JP2010034491A - Annealing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an annealing apparatus that heats a subject to be processed in a short time in a state wherein in-surface temperature is uniform by irradiating a rear surface of the subject to be processed in a homogeneous surface state with laser light as heating light, and increases energy conversion efficiency to contribute to energy saving. <P>SOLUTION: The annealing apparatus which anneals the subject W to be processed is provided with: a processing container 4 wherein the subject to be processed is stored; a supporting means 10 which supports the subject to be processed in the processing chamber; a gas supply means 16 which supplies a processing gas into the processing container; an air-discharging means 24 which discharges the atmosphere from the processing container; and a rear-side heating means 34 having a plurality of laser elements 68 which radiate the heating light toward the entire rear surface of the subject to be processed. Consequently, the rear surface of the subject to be processed in a homogeneous surface state is irradiated with the laser light as the heating light. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an annealing apparatus that performs an annealing process on an object to be processed such as a semiconductor wafer, and more particularly to an annealing apparatus that performs an annealing process by irradiating heating light from a laser element or an LED (Light Emitting Diode) element.

  In general, in order to manufacture a semiconductor integrated circuit, various processes such as a film formation process, an oxidation diffusion process, a modification process, an etching process, and an annealing process are repeatedly performed on a semiconductor wafer such as a silicon substrate. In the annealing process for activating impurity atoms doped in the wafer after the ion plantation, it is necessary to raise and lower the temperature of the semiconductor wafer at a higher speed in order to minimize the diffusion of impurities.

  In this case, in the conventional annealing apparatus, the wafer is heated using a halogen lamp or the like. However, since the halogen lamp needs to be at least about 1 second until it becomes stable as a heat source after being turned on, recently, In this case, an annealing process (for example, Patent Document 1) using an LED element that is superior in switching responsiveness and capable of higher temperature rise / lower than a halogen lamp as a heating source has been proposed.

  In addition, a technique has been proposed in which a laser element is used as another heating source and the wafer is heated while scanning the surface of the wafer with heating light generated from the laser element (for example, Patent Document 2).

JP 2005-536045 gazette JP 2005-244191 A

  Thus, when an LED element or a laser element is used as a heating source, there is an advantage that a high-speed heating / cooling operation on the wafer is relatively possible. In the case of the LED element, since the generation wavelength of the heating light has a certain width, it has an advantage that it can be heated uniformly in a plane without depending on the surface state of the wafer.

  However, when this LED element is used, the light emission efficiency is about 10 to 30%, which is considerably lower than the light emission efficiency of the laser element of about 40 to 50%. As a result, there is a problem that energy efficiency is lowered.

  On the other hand, in the case of a laser element, it is superior in terms of light emission efficiency as compared with an LED element as described above, but since the emission wavelength that is heating light is monochromatic light, There has been a problem that temperature distribution occurs depending on the surface state. For example, on the wafer surface, there are mixed amorphous parts, metal parts, insulating film parts, etc., and these have different light absorption wavelengths depending on the material, so when irradiated with laser light (heating light) that is monochromatic light, The temperature distribution as described above may occur due to the difference in absorption rate depending on the wavelength.

  The present invention has been devised to pay attention to the above problems and to effectively solve them. An object of the present invention is to irradiate a processing object in a short time and with a uniform in-plane temperature by irradiating laser light, which is heating light, from the back surface having a uniform surface condition of the processing object. Another object of the present invention is to provide an annealing apparatus capable of contributing to energy saving by increasing energy conversion efficiency.

  The invention according to claim 1 is an annealing apparatus that performs an annealing process on an object to be processed, a processing container in which the object to be processed is accommodated, and a support unit that supports the object to be processed in the processing container, A back surface having a gas supply means for supplying a processing gas into the processing container, an exhaust means for exhausting the atmosphere in the processing container, and a plurality of laser elements that radiate heating light toward the entire back surface of the object to be processed An annealing apparatus comprising: a side heating means.

  As described above, in the annealing apparatus that performs the annealing process on the object to be processed, the back surface side heating unit having a plurality of laser elements that irradiate the heating light toward the entire back surface of the object to be processed is provided, which is the heating light. By irradiating the laser beam from the back surface with a uniform surface state of the object to be processed, the object to be processed can be heated in a short time and with a uniform in-plane temperature, and energy conversion efficiency is also increased. It can contribute to energy saving.

According to a second aspect of the present invention, in the first aspect of the present invention, the plurality of laser elements are arranged over a region having a size capable of covering at least the entire back surface of the object to be processed.
A third aspect of the invention is characterized in that, in the first or second aspect of the invention, the laser element comprises a semiconductor laser element, a solid-state laser element, or a gas laser element.
According to a fourth aspect of the invention, in the invention according to any one of the first to third aspects, the heating light generated by the laser element is made in a wavelength band capable of selectively heating the silicon substrate. It is characterized by being.

The invention of claim 5 is the invention according to any one of claims 1 to 4, wherein either one of the support means and the back surface side heating means is rotatably supported, and It has a rotation mechanism for rotating.
The invention according to claim 6 is the surface according to any one of claims 1 to 5, wherein the surface is disposed opposite to the back surface side heating means and irradiates the surface of the object with heating light. It has the side heating means.

  A seventh aspect of the invention is the invention according to any one of the first to sixth aspects, wherein the surface side heating means is disposed over a region having a size capable of covering at least the entire surface of the object to be processed. It has a plurality of LED (Light Emitting Diode) elements or SLD (Super Luminescent Diode) elements.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein at least one of the back surface side heating means and the front surface side heating means is cooled by a refrigerant. A cooling mechanism is provided.

The invention of claim 9 is the invention of claim 8, wherein the cooling mechanism has a refrigerant passage for flowing the refrigerant, and the refrigerant passage is cut off from the refrigerant inlet toward the refrigerant outlet. The area is set so as to decrease sequentially.
In this way, by setting the flow passage area of the refrigerant passage to be gradually reduced from the refrigerant inlet to the refrigerant outlet, the amount of heat per unit length of the refrigerant passage taken by the refrigerant from the object to be cooled becomes constant. As a result, the temperature of the cooling object can be made uniform along the length direction of the refrigerant passage.

  The invention of claim 10 is the invention of claim 9, wherein the width of the refrigerant passage is constant, and the height of the refrigerant passage is the flow rate of the refrigerant, the specific heat of the refrigerant, the density of the refrigerant, and the refrigerant inlet. It is determined based on the distance from

The invention of claim 11 is characterized in that, in the invention of claim 10, the height f (x) of the refrigerant passage is given by the following equation.
f (x) = A ² · (To−T (x)) ² / (Q · cp ² · ρ ² · (T ′ (x)) ² )
A: Constant for obtaining heat transfer coefficient Q: Flow rate of refrigerant cp: Specific heat of refrigerant ρ: Density of refrigerant x: Distance from refrigerant inlet T (x): Temperature (function) of refrigerant at distance x
T ′ (x): differentiation of function T (x) To: target temperature

According to a twelfth aspect of the present invention, in the invention according to any one of the eighth to eleventh aspects, the cooling mechanism is provided with a plurality of heat pipes that promote cooling.
A thirteenth aspect of the invention is characterized in that, in the invention according to any one of the first to twelfth aspects, a reflection surface is formed on the back surface side heating means.

According to the annealing treatment according to the present invention, the following excellent operational effects can be exhibited.
In an annealing apparatus that performs an annealing process on an object to be processed, a back surface side heating unit having a plurality of laser elements that irradiate heating light toward the entire back surface of the object to be processed is provided to receive laser light as heating light. By irradiating from the back surface with a uniform surface state of the treatment object, the object to be treated can be heated in a short time and with a uniform in-plane temperature, and the energy conversion efficiency is also increased, contributing to energy saving. be able to.

In particular, according to the invention of claim 7, if an LED element or an SLD element is used as the surface side heating means, it is possible to irradiate heating light having a wide emission wavelength from the surface side of the object to be processed. Heating can be performed in a shorter time and with a uniform in-plane temperature without depending on the surface state of the body.
In particular, according to the invention according to claim 9, by setting the flow passage area of the refrigerant passage to be gradually reduced from the refrigerant inlet to the refrigerant outlet, the refrigerant per unit length of the refrigerant passage taken away from the object to be cooled by the refrigerant is determined. As a result, the temperature of the object to be cooled can be made uniform along the length direction of the refrigerant passage.

Hereinafter, an embodiment of an annealing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
1 is a sectional view showing a schematic configuration of an annealing apparatus according to the present invention, FIG. 2 is a plan view showing a surface (lower surface) of a surface side heating means, and FIG. 3 is a part of the surface side heating means in FIG. FIG. 4 is a plan view showing the surface (upper surface) of the back surface side heating means, FIG. 5 is an enlarged explanatory view for explaining the light emission state of the semiconductor laser element, and FIG. 6 is a laser beam from the laser element. It is a schematic diagram which shows the irradiation state of (heating light). Here, a case where a semiconductor wafer made of, for example, a silicon substrate is used as an object to be processed and this wafer having impurities implanted on the surface thereof is annealed will be described as an example.

  As shown in FIG. 1, the annealing apparatus 2 has a processing vessel 4 whose inside is made hollow with aluminum or an aluminum alloy. The processing container 4 includes a cylindrical side wall 4A, a ceiling plate 4B bonded to the upper end of the side wall, and a bottom plate 4C bonded to the bottom of the side wall. On the side wall 4A, a loading / unloading port 6 having a size capable of loading / unloading a semiconductor wafer W as an object to be processed is formed, and a gate valve 8 that can be opened and closed is attached to the loading / unloading port 6.

  In the processing container 4, support means 10 for supporting the wafer W is provided. The support means 10 has a plurality of, for example, three support pins 12 (only two are shown in FIG. 1) and a lifting arm 14 connected to the lower ends of these support pins 12. Each elevating arm 14 can be moved up and down by an actuator (not shown). Thereby, the whole can be moved up and down while the wafer W is supported on the upper end portion of the support pins 12.

A gas supply means 16 is formed in a part of the periphery of the ceiling plate 4B. The gas supply means 16 includes a gas introduction port 18 formed in the ceiling plate 4B and a gas pipe 20 connected to the gas introduction port 18, and a processing gas necessary for the processing container 4 is not shown. It can be introduced while the flow rate is controlled by the flow rate controller. Here, N ₂ gas or a rare gas such as Ar or He can be used as the processing gas. The ceiling plate 4B is formed with an upper refrigerant passage 19 through which a refrigerant for cooling the ceiling plate 4B flows.

  A gas exhaust port 22 is formed in a part of the periphery of the bottom plate 4C, and the gas exhaust port 22 is provided with an exhaust means 24 for exhausting the atmosphere in the processing container 4. The exhaust means 24 has a gas exhaust pipe 26 connected to the gas exhaust port 22, and a pressure regulating valve 28 and an exhaust pump 30 are sequentially provided in the gas exhaust pipe 26. The bottom plate 4C is formed with a lower refrigerant passage 31 through which a refrigerant for cooling the bottom plate 4C flows.

  A large-diameter opening is formed in the center of the ceiling plate 4B, and a surface side heating means 32 is provided in the opening to heat the surface (upper surface) of the wafer W. In addition, an opening having a large diameter is formed in the central portion of the bottom plate 4C, and a back-side heating unit 34, which is a feature of the present invention, is provided so as to face the opening-side heating unit 32. The back surface (lower surface) of the wafer W is heated. Here, the surface of the wafer W refers to the surface on which various processes such as film formation and etching are performed. Moreover, when the heating amount of the said back surface side heating means 34 is large enough, it can also be abbreviate | omitted without providing the said surface side heating means 32. FIG.

<Description of surface side heating means>
Next, the surface side heating means 32 will be described. The surface heating means 32 has an element mounting head 36 that is fitted into the opening of the ceiling plate 4B with a slight gap. The element mounting head 36 is made of a material having high thermal conductivity such as aluminum or aluminum alloy. This element mounting head 36 is supported by a circular ring-shaped mounting flange 36A formed on the upper side of the element mounting head 36 with a thermal insulator 38 made of polyetherimide or the like interposed between the element mounting head 36 and the ceiling plate 4B.

  In addition, a sealing material 40 made of an O-ring or the like is interposed on the upper and lower sides of the thermal insulator 38 so as to maintain the airtightness of this portion. An element mounting recess 42 having a diameter slightly larger than the diameter of the wafer W is formed on the lower surface of the element mounting head 36, and at least a portion of the wafer W is formed on a flat portion of the element mounting recess 42. A plurality of LED modules 44 are provided over an area large enough to cover the entire surface. A light transmission plate 45 made of, for example, a quartz plate is attached to the opening portion of the element attachment recess 42.

  As shown in FIG. 2 (A), the LED module 44 has a regular hexagonal shape, for example, having a side of about 25 mm, and is arranged close to each other so that adjacent sides are substantially in contact with each other. Has been. For example, when the diameter of the wafer W is 300 mm, about 80 LED modules 44 are provided. FIG. 2B shows an enlarged plan view of one LED module. As shown in FIGS. 2B and 3, each LED module 44 has a large number of LED elements 46 vertically and horizontally on the surface thereof. It is arranged and arranged. In this case, the size of each LED element 46 is about 0.5 mm × 0.5 mm, and about 1000 to 2000 LED elements 46 are mounted on one LED module 44. The LED elements 46 are grouped into a plurality of groups within one LED module 44, and the LED elements 46 in the same group are connected in series.

  An upper cooling mechanism 48 is provided above the LED module 44. The upper cooling mechanism 48 has a refrigerant passage 50 having a rectangular cross section provided in the element mounting head 36, and a refrigerant inlet pipe 50 </ b> A is connected to a refrigerant inlet 51 at one end of the refrigerant passage 50. At the same time, a refrigerant discharge pipe 50B is connected to the refrigerant outlet 53 at the other end, and the refrigerant can be cooled by flowing the refrigerant therethrough to take away the heat generated from the LED module 44. As this refrigerant, Fluorinert, Galden (trade name), or the like can be used. The refrigerant passage 50 is formed so as to be folded in a meandering manner, for example, over substantially the entire surface of the element mounting head 36, so that heat is taken from the upper surface side of the LED module 44 to cool it. It has become.

  As shown in FIG. 3, a heat pipe 52 having a U-shape extending in the vertical direction is provided on both side wall portions of each refrigerant passage 50 so as to be embedded. It can cool efficiently.

  Further, a power supply control box 54 is provided above the ceiling plate 4B, and a control board 56 corresponding to each LED module 44 is provided here. And from this control board 56, the electric power feeding line 58 is extended with respect to each LED module 44, and can supply electric power to each said LED module 44 now.

<Description of backside heating means>
Next, the back side heating means 34 will be described. First, a thick light transmission plate 62 made of, for example, a transparent quartz glass plate is airtightly attached to the opening of the bottom plate 4C by a fixture 66 through a seal member 64 such as an O-ring, and the back surface side heating means. 34 has a plurality of laser modules 60 arranged below the light transmission plate 62. Specifically, a laser mounting casing 61 is attached so as to cover the lower part of the light transmission plate 62 provided in the opening of the bottom plate 4C, and the plurality of laser modules 60 are attached and fixed to the laser mounting casing 61. ing.

  As shown in FIG. 4, the laser modules 60 are arranged so as to be distributed substantially evenly over the entire area of a size that can cover at least the entire back surface of the wafer W. In this case, the size of one laser module 60 is set to a size of, for example, about 50 mm × 60 mm × 25 mm, which is considerably larger than the LED module 44 and the output of one laser module 60 is large. Unlike the LED module 44, it is not necessary to provide it as closely packed.

  Accordingly, here, when the diameter of the wafer W is 300 mm, about 50 to 100 laser modules 60 are provided. Each laser module 60 has one laser element 68 and a cooling unit 70 as a cooling mechanism. Therefore, the laser element 68 is arranged over a region that can cover the entire back surface of the wafer W. The laser element 68 has a light emitting layer 72 sandwiched between two electrodes as shown in FIG. 5, and irradiation of laser light emitted from the light emitting layer 72, that is, heating light L1. The area 74 has an elliptical shape having a major axis in a direction perpendicular to the extending direction of the light emitting layer 72.

  In this case, the spreading angle of the heating light L1 in the major axis direction is about 30 to 50 degrees, and the spreading angle in the minor axis direction is 10 degrees or less. Therefore, in order to uniformly heat the back surface of the wafer W in the plane, it is preferable to set the major axis direction of the elliptical irradiation area 74 to be the radial direction of the wafer W as shown in FIG. . The emission wavelength of the laser element 68 is a specific wavelength within a range of ultraviolet light to near infrared light, for example, a range of 360 to 1000 nm, in particular, a range of 800 to 970 nm having a high absorption rate on the wafer W of the silicon substrate. It is preferable to use a specific wavelength (monochromatic light). As the laser element 68, for example, a semiconductor laser element using GaAs can be used. Here, the arrangement of the laser modules 60 shown in FIG. 4 is merely an example, and is not limited thereto.

  Returning to FIG. 1, a power feed line 76 is connected to each laser element 68 of the laser module 60 so as to feed power. The cooling units 70 of the laser module 60 are connected in series with each other through a refrigerant passage 78. A cooling medium introduction pipe 80 is connected to the cooling section 70 on the most upstream side, and a cooling medium discharge pipe 82 is connected to the cooling section 70 on the most downstream side. Is supposed to cool. As this refrigerant, water, Fluorinert or Galden (trade name) can be used.

  Further, a reflection surface 84 that has been subjected to a surface treatment or the like is formed on the inner side surface of the laser mounting casing 61, and the heating light reflected from the back side of the wafer W is again reflected upward. It is supposed to be. Here, the case where the laser module 60 in which the laser element 68 and the cooling unit 70 are integrated is described as an example, but a structure in which both are separated and provided separately may be employed.

  Control of the overall operation of the annealing apparatus 2 formed in this way, for example, various controls such as process temperature, process pressure, gas flow rate, on / off of the front side heating means 32 and the back side heating means 34, etc. are made of, for example, a computer. A computer-readable program executed by the control unit 86 and necessary for this control is stored in the storage medium 88. As the storage medium 88, for example, a flexible disk, a CD (Compact Disc), a CD-ROM, a hard disk, a flash memory, a DVD, or the like is used.

  Next, an annealing process performed using the annealing apparatus 2 configured as described above will be described. First, a semiconductor wafer W made of, for example, a silicon substrate is previously brought into a reduced-pressure atmosphere from a load-lock chamber or transfer chamber chamber (not shown) that has been previously in a reduced-pressure atmosphere by a transfer mechanism (not shown) through an opened gate valve 8. Into the processing container 4.

  On the surface of the wafer W, amorphous silicon, a metal, an oxide film, or the like as described above is formed, and a surface state in which various fine regions having different absorptances depending on the wavelength of the heating light are formed. . The loaded wafer W is transferred onto the support pins 12 provided on the elevating arm 14 by driving the elevating arm 14 up and down. After the transfer mechanism is retracted, the gate valve 8 is moved. Is closed to close the inside of the processing container 4.

Next, while controlling the flow rate from the gas pipe 20 of the gas supply means 16, a processing gas, for example, N ₂ gas or Ar gas is flowed here, and the inside of the processing container 4 is maintained at a predetermined pressure. At the same time, the front side heating means 32 provided on the ceiling plate 4B and the back side heating means 34 provided on the bottom plate 4C are both turned on, and the LED elements 46 and the back side heating means 34 of the front side heating means 32 are turned on. Both the laser elements 68 are turned on and irradiated with heating light from each of them, and the wafer W is heated from both the upper and lower surfaces and annealed. In this case, the process pressure is, for example, about 100 to 10000 Pa, the process temperature (wafer temperature) is, for example, about 800 to 1100 ° C., and the lighting time of the LED element 46 and the laser element 68 is about 1 to 10 seconds, respectively.

  As a result, the surface (upper surface) of the wafer W is irradiated with heating light having a certain width to the emission wavelength emitted from each LED element 46, so that the wafer W does not depend on the surface state of the wafer W. The surface side can be heated so that the in-plane temperature is substantially uniform.

  Further, monochromatic heating light is radiated from the laser elements 68 to the back surface (lower surface) of the wafer W, and an elliptical irradiation area 74 is formed on the back surface of the wafer W by the radiated light as shown in FIG. It is formed in a distributed state so as to be substantially uniform over the entire back surface of the wafer. In this case, the heating light L1 (see FIG. 5) emitted from the laser element 68 is monochromatic light as described above, but the back surface of the wafer W is in a uniform state on the silicon surface in this case. Moreover, the wavelength of the heating light L1 is set to a wavelength having a high absorption rate with respect to silicon, for example, a specific wavelength in the range of 360 to 1000 nm, more preferably a specific wavelength in the range of 800 to 970 nm. The back side of the wafer can be heated so that the in-plane temperature is substantially uniform. Therefore, it is possible to heat the wafer W evenly and quickly in a short time from the front surface side and from the back surface side with high uniformity of the in-plane temperature.

  Further, the laser element 68 (light conversion efficiency: 40 to 50%) used for the back surface side heating means 34 is more than the LED element 46 (light conversion efficiency: 10 to 30%) used for the front surface side heating means 32. Since energy conversion efficiency is high, it can contribute to energy saving rather than the case where a LED element is used as a back surface side heating means.

  Further, since the front surface side heating means 32 and the back surface side heating means 34 are heated from both the front and back (upper and lower) surfaces of the wafer W, there is almost no temperature distribution in the thickness direction of the wafer W, and the wafer It is possible to prevent W from being warped due to the temperature difference between the front and back surfaces.

  The element mounting head 36 is heated by a large amount of heat generated in the surface side heating means 32, and this is caused by flowing a refrigerant through the refrigerant passage 50 of the upper cooling mechanism 48 provided in the element mounting head 36. It can be cooled efficiently. Further, in this case, since the heat pipe 52 is provided along the height direction of the refrigerant passage 50 as shown in FIGS. 1 and 3, the heat conversion efficiency in this portion is increased, and accordingly, the above-described element is increased. The cooling efficiency of the mounting head 36 can be further increased. For example, when copper is used as the material of the element mounting head 36, the thermal conductivity is 300 to 350 W / m · deg, whereas the heat pipe 52 is provided to improve the thermal conductivity to 400 to 600 W / m · deg. Can be made.

  Similarly, a large amount of heat is also generated in the back surface side heating means 34, and the laser element 68 is heated. However, by generating a coolant through the cooling unit 70 serving as a cooling mechanism provided in each laser module 60, the above generation occurs. Since the heat thus discharged is discharged, each of the laser elements 68 can be efficiently cooled.

  Here, both the front side heating unit 32 and the back side heating unit 34 are provided. However, as described above, only the back side heating unit 34 may be provided without providing the front side heating unit 32. . In this case, the rate of temperature rise is slightly lower than when both the heating means 32 and 34 are provided, but in this case as well, the entire wafer W is rapidly heated in a state where the in-plane temperature is highly uniform. can do.

  As described above, in the annealing apparatus that performs the annealing process on the object to be processed, for example, the semiconductor wafer W, the back surface side heating unit 34 having the plurality of laser elements 68 that irradiate the heating light toward the entire back surface of the object to be processed. By providing and irradiating the laser beam as the heating light L1 from the back surface having a uniform surface state of the object to be processed, the object to be processed can be heated in a short time and with a uniform in-plane temperature. Also, the energy conversion efficiency can be increased to contribute to energy saving.

<Modification of heat pipe>
In the above embodiment, the heat pipe 52 provided in the element mounting head 36 is provided so as to be completely embedded outside the refrigerant passage 50 as shown in FIG. You may comprise as shown. FIG. 7 is an enlarged perspective view showing one refrigerant passage in the upper cooling mechanism of the element mounting head.

  Here, the upper end portion of the heat pipe 52 formed in a U-shape is exposed and provided at the upper portion in the refrigerant passage 50. A plurality (many) of such heat pipes 52 are arranged at a substantially equal pitch along the flow direction of the refrigerant passage 50. According to this, since the upper end portion of the heat pipe 52 is in direct contact with the refrigerant, the heat exchange rate for cooling can be further improved, and the cooling efficiency can be increased accordingly.

<Modified Embodiment>
Next, a modified embodiment of the annealing apparatus of the present invention will be described. In the previous embodiment, the position of the irradiation area 74 irradiated on the back surface of the semiconductor wafer W is fixed, and therefore there is a possibility that a slight temperature distribution occurs in the in-plane direction of the wafer W. Therefore, in this modified embodiment, the irradiation area 74 is configured to be relatively movable so that the uniformity of the wafer temperature in the in-plane direction is further improved. FIG. 8 is a partial configuration diagram showing the lower part of the processing vessel including the supporting means of the modified embodiment of the annealing apparatus of the present invention. 8, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  In order to move the irradiation area 74 relatively, here, the support means 10 for supporting the semiconductor wafer W is attached to the rotation mechanism 89 and is rotated. In other words, here, the support means 10 for supporting the wafer W is configured integrally with the rotating floating body 90 that forms a part of the rotating mechanism 89. The base end portion of each lifting arm 14 of the support means 10 is attached and fixed to a ring-shaped fixing member 92. The rotary levitation body 90 has a plurality of strip-shaped support pillars 93 extending in the vertical direction arranged in a ring shape at an equal pitch along the circumferential direction, and the upper end side of these levitation bodies 90 is formed in the cylindrical floating upper upper strength. The magnetic body 94 is connected, and the lower end side of each support post 93 is connected to a circular ring-shaped floating upper lower ferromagnetic body 96.

  The circular ring-shaped floating upper lower ferromagnetic body 96 extends in a flange shape in the horizontal direction. Further, the fixing member 92 is connected to the floating upper ferromagnetic body 94, and as a result, the wafer W is moved up and down in a state where the rotating floating body 90 is lifted up and down as will be described later. The support pin 12 that supports can be moved up and down.

  The bottom plate 4C of the lower part of the processing container 4 is a floating surface of a double cylindrical structure in which a space of a size capable of accommodating the rotary levitating body 90 and moving up and down by a predetermined stroke amount is formed. An accommodating portion 98 is connected. The lower portion of the floating housing portion 98 houses the floating upper lower ferromagnetic member 96 therein, and is a horizontal housing portion 100 having a size that allows the vertical movement.

  A plurality of levitation electromagnet assemblies 102 are arranged at a predetermined pitch on the upper surface side of the upper partition wall 100A that partitions the horizontal housing portion 100 in the circumferential direction. Further, a ferromagnetic body 104 is attached to the lower surface side of the upper partition wall 100A. Further, on the inner surface side (upper surface side) of the lower partition wall 100B that partitions the horizontal housing portion 100, a vertical position sensor is sandwiched with the floating lower ferromagnetic member 96 between the ferromagnetic member 104 and the floating member lower ferromagnetic member 96. 106 is attached.

  As a result, the supporting means 10 is adjusted to an arbitrary height by adjusting the electromagnetic force of the levitation electromagnet assembly 102 while the vertical position sensor 106 detects the height position of the floating lower ferromagnetic body 96. It can be set. In this case, a plurality of the vertical position sensors 106 are provided along the circumferential direction, and the tilt of the rotating levitated body 90 is prevented.

  Here, the rotation control is performed with the position where the rotary levitation body 90 is lifted, for example, 2 mm from the state of being in contact with the bottom plate side as a fixed position, and the position where the position is raised by 10 mm from the fixed position is a transfer position where the wafer W is transferred. It is in the loading position.

  A plurality of rotating electromagnet assemblies 108 are arranged at a predetermined pitch along the circumferential direction on the outer side of the outer peripheral wall 98A of the levitation accommodating portion 98. A ferromagnetic body 110 is attached to the inner side of the outer peripheral wall 98A. A horizontal position sensor 112 is attached to the outside of the inner peripheral wall 98 </ b> B of the floating housing portion 98 with the ferromagnetic body 110 with the floating upper ferromagnetic body 94 interposed therebetween. As a result, a rotating magnetic field is applied to the rotating electromagnet assembly 108 while detecting the position of the floating upper ferromagnetic body 94 by the horizontal position sensor 112, thereby rotating the rotating levitating body 90 in a fixed position. Can be done.

  In this way, the wafer W can be rotated while being supported on the rotating levitated body 90, so that the elliptical irradiation area 74 irradiated on the back surface of the wafer W as shown in FIG. Is relatively rotated in the circumferential direction of the wafer W, the uniformity of the in-plane temperature of the wafer W can be further improved.

  Further, by rotating the wafer W in this way, it is possible to cancel the non-uniformity of the thermal condition in the circumferential direction of the inner wall surface of the processing container 4, so that the in-plane temperature of the wafer W is also uniform from this point. The property can be further improved. The configuration of the rotation mechanism 89 is merely an example, and is not limited thereto. For example, a rotation mechanism disclosed in JP-A-2002-280318 may be used. Furthermore, the semiconductor wafer W side is rotated here, but instead, the back surface side heating means 34 side may be rotated.

<Modification of cooling mechanism>
In the above-described upper cooling mechanism 48, heat is taken from the upper surface side of the LED module 44 by flowing the refrigerant through the refrigerant passage 50, and this is cooled. The cross-sectional area of the channel having a rectangular cross section is set to be constant along the flow direction of the refrigerant passage 50. Therefore, in the portion close to the refrigerant inlet, the refrigerant is from the LED module 44 side that is the object to be cooled. Although cooling is efficiently performed with sufficient heat removal, it is conceivable that the cooling efficiency gradually decreases as the refrigerant flows downstream.

  For this reason, since the cooling efficiency changes along the flow direction of the refrigerant passage 50, there is a concern that the temperature distribution is generated according to the arrangement position of the LED modules 44 that are the objects to be cooled and the temperature becomes non-uniform. there were. That is, the LED modules 44 arranged on the upstream side of the refrigerant passage 50 are efficiently cooled, whereas the LED modules 44 arranged on the downstream side are not efficiently cooled, and the entire LED module 44 is There was a concern that temperature distribution would occur.

  Therefore, in this modification of the cooling mechanism, in order to remove the fear, the flow passage cross-sectional area is set so as to gradually decrease from the refrigerant inlet 51 to the refrigerant outlet 53 of the refrigerant passage 50. The cooling efficiency is made constant along the flow direction of the refrigerant passage 50 so that the temperature of the whole cooling object is kept constant so that the temperature does not become uneven.

  Here, the principle for making the cooling efficiency constant along the flow direction of the refrigerant passage 50 and making the temperature of the cooling object constant will be described. FIG. 9 is a schematic view for determining the temperature change of the refrigerant in a minute section in the length direction of the refrigerant passage. Here, in order to facilitate understanding of the present invention, the width of the refrigerant passage is constant (unit length = 1 m), and the height of the refrigerant passage is expressed as a function “f (x)”. In FIG. 9, the horizontal axis “x” indicates the distance from the refrigerant inlet 51 to the refrigerant outlet 53, and the vertical axis “y” indicates the height “f (x)” of the refrigerant passage 50.

  It is assumed that the refrigerant flows from the refrigerant inlet 51 toward the refrigerant outlet 53 at a flow rate “Q”. And the temperature of the refrigerant | coolant in the position of distance "x" is represented as "T (x)." Here, if the condition that the temperature of the bottom surface of the refrigerant passage 50 along the x axis is constant at To is satisfied, the temperature of the object to be cooled can be maintained constant along the flow direction of the refrigerant passage 50.

  First, the heat transfer coefficient h of the refrigerant is expressed as in the following Equation 1, and if it is considered that there is not much temperature change, it can be set as a constant A except for the speed of the refrigerant, and can be regarded as a function of only the speed. .

h = 0.664 (ρ ^1/2 ) (μ ^−1/6 ) (cp ^1/3 ) (k ^2/3 ) (L ^−1/2 ) (u ^1/2 ) (1)
Here, the above symbols are as follows.
ρ: Density of refrigerant (kg / m ³ )
μ: Viscosity of refrigerant (kg / m · sec)
cp: Specific heat of refrigerant (J / kg · K)
k: Refrigerant thermal conductivity (W / m · K)
L: Cooling part length (m)
u: Refrigerant speed (m / sec)

Further, a constant A is defined as follows.
0.664 (ρ ^1/2 ) (μ ^−1/6 ) (cp ^1/3 ) (k ^2/3 ) (L ^−1/2 ) = A (constant)
In FIG. 9, when the amount of heat flowing into the refrigerant when the refrigerant advances by Δx is “W”, the following equation 2 is obtained.

W = {T (x + Δx) −T (x)} · cp · ρ · Δx · f (x)
= A · Δx · (To−T (x)) · Δt√u (x) (2)
cp: Refrigerant specific heat ρ: Refrigerant density u (x): Refrigerant flow velocity at position x Δt: Time required for the refrigerant to travel Δx A: Constant for obtaining heat transfer coefficient

Here, when the above equations are summarized as Δt / Δx = 1 / u (x) and u (x) = Q / f (x), the following equation 3 is obtained.
cp · ρ · (T (x + Δx) −T (x)) / Δx = A · (To−T (x)) / √ (Q · f (x)) (3)
If the above formula 3 is arranged, the following formula 4 is obtained.
f (x) = A ² · (To−T (x)) ² / (Q · cp ² · ρ ² · (T ′ (x)) ² ) (4)
Note that “T ′ (x) = (T (x + Δx) −T (x)) / Δx”.

  As described above, the height function f (x) of the refrigerant passage 50 is dependent on the temperature change T (x) of the refrigerant. In other words, if the temperature change is determined, the height of the refrigerant passage 50 is naturally determined.

Here, using a specific numerical example, when substituting into Equation 4 above, Equation 5 is obtained. Specific numerical examples are as follows.
Refrigerant flow rate Q: 2 liters / min (= 2 × 10 ⁻³ / 60 m ³ / sec)
Target temperature To: 100 ° C
Refrigerant passage width: 10mm
Length of refrigerant passage: 5m
Assuming that the medium inlet temperature: −50 ° C., the medium outlet temperature: −40 ° C., and the temperature change changes temporarily, “T (x) = 2 · x−50”.
Specific heat of refrigerant cp: 1000 J / kg · K
Refrigerant density ρ: 1800 kg / m ³
Constant A: 230
In the calculation of the numerical example, the refrigerant flow rate Q is converted into the unit [m ³ / sec] in consideration of the unit and the width of the refrigerant passage. As described above, the width of the refrigerant passage is the unit in the simulation as described above. Since the length is set to 1 m (= 1000 mm), f (x) is multiplied by 1/100 to convert this into the width of the refrigerant passage of 10 mm.

f (x) = 230 ² · [100− (2 · x−50)] ² / [(2 × 10 ⁻³ / 60) × 1000 ² × 1800 ² × 2 ² × 100] (5)

  Here, the above equation 5 is represented in a graph as shown in FIG. That is, at the refrigerant inlet 51 of the refrigerant passage 50, the height of the refrigerant passage 50 is set to about 27.6 mm, and the height of the refrigerant passage 50 is sequentially reduced according to the distance from the refrigerant inlet 51 to increase the flow passage cross-sectional area. The height of the refrigerant passage 50 is set to about 24 mm at the refrigerant outlet 53.

An example of the change in the height of the cross-sectional shape of the refrigerant passage 50 at this time is shown as shown in FIG. 11, and the height of the refrigerant passage 50 is gradually lowered toward the downstream side. In this case, it goes without saying that the flow rate of the refrigerant gradually increases as it goes downstream.
In this way, by setting the height of the refrigerant passage 50 to be gradually lower toward the downstream side (when the width of the refrigerant passage 50 is constant), the temperature of the lower surface of the refrigerant passage 50 is set to 10 ° C. (= To ) Can be kept constant.

  In the above specific example, the case where the width of the refrigerant passage 50 is made constant has been described. However, when the height of the refrigerant passage 50 is made constant, the width of the refrigerant passage 50 is gradually reduced to gradually increase the cross-sectional area of the flow path. It will be narrowed. Of course, the above numerical examples are merely examples, and the present invention is not limited thereto.

  In this way, by setting the flow passage area of the refrigerant passage 50 to be gradually reduced from the refrigerant inlet 51 toward the refrigerant outlet 53, the unit length of the refrigerant passage 50 taken by the refrigerant from the object to be cooled, for example, the LED module 44. The amount of heat per unit is constant, and as a result, the temperature of the object to be cooled can be made uniform along the length direction of the refrigerant passage 50.

  In the above description, the semiconductor element using GaAs, for example, is used as the laser element 68. However, the present invention is not limited to this, and other solid-state laser elements such as a YAG laser element and a garnet laser element may be used. Of course, a gas laser element can also be used. Although the case where the LED element 46 is used as the surface side heating unit 32 is described as an example here, the present invention is not limited to this, and an SLD (Super Luminescent Diode) element can be used.

  Although the semiconductor wafer is described as an example of the object to be processed here, the semiconductor wafer includes a silicon substrate and a compound semiconductor substrate such as GaAs, SiC, GaN, and the like, and is not limited to these substrates. The present invention can also be applied to glass substrates, ceramic substrates, and the like used in display devices.

It is sectional drawing which shows schematic structure of the annealing apparatus which concerns on this invention. It is a top view which shows the surface (lower surface) of a surface side heating means. It is an expanded sectional view which shows the A section in FIG. 1 which is a part of surface side heating means. It is a top view which shows the surface (upper surface) of a back surface side heating means. It is an expanded explanatory view explaining the light emission state of a semiconductor laser element. It is a schematic diagram which shows the irradiation state of the laser beam (heating light) from a laser element. It is an expansion perspective view which shows one refrigerant path in the upper side cooling mechanism of an element attachment head. It is a partial block diagram which shows the lower part of the processing container containing the support means of the deformation | transformation embodiment of the annealing apparatus of this invention. It is a schematic diagram for calculating | requiring the temperature change of the refrigerant | coolant of the micro area in the length direction of a refrigerant path. It is a graph which shows the height function f (x) of a refrigerant path. It is a figure which shows an example of the height change of the cross-sectional shape of a refrigerant path.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Annealing apparatus 4 Processing container 10 Support means 16 Gas supply means 24 Exhaust means 30 Exhaust pump 32 Surface side heating means 34 Back surface side heating means 36 Element attachment head 44 LED module 45 Light transmission window 46 LED element 48 Upper cooling mechanism 50 Refrigerant passage 51 Refrigerant Inlet 52 Heat Pipe 53 Refrigerant Outlet 60 Laser Module 62 Light Transmission Window 68 Laser Element 70 Cooling Unit (Cooling Mechanism)
72 Light emitting layer 74 Irradiation area 84 Reflecting surface 89 Rotating mechanism 90 Rotating levitated body 102 Levitation electromagnet assembly 108 Rotating electromagnet assembly W Semiconductor wafer (object to be processed)

Claims (13)

In an annealing apparatus that performs an annealing process on a workpiece,
A processing container in which the object to be processed is accommodated;
A support means for supporting the object to be processed in the processing container;
Gas supply means for supplying a processing gas into the processing container;
Exhaust means for exhausting the atmosphere in the processing vessel;
Back surface side heating means having a plurality of laser elements that irradiate heating light toward the entire back surface of the object to be processed;
An annealing apparatus comprising: The annealing apparatus according to claim 1, wherein the plurality of laser elements are arranged over a region having a size capable of covering at least the entire back surface of the object to be processed. The annealing apparatus according to claim 1 or 2, wherein the laser element comprises a semiconductor laser element, a solid-state laser element, or a gas laser element. The annealing apparatus according to any one of claims 1 to 3, wherein the heating light generated by the laser element is in a wavelength band capable of selectively heating a silicon substrate. 5. Either one of the said support means and the said back surface side heating means is supported so that rotation is possible, and it has a rotation mechanism which rotates this, It is any one of Claim 1 thru | or 4 characterized by the above-mentioned. The annealing apparatus according to item. 6. The apparatus according to claim 1, further comprising a front-side heating unit that is disposed to face the back-side heating unit and irradiates heating light toward the surface of the object to be processed. An annealing apparatus as described in 1. The surface-side heating means includes a plurality of LED (Light Emitting Diode) elements or SLD (Super Luminescent Diode) elements arranged over a region that can cover at least the entire surface of the object to be processed. The annealing apparatus according to any one of claims 1 to 6, characterized in that: The cooling mechanism for cooling with a refrigerant is provided in at least one of the backside heating means and the frontside heating means. Annealing equipment. The cooling mechanism has a refrigerant passage for flowing the refrigerant, and the refrigerant passage is set so that a cross-sectional area of the flow passage gradually decreases from the refrigerant inlet toward the refrigerant outlet. An annealing apparatus according to claim 8. The width of the refrigerant passage is constant, and the height of the refrigerant passage is determined based on the flow rate of the refrigerant, the specific heat of the refrigerant, the density of the refrigerant, and the distance from the refrigerant inlet. Item 10. An annealing apparatus according to Item 9. The annealing apparatus according to claim 10, wherein a height f (x) of the refrigerant passage is given by the following expression.
f (x) = A ² · (To−T (x)) ² / (Q · cp ² · ρ ² · (T ′ (x)) ² )
A: Constant for obtaining heat transfer coefficient Q: Flow rate of refrigerant cp: Specific heat of refrigerant ρ: Density of refrigerant x: Distance from refrigerant inlet T (x): Temperature (function) of refrigerant at distance x
T ′ (x): differentiation of function T (x) To: target temperature The annealing apparatus according to any one of claims 8 to 11, wherein the cooling mechanism includes a plurality of heat pipes that promote cooling. The annealing apparatus according to any one of claims 1 to 12, wherein a reflective surface is formed on the back surface side heating means.

Images