JP4111937B2 - Heat treatment equipment - Google Patents

Description

  The present invention relates to a heat treatment apparatus for performing heat treatment on a substrate such as a semiconductor wafer, a glass substrate for a photomask, a glass substrate for liquid crystal display, and an optical disk substrate.

  2. Description of the Related Art Conventionally, a heat treatment apparatus such as lamp annealing has been used as a heat treatment for a substrate such as a semiconductor wafer (hereinafter referred to as “wafer”).

  FIG. 5 is a longitudinal sectional view of lamp annealing, which is a kind of conventional heat treatment apparatus. The heat treatment apparatus 100 mainly includes a furnace body 110, a light emitting unit 120, quartz glass 130, a wafer holding / rotating unit 140, a reflecting plate 147, a temperature / reflectance measuring unit 150, and a control unit 160.

  The furnace body 110 is a cylindrical furnace body having a reflector 111 at the top and a housing 112 at the bottom, and a carry-in / out port 110a is provided on one side of the furnace body 110. The wafer W is carried into and out of the furnace body 110 by an external transfer device that does not.

  The light emitting unit 120 includes a number of lamps 121 provided inside the reflector 111. When the lamp driver 122 receiving the control signal from the control unit 160 supplies power corresponding to the signal to the lamp 121, the lamp 121 is turned on, and the wafer W is heated by the emitted light.

  The quartz glass 130 is provided above the wafer W and below the light emitting unit 120, and transmits the radiated light from the lamp 121.

  The wafer holding / rotating unit 140 holds the peripheral portion of the wafer W over the entire circumference, and a soaking ring 141 that compensates for the release of heat from the peripheral portion has a cylindrical support leg having an inner diameter larger than the diameter. 142. And the bearing 143 is provided in the lower end of the support leg 142 along the outer periphery. Further, the gear provided on the outer periphery of the bearing 143 meshes with the gear 144a of the rotating shaft of the rotating motor 144, and the heat equalizing ring 141 can be rotated about the vertical direction by driving thereof. Then, the motor driver 145 supplies electric power to the motor 144 in accordance with the drive signal of the control unit 160, thereby rotating the wafer W together with the heat equalizing ring 141 at a predetermined speed.

  The reflection plate 147 reflects the emitted light from the back surface of the wafer W, thereby causing multiple reflections with the back surface of the wafer W. The temperature / reflectance of the multiple reflected radiation is measured by the temperature / reflectance measuring unit 150. The temperature measuring unit 150 includes a detector 157 that substantially measures temperature, a rotating sector 153 having a disk-shaped plate member, a motor 154 that rotates the rotating sector 153, and a motor driver 155. Yes. Due to the rotation of the motor 154 by the electric power supplied from the motor driver 155, the rotating sector 153 is rotatable within a plane parallel to the plate surface of the plate-like member. The detector 157 is electrically connected to the calculation unit 158 and detects light passing through each of the slits and cutouts of the plate member of the rotating sector 153. The detected light is transmitted to the calculation unit 158 using the radiation intensity as a signal.

  In the conventional heat treatment apparatus, the reflection surface of the reflection plate 147 is made a mirror surface by processing a metal such as stainless steel by lapping, buffing, or the like, thereby increasing the reflectance. However, when a stainless material is used, the reflectance of the stainless steel itself can only be increased to about 0.6. In addition, it is conceivable to use a higher reflectivity aluminum material or the like for the reflector 147, but in the case of an aluminum material, the aluminum material itself is very easy to oxidize, so that the reflective surface is easily clouded and the metal itself is There is a problem that it is easily damaged because it is soft.

  This invention is made | formed in view of this situation, Comprising: It aims at providing the heat processing apparatus which can suppress the fall of the reflectance of the reflective surface of a reflecting plate.

  In order to solve the above-mentioned problems, the present invention is a heat treatment apparatus for performing a heat treatment on a substrate, a holding means for holding the substrate, a heat source for performing a heat treatment on the substrate held by the holding means, A reflecting plate having a reflecting surface facing the substrate surface held by the holding means and having a hole formed therein; a temperature measuring means provided in the hole for measuring the temperature of the substrate; and covering the reflecting plate And a cylindrical transmission cap having light transmittance and having an upper end closed with a flat surface. Note that “holding the substrate by the holding means” includes holding the substrate by supporting the back surface of the substrate with a support member, holding the substrate by holding the peripheral portion of the substrate by the holding member, and the like.

  Further, the present invention is characterized in that the translucent cap is made of quartz. In the present invention, the holding means holds a peripheral portion of the substrate, a support pin for supporting the substrate is provided on an upper surface of the transmission cap, and the transmission cap is moved up and down, whereby the substrate is held by the holding means. And the support pin. Further, the present invention is characterized in that a metal thin film is formed on the reflection surface of the reflection plate around the hole.

  According to the present invention, a reflecting plate having a reflecting surface facing the substrate surface held by the holding means and having a hole formed therein, a temperature measuring means provided in the hole and measuring the temperature of the substrate, Since it includes a cylindrical transmission cap that covers the reflection plate, has light transmissivity, and is closed at the upper end with a flat surface, the reflection surface of the reflection plate is prevented from reacting with the processing gas and reducing the reflectance. be able to.

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

  FIG. 1 is a longitudinal sectional view of lamp annealing which is a kind of heat treatment apparatus according to an embodiment of the present invention.

  The heat treatment apparatus 1 mainly includes a chamber 10, a light emitting unit 20, a transmission cover 30, a holding rotation unit 40, a reflection unit 50, a transmission cap 60, a temperature measurement unit 70, a lift drive unit 80, and a control unit 90.

  The chamber 10 is a cylindrical furnace body having a reflector 11 in the upper part and a housing 12 in the lower part. The inner wall surface of the furnace body is covered with quartz, and a wafer W that is a kind of substrate is placed inside the furnace body. It has a processing space PS which is a space for performing heat treatment and serves as a processing chamber. In addition, a large number of cooling pipes 13 (a part of the reference numerals are omitted) are provided inside the reflector 11 for cooling through the refrigerant. The reflector 11 and the housing 12 are separated into upper and lower parts, and both are connected by an extendable metal bellows 14 that covers the outer periphery of the housing 12.

  In addition to the loading / unloading port 10a for transferring the wafer W to / from an external substrate transfer mechanism (not shown) on the side surface of the chamber 10 and loading / unloading it into / from the chamber 10, an upper gas supply path 10b and an upper gas discharge path 10c. A lower gas supply path 10d is provided. Among them, the upper gas supply path 10b is provided outside the chamber 10 for supplying a processing gas such as nitrogen monoxide gas (N 2 O) or oxygen gas (O 2) to form a nitride film or an oxide film by a chemical reaction. And an external replacement gas supply for supplying a replacement gas such as nitrogen gas (N2) having a low chemical reactivity for replacing the process gas filled in the chamber 10 and discharging it. Connected to the source 16. Further, the upper gas discharge path 10c discharges the processing gas and the replacement gas (hereinafter simply referred to as “gas” when they are collectively referred to) supplied into the chamber 10 to the outside. Further, the lower gas supply path 10 d is connected only to the replacement gas supply source 16.

  Further, a shutter 17 is provided outside the carry-in / out port 10a, and the shutter 17 can be opened / closed in the vertical direction with respect to the carry-in / out port 10a by driving an elevating mechanism (not shown).

  The light emitting unit 20 is provided below the reflector 11 and includes a large number of lamps 21 that are halogen lamps as heat sources. The lamps 21 are provided so as to face the surface of the wafer W and be distributed substantially uniformly in a plane parallel to the wafer W. Therefore, when the lamp 21 is turned on, the light is applied to the wafer W, and the wafer W is heated uniformly.

  The transmission cover 30 is a quartz cover with low chemical reactivity provided below the light emitting unit 20 and transmits the light emitted from the lamp 21. A gas reservoir 30a communicating with the upper gas supply path 10b is formed inside the upper surface of the transmission cover 30.

  In addition, an upper gas inlet 30b, which is a plurality of pores communicating with the gas reservoir 30a, is provided on the lower surface of the transmission cover 30. When supplying the gas, the gas is supplied to the processing space PS in the form of a shower through the upper gas inlet 30b. Thus, in this heat treatment apparatus 1, since the upper gas inlet 30b is provided uniformly in a plane parallel to the surface to be processed of the wafer W, the gas flow in the surface to be processed of the wafer W becomes uniform, Nonuniformity in the temperature drop of the wafer W due to the gas flow can also be suppressed.

  The holding rotating unit 40 holds the edge of the wafer W over the entire periphery, and a soaking ring 41 made of SiC that compensates for the release of heat from the periphery has a cylindrical inner diameter larger than its diameter. It is supported by support legs 42. A rotor 43 a is provided at the lower end of the outer peripheral surface of the support leg 42, and a corresponding stator 43 b is attached to the fixing member 52. When the rotor 43a rotates, the support leg 42 rotates about the center of the cylinder, and accordingly, the heat equalizing ring 41 is also parallel to the surface to be processed (upper surface) of the wafer W about the center in the horizontal plane. It can rotate in a horizontal plane.

  The reflecting portion 50 is obtained by fixing a reflecting plate 51 whose upper surface is a mirror surface having a high reflectivity to the housing 12 via a fixing member 52 in parallel with the wafer W held by the soaking ring 41. The reflected light from the wafer W is reflected. Further, the lower surface of the wafer W further reflects the reflected light, thereby causing a multiple reflection phenomenon in which the reflection of the radiated light is repeated between the wafer W and the reflection plate 51. In addition, the reflecting plate 51 is provided with a plurality of holes 51a.

  The transmission cap 60 is a member made of quartz having a low light reactivity and a cylindrical shape with a top end closed by a flat surface, and covers the upper part of the reflection part 50. Thereby, it is suppressed that the reflective surface of the reflecting plate 51 reacts with the processing gas and becomes “clouded” to reduce the reflectance. Further, three concentric support pins 61 made of quartz are provided on the upper surface of the transmission cap 60, and the wafer W can be placed horizontally on the upper ends of the support pins 61 as holding means. Yes.

  In addition, an air cylinder 62 for raising and lowering the entire transmission cap 60 is provided below the transmission cap 60. When the wafer W is received due to the expansion and contraction of the air cylinder 62, the transmissive cap 60 is raised, the wafer W is placed on the support pins 61, and then the transmissive cap 60 is lowered to lower the holding rotation unit 40. The wafer W is placed on the soaking ring 41. Conversely, the reverse procedure is performed when the wafer W is transferred to the substrate transfer mechanism.

  In addition, since the inner walls of the transmission cover 30, the transmission cap 60, and the chamber 10 are made of quartz and the soaking ring 41 is made of SiC, the metal member is directly exposed to the processing gas inside the chamber 10. Since there are few, metal contamination will not be given to the wafer W.

  The temperature measurement unit 70 is attached below each of a plurality of cylindrical holes 51a provided in the reflection plate 51, and can take light after multiple reflections through the holes 51a. Then, a radiation thermometer (not shown) provided in the temperature measurement unit 70 measures the temperature of the wafer W based on the light, and transmits the temperature signal to the control unit 90 described later. The specific structure of the temperature measuring unit 70 will be described later.

  The elevating drive unit 80 includes a ball screw 81 and a motor 82, and as the motor 82 rotates, the housing 12 and the reflecting unit 50 attached thereto, the holding rotating unit 40, and the temperature measuring unit 70 are moved up and down (reflector 11). Relative to and close to each other). As a result, the wafer W placed on the soaking ring 41 can be moved up and down.

  The control unit 90 includes a CPU, a memory, and the like (not shown) inside, and an electrical connection with each unit is not shown, but a driver (not shown) that supplies power to each of the shutter 17, the lamp 21, the linear motor 43, and the motor 82. And controls the operation of each of the above parts through control of the power supplied by these drivers, as well as the electromagnetic supply (not shown) provided in the air supply source (not shown), the processing gas supply source 15 and the replacement gas supply source 16 to the air cylinder 62. The supply amount of air and gas is controlled by opening and closing the valve.

  FIG. 2 is a diagram showing the configuration of the temperature measurement unit of the heat treatment apparatus according to the embodiment of the present invention.

  As shown in FIG. 2, a cylindrical hole 72 is formed in a reflecting plate 71 made of stainless steel or the like having a surface facing the lower surface of the wafer W, and the temperature measuring unit 70 is formed in and below the hole 72. A casing 73 is provided, and the inner surface of the hole 72 is a cylindrical cavity CP at the top of the casing 73. A disc-shaped rotating sector 74 is provided below the hollow portion CP. Further, a cooling pipe 730 is provided inside the casing 73 so that the temperature inside the casing 73 is suppressed. A specific structure of the cooling pipe 730 will be described later.

  In the rotating sector 74, the two sectors that are not adjacent to each other, divided into four equal parts by two orthogonal diameters, are reflective portions whose front and back surfaces are mirror surfaces, and the other sector portions are blackened. It is an absorbed part. Moreover, the slit of an arc is provided in the reflection part and the absorption part. The center CE of the rotating sector 74 is attached to the rotating shaft 750 of the motor 75. Therefore, the rotation sector 74 is rotatable in a plane parallel to the plate surface of the rotation sector 74 by the rotation of the motor 75 by the electric power supplied from the motor driver 76.

  Further, the inner surface 731 of the casing 73 below the rotating sector 74 is blackened, and most of the light that has passed through the slits of the absorbing part or the reflecting part of the rotating sector 74 is blackened. It is absorbed by the inner surface 731 and is not reflected. A hole 732 is formed in the inner surface 731, and a lens 733 and a detector 734 are provided in the hole 732. Light entering the hole 732 is detected by the detector 734 through the lens 733. The detector 734 detects the light that has passed through the slits of the reflecting part and the absorbing part of the rotating sector 74 and obtains the respective radiation intensity (radiant energy). Then, the temperature of the wafer W is obtained based on each radiation intensity, and the temperature signal is transmitted to the control unit 90.

  FIG. 3 is a cross-sectional view showing the reflecting plate and the reflecting surface of the reflecting plate. The reflecting plate 71 itself is made of stainless steel, and the reflecting surface facing the lower surface of the wafer W is buffed and further mirror-finished. Aluminum is vapor-deposited on the reflection surface of the reflection plate 71 that has been subjected to the mirror surface treatment. Furthermore, SiO2 is deposited as a protective film on the surface of the aluminum.

  FIG. 4 is a schematic diagram showing the structure of the cooling unit. As shown in FIG. 4, the cylindrical cooling pipe 730 is formed in the casing 73 while being arranged around the cylindrical hole 72. On the lower surface of the cooling pipe 730, a supply port 730a for supplying the cooling water into the cooling pipe 730 and a discharge port 730b for discharging the cooling water from the cooling pipe 730 are formed. The supply port 730 a and the discharge port 730 b are formed at positions symmetrical with respect to the hole 72. The supply port 730a is connected in communication with a supply pipe 730c. Cooling water flows from a cooling water supply source (not shown) as indicated by an arrow A and is supplied from the supply port 730a to the cooling pipe 730. The cooling water supplied into the cooling pipe 730 flows around the hole 72 as indicated by an arrow B. The cooling water that has flowed through the cooling pipe 730 is discharged from the discharge port 730b through the cooling pipe 730d as indicated by an arrow C.

  The heat treatment apparatus according to the embodiment of the present invention has the following effects. That is, since the aluminum which is a metal thin film is formed in the processing surface of the reflecting plate 71 which has the reflecting surface facing the surface of the wafer W and in which the cylindrical hole 72 is formed, the reflecting plate has a simple configuration. The reflective surface of 71 can be kept in a high reflectance state, and the multiple reflection effect in temperature measurement can be amplified.

  In addition, since an oxide film (SiO 2) is deposited as a protective film on the surface of aluminum, there is an effect that the surface of aluminum, which is a metal thin film, is not damaged.

  Further, since the reflection surface of the reflection plate 71 is mirror-finished, heat absorption into the reflection plate 71 can be suppressed, and the thermal efficiency for heating the wafer W can be improved.

  Further, since the water-cooled tube 73 is provided on the opposite side of the reflecting surface of the reflecting plate 71, the temperature rise of the reflecting plate 71 can be suppressed, and disturbance that becomes an error factor for temperature measurement can be prevented.

  Also, since the surface of the hole 72 is formed with aluminum, which is a metal thin film, like the reflecting surface of the reflecting plate 71, the reflecting surface of the reflecting plate 71 and the surface of the hole 72 can be kept in a high reflectance state. And the multiple reflection effect in temperature measurement can be further amplified.

  Further, a cooling pipe 730 is disposed around the cylindrical hole 72, and a supply port 730 a for supplying cooling water into the cooling pipe 730 and a cooling water are cooled on the lower surface of the cooling pipe 730. Since the discharge port 730b for discharging from the inside of the tube 730 is formed, the temperature rise of the reflector 71 and the hole 72 can be suppressed, and disturbances that cause errors in temperature measurement can be more effectively prevented.

It is a longitudinal cross-sectional view of the lamp annealing which is 1 type of the heat processing apparatus which is embodiment of this invention. It is a figure which shows the structure of a temperature measurement part. It is sectional drawing which shows the reflective surface of a reflecting plate and a reflecting plate. It is a schematic diagram which shows the structure of a cooling unit. It is a longitudinal cross-sectional view of the lamp annealing which is 1 type of the conventional heat processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Chamber 11 Reflector 12 Housing 21 Lamp 50 Reflection part 60 Transmission cap 61 Support pin 62 Air cylinder 70 Temperature measurement part 71 Reflection plate 141 Soaking ring W Wafer

Claims (4)

A heat treatment apparatus for performing heat treatment on a substrate,
Holding means for holding the substrate;
A heat source for performing a heat treatment on the substrate held by the holding means;
A reflecting plate having a reflecting surface facing the substrate surface held by the holding means and having a hole;
Temperature measuring means provided in the hole and measuring the temperature of the substrate;
A cylindrical transmission cap that covers the reflection plate, has light transmittance, and is closed at the upper end with a flat surface;
A heat treatment apparatus comprising: The heat treatment apparatus according to claim 1,
A heat treatment apparatus, wherein the transmission cap is made of quartz. The heat treatment apparatus according to claim 1 or 2,
The holding means holds a peripheral portion of the substrate;
Support pins for supporting the substrate are provided on the upper surface of the transmission cap,
A heat treatment apparatus, wherein the substrate is transferred between the holding means and the support pins by raising and lowering the transmission cap. A heat treatment apparatus according to any one of claims 1 to 3,
A heat treatment apparatus, wherein a metal thin film is formed on a reflection surface of the reflection plate around the hole.

Images