JP7338977B2 - Gas detection method and heat treatment device - Google Patents

Description

The present invention relates to 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 light , and a gas detection method using the heat treatment apparatus .

Flash lamp annealing (FLA), which heats a semiconductor wafer in an extremely short time, has attracted attention in the manufacturing process of semiconductor devices. 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, so that only the surface of the semiconductor wafer is extremely annealed. It is a heat treatment technology 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, 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.

Such flash lamp annealing is used in processes that require very short heating times, such as activation of impurities typically implanted in semiconductor wafers. By irradiating the surface of a semiconductor wafer into which impurities have been implanted by ion implantation with flash light from a flash lamp, the surface of the semiconductor wafer can be heated to the activation temperature for a very short period of time, and the impurities can be deeply diffused. Therefore, only impurity activation can be performed without causing the activation of the impurities.

Although the impurity activation process is performed in an inert nitrogen gas atmosphere, there is a growing demand to perform flash lamp annealing in various other gas atmospheres. For example, Patent Document 1 discloses performing post-deposition heat treatment (PDA: Post Deposition Anneal) of a high dielectric constant gate insulating film (high-k film) in an ammonia atmosphere. Since ammonia is a toxic gas, leakage of the ammonia used for the treatment to the outside of the flash lamp annealing apparatus is not allowed. Therefore, in the apparatus disclosed in Patent Document 1, after the flash heat treatment, the inside of the processing chamber is depressurized to discharge harmful ammonia, nitrogen gas is purged, the pressure is restored, and then the gate valve is opened to release the semiconductor wafer. are being carried out.

JP 2017-045982 A

However, for example, when processing is performed in an atmosphere of 100% ammonia, if the pressure inside the processing chamber is reduced to 100 Pa and then the pressure is restored with nitrogen gas, ammonia with a concentration of 1000 ppm remains. Even if the pressure in the processing chamber is reduced to 10 Pa, ammonia with a concentration of 100 ppm remains. Therefore, when the gate valve is opened after the pressure is restored with nitrogen gas, a small amount of ammonia may leak out of the processing chamber. If the inside of the processing chamber is depressurized to a high vacuum state, the ammonia concentration can be brought close to zero, but such depressurization takes a long time, resulting in a problem of reduced throughput.

In addition, maintenance work is performed regularly or irregularly for semiconductor manufacturing equipment such as flash lamp annealing equipment. During maintenance, the processing chamber must be opened to carry out the work. When the processing chamber is opened, if even a small amount of harmful gas such as ammonia remains in the processing chamber, such gas is released outside the apparatus, which is dangerous.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat treatment apparatus capable of detecting a minute amount of residual gas in a processing chamber.

In order to solve the above-mentioned problems, the invention of claim 1 provides a heat treatment apparatus for heating a substrate by irradiating the substrate with light, comprising: a processing chamber containing the substrate; a light irradiation unit that irradiates a light, a gas supply unit that supplies a processing gas to the processing chamber, an exhaust unit that exhausts the atmosphere in the processing chamber, and the processing gas contained in the atmosphere in the processing chamber. and a first gas detection unit that detects the gas.

According to the invention of claim 2, in the heat treatment apparatus according to the invention of claim 1, the first gas detector is a zirconia oxygen concentration meter installed in the treatment chamber.

According to a third aspect of the present invention, there is provided the heat treatment apparatus according to the first aspect of the present invention, further comprising an exhaust path that guides only the atmosphere in the processing chamber to the exhaust section, wherein the first gas detection section is located in the exhaust path. It is characterized by being a gas detector provided.

Further, the invention of claim 4 is the heat treatment apparatus according to any one of claims 1 to 3, wherein the first gas detection unit detects the processing gas before opening the processing chamber during maintenance of the heat treatment apparatus. It is characterized by detecting the processing gas contained in the atmosphere inside the chamber.

According to a fifth aspect of the present invention, in the heat treatment apparatus according to any one of the first to fourth aspects, a transport robot is provided adjacent to the processing chamber and accommodates a transfer robot for loading and unloading substrates into and out of the processing chamber. and a second gas detector for detecting the processing gas contained in the atmosphere in the transfer chamber.

According to a sixth aspect of the invention, in the heat treatment apparatus according to the fifth aspect of the invention, the second gas detector is a zirconia oxygen concentration meter.

Further, the invention of claim 7 is the heat treatment apparatus according to the invention of claim 5 or claim 6, wherein the second gas detection unit is included in the atmosphere in the transfer chamber during processing in the heat treatment apparatus. It is characterized by detecting gas.

Further, according to the eighth aspect of the invention, in the heat treatment apparatus according to any one of the fifth to seventh aspects, a It is characterized by further comprising a judging unit for judging the danger of the processing gas in the heat treatment apparatus by means of artificial intelligence.

According to a ninth aspect of the invention, in the heat treatment apparatus according to the eighth aspect of the invention, the heat treatment apparatus further comprises an alarm unit that issues an alarm when it is determined that the processing gas is dangerous. .

According to a tenth aspect of the present invention, in the heat treatment apparatus according to any one of the first to ninth aspects, the processing gas is ammonia or nitrogen oxide.

According to the invention of claims 1 to 10, since the first gas detection unit is provided for directly detecting the processing gas contained in the atmosphere inside the processing chamber, the first gas detection unit detects the atmosphere inside the processing chamber. Increased sensitivity allows detection of trace amounts of residual gas within the process chamber.

In particular, according to the fifth aspect of the present invention, since the second gas detector is provided for detecting the processing gas contained in the atmosphere inside the transfer chamber, it is possible to detect the processing gas that has flowed out from the processing chamber to the transfer chamber. .

1 is a plan view showing a heat treatment apparatus according to the present invention; FIG. FIG. 2 is a front view of the heat treatment apparatus of FIG. 1; It is a longitudinal cross-sectional view which shows the structure of a heat processing part. 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; FIG. 4 is a diagram schematically showing the configuration of an exhaust mechanism in the heat treatment apparatus; 3 is a block diagram showing the configuration of a control unit; FIG. It is a figure which shows the concept of the judgment of the danger by artificial intelligence.

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>
First, the overall configuration of the heat treatment apparatus according to the present invention will be described. FIG. 1 is a plan view showing a 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. As shown in FIG. Although the size of the semiconductor wafer W to be processed is not particularly limited, it is, for example, φ300 mm or φ450 mm. In addition, in FIG. 1 and subsequent figures, the dimensions and numbers of each part are exaggerated or simplified as necessary for easy understanding. 1 to 3, in order to clarify their directional relationship, an XYZ orthogonal coordinate system is attached in which the Z-axis direction is the vertical direction and the XY plane is the horizontal plane.

As shown in FIGS. 1 and 2, the heat treatment apparatus 100 includes an indexer section 101 for loading unprocessed semiconductor wafers W into the apparatus from the outside and unloading processed semiconductor wafers W from the apparatus. alignment section 230 for positioning the semiconductor wafer W, two cooling sections 130 and 140 for cooling the semiconductor wafer W after heat treatment, a heat treatment section 160 for performing flash heat treatment on the semiconductor wafer W, cooling sections 130 and 140, and A transfer robot 150 is provided for transferring the semiconductor wafer W to and from the heat treatment section 160 . The heat treatment apparatus 100 also includes a control unit 3 that controls the operation mechanism and the transfer robot 150 provided in each of the processing units described above to proceed with the flash heat treatment of the semiconductor wafer W. FIG.

The indexer unit 101 includes a load port 110 on which a plurality of carriers C (two in this embodiment) are placed side by side, an unprocessed semiconductor wafer W taken out from each carrier C, and a processed semiconductor wafer loaded onto each carrier C. and a delivery robot 120 for storing W. A carrier C containing unprocessed semiconductor wafers W is transported by an automatic guided vehicle (AGV, OHT) or the like and placed on a load port 110, while a carrier C containing processed semiconductor wafers W is transported by an automatic guided vehicle. is carried away from the load port 110 by the .

In the load port 110, the carrier C is configured to move up and down as indicated by the arrow CU in FIG. ing. In addition to a FOUP (front opening unified pod) in which the semiconductor wafers W are stored in a closed space, the carrier C may be a SMIF (Standard Mechanical Interface) pod or an OC (open pod) in which the stored semiconductor wafers W are exposed to the outside air. cassette).

In addition, the delivery robot 120 is capable of sliding movement as indicated by the arrow 120S in FIG. 1, and turning and ascending/descending movements as indicated by the arrow 120R. As a result, the delivery robot 120 takes the semiconductor wafers W into and out of the two carriers C and delivers the semiconductor wafers W to the alignment section 230 and the two cooling sections 130 and 140 . The transfer robot 120 takes the semiconductor wafer W into and out of the carrier C by sliding the hand 121 and moving the carrier C up and down. The transfer of the semiconductor wafer W between the delivery robot 120 and the alignment unit 230 or the cooling units 130 and 140 is performed by sliding the hand 121 and lifting the delivery robot 120 .

The alignment section 230 is provided to be connected to the side of the indexer section 101 along the Y-axis direction. The alignment section 230 is a processing section that rotates the semiconductor wafer W in a horizontal plane to orient it appropriately for flash heating. The alignment unit 230 includes a mechanism for supporting and rotating the semiconductor wafer W in a horizontal position inside an alignment chamber 231, which is a housing made of aluminum alloy, and a notch, an orientation flat, etc. formed on the peripheral edge of the semiconductor wafer W. is provided with a mechanism for optically detecting the

The transfer robot 120 transfers the semiconductor wafer W to the alignment section 230 . The semiconductor wafer W is transferred from the transfer robot 120 to the alignment chamber 231 so that the center of the wafer is positioned at a predetermined position. The alignment unit 230 rotates the semiconductor wafer W received from the indexer unit 101 around the vertical axis with the central portion of the semiconductor wafer W as the rotation center, and adjusts the orientation of the semiconductor wafer W by optically detecting a notch or the like. 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 that accommodates 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 section 160 , the first cool chamber 131 of the cooling section 130 , and the second cool chamber 141 of the cooling section 140 are connected to three sides of the transfer chamber 170 .

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

The two cooling units 130, 140 have substantially the same configuration. The cooling units 130 and 140 respectively include 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. (both not shown). The cooling plate is temperature-controlled to room temperature (approximately 23° C.) by a Peltier element or constant temperature water circulation. The semiconductor wafer W subjected to the flash heat treatment in the heat treatment section 160 is carried into the first cool chamber 131 or the second cool chamber 141 and placed on the quartz plate to be cooled.

Both the first cool chamber 131 and the second cool chamber 141 are connected to both the indexer section 101 and the transfer chamber 170 between them. The first cool chamber 131 and the second cool chamber 141 are formed with two openings through which the semiconductor wafer W is carried in and out. Of the two openings of the first cool chamber 131 , the opening connected to the indexer section 101 can be opened and closed by a 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 a gate valve 183 . That is, the first cool chamber 131 and the indexer section 101 are connected through the gate valve 181 , and the first cool chamber 131 and the transfer chamber 170 are connected through the gate valve 183 .

When transferring the semiconductor wafer W between the indexer section 101 and the first cool chamber 131, the gate valve 181 is opened. Further, when transferring the semiconductor wafer W 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.

The opening connected to the indexer section 101 of the two openings of the second cool chamber 141 can be opened and closed by a 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 a gate valve 184 . That is, the second cool chamber 141 and the indexer section 101 are connected through the gate valve 182 , and the second cool chamber 141 and the transfer chamber 170 are connected through the gate valve 184 .

When transferring the semiconductor wafer W between the indexer section 101 and the second cool chamber 141, the gate valve 182 is opened. Further, when transferring the semiconductor wafer W 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.

A transfer robot 150 provided in a transfer chamber 170 installed adjacent to the processing chamber 6 is capable of turning about an axis along the vertical direction as indicated by an arrow 150R. The transfer robot 150 has two link mechanisms consisting of a plurality of arm segments, and transfer hands 151a and 151b for holding semiconductor wafers W are provided at the ends of these two link mechanisms, respectively. These transfer hands 151a and 151b are vertically arranged with a predetermined pitch therebetween, and are linearly slidable in the same horizontal direction independently by a link mechanism. In addition, the transport robot 150 vertically moves the two transport hands 151a and 151b while keeping them separated by a predetermined pitch by vertically moving the base on which the two link mechanisms are provided.

When the transfer robot 150 transfers (inserts and removes) the semiconductor wafer W to and from the first cool chamber 131, the second cool chamber 141, or the processing chamber 6 of the heat treatment section 160, first, both transfer hands 151a and 151b are It turns so as to face the transfer partner, and after that (or while it is turning) it moves up and down to a height where one of the transfer hands transfers the semiconductor wafer W to the transfer partner. Then, the transfer hand 151a (151b) is linearly slid in the horizontal direction to transfer the semiconductor wafer W to the transfer partner.

Transfer of the semiconductor wafer W between the transfer robot 150 and the transfer 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 transferring the semiconductor wafer W between the transfer robot 150 and the delivery robot 120. . Specifically, the transfer of the semiconductor wafer W is performed by one of the transfer robot 150 and the transfer robot 120 receiving the semiconductor wafer W transferred to the first cool chamber 131 or the second cool chamber 141 by the other. The transfer robot 150 and the delivery robot 120 constitute a transfer mechanism for transferring the semiconductor wafer W from the carrier C to the heat treatment section 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 section 101, respectively. 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. Furthermore, a gate valve 185 is provided between the transfer chamber 170 and the processing chamber 6 of the thermal processing section 160 . When the semiconductor wafer W is transported within the heat treatment apparatus 100, these gate valves are appropriately opened and closed.

Next, the configuration of the thermal processing section 160 will be described. FIG. 3 is a vertical cross-sectional view showing the structure of the thermal processing section 160. As shown in FIG. The heat treatment section 160 includes a processing chamber 6 for housing a semiconductor wafer W and performing heat treatment, a flash lamp house 5 containing a plurality of flash lamps FL, and a halogen lamp house 4 containing a plurality of halogen lamps HL. Prepare. 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. The thermal processing unit 160 also includes a holding unit 7 that holds the semiconductor wafer W in a horizontal posture inside the processing chamber 6, and a transfer mechanism 10 that transfers the semiconductor wafer W between the holding unit 7 and the transfer robot 150. And prepare.

The processing 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 that forms the ceiling of the processing chamber 6 is a disk-shaped member made of quartz and functions as a quartz window that transmits flash light emitted from the flash lamp FL into the processing chamber 6 . The lower chamber window 64 forming the floor of the processing chamber 6 is also a disk-shaped member made of quartz and functions as a quartz window through which the light from the halogen lamp HL is transmitted into the processing 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 processing chamber 6 , ie, 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 processing 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 processing 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 processing 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 processing space 65 in the processing chamber 6 becomes a sealed space.

A gas supply hole 81 for supplying a processing gas to the heat processing space 65 is formed in the upper portion of the inner wall of the processing 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 processing 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 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 . The processing gas includes inert gases such as nitrogen (N ₂ ), argon (Ar), helium (He), etc., or ammonia (NH ₃ ), oxygen (O ₂ ), hydrogen (H ₂ ), chlorine (Cl _{2 )} . ), hydrogen chloride (HCl), ozone (O ₃ ), nitric oxide (NO), nitrous oxide (N ₂ O), nitrogen dioxide (NO ₂ ), or a mixture thereof. can be done.

On the other hand, a gas exhaust hole 86 for exhausting the gas in the heat treatment space 65 is formed in the lower inner wall of the processing 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 process exhaust pipe 88 through an annular buffer space 87 formed inside the side wall of the process chamber 6 . The processing exhaust pipe 88 is connected to an exhaust section 190 . A valve 89 is inserted in the middle of the path of the processing 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 through the buffer space 87 to the process exhaust pipe 88 . 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.

The exhaust section 190 includes an exhaust pump. By opening the valve 89 while operating the exhaust part 190 , the atmosphere in the processing chamber 6 is discharged from the process exhaust pipe 88 to the exhaust part 190 . By exhausting the atmosphere of the heat treatment space 65, which is a closed space, by the exhaust part 190 without supplying any gas from the gas supply hole 81, the pressure inside the processing chamber 6 can be reduced to less than the atmospheric pressure.

FIG. 4 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. By placing the base ring 71 on the bottom surface of the recess 62, the base ring 71 is supported by the wall surface of the processing chamber 6 (see FIG. 3). 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 . FIG. 5 is a plan view of the susceptor 74. FIG. 6 is a cross-sectional view of the susceptor 74. As shown in 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. 4, 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 processing chamber 6 by supporting the base ring 71 of the holder 7 on the wall surface of the processing chamber 6 . When the holding part 7 is attached to the processing chamber 6, the holding plate 75 of the susceptor 74 is in a horizontal posture (a posture in which the normal line is aligned with the vertical direction). That is, the holding surface 75a of the holding plate 75 becomes a horizontal surface.

The semiconductor wafer W loaded into the processing chamber 6 is placed and held in a horizontal position on the susceptor 74 of the holding section 7 mounted in the processing chamber 6 . At this time, the semiconductor wafer W is held by the susceptor 74 while being supported by 12 substrate support 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 horizontally positioned 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. 4 and 5, 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 20 (see FIG. 3) receives radiation light (infrared light) emitted from the lower surface of the semiconductor wafer W held by the susceptor 74 . That is, the radiation thermometer 20 measures the temperature of the semiconductor wafer W by receiving light emitted from the lower surface of the semiconductor wafer W held by the susceptor 74 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. 7 is a plan view of the transfer mechanism 10. FIG. 8 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 . 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. 7) that does not overlap in plan view. The transfer operation position is below the susceptor 74 and the retracted position is outside the susceptor 74 . 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 lifts 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. 4 and 5) 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 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 lamps FL inside a housing 51, and a light source for the light source. and a reflector 52 provided to cover the top. A lamp light radiation window 53 is attached to the bottom of the housing 51 of the flash lamp house 5 . The lamp light emission window 53 forming 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 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 processing 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 light is emitted by the excitation of xenon atoms or molecules at that time. 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.

A halogen lamp house 4 provided below the processing chamber 6 incorporates a plurality of (40 in this embodiment) halogen lamps HL inside a housing 41 . A plurality of halogen lamps HL irradiate the heat treatment space 65 from below the treatment chamber 6 through the lower chamber window 64 .

FIG. 9 is a plan view showing the arrangement of multiple halogen lamps HL. In this embodiment, 20 halogen lamps HL are arranged in each of the upper and lower two stages. 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 such 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. 9, the 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 lamp HL.

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 so that the longitudinal direction of each halogen lamp HL in the upper stage is orthogonal to the longitudinal direction of each halogen lamp HL in the lower stage.

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.

A reflector 43 is also provided below the two-tiered halogen lamps HL in the housing 41 of the halogen lamp house 4 (FIG. 3). The reflector 43 reflects the light emitted from the plurality of halogen lamps HL to the heat treatment space 65 side.

In addition to the above configuration, the thermal processing section 160 prevents excessive temperature rise of the halogen lamp house 4, the flash lamp house 5, and the processing chamber 6 due to thermal energy generated from the halogen lamps HL and the flash lamps FL during the thermal processing of the semiconductor wafer W. Therefore, it has various cooling structures. For example, the wall of the processing chamber 6 is provided with water cooling pipes (not shown). Further, the halogen lamp house 4 and the flash lamp house 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 lamp house 5 and the upper chamber window 63 .

FIG. 10 is a diagram schematically showing the configuration of the exhaust mechanism in the heat treatment apparatus 100. As shown in FIG. The first cool chamber 131 , the second cool chamber 141 , the transfer chamber 170 and the processing chamber 6 excluding the indexer section 101 of the heat treatment apparatus 100 are housed inside a housing 200 of the entire apparatus. As described above, gate valves 181 and 182 open and close between the first cool chamber 131, the second cool chamber 141 and the indexer section 101, respectively. Gate valves 183 and 184 open and close between the first cool chamber 131, the second cool chamber 141 and the transfer chamber 170, respectively. A gate valve 185 opens and closes between the transfer chamber 170 and the processing chamber 6 .

A processing gas such as ammonia is supplied to the processing chamber 6 of the thermal processing unit 160 from a gas supply unit including a processing gas supply source 85 and a valve 84 (FIG. 3). Nitrogen gas is also supplied to each of the first cool chamber 131, the second cool chamber 141, and the transfer chamber 170 from a gas supply unit (not shown).

A processing exhaust pipe 88 is connected to the processing chamber 6 . A valve 89 is provided in the middle of the path of the processing exhaust pipe 88 . A transfer exhaust pipe 171 is connected to the transfer chamber 170 . A valve 172 is provided in the middle of the route of the conveying exhaust pipe 171 . Furthermore, a cooling exhaust pipe 135 is connected to the first cool chamber 131 and the second cool chamber 141 (for convenience of illustration, only the cooling exhaust pipe 135 connected to the second cool chamber 141 is shown in FIG. 10). . A valve 136 is provided in the middle of the cooling exhaust pipe 135 .

The processing exhaust pipe 88 , the transport exhaust pipe 171 and the cooling exhaust pipe 135 merge into the gas exhaust pipe 191 . A gas exhaust pipe 191 is connected to the exhaust section 190 . In the middle of the route of the gas exhaust pipe 191, a portion where the processing exhaust pipe 88, the transport exhaust pipe 171 and the cooling exhaust pipe 135 all meet (in the example of FIG. 10, the gas exhaust pipe 191 and the processing exhaust pipe 88 join part) and the exhaust part 190, an exhaust gas detector 192 is provided. The exhaust gas detector 192 of this embodiment is an ammonia detector using an electrolytic solution system. The exhaust gas detector 192 detects ammonia contained in the gas flowing through the gas exhaust pipe 191 .

Under the control of the control unit 3, the processing chamber 6, the transfer chamber 170, the first cool chamber 131 or the second cool chamber 141 is operated by appropriately opening and closing the valves 89, 172, 136 while operating the exhaust unit 190. The exhaust from the can be controlled. For example, when all the valves 89 , 172 , 136 are opened, all the atmospheres of the processing chamber 6 , the transfer chamber 170 , the first cool chamber 131 and the second cool chamber 141 are exhausted from the gas exhaust pipe 191 to the exhaust section 190 . be. Further, for example, when the valve 89 is opened and the valves 172 and 136 are closed, only the atmosphere inside the processing chamber 6 is discharged from the gas exhaust pipe 191 to the exhaust section 190 .

Further, an oxygen concentration meter 251 is connected to the processing chamber 6 through a pipe. A valve 252 is provided in the middle of the pipe path connecting the processing chamber 6 and the oxygen concentration meter 251 . When the valve 252 is opened, the atmosphere inside the processing chamber 6 is taken into the oxygen concentration meter 251 .

The oxygen concentration meter 251 is, for example, a zirconia type oxygen concentration meter using stabilized zirconia. Stabilized zirconia is obtained by adding yttria (Y ₂ O ₃ ) as a stabilizer to zirconia (ZrO ₂ ), has excellent ionic conductivity, and becomes a solid electrolyte at high temperatures. If there is a difference in oxygen concentration between the two sides of a zirconia solid electrolyte at a high temperature (for example, about 700° C.), oxygen ions (O ²⁻ ) are generated by a reduction reaction on the high oxygen concentration side, and the oxygen ions are stored in the zirconia solid electrolyte. and becomes oxygen (O ₂ ) through an oxidation reaction on the low oxygen concentration side. An electromotive force is generated by the transfer of electrons in the oxidation/reduction reaction that occurs on both sides of the zirconia solid electrolyte, and the magnitude of the electromotive force is defined by the oxygen concentration difference. Therefore, one side of the high-temperature zirconia solid electrolyte is brought into contact with a reference gas having a known oxygen concentration, and the other side is brought into contact with the gas to be measured. Oxygen concentration in gas can be measured. The oxygen concentration meter 251 can measure the oxygen concentration in the processing chamber 6 by measuring the oxygen concentration in the gas taken from the processing chamber 6 using this principle.

Further, an oxygen concentration meter 175 is connected to the transport exhaust pipe 171 from the transport chamber 170 . A valve 176 is provided in the middle of the path of the pipe connecting the conveying exhaust pipe 171 and the oxygen concentration meter 175 . When the valve 176 is opened, the atmosphere inside the transfer chamber 170 is drawn into the oxygen concentration meter 175 through the transfer exhaust pipe 171 . The oxygen concentration meter 175 is also a zirconia type oxygen concentration meter similar to the oxygen concentration meter 251 described above. Thus, by opening valve 176 , oximeter 175 can measure the oxygen concentration in transfer chamber 170 .

Furthermore, an exhaust gas detector 281 is provided on a housing exhaust pipe 280 from the housing 200 . The gas inside the housing 200 is discharged from the housing exhaust pipe 280 . Exhaust gas detector 281 is an ammonia detector similar to exhaust gas detector 192 described above. The exhaust gas detector 281 detects ammonia contained in gas flowing through the housing exhaust pipe 280 . An opening 285 is formed in a part of the wall surface of the housing 200 that is in contact with the indexer section 101 . When the gate valve 181 or the gate valve 182 is open, part of the gas that has flowed out from the first cool chamber 131 or the second cool chamber 141 into the indexer section 101 flows into the housing 200 through the opening 285 and exits the housing. It is discharged from the body exhaust pipe 280 . Therefore, the exhaust gas detector 281 can also detect ammonia contained in the gas flowing out from the first cool chamber 131 or the second cool chamber 141 to the indexer unit 101 .

FIG. 11 is a block diagram showing the configuration of the control section 3. As shown in FIG. The control unit 3 controls the various operating mechanisms provided in the heat treatment apparatus 100 . 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. A magnetic disk 35 for storing is provided. The processing in the heat treatment apparatus 100 proceeds as the CPU of the control unit 3 executes a predetermined processing program. The determination unit 31 and the notification 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 determination unit 31 and the notification unit 32 will be further described later. Although FIG. 1 shows the control unit 3 within the indexer unit 101 , the control unit 3 is not limited to this, and the control unit 3 can be arranged at any position within the heat treatment apparatus 100 . The readable/writable memory for storing various information may be an SSD or the like with integrated flash memory.

An input section 33 , a display section 34 and a speaker 36 are connected to the control section 3 . The control unit 3 displays various information on the display unit 34 . An operator of the heat treatment apparatus 100 can input various commands and parameters from the input section 33 while confirming the information displayed on the display section 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 employed to provide both functions. The control unit 3 can also output sound from the speaker 36 .

Next, processing operations in the heat treatment apparatus 100 will be described. The semiconductor wafer W to be processed here is a silicon semiconductor substrate on which a high dielectric constant film is formed as a gate insulating film. The high dielectric constant film is deposited on the surface of the semiconductor wafer W by a method such as ALD (Atomic Layer Deposition) or MOCVD (Metal Organic Chemical Vapor Deposition). The heat treatment apparatus 100 irradiates the semiconductor wafer W with flash light in an ammonia atmosphere to perform post-deposition heat treatment (PDA), thereby eliminating defects in the high dielectric constant film after deposition. The procedure described below proceeds as the control unit 3 controls each operation mechanism of the heat treatment apparatus 100 according to the recipe (FIG. 11) stored in the magnetic disk 35 . A recipe defines a processing procedure and processing conditions for the heat treatment of the semiconductor wafer W. As shown in FIG.

First, a plurality of unprocessed semiconductor wafers W on which a high dielectric constant film is formed are placed on the load port 110 of the indexer section 101 in a state in which they are housed in a carrier C. As shown in FIG. 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 section 230 . In the alignment chamber 231, the orientation of the semiconductor wafer W is adjusted by rotating the semiconductor wafer W around the vertical axis in the horizontal plane with its central portion as the center of rotation, and optically detecting notches and the like.

Next, the transfer robot 120 of the indexer section 101 takes out the semiconductor wafer W whose orientation has been adjusted from the alignment chamber 231 and carries it into the first cool chamber 131 of the cooling section 130 or the second cool chamber 141 of the cooling section 140 . The unprocessed semiconductor wafer W carried into the first cool chamber 131 or the second cool chamber 141 is carried out to the carrier chamber 170 by the carrier robot 150 . When the unprocessed semiconductor wafer W is transferred from the indexer section 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 kept in contact with the semiconductor wafer W. It acts as a path for the passing of

The transfer robot 150 that has taken out the semiconductor wafer W turns to face the heat treatment section 160 . Subsequently, the gate valve 185 opens the space between the processing chamber 6 and the transfer chamber 170 , and the transfer robot 150 loads the unprocessed semiconductor wafer W into the processing chamber 6 . At this time, if a preceding heat-treated semiconductor wafer W exists in the processing chamber 6, one of the transfer hands 151a and 151b takes out the heat-treated semiconductor wafer W, and then removes the untreated semiconductor wafer W. W is carried into the processing chamber 6 and the wafers are exchanged. The gate valve 185 then closes between the processing chamber 6 and the transfer chamber 170 .

The semiconductor wafer W loaded into the processing chamber 6 is preheated by the halogen lamps HL, and then flash heat-treated by flash light irradiation from the flash lamps FL. The post-deposition heat treatment of the high dielectric constant film formed on the surface of the semiconductor wafer W is performed by this flash heat treatment.

After the flash heat treatment is finished, the gate valve 185 opens the space between the processing chamber 6 and the transfer chamber 170 again, and the transfer robot 150 unloads the semiconductor wafer W after the flash heat treatment from the process chamber 6 to the transfer chamber 170. . The transfer robot 150 that has taken out the semiconductor wafer W turns from the processing chamber 6 toward the first cool chamber 131 or the second cool chamber 141 . A gate valve 185 also 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 section 130 or the second cool chamber 141 of the cooling section 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 after the heat treatment, and passed 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 after the flash heat treatment is cooled. Since the temperature of the entire semiconductor wafer W is relatively high when it is unloaded from the processing chamber 6 of the thermal processing section 160, it is cooled to near room temperature in the first cool chamber 131 or the second cool chamber 141. be.

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

The description of the heat treatment in the heat treatment unit 160 will be continued. 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 . The transport robot 150 advances the transport hand 151a (or the transport hand 151b) holding the unprocessed semiconductor wafer W to a position directly above the holding part 7 and stops it. 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 unprocessed semiconductor wafer W is placed on the lift pins 12 , the transport robot 150 moves the transport hand 151 a out of the heat treatment space 65 and the transport 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 . The semiconductor wafer W is held by the holding portion 7 with the surface on which the high dielectric constant film is formed 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 .

After the semiconductor wafer W is accommodated in the processing chamber 6 and the transfer opening 66 is closed by the gate valve 185, the pressure inside the processing chamber 6 is reduced to a pressure lower than the atmospheric pressure. Specifically, the heat treatment space 65 in the processing chamber 6 becomes a sealed space by closing the transfer opening 66 . In this state, the valve 84 for air supply is closed while the valve 89 for exhaust is opened. As a result, the processing chamber 6 is exhausted without being supplied with gas, and the heat processing space 65 within the processing chamber 6 is depressurized below the atmospheric pressure. Exhaust from the processing chamber 6 may be performed quietly at a relatively low exhaust flow rate in the initial stage, and then switched to a high exhaust flow rate. By doing so, particles in the processing chamber 6 can be prevented from being stirred up.

After the pressure (degree of vacuum) of the processing chamber 6 reaches a predetermined pressure (for example, about 100 Pa), the valve 84 for air supply is opened, and ammonia is supplied from the processing gas supply source 85 to the heat processing space 65 in the processing chamber 6. supply. As a result, an ammonia atmosphere is formed around the semiconductor wafer W held by the holding portion 7 within the processing chamber 6 . The concentration of ammonia in the ammonia atmosphere (that is, the mixing ratio of ammonia and nitrogen gas) is not particularly limited and can be set to an appropriate value, for example, 100%.

By supplying ammonia into the processing chamber 6, the pressure in the processing chamber 6 rises and returns to 5000 Pa, for example. After the ammonia atmosphere is formed in the processing chamber 6, the 40 halogen lamps HL are turned on at once to start preheating (assist heating) of the semiconductor wafer W. As shown in FIG. 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 onto the back 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.

The temperature of the semiconductor wafer W is measured by the radiation thermometer 20 when preheating is performed by the halogen lamp HL. That is, the radiation thermometer 20 receives infrared light emitted from the lower surface of the semiconductor wafer W held by the susceptor 74 through the opening 78 to measure the temperature of the wafer during heating. 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 20 so that the temperature of the semiconductor wafer W reaches the preheating temperature T1. The preheating temperature T1 is 300° C. or higher and 600° C. or lower, and is 450° C. in this embodiment.

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 20 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, which is more susceptible to heat dissipation, tends to be lower than that of the central portion. The region facing the peripheral portion of the semiconductor wafer 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.

Next, after a predetermined time has elapsed since the temperature of the semiconductor wafer W reached the preheating temperature T1, the flash lamps FL irradiate the surface of the semiconductor wafer W held by the susceptor 74 with flash light. At this time, part of the flash light emitted from the flash lamp FL goes directly into the processing chamber 6, and the other part goes into the processing chamber 6 after once being reflected by the reflector 52. Flash heating of the semiconductor wafer W is performed by the irradiation of light.

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, by irradiating the surface of the semiconductor wafer W on which the high dielectric constant film is formed with flash light from the flash lamps FL, the surface of the semiconductor wafer W including the high dielectric constant film instantaneously rises to the processing temperature T2. After heating, heat treatment is performed after film formation. A processing temperature T2, which is the highest temperature (peak temperature) reached by the surface of the semiconductor wafer W due to flash light irradiation, is 600° C. or higher and 1200° C. or lower, and is 1000° C. in this embodiment.

When the surface of the semiconductor wafer W is heated to the processing temperature T2 in an ammonia atmosphere and the heat treatment after film formation is performed, the nitridation of the high dielectric constant film is promoted, and at the same time, the high dielectric constant film exists in the high dielectric constant film. Defects such as point defects that were present disappear. Since the irradiation time from the flash lamps FL is short, approximately 0.1 millisecond or more and 100 milliseconds or less, the surface temperature of the semiconductor wafer W rises from the preheating temperature T1 to the processing temperature T2. The required time is also extremely short, less than 1 second. The surface temperature of the semiconductor wafer W after flash light irradiation immediately and rapidly drops from the processing temperature T2.

After a predetermined period of time has elapsed since the flash heat treatment was completed, the control unit 3 closes the valve 84 to reduce the pressure in the processing chamber 6 to about 100 Pa again. Thereby, harmful ammonia can be discharged from the heat treatment space 65 inside the treatment chamber 6 . Subsequently, the control unit 3 closes the valve 89 and opens the valve 84 to supply nitrogen gas, which is an inert gas, from the processing gas supply source 85 into the processing chamber 6 to restore the pressure to atmospheric pressure. Further, the halogen lamp HL is also turned off, whereby the temperature of the semiconductor wafer W is also lowered from the preheating temperature T1. The temperature of the semiconductor wafer W during cooling is measured by the radiation thermometer 20 and the measurement result is transmitted to the 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. Then, the processing chamber 6 is replaced with a nitrogen atmosphere and restored to atmospheric pressure, and after the temperature of the semiconductor wafer W drops below a predetermined level, the pair of transfer arms 11 of the transfer mechanism 10 moves again from the retracted position. The lift pins 12 protrude from the upper surface of the susceptor 74 and receive the semiconductor wafer W after the heat treatment from the susceptor 74 by horizontally moving and rising to the mounting operation position. Subsequently, the transfer opening 66 closed by the gate valve 185 is opened, and the semiconductor wafer W placed on the lift pins 12 is carried out by the transfer hand 151b (or the transfer hand 151a) of the transfer robot 150. FIG. The transport robot 150 advances the transport hand 151b to a position directly below the semiconductor wafer W pushed up by the lift pins 12 and stops it. By lowering the pair of transfer arms 11, the flash-heated semiconductor wafer W is transferred to and placed on the transfer hand 151b. After that, the transport robot 150 moves the transport hand 151b out of the processing chamber 6 and unloads the semiconductor wafer W after processing.

By the way, maintenance work is performed on the heat treatment apparatus 100 regularly or irregularly. Irregular maintenance work is performed when, for example, trouble such as wafer cracking occurs during flash heating and recovery processing is required. During maintenance work, the processing chamber 6 is opened. Specifically, the upper chamber window 63 needs to be opened. If even a small amount of harmful gas such as ammonia remains in the processing chamber 6 when the processing chamber 6 is opened, such gas may be released into the working environment outside the heat treatment apparatus 100 .

Therefore, in the first embodiment, the residual gas contained in the atmosphere inside the processing chamber 6 is detected before the processing chamber 6 is opened during maintenance of the heat treatment apparatus 100 . Before opening the processing chamber 6 for maintenance, nitrogen gas is supplied from the processing gas supply source 85 so that the inside of the processing chamber 6 has a nitrogen atmosphere of atmospheric pressure. The valve 89 is opened and the valves 172 and 136 are closed while the inside of the processing chamber 6 is in a nitrogen atmosphere of atmospheric pressure. As a result, the processing exhaust pipe 88 and the gas exhaust pipe 191 serve as an exhaust path that guides only the atmosphere inside the processing chamber 6 to the exhaust section 190 . Then, the exhaust gas detector 192 is provided in the middle of the exhaust route.

When the valve 172 and/or the valve 136 are opened in addition to the valve 89, the atmosphere of the processing chamber 6 and the transfer chamber 170 and/or the first cool chamber 131 (the second cool chamber 141) are supplied to the gas exhaust pipe 191. The exhaust air mixed with the atmosphere of As a result, the atmosphere in the processing chamber 6 is diluted, making it difficult for the exhaust gas detector 192 to detect a trace amount of ammonia or the like remaining in the processing chamber 6 .

In the first embodiment, only the valve 89 is opened and the valves 172 and 136 are closed, so that only the atmosphere in the processing chamber 6 flows from the process exhaust pipe 88 through the gas exhaust pipe 191 to the exhaust gas detector 192 . will pass through That is, by operating the valve, only the atmosphere within the processing chamber 6 is targeted for detection by the exhaust gas detector 192, and residual ammonia contained in the atmosphere within the processing chamber 6 is directly detected. Therefore, the detection sensitivity of the exhaust gas detector 192 to ammonia remaining in the processing chamber 6 is increased, and the exhaust gas detector 192 can detect a very small amount of ammonia remaining in the processing chamber 6 . Thus, safety can be confirmed before opening the processing chamber 6 during maintenance of the heat treatment apparatus 100 .

When the exhaust gas detector 192 detects ammonia remaining in the processing chamber 6 before the processing chamber 6 is opened, the alarm unit 32 (FIG. 11) of the control unit 3 displays an alarm on the display unit 34. , the speaker 36 may issue an audible warning. In this way, danger can be more reliably communicated to maintenance workers.

<Second embodiment>
Next, a second embodiment of the invention will be described. The configuration of the heat treatment apparatus 1 and the processing procedure of the semiconductor wafer W of the second embodiment are the same as those of the first embodiment. In the first embodiment, residual ammonia in the processing chamber 6 was detected before opening the processing chamber 6 during maintenance of the heat treatment apparatus 100. Detects ammonia contained in the internal atmosphere.

As described above, the heat treatment section 160 heats the semiconductor wafer W in an ammonia atmosphere, and after the heat treatment is completed, the pressure in the processing chamber 6 is reduced to exhaust the ammonia. However, for example, when the semiconductor wafer W is heat-treated in an atmosphere of 100% ammonia, even if the pressure inside the processing chamber 6 is reduced to 100 Pa and the ammonia is discharged, the pressure is restored to the atmospheric pressure with nitrogen gas. 1000 ppm of ammonia will remain in the chamber 6 . This residual concentration is high even compared to 25 ppm, which is defined as the permissible concentration of ammonia in the working environment.

Residual ammonia may flow into the transfer chamber 170 together with the semiconductor wafer W when the gate valve 185 is opened and the processed semiconductor wafer W is transferred from the processing chamber 6 to the transfer chamber 170 by the transfer robot 150 . Ammonia that has flowed into the transfer chamber 170 may further pass through the first cool chamber 131 or the second cool chamber 141 and leak from the indexer unit 101 into the work environment. In the heat treatment apparatus 100, residual ammonia in the processing chamber 6 is prevented from leaking into the work environment by adjusting the pressure relationship between the chambers, but residual ammonia may leak due to some trouble or human error. It is difficult to eliminate the possibility completely. Further, when the sealing performance of the O-ring of the gate valve 185 deteriorates, ammonia may leak from the processing chamber 6 to the transfer chamber 170 during the heat treatment of the semiconductor wafer W.

Therefore, in the second embodiment, ammonia contained in the atmosphere in the transfer chamber 170 is detected during processing of the semiconductor wafer W in the heat treatment apparatus 100 (including transfer, cooling, etc. in addition to heat treatment). I'm trying Specifically, when the semiconductor wafer W is processed in the heat treatment apparatus 100 , the presence or absence of ammonia in the atmosphere inside the transfer chamber 170 is constantly monitored by the oxygen concentration meter 175 .

Oxygen concentration meter 175 is essentially a zirconia type oxygen concentration meter that measures the oxygen concentration in transfer chamber 170 . When a zirconia oxygen analyzer comes into contact with oxygen, an electromotive force is generated by the movement of oxygen ions. When the zirconia oxygen analyzer comes into contact with ammonia, hydrogen ions ( H ⁺ ) moves through the zirconia solid electrolyte to generate an electromotive force (an electromotive force having a potential opposite to that of oxygen). Therefore, although the oxygen concentration meter 175 cannot quantitatively evaluate the concentration of ammonia, it can detect the presence or absence of ammonia. Moreover, the detection sensitivity of the oxygen concentration meter 175 is high. Total 175 can detect concentrations of ammonia one order of magnitude lower.

During the processing of the semiconductor wafers W in the heat treatment apparatus 100 , the valve 176 is always opened to take the atmosphere in the transfer chamber 170 into the oxygen concentration meter 175 . The oxygen concentration meter 175 with high detection sensitivity detects ammonia contained in the atmosphere of the transfer chamber 170 during processing in the heat treatment apparatus 100 . As a result, it is possible to detect the presence or absence of outflow of ammonia from the processing chamber 6 to the transfer chamber 170 during processing in the heat treatment apparatus 100, and to confirm safety.

As in the first embodiment, when the oxygen concentration meter 175 detects ammonia contained in the atmosphere of the transfer chamber 170 during processing in the heat treatment apparatus 100, the alarm unit 32 displays an alarm on the display unit 34, An audio warning may be issued from the speaker 36 . In this way, the operator of the heat treatment apparatus 100 can be more reliably informed of the outflow of ammonia to the transfer chamber 170 .

<Third Embodiment>
Next, a third embodiment of the invention will be described. The configuration of the heat treatment apparatus 1 and the processing procedure of the semiconductor wafer W of the third embodiment are the same as those of the first embodiment. In the third embodiment, artificial intelligence (AI) is used to determine the danger of ammonia.

In the first embodiment, ammonia in the processing chamber 6 is detected by the exhaust gas detector 192, which is an ammonia detector using an electrolytic solution system. Ammonia in the chamber 170 was detected. However, the exhaust gas detector 192 is also sensitive to hydrogen containing molecules and nitrogen oxides. Also, the oxygen concentration meter 175 is naturally affected by oxygen in the atmosphere. Therefore, even if ammonia is detected by the exhaust gas detector 192 or the oxygen concentration meter 175, no ammonia actually exists, or even if ammonia exists, its concentration reaches a dangerous level. sometimes they don't.

In the third embodiment, the danger of ammonia is determined by a determination unit 31 having an artificial intelligence function. FIG. 12 is a diagram showing the concept of risk determination by artificial intelligence. A determination unit 31 having an artificial intelligence function analyzes a large number of data sets using knowledge obtained by machine learning including deep learning to determine the danger of ammonia. The input data to the determination unit 31 include, in addition to detection information by the exhaust gas detector 192 or the oxygen concentration meter 175, information on the type of gas supplied to the processing chamber 6, opening/closing information on each valve including the gate valve, And the processing conditions for the semiconductor wafer W are illustrated. Processing conditions for the semiconductor wafer W can be acquired from recipes stored in the magnetic disk 35 .

The determination unit 31 equipped with an artificial intelligence function learns from data obtained in the past under what kind of situation danger occurs. Using the knowledge obtained by the machine learning, the determination unit 31 analyzes the set of data illustrated in FIG. 12 to determine the presence or absence of the danger of ammonia. Since a large amount of data will be handled for this determination, it is preferable to use artificial intelligence.

When the judging section 31 judges that there is danger, the issuing section 32 may issue a warning. At this time, similarly to the first and second embodiments, the alarm unit 32 may display an alarm on the display unit 34 and may issue a warning by sound from the speaker 36 .

<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, in the first embodiment, the residual ammonia in the processing chamber 6 is detected by the exhaust gas detector 192 provided in the gas exhaust pipe 191. The residual ammonia in 6 may be detected. As described above, even the zirconia oxygen concentration meter 251, which is originally intended to measure the oxygen concentration, can detect the presence or absence of ammonia with high sensitivity. Before opening the processing chamber 6 during maintenance of the heat treatment apparatus 100, the valve 252 is opened to take the atmosphere in the processing chamber 6 into the oxygen concentration meter 251, and ammonia remaining in the processing chamber 6 is detected. Since the oxygen concentration meter 251 also detects only the atmosphere inside the processing chamber 6 , residual ammonia contained in the atmosphere inside the processing chamber 6 can be directly detected. Therefore, as in the first embodiment, a trace amount of ammonia remaining in the processing chamber 6 can be detected by the oxygen concentration meter 251 .

Further, in the above embodiment, ammonia is used as the processing gas, and ammonia is detected during maintenance or the like, but the processing gas is not limited to ammonia, and other poisonous gases good. Nitrogen oxides (NO _x such as nitric oxide (NO), nitrous oxide (N ₂ O), nitrogen dioxide (NO ₂ ), etc.) are exemplified as such toxic gases. When the zirconia oxygen analyzer comes into contact with nitrogen oxides, oxygen ions generated by the decomposition of the nitrogen oxides move through the zirconia solid electrolyte, generating an electromotive force. It is possible to detect the presence or absence of oxides.

Further, in the above embodiment, the flash lamp house 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. Further, the number of halogen lamps HL provided in the halogen lamp house 4 is not limited to 40, and may be any number.

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 100 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.

3 Control Unit 4 Halogen Lamp House 5 Flash Lamp House 6 Processing Chamber 7 Holding Unit 10 Transfer Mechanism 31 Judgment Unit 32 Reporting Unit 33 Input Unit 34 Display Unit 35 Magnetic Disk 36 Speaker 65 Heat Treatment Space 74 Susceptor 85 Processing Gas Supply Source 100 Heat Treatment Apparatus 101 Indexer Section 120 Delivery Robot 130, 140 Cooling Section 150 Transfer Robot 151a, 151b Transfer Hand 160 Heat Treatment Section 170 Transfer Chamber 175, 251 Oxygen Analyzer 190 Exhaust Section 192, 281 Exhaust Gas Detector FL Flash Lamp HL Halogen Lamp W semiconductor wafer

Claims (9)

A gas detection method using a heat treatment apparatus that heats a substrate by irradiating the substrate with light,
The heat treatment apparatus is
a processing chamber containing a substrate;
a light irradiation unit that irradiates light onto the substrate housed in the processing chamber;
a gas supply unit that supplies a processing gas to the processing chamber;
an exhaust unit for exhausting the atmosphere in the processing chamber;
a gas exhaust pipe that is connected to the exhaust part and guides the atmosphere in the processing chamber to the exhaust part;
a processing exhaust pipe connected to the processing chamber and the gas exhaust pipe;
a first valve interposed in the middle of the path of the process exhaust pipe;
a first gas detection unit provided in the middle of the path of the gas exhaust pipe for detecting the processing gas contained in the atmosphere within the processing chamber;
a transfer chamber that is provided adjacent to the processing chamber and houses a transfer robot that transfers substrates into and out of the processing chamber;
a transport exhaust pipe connected to the transport chamber and the gas exhaust pipe;
a second valve provided in the middle of the path of the transport exhaust pipe;
with
During maintenance of the heat treatment apparatus, before opening the processing chamber, the first valve is opened and the second valve is closed, and the first gas detection unit is included in the atmosphere in the processing chamber. A gas detection method comprising detecting a processing gas. In the gas detection method using the heat treatment apparatus according to claim 1,
The gas detection method, wherein the first gas detection unit is a zirconia oxygen concentration meter installed in the processing chamber. In the gas detection method using the heat treatment apparatus according to claim 1 or claim 2,
The heat treatment apparatus is
further comprising a second gas detection unit that detects the processing gas contained in the atmosphere within the transfer chamber;
A gas detection method, wherein the second gas detection unit detects the processing gas contained in the atmosphere within the transfer chamber during processing in the heat treatment apparatus. In the gas detection method using the heat treatment apparatus according to claim 3,
The gas detection method, wherein the second gas detection unit is a zirconia oxygen concentration meter. In the gas detection method using the heat treatment apparatus according to claim 3 or 4,
The heat treatment apparatus is
The apparatus further comprises a judging section for judging danger of the processing gas in the heat treatment apparatus by artificial intelligence based on detection information of the first gas detecting section and the second gas detecting section and processing conditions for the substrate. gas detection method. In the gas detection method using the heat treatment apparatus according to claim 5,
The heat treatment apparatus is
A gas detection method, further comprising: a warning unit that issues a warning when it is determined that the processing gas is dangerous. In the gas detection method using the heat treatment apparatus according to any one of claims 1 to 6,
The gas detection method, wherein the processing gas is ammonia or nitrogen oxide. A heat treatment apparatus for heating a substrate by irradiating the substrate with light,
a processing chamber containing a substrate;
a light irradiation unit that irradiates light onto the substrate housed in the processing chamber;
a gas supply unit that supplies a processing gas to the processing chamber;
an exhaust unit for exhausting the atmosphere in the processing chamber;
a first gas detection unit provided in the middle of a path of a gas exhaust pipe leading the atmosphere in the processing chamber to the exhaust unit and detecting the processing gas contained in the atmosphere in the processing chamber;
a transfer chamber that is provided adjacent to the processing chamber and houses a transfer robot that transfers substrates into and out of the processing chamber;
a second gas detection unit that detects the processing gas contained in the atmosphere in the transfer chamber;
with
The apparatus further comprises a judging section for judging danger of the processing gas in the heat treatment apparatus by artificial intelligence based on detection information of the first gas detecting section and the second gas detecting section and processing conditions for the substrate. heat treatment equipment. In the heat treatment apparatus according to claim 8,
A heat treatment apparatus, further comprising: a warning unit that issues a warning when it is determined that the processing gas is dangerous.

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