thickness of the guide ring 76 is larger than the height of the substrate support pin 77. Therefore, the horizontal misalignment of the semiconductor wafer W supported by the plurality of substrate support pins 77 is prevented by the guide ring 76.

Further, as shown in FIGS. 4 and 5, an opening 78 is formed in the holding plate 75 of the susceptor 74 so as to penetrate vertically. The opening 78 is provided for the radiation thermometer 20 (see FIG. 3) to receive synchrotron radiation (infrared light) emitted from the lower surface of the semiconductor wafer W held by the susceptor 74. That is, the radiation thermometer 20 receives the light radiated from the lower surface of the semiconductor wafer W held by the susceptor 74 through the opening 78 and measures the temperature of the semiconductor wafer W. Further, the holding plate 75 of the susceptor 74 is provided with four through holes 79 through which the lift pin 12 of the transfer mechanism 10 described later penetrates for the transfer of the semiconductor wafer W.

FIG. 7 is a plan view of the transfer mechanism 10. Further, FIG. 8 is a side view of the transfer mechanism 10. The transfer mechanism 10 includes two transfer arms 11. The transfer arm 11 has an arc shape that generally follows an annular recess 62. Two lift pins 12 are erected on each transfer arm 11. Each transfer arm 11 is rotatable by a horizontal movement mechanism 13. The horizontal movement mechanism 13 has a transfer operation position (solid line position in FIG. 7) for transferring the semiconductor wafer W to the holding portion 7 and the semiconductor wafer W held by the holding portion 7. It is horizontally moved to and from the retracted position (two-dot chain line position in FIG. 7) that does not overlap in a plan view. The transfer operation position is below the susceptor 74, and the retract position is outside the susceptor 74. The horizontal movement mechanism 13 may be one in which each transfer arm 11 is rotated by an individual motor, or a pair of transfer arms 11 are interlocked and rotated by one motor using a link mechanism. It may be something to move.

Further, the pair of transfer arms 11 are moved up and down together with the horizontal movement mechanism 13 by the elevating mechanism 14. When the elevating mechanism 14 raises the pair of transfer arms 11 at the transfer operation position, a total of four lift pins 12 pass through the through holes 79 (see FIGS. 4 and 5) formed in the susceptor 74, and the lift pins The upper end of 12 protrudes from the upper surface of the susceptor 74. On the other hand, when the evacuation mechanism 14 lowers the pair of transfer arms 11 at the transfer operation position, the lift pin 12 is pulled out from the through hole 79, and the horizontal movement mechanism 13 moves the pair of transfer arms 11 so as to open each. 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 portion 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 unit (horizontal movement mechanism 13 and elevating mechanism 14) of the transfer mechanism 10 is provided, and the atmosphere around the drive unit of the transfer mechanism 10 is provided. Is configured to be discharged to the outside of the processing chamber 6.

Returning to FIG. 3, the flash lamp house 5 provided above the processing chamber 6 has a light source composed of a plurality of (30 in this embodiment) xenon flash lamp FL inside the housing 51, and a light source thereof. It is configured to include a reflector 52 provided so as to cover the upper part. Further, a lamp light emitting window 53 is attached to the bottom of the housing 51 of the flash lamp house 5. The lamp light emitting window 53 constituting the floor of the flash lamp house 5 is a plate-shaped quartz window made of quartz. By installing the flash lamp house 5 above the processing chamber 6, the lamp light emitting window 53 faces the upper chamber window 63. The flash lamp FL irradiates the heat treatment space 65 with flash light from above the processing chamber 6 through the lamp light emitting window 53 and the upper chamber window 63.

Each of the plurality of flash lamps FL is a rod-shaped lamp having a long cylindrical shape, and the longitudinal direction thereof 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 lamp FL is also a horizontal plane.

The xenon flash lamp FL is attached to a rod-shaped glass tube (discharge tube) in which xenon gas is sealed inside and an anode and a cathode connected to a condenser are arranged at both ends thereof, and on the outer peripheral surface of the glass tube. It is provided with a cathode electrode. Since xenon gas is electrically an insulator, electricity does not flow in the glass tube under normal conditions even if electric charges are accumulated in the condenser. However, when a high voltage is applied to the trigger electrode to break the insulation, the electricity stored in the capacitor instantly flows into the glass tube, and light is emitted by the excitation of xenon atoms or molecules at that time. In such a xenon flash lamp FL, the electrostatic energy stored in the capacitor in advance is converted into an extremely short optical pulse of 0.1 millisecond to 100 millisecond, so that the halogen lamp HL is continuously lit. It has the feature that it can irradiate extremely strong light compared to a 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 supply that supplies power to the flash lamp FL.

Further, the reflector 52 is provided above the plurality of flash lamps FL so as to cover all of them. The basic function of the reflector 52 is to reflect the flash light emitted from the plurality of flash lamps FL toward the heat treatment space 65. 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 lamp house 4 provided below the processing chamber 6 contains a plurality of halogen lamps HL (40 in this embodiment) inside the housing 41. The plurality of halogen lamps HL irradiate the heat treatment space 65 with light from below the processing chamber 6 through the lower chamber window 64.

FIG. 9 is a plan view showing the arrangement of a plurality of halogen lamps HL. In the present embodiment, 20 halogen lamps HL are arranged in two upper and lower stages in a rectangular light source region. Each halogen lamp HL is a rod-shaped lamp having a long cylindrical shape. The 20 halogen lamps HL in both the upper and lower stages 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 and lower stages is a horizontal plane.

Further, as shown in FIG. 9, the arrangement density of the halogen lamp HL in the region facing the peripheral edge portion is higher than the region facing the central portion of the semiconductor wafer W held by the holding portion 7 in both the upper and lower stages. There is. That is, in both the upper and lower stages, the arrangement pitch of the halogen lamp 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 on the peripheral edge of the semiconductor wafer W, which tends to have a temperature drop during heating by light irradiation from the halogen lamp HL.

Further, the lamp group composed of the halogen lamp HL in the upper stage and the lamp group composed of the halogen lamp HL in the lower stage are arranged so as to intersect in a grid pattern. That is, a total of 40 halogen lamps HL are arranged so that the longitudinal direction of each halogen lamp HL in the upper stage and the longitudinal direction of each halogen lamp HL in the lower stage are orthogonal to each other.

The halogen lamp HL is a filament type light source that incandescents the filament and emits light by energizing the filament arranged inside the glass tube. Inside the glass tube, a gas in which a small amount of a halogen element (iodine, bromine, etc.) is introduced into an inert gas such as nitrogen or argon is sealed. By introducing the halogen element, it becomes possible to set the temperature of the filament to a high temperature while suppressing the breakage of the filament. Therefore, the halogen lamp HL has a characteristic that it has a longer life and can continuously irradiate strong light as compared with a normal incandescent lamp. That is, the halogen lamp HL is a continuously lit lamp that continuously emits light for at least 1 second or longer. Further, since the halogen lamp HL is a rod-shaped lamp, it has a long life, and by arranging the halogen lamp HL along the horizontal direction, the radiation efficiency to the upper semiconductor wafer W becomes excellent.

Further, in the housing 41 of the halogen lamp house 4, a reflector 43 is provided under the two-stage halogen lamp HL (FIG. 3). The reflector 43 reflects the light emitted from the plurality of halogen lamps HL toward the heat treatment space 65.

In addition to the above configuration, the heat treatment unit 160 prevents excessive temperature rise of the halogen lamp house 4, the flash lamp house 5, and the processing chamber 6 due to the thermal energy generated from the halogen lamp HL and the flash lamp FL during the heat treatment of the semiconductor wafer W. Therefore, it has various cooling structures. For example, a water cooling pipe (not shown) is provided on the wall of the processing chamber 6. Further, the halogen lamp house 4 and the flash lamp house 5 have an air-cooled structure in which a gas flow is formed inside to exhaust heat. In addition, air is also supplied to the gap between the upper chamber window 63 and the lamp light emitting window 53 to cool the flash lamp house 5 and the upper chamber window 63.

FIG. 10 is a block diagram showing the configuration of the control unit 3. The control unit 3 controls the various operation mechanisms provided in the heat treatment apparatus 100. The configuration of the control unit 3 as hardware is the same as that of a general computer. That is, the control unit 3 stores a CPU, which is a circuit that performs various arithmetic processes, a ROM, which is a read-only memory that stores basic programs, a RAM, which is a read / write memory that stores various information, and control software and data. A magnetic disk 35 for storing is provided. The processing in the heat treatment apparatus 100 proceeds when the CPU of the control unit 3 executes a predetermined processing program. The detection unit 31 and the alarm 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 detection unit 31 and the alarm unit 32 will be further described later. Although the control unit 3 is shown in the indexer unit 101 in FIG. 1, the control unit 3 is not limited to this, and the control unit 3 can be arranged at an arbitrary position in the heat treatment apparatus 100.

Further, an input unit 33 and a display unit 34 are connected to the control unit 3. The control unit 3 displays various information on the display unit 34. The operator of the heat treatment apparatus 100 can input various commands and parameters from the input unit 33 while checking the information displayed on the display unit 34. As the input unit 33, for example, a keyboard or a mouse can be used. As the display unit 34, for example, a liquid crystal display can be used. In the present embodiment, as the display unit 34 and the input unit 33, a liquid crystal touch panel provided on the outer wall of the heat treatment apparatus 100 is adopted so as to have both functions.

Next, the processing procedure of the semiconductor wafer W in the heat treatment apparatus 100 will be described. The semiconductor wafer W to be processed here is a semiconductor substrate to which impurities (ions) have been added by the ion implantation method. Activation of the impurities is carried out by flash light irradiation heat treatment (annealing) by the heat treatment apparatus 100. The processing procedure of the heat treatment apparatus 100 described below proceeds by the control unit 3 controlling each operation mechanism of the heat treatment apparatus 100.

First, a plurality of untreated semiconductor wafers W in which impurities are injected are placed in the load port 110 of the indexer section 101 in a state of being housed in the carrier C. Then, the delivery robot 120 takes out the unprocessed semiconductor wafers W one by one from the carrier C and carries them into the alignment chamber 231 of the alignment unit 230. In the alignment chamber 231, the semiconductor wafer W is rotated around the vertical axis in the horizontal plane with the central portion thereof as the center of rotation, and the orientation of the semiconductor wafer W is adjusted by optically detecting the notch and the like.

Next, the delivery robot 120 of the indexer unit 101 takes out the semiconductor wafer W whose orientation is adjusted from the alignment chamber 231 and carries it into the first cool chamber 131 of the cooling unit 130 or the second cool chamber 141 of the cooling unit 140. The unprocessed semiconductor wafer W carried into the first cool chamber 131 or the second cool chamber 141 is carried out to the transfer chamber 170 by the transfer robot 150. When the untreated semiconductor wafer W is transferred from the indexer portion 101 to the transfer chamber 170 via the first cool chamber 131 or the second cool chamber 141, the first cool chamber 131 and the second cool chamber 141 are the semiconductor wafer W. It functions as a path for the delivery of.

The transfer robot 150 from which the semiconductor wafer W has been taken out rotates so as to face the heat treatment unit 160. Subsequently, the gate valve 185 opens between the processing chamber 6 and the transfer chamber 170, and the transfer robot 150 carries the unprocessed semiconductor wafer W into the processing chamber 6. At this time, if the preceding heat-treated semiconductor wafer W is present in the processing chamber 6, the heat-treated semiconductor wafer W is taken out by one of the transfer hands 151a and 151b, and then the untreated semiconductor wafer W is taken out. W is carried into the processing chamber 6 to replace the wafer. The gate valve 185 then closes between the processing chamber 6 and the transfer chamber 170.

The semiconductor wafer W carried into the processing chamber 6 is preheated by the halogen lamp HL, and then the flash heat treatment is performed by irradiating the flash light from the flash lamp FL. This flash heat treatment activates the impurities injected into the semiconductor wafer W.

After the flash heat treatment is completed, the gate valve 185 opens the space between the processing chamber 6 and the transfer chamber 170 again, and the transfer robot 150 carries out the semiconductor wafer W after the flash heat treatment from the processing chamber 6 to the transfer chamber 170. .. The transfer robot 150 from which the semiconductor wafer W has been taken out rotates so as to face the first cool chamber 131 or the second cool chamber 141 from the processing chamber 6. Further, the gate valve 185 closes between the processing chamber 6 and the transfer chamber 170.

After that, the transfer robot 150 carries the heat-treated semiconductor wafer W into the first cool chamber 131 of the cooling unit 130 or the second cool chamber 141 of the cooling unit 140. At this time, if the semiconductor wafer W has passed through the first cool chamber 131 before the heat treatment, it is carried into the first cool chamber 131 even after the heat treatment and passes through the second cool chamber 141 before the heat treatment. If so, it is carried into the second cool chamber 141 even after the heat treatment. In the first cool chamber 131 or the second cool chamber 141, the semiconductor wafer W is cooled after the flash heat treatment. Since the temperature of the entire semiconductor wafer W at the time of being carried out from the processing chamber 6 of the heat treatment unit 160 is relatively high, it is cooled to near room temperature in the first cool chamber 131 or the second cool chamber 141. is there.

After the predetermined cooling processing time has elapsed, the delivery robot 120 carries out the cooled semiconductor wafer W from the first cool chamber 131 or the second cool chamber 141 and returns it to the carrier C. When a predetermined number of processed semiconductor wafers W are accommodated in the carrier C, the carrier C is carried out from the load port 110 of the indexer section 101.

The heat treatment in the heat treatment unit 160 will be described continuously. FIG. 11 is a flowchart showing a processing procedure of the semiconductor wafer W in the heat treatment unit 160. Prior to carrying the semiconductor wafer W into the processing chamber 6, the valve 84 for air supply is opened, and the valve 89 for exhaust is opened to start air supply / exhaust to the inside of the processing chamber 6. When the valve 84 is opened, nitrogen gas is supplied to the heat treatment space 65 from the gas supply hole 81. When the valve 89 is opened, the gas in the processing chamber 6 is exhausted from the gas exhaust hole 86. As a result, the nitrogen gas supplied from the upper part of the heat treatment space 65 in the processing chamber 6 flows downward and is exhausted from the lower part of the heat treatment space 65.

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 processing chamber 6 through the transfer opening 66 by the transfer robot 150 (step). S1). The transfer robot 150 advances the transfer hand 151a (or transfer hand 151b) for holding the unprocessed semiconductor wafer W to a position directly above the holding unit 7 and stops the transfer robot 150. Then, the pair of transfer arms 11 of the transfer mechanism 10 move horizontally from the retracted position to the transfer operation position and rise, so that the lift pin 12 protrudes from the upper surface of the holding plate 75 of the susceptor 74 through the through hole 79. Receives the semiconductor wafer W. At this time, the lift pin 12 rises above the upper end of the substrate support pin 77.

After the untreated semiconductor wafer W is placed on the lift pin 12, the transfer robot 150 ejects the transfer hand 151a from the heat treatment space 65, and the transfer opening 66 is closed by the gate valve 185. Then, when the pair of transfer arms 11 are lowered, the semiconductor wafer W is handed over from the transfer mechanism 10 to the susceptor 74 of the holding portion 7 and held in a horizontal posture from below. The semiconductor wafer W is supported by a plurality of substrate support pins 77 erected on the holding plate 75 and held by the susceptor 74. Further, the semiconductor wafer W is held by the holding portion 7 with the surface on which the pattern is formed and the impurities are injected as the upper surface. A predetermined distance 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 75a of the holding plate 75. The pair of transfer arms 11 lowered to the lower side of the susceptor 74 are retracted to the retracted position, that is, inside the recess 62 by the horizontal movement mechanism 13.

After the semiconductor wafer W is held from below in a horizontal position by the susceptor 74 of the holding portion 7, the 40 halogen lamps HL are turned on all at once and preheating (assist heating) is started (step S2). The halogen light emitted from the halogen lamp HL passes through the lower chamber window 64 and the susceptor 74 made of quartz and is irradiated from the lower surface of the semiconductor wafer W. By receiving the light irradiation from the halogen lamp HL, the semiconductor wafer W is preheated 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 heating by the halogen lamp HL.

When preheating with the halogen lamp HL, the temperature of the semiconductor wafer W is measured by the radiation thermometer 20. That is, the radiation thermometer 20 receives infrared light radiated from the lower surface of the semiconductor wafer W held by the susceptor 74 through the opening 78, and measures the wafer temperature during temperature rise. The measured temperature of the semiconductor wafer W is transmitted to the control unit 3. The control unit 3 controls the output of the halogen lamp HL while monitoring whether or not the temperature of the semiconductor wafer W, which is raised by irradiation with light from the halogen lamp HL, has reached a predetermined preheating temperature T1. That is, the control unit 3 feedback-controls the output of the halogen lamp HL so that the temperature of the semiconductor wafer W becomes the preheating temperature T1 based on the measured value by the radiation thermometer 20. The preheating temperature T1 is set to about 600 ° C. to 800 ° C. (700 ° C. in the present embodiment) so that impurities added to the semiconductor wafer W do not diffuse due to heat.

After the temperature of the semiconductor wafer W reaches the preheating temperature T1, the control unit 3 maintains the semiconductor wafer W at the preheating temperature T1 for a while. Specifically, when the temperature of the semiconductor wafer W measured by the radiation thermometer 20 reaches the preheating temperature T1, the control unit 3 adjusts the output of the halogen lamp HL to substantially reserve the temperature of the semiconductor wafer W. The heating temperature is maintained at T1.

Further, after the preheating is started, the measurement of the air particle concentration in the processing chamber 6 is started before the subsequent flash heating is executed (step S3). That is, when the semiconductor wafer W is heated by the halogen lamp HL, the measurement of the air particle concentration is started. Specifically, the gas in the processing chamber 6 is exhausted through the gas exhaust pipe 88, and the concentration of air particles of the gas flowing through the gas exhaust pipe 88 is measured by the air particle counter 99. The measurement of the air particle concentration by the air particle counter 99 is continuously performed until a predetermined time elapses after the end of the subsequent flash heating.

FIG. 12 is a diagram showing changes in the air particle concentration in the processing chamber 6 measured by the air particle counter 99. After the preheating by the halogen lamp HL is started, the measurement of the air particle concentration in the processing chamber 6 by the air particle counter 99 is started at time t1. Although the inside of the processing chamber 6 is cleaned before the semiconductor wafer W is processed, particles inevitably remain in the processing chamber 6, and the residual particles are detected by the aerial particle counter 99. Has been done. The air particle concentration C1 measured by the air particle counter 99 during preheating is a concentration that serves as a background for particle concentration measurement.

At time t2 when the temperature of the semiconductor wafer W reaches the preheating temperature T1 and a predetermined time elapses, the flash lamp FL irradiates the surface of the semiconductor wafer W with flash light (step S4). At this time, a part of the flash light radiated from the flash lamp FL goes directly into the processing chamber 6, and the other part is once reflected by the reflector 52 and then goes into the processing chamber 6, and these flashes. Flash heating of the semiconductor wafer W is performed by irradiation with light.

The time t1 at which the measurement of the air particle concentration in the processing chamber 6 by the air particle counter 99 is started may be immediately before the time t2 at which the flash lamp FL irradiates the surface of the semiconductor wafer W with the flash light. That is, it suffices if the value of the air particle concentration C1 which is the reference value in the particle concentration measurement can be acquired or estimated.

Since the flash heating is performed by irradiating the flash light (flash) from the flash lamp 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 0.1 millisecond or more and 100 millisecond or less, in which the electrostatic energy stored in the capacitor in advance is converted into an extremely short optical pulse. It is a strong flash. Then, the surface temperature of the semiconductor wafer W flash-heated by the flash light irradiation from the flash lamp FL momentarily rises to the processing temperature T2 of 1000 ° C. or higher, and the impurities injected into the semiconductor wafer W are activated. After that, the surface temperature drops rapidly. As described above, since the surface temperature of the semiconductor wafer W can be raised or lowered in an extremely short time by flash heating, impurities can be activated while suppressing diffusion of impurities injected into the semiconductor wafer W due to heat. .. Since the time required for activating impurities is extremely short compared to the time required for thermal diffusion, activation can be performed even for a short time in which diffusion of about 0.1 msecond to 100 msecond does not occur. Complete.

During flash light irradiation, the surface of the semiconductor wafer W is irradiated with flash light having an extremely short irradiation time and high energy, so that the temperature of the surface of the semiconductor wafer W momentarily rises to a processing temperature T2 of 1000 ° C. or higher. The temperature of the back surface at that moment does not rise so much from the preheating temperature T1. Therefore, rapid thermal expansion occurs only on the front surface of the semiconductor wafer W, and the back surface hardly undergoes thermal expansion, so that the semiconductor wafer W momentarily warps so as to make the front surface convex. Then, at the next moment, the semiconductor wafer W is deformed in the opposite direction so that the warp returns. When the semiconductor wafer W is suddenly deformed in this way, it may collide with the susceptor 74 and wafer cracking may occur.

When the semiconductor wafer W is cracked by flash heating, a large amount of particles are generated and the concentration of airborne particles in the processing chamber 6 rises sharply. Therefore, it is possible to detect cracks in the semiconductor wafer W by monitoring the concentration of air particles in the processing chamber 6. In the heat treatment apparatus 100, the detection unit 31 of the control unit 3 of the semiconductor wafer W is based on the air particle concentration in the processing chamber 6 measured by the air particle counter 99 during the heat treatment of the semiconductor wafer W. Detecting cracks (step S5). More specifically, in the first embodiment, when the increase in the concentration of air particles in the processing chamber 6 measured by the air particle counter 99 exceeds a predetermined threshold value set in advance, the detection unit 31 Determines that the semiconductor wafer W to be processed is broken.

Even when the wafer is not cracked, the semiconductor wafer W is rapidly deformed during flash light irradiation, so that corresponding particles are rolled up in the processing chamber 6 and the concentration of particles in the air increases. In the first embodiment, the detection unit 31 calculates the difference ΔC between the air particle concentration C2, which is the highest measured value during the period measured by the air particle counter 99, and the air particle concentration C1 which is the background. To do. This difference ΔC is a concentration increase value from the background air particle concentration C1.

Detector 31 determines that the difference ΔC is the concentration increase value is at greater than the predetermined threshold value C _th, the semiconductor wafer W is cracked in the process chamber 6. That is, when the air particle concentration measured by the air particle counter 99 greatly increases beyond the threshold value _Cth , it is determined that the semiconductor wafer W is cracked and a large amount of particles are generated. On the other hand, the detection unit 31 determines that the difference ΔC is at or less than the threshold value C _th is cracking of the semiconductor wafer W is not generated. That is, when the air particle concentration measured by the air particle counter 99 does not exceed the threshold value _Cth , the increase in the air particle concentration is within the range of the normal particle concentration increase due to the flash light irradiation. It will be judged. The threshold value _Cth may be set in advance by measuring the concentration of particles in the air when wafer cracking occurs by an experiment or the like, and may be stored in a storage unit such as a magnetic disk 35 of the control unit 3. The smaller the threshold value C _th is set, the more severe the crack determination is made.

Larger than the difference ΔC is the threshold C _th, when the detector 31 is determined to crack the semiconductor wafer W, the process proceeds from step S5 to step S6, alarm unit 32 to alarm the alarm. For example, the alarm unit 32 causes the display unit 34 to display an alarm indicating that the semiconductor wafer W has been cracked.

Subsequently, the control unit 3 stops the process in the heat treatment apparatus 100 (step S7). Therefore, the gate valve 185 is not opened even after the flash heating is completed, and the cracked semiconductor wafer W remains in the processing chamber 6. As a result, a large amount of particles generated by the cracking of the semiconductor wafer W are prevented from flowing out from the processing chamber 6 to the transfer chamber 170. After that, the operator of the heat treatment apparatus 100 opens the processing chamber 6 to perform necessary restoration work such as collecting fragments of the semiconductor wafer W.

On the other hand, when the difference ΔC is equal to or less than the threshold value C _th and the detection unit 31 determines that the semiconductor wafer W is not cracked, the process proceeds from step S5 to step S8, the processing is continued, and the semiconductor wafer W is carried out from the processing chamber 6. Will be done. When the flash heat treatment is normally completed without breaking the semiconductor wafer W, the halogen lamp HL is also turned off. As a result, the semiconductor wafer W rapidly drops from the preheating temperature T1. The temperature of the semiconductor wafer W during the temperature decrease is measured by the radiation thermometer 20, and the measurement result is transmitted to the control unit 3. The control unit 3 monitors whether or not the temperature of the semiconductor wafer W has dropped to a predetermined temperature based on the measurement result of the radiation thermometer 20. Then, after the temperature of the semiconductor wafer W is lowered to a predetermined value or less, the pair of transfer arms 11 of the transfer mechanism 10 horizontally move from the retracted position to the transfer operation position again and rise, so that the lift pin 12 is a susceptor. The semiconductor wafer W that protrudes from the upper surface of the 74 and has been heat-treated is received from the susceptor 74. Subsequently, the transfer opening 66 closed by the gate valve 185 is opened, and the processed semiconductor wafer W placed on the lift pin 12 is carried out by the transfer hand 151b (or transfer hand 151a) of the transfer robot 150. To. The transfer robot 150 advances the transfer hand 151b to a position directly below the semiconductor wafer W pushed up by the lift pin 12 and stops the transfer robot 150. Then, as the pair of transfer arms 11 are lowered, the semiconductor wafer W after flash heating is passed to the transfer hand 151b and placed on the transfer hand 151b. After that, the transfer robot 150 ejects the transfer hand 151b from the processing chamber 6 to carry out the processed semiconductor wafer W.

In the first embodiment, when the increase in the air particle concentration in the processing chamber 6 measured by the air particle counter 99 during the heat treatment of the semiconductor wafer W exceeds a predetermined threshold value _Cth. In addition, it is determined that the semiconductor wafer W is broken. Since crack detection is performed with a simple configuration in which the concentration of air particles in the processing chamber 6 is measured and the increase is only compared with the threshold value _Cth , cracks in the semiconductor wafer W during heat treatment can be easily detected. can do.

<Second Embodiment>
Next, the second embodiment of the present invention will be described. The configuration of the heat treatment apparatus 100 and the processing procedure of the semiconductor wafer W of the second embodiment are the same as those of the first embodiment. The second embodiment differs from the first embodiment in the method for determining cracks in the semiconductor wafer W.

In the second embodiment, a normal concentration pattern showing a change in the air particle concentration in the processing chamber 6 measured by the air particle counter 99 when the semiconductor wafer W is normally processed without cracking during the heat treatment. 36 is acquired in advance and stored in the magnetic disk 35 (FIG. 10). From the viewpoint of improving the accuracy of crack determination, it is preferable to acquire as many normal density patterns 36 as possible and store them in the magnetic disk 35.

When the semiconductor wafer W is heat-treated in the second embodiment, the detection unit 31 measures the change in the air particle concentration in the processing chamber 6 measured by the air particle counter 99 (the pattern shown in FIG. 12). ) And the normal density pattern 36 are compared. Then, when the measured pattern of the air particle concentration deviates from the normal concentration pattern 36 by a certain amount or more, the detection unit 31 determines that the semiconductor wafer W is broken in the processing chamber 6. That is, when the measured pattern of the air particle concentration measured by the air particle counter 99 is significantly different from the pattern when the heat treatment is normally performed, it is determined that the semiconductor wafer W is cracked. On the other hand, the detection unit 31 determines that the semiconductor wafer W is not cracked when the measured pattern of the air particle concentration deviates from the normal concentration pattern 36 by less than a certain level.

When the detection unit 31 determines that the semiconductor wafer W is broken, the alarm unit 32 issues an alarm and the control unit 3 stops the processing in the heat treatment apparatus 100, as in the first embodiment. When the detection unit 31 determines that the semiconductor wafer W is not cracked, the process is continued and the semiconductor wafer W is carried out from the processing chamber 6.

In the second embodiment, when the actual measurement pattern of the change in the air particle concentration in the processing chamber 6 measured by the air particle counter 99 during the heat treatment of the semiconductor wafer W is different from the normal concentration pattern 36. In addition, it is determined that the semiconductor wafer W is broken. Since crack detection is performed with a simple configuration in which the concentration of air particles in the processing chamber 6 is measured and the actual measurement pattern of the change is compared with the normal concentration pattern 36, cracks in the semiconductor wafer W during heat treatment are detected. It can be easily detected.

<Modification example>
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 spirit of the present invention. For example, in the above embodiment, the air particle counter 99 is connected to the gas exhaust pipe 88, but instead of this, the air particle counter 99 may be provided directly in the processing chamber 6. That is, the air particle counter 99 may be provided at a position in the processing chamber 6 where the air particle concentration can be measured. However, when the air particle counter 99 is directly provided in the processing chamber 6, it may be difficult to detect the particles generated when the semiconductor wafer W is cracked, depending on the mounting position of the air particle counter 99. Since all the atmosphere of the heat treatment space 65 in the processing chamber 6 flows into the gas exhaust pipe 88, it is more reliable to provide the aerial particle counter 99 in the gas exhaust pipe 88 as in the above embodiment. Particles can be detected.

Further, the air particle counter 99 may be provided in the exhaust pipe from the first cool chamber 131 or the second cool chamber 141 to measure the air particle concentration in those cool chambers. The high-temperature semiconductor wafer W that has been processed in the processing chamber 6 of the heat treatment unit 160 is carried into the first cool chamber 131 or the second cool chamber 141 and cooled. The semiconductor wafer W may crack even in this cooling step. When the semiconductor wafer W is being cooled in the first cool chamber 131 or the second cool chamber 141, the cool chamber measured by the air particle counter 99 in the same manner as in the first embodiment or the second embodiment. Cracks in the semiconductor wafer W can be detected based on the concentration of particles in the air.

In short, the concentration of air particles in the chamber during heat treatment of the semiconductor wafer W may be measured, and cracks in the semiconductor wafer W during heat treatment may be detected based on the air particle concentration. Heat treatment as used herein is a concept that includes both heat treatment and cooling treatment.

Further, the air particle counter 99 may be provided in the exhaust pipe from the transport chamber 170 to measure the air particle concentration in the transport chamber 170. Normally, it is unlikely that the semiconductor wafer W will crack in the transfer chamber 170. However, if cracks occur in the semiconductor wafer W in the processing chamber 6 of the heat treatment unit 160 and the gate valve 185 opens without detecting the cracks, particles flow out from the processing chamber 6 to the transfer chamber 170. Will be done. In such a case, the processing chamber 6 is subjected to the crack determination based on the air particle concentration in the transport chamber 170 measured by the air particle counter 99 as in the first embodiment or the second embodiment. Cracks in the semiconductor wafer W inside can be detected.

Further, for example, the techniques presented in Patent Documents 1 to 3 may be combined with the crack detection techniques described in the first embodiment and the second embodiment. By doing so, the crack detection accuracy of the semiconductor wafer W can be further improved.

Further, the air particle concentration in the chamber is monitored by the air particle counter 99 directly provided in the processing chamber 6 or the transport chamber 170 or in the exhaust pipe, and an alarm is generated when the air particle concentration exceeds a predetermined level. May be issued and the processing in the heat treatment apparatus 100 may be stopped. Further, an air particle counter 99 may be provided in the gas supply pipe to the processing chamber 6 or the transfer chamber 170 to monitor the concentration of air particles in the gas supplied to the chamber.

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

Further, in the above embodiment, the semiconductor wafer W is preheated by using a filament type halogen lamp HL as a continuous lighting lamp that continuously emits light for 1 second or longer, but the present invention is not limited to this. Instead of the halogen lamp HL, a discharge type arc lamp (for example, a xenon arc lamp) may be used as a continuous lighting lamp to perform preheating.

Further, the substrate to be processed by the heat treatment apparatus 100 is not limited to the semiconductor wafer, and may be a glass substrate used for a flat panel display such as a liquid crystal display device or a substrate for a solar cell.

3 Control unit 4 Halogen lamp house 5 Flash lamp house 6 Processing chamber 7 Holding unit 10 Transfer mechanism 31 Detection unit 32 Notification unit 35 Magnetic disk 36 Normal concentration pattern 65 Heat treatment space 74 Suceptor 99 Air particle counter 100 Heat treatment device 101 Indexer Part 120 Delivery robot 130, 140 Cooling part 131 First cool chamber 141 Second cool chamber 150 Transfer robot 151a, 151b Transfer hand 160 Heat treatment unit 170 Transfer chamber FL Flash lamp HL Halogen lamp W Semiconductor wafer

Claims (10)

A heat treatment method that heat-treats a substrate.
A processing process that heat-treats the substrate housed in the chamber,
A measurement step for measuring the concentration of air particles in the chamber during the heat treatment, and a measurement step.
A detection step of detecting cracks in the substrate based on the air particle concentration measured in the measurement step, and a detection step of detecting cracks in the substrate.
A heat treatment method characterized by comprising. In the heat treatment method according to claim 1,
The heat treatment method is characterized in that, in the detection step, it is determined that the substrate is cracked when the increase in the concentration of air particles measured in the measurement step exceeds a predetermined threshold value. In the heat treatment method according to claim 1,
In the detection step, it is determined that the substrate is cracked when the actual measurement pattern of the change in the air particle concentration measured in the measurement step is different from the normal concentration pattern acquired when the heat treatment is normally performed. A heat treatment method characterized by that. In the heat treatment method according to any one of claims 1 to 3.
A heat treatment method characterized by issuing a warning and stopping the heat treatment when a crack in the substrate is detected in the detection step. In the heat treatment method according to any one of claims 1 to 4.
The heat treatment method is a heat treatment method in which the substrate is irradiated with flash light from a flash lamp. A heat treatment device that heat-treats a substrate.
The chamber that houses the board and
A heat treatment unit that heat-treats the substrate housed in the chamber,
A measuring unit that measures the concentration of air particles in the chamber,
A detection unit that detects cracks in the substrate based on the concentration of air particles in the chamber measured by the measurement unit during the heat treatment.
A heat treatment apparatus comprising. In the heat treatment apparatus according to claim 6,
The heat treatment apparatus is characterized in that the detection unit determines that the substrate is cracked when the increase in the concentration of air particles measured by the measurement unit exceeds a predetermined threshold value during the heat treatment. .. In the heat treatment apparatus according to claim 6,
Further provided with a storage unit for storing a normal concentration pattern indicating a change in the air particle concentration measured by the measuring unit when the heat treatment is normally performed without cracking the substrate.
The detection unit is characterized in that it determines that the substrate is cracked when the actual measurement pattern of the change in the air particle concentration measured by the measurement unit during the heat treatment is different from the normal concentration pattern. Heat treatment equipment. In the heat treatment apparatus according to any one of claims 6 to 8.
A heat treatment apparatus comprising: a control unit for issuing a warning and further stopping the heat treatment when the detection unit detects a crack in the substrate. In the heat treatment apparatus according to any one of claims 6 to 9.
The heat treatment unit is a heat treatment apparatus including a flash lamp that irradiates the substrate with flash light to heat the substrate.

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