JP2009164483A - Method of manufacturing semiconductor device, and semiconductor substrate processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a semiconductor substrate processing device improved in a temperature transition characteristic in raising/lowering the temperature of the semiconductor substrate, and temperature uniformity in a substrate surface; and a method of manufacturing a semiconductor device. <P>SOLUTION: Heaters 6 are incorporated in a pedestal 4 heating a semiconductor substrate 1, and thermometers 9 are incorporated in a thermally-conductive plate 5 installed in contact with a surface of the pedestal 4 at positions facing the heaters 6. Based on a measurement temperature measured with the thermometers 9 by a temperature control unit 10 with the facing surfaces of the semiconductor substrate 1 and the thermally-conductive plate 5 held in parallel to each other at a certain minute distance by support bodies 7, and a preset set temperature, contact pressure between the pedestal 4 and the thermally-conductive plate 5 is adjusted by controlling fixing screws 2 and motors 3 along with temperature control of the heaters 6 to set the measurement temperature at the set temperature. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device and a semiconductor substrate processing apparatus, and for example, relates to a method for manufacturing a semiconductor device and a semiconductor substrate processing apparatus applied when performing a baking process on a semiconductor substrate in a pattern forming process.

  In the pattern forming process of semiconductor substrate processing, a lithography technique is used for converting designed circuit pattern layout information into a resist pattern necessary for fine processing. In this lithography technique, a resist that is a photosensitive resin is applied to a semiconductor substrate (wafer). When a chemically amplified resist is used, a circuit pattern is exposed on the resist on the wafer, and then the wafer is baked to form a resist. Sub-steps such as a step of promoting the internal reaction and a step of developing the exposed resist are included.

  Of the above-described sub-processes, a wafer heating apparatus is used in a baking process in which a wafer is baked after a resist is applied or a pattern is exposed on a resist film (for example, Patent Document 1). reference.). FIG. 5 is a schematic sectional view showing a conventional wafer heating apparatus.

  The wafer heating apparatus shown in FIG. 5 is used in a photolithography process (hereinafter referred to as a photolithography process) in a recent semiconductor manufacturing process of 250 nm node to 45 nm node. In such a photolithography process of the semiconductor manufacturing process, a chemically amplified resist for KrF or ArF excimer lithography is employed, and after exposure, the wafer is baked by this wafer heating apparatus. The baking promotes the dehydration reaction between the acid generated in the exposed resist film and the hydroxyl portion of the resin that is the resist substrate. The portion where the dehydration reaction has occurred becomes soluble in the developer.

  As shown in FIG. 5, the conventional wafer heating apparatus includes a pedestal 4 on which the wafer 1 is placed. Inside the pedestal 4, a heater 6 for heating the wafer 1 and a thermometer 9 made of a thermocouple, a resistance temperature sensor, and the like are embedded. The temperature control unit 10 controls the temperature of the pedestal 4 by changing the voltage applied to the heater 6 based on the temperature information from the thermometer 9.

  A hot plate cover 8 made of a material such as stainless steel or aluminum is provided around the base 4. The hot plate cover 8 has a function of transmitting the heat generated and propagated by the base 4 (heater 6) to the wafer 1 by radiant heat. The wafer 1 is placed on a plurality of gap pins 7 arranged on the peripheral edge of the upper surface of the pedestal 4, and a very narrow gap interposed between the back surface of the wafer 1 and the surface of the pedestal 4. The wafer 1 is indirectly heated from the pedestal 4 via.

In this way, the wafer 1 receives radiation from the hot plate cover 8 and heat supply from the pedestal 4 under temperature control by the temperature control unit 10. In this wafer heating apparatus, air is supplied from the gap 11 between the pedestal 4 and the hot plate cover 8, and the air is exhausted from the exhaust port 12 provided at the center of the hot plate cover 8. ing.
JP 2006-245505 A

  By the way, the pattern size after development when a circuit pattern is exposed to a wafer coated with a chemically amplified resist and then subjected to a baking process, followed by a development process, considering the reaction mechanism in the resist after the exposure, It is determined by how much heat is received in the baking process, that is, an integrated temperature which is a time integral of the temperature. In order to stably manufacture recent semiconductor integrated circuits having fine pattern dimensions such as 65 nm and 45 nm, it has become more severely required to stably form resist dimensions. For this purpose, not only the baking temperature itself but also integration is required. It is necessary to precisely control the temperature.

  However, in the conventional wafer heating apparatus as shown in FIG. 5, the only parameter used for temperature control is the power (voltage or current) supplied to the heater 6. For this reason, there is a problem that it is difficult to control the transient characteristics when the wafer 1 is heated and lowered by temperature control, that is, the rate of change in temperature. The reason is that the temperature response when the temperature detected by the thermometer 9 is input to the temperature control unit 10 and the temperature control unit 10 controls the electric power of the heater 6 based on the detected temperature to reach a predetermined temperature is so fast. This is because there are also factors such as individual differences in the thermometer 9.

  Thus, in the conventional apparatus, the poor controllability of the transient characteristic when the temperature is raised or lowered means that the controllability of the set temperature itself is finally bad. Therefore, the range of temperature uniformity required to stably form a pattern of a 65 nm and 45 nm node semiconductor integrated circuit using a highly temperature-dependent resist such as a chemically amplified resist is ± 0.05. It is difficult to realize a temperature control of less than 0 ° C. with a conventional wafer heating apparatus.

  For example, when the rate of temperature rise at the center of the wafer 1 that is temperature-controlled is 2.5 ° C./second, the rate of temperature rise at the outer periphery of the wafer 1 is the flow rate of air in the hot plate cover 8 or The temperature is about 2.0 ° C./second due to variations in temperature control due to the characteristics of the heater 6 and the thermometer 9 and the difference in the amount of heat radiation from the hot plate cover 8. Further, when the heater 6 is controlled only by electric power, it is difficult to control the entire surface of the wafer 1 uniformly as described above. For example, the range of temperature uniformity within the wafer surface is ± 0.2 ° C. Degree. Due to such a difference in temperature increase rate and temperature variation in the wafer surface, for example, the dimensional variation after development in a resist having high temperature dependency reaches ± 0.4 nm. When this variation occurs in the gate electrode of a MOS transistor, it becomes impossible to satisfy uniform transistor performance within the wafer surface.

  SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and improves the temperature during semiconductor substrate processing by improving the temperature transient characteristics when the semiconductor substrate is raised and lowered and the temperature uniformity within the substrate surface. An object of the present invention is to provide a method for manufacturing a semiconductor device and a semiconductor substrate processing apparatus.

  In order to achieve the above object, the present invention employs the following technical means. That is, in the method for manufacturing a semiconductor device according to the present invention, first, a resist film is formed on the surface of the semiconductor substrate. Next, a predetermined pattern is exposed on the resist film on the semiconductor substrate. The exposed semiconductor substrate is arranged in parallel to the surface of the heat conduction plate at a certain distance from the heat conduction plate installed on the surface of the pedestal containing the heater. Then, the semiconductor substrate is heated. At this time, the amount of heat transferred from the heater to the semiconductor substrate is adjusted by adjusting the contact pressure between the heat conductive plate and the pedestal based on the temperature of the heat conductive plate at the position corresponding to the heater. The resist film is developed after heating to form a resist pattern.

  According to this configuration, during the heat treatment of the semiconductor substrate, not only the temperature control of the heater but also the contact pressure between the pedestal and the heat conducting plate can be adjusted. The amount of heat transmitted (temperature transmission speed) can be adjusted in a very short time. In addition, since the number of temperature control items is increased as compared with the prior art, the in-plane temperature uniformity of the semiconductor substrate can be further improved. As a result, the quality of the semiconductor device can be improved.

  In the heating step, the contact pressure between the pedestal and the heat conducting plate is adjusted, for example, to a state where the measured temperature becomes a preset temperature. Further, the contact pressure between the pedestal and the heat conductive plate may be adjusted to a state in which the temporal change rate of the measured temperature calculated from the measured temperature is constant. In this case, since the temperature transient characteristic at the time of raising and lowering the temperature of the semiconductor substrate can be made constant, the integrated temperature can be controlled precisely, and the dimensional accuracy of the circuit pattern can be further increased.

  Further, the temperature of the heat conduction plate is measured at a plurality of different locations in a plane parallel to the semiconductor substrate, and a pedestal and a heat conduction plate at a position corresponding to each temperature measurement location according to each measured temperature. It is preferable to employ a configuration that adjusts the contact pressure with the. Thereby, the temperature control of the semiconductor substrate is further facilitated, and the temperature control accuracy can be further increased.

  In another method for manufacturing a semiconductor device according to the present invention, a resist film is first formed on the surface of a semiconductor substrate. Next, a predetermined pattern is exposed on the resist film on the semiconductor substrate. The exposed semiconductor substrate is arranged in parallel to the surface of the heating block at a certain distance from the surface of the heating block incorporating the heater. Then, the semiconductor substrate is heated. At this time, the heater is moved by adjusting the distance between the semiconductor substrate and the heating block by moving the heating block based on the temperature of the heating block between the semiconductor substrate and the heater at a position corresponding to the heater. The amount of heat transferred from the semiconductor substrate to the semiconductor substrate is adjusted. The resist film is developed after heating to form a resist pattern.

  According to this configuration, during the heat treatment of the semiconductor substrate, not only the temperature control of the heater but also the distance between the semiconductor substrate and the heating block can be adjusted. It is possible to adjust the amount of heat (temperature transmission speed) transmitted to the heat in a very short time. In addition, since the number of temperature control items is increased as compared with the prior art, the in-plane temperature uniformity of the semiconductor substrate can be further improved. As a result, the quality of the semiconductor device can be improved.

  In the heating step, the distance between the semiconductor substrate and the heating block is adjusted to a state in which the measured temperature becomes a preset temperature, for example. Further, the distance between the semiconductor substrate and the heating block may be adjusted so that the temporal change rate of the measured temperature calculated from the measured temperature is constant. In this case, since the temperature transient characteristic at the time of raising and lowering the temperature of the semiconductor substrate can be made constant, the integrated temperature can be controlled precisely, and the dimensional accuracy of the circuit pattern can be further increased.

  Furthermore, it is possible to employ a configuration in which a plurality of the heating blocks are arranged at positions facing the semiconductor substrate, and the distance between the semiconductor substrate and each heating block is adjusted according to each temperature measured in each heating block. preferable. Thereby, the temperature control of the semiconductor substrate is further facilitated, and the temperature control accuracy can be further increased.

  The semiconductor device manufacturing method described above is particularly suitable when the resist film is a chemically amplified resist film because it can be controlled so that the temperature range in the semiconductor substrate surface is ± 0.05 ° C. or less. is there.

  On the other hand, in another aspect, the present invention can provide a semiconductor substrate processing apparatus that heats and heat-treats a semiconductor substrate. In other words, a semiconductor substrate processing apparatus according to the present invention includes a pedestal with a built-in heater for heating a semiconductor substrate. A heat conducting plate is installed on the surface of the pedestal. Further, the heat conducting plate incorporates temperature measuring means corresponding to the heater. The semiconductor substrate is held parallel to the surface of the heat conducting plate by a support at a certain distance from the surface of the heat conducting plate. Further, the semiconductor substrate processing apparatus includes a contact pressure adjusting unit that adjusts a contact pressure between the pedestal and the heat conducting plate, and a control unit that controls the contact pressure adjusting unit based on the temperature measured by the temperature measuring unit. With.

  According to this semiconductor substrate processing apparatus, during the heat treatment of the semiconductor substrate, the contact pressure between the pedestal and the heat conducting plate can be adjusted not only by the heater temperature control but also by the contact pressure adjusting means. The amount of heat (temperature transmission speed) transmitted from the heater to the semiconductor substrate can be adjusted in a very short time. Further, since the number of temperature control items is increased as compared with the conventional case, the in-plane temperature uniformity of the semiconductor substrate can be further improved, and the quality of the semiconductor device can be improved.

  In this semiconductor substrate processing apparatus, for example, the control means adjusts the contact pressure between the pedestal and the heat conducting plate so that the temperature measured by the temperature measuring means becomes a preset temperature. The control means may adjust the contact pressure between the pedestal and the heat conducting plate so that the temporal change rate of the measured temperature calculated from the temperature measured by the temperature measuring means is constant.

  Further, as the contact pressure adjusting means, for example, by adopting a configuration including a fixing screw screwed to the pedestal and a motor that rotationally drives the fixing screw, the pedestal and the heat conduction can be made with a simple and inexpensive configuration. The contact pressure with the plate can be adjusted. Further, it is preferable that the temperature measuring means is distributed and arranged at a plurality of locations in the surface facing the semiconductor substrate, and the heater and the contact pressure adjusting means are provided corresponding to each of the plurality of temperature measuring means.

  In addition, another semiconductor substrate processing apparatus according to the present invention includes a heating block including a heater for heating the semiconductor substrate. The semiconductor substrate is held parallel to the surface of the heating block by a support at a certain distance from the surface of the heating block. In the heating block between the semiconductor substrate held on the support and the heater, temperature measuring means corresponding to the heater is incorporated. Further, the semiconductor substrate processing apparatus is measured by a position adjusting unit that changes a distance between the semiconductor substrate held on the support and the heating block by moving the position of the heating block, and the temperature measuring unit. Control means for controlling the position adjusting means based on the measured temperature.

  According to the present semiconductor substrate processing apparatus, during the heat treatment of the semiconductor substrate, not only the temperature control of the heater but also the distance between the semiconductor substrate held on the support by the position adjusting means and the heating block can be adjusted. When the temperature is raised or lowered with respect to the substrate, the amount of heat (temperature transmission speed) transmitted from the heater to the semiconductor substrate can be adjusted in a very short time. Further, since the number of temperature control items is increased as compared with the conventional case, the in-plane temperature uniformity of the semiconductor substrate can be further improved, and the quality of the semiconductor device can be improved.

  In this semiconductor substrate processing apparatus, the control means, for example, sets the distance between the semiconductor substrate held on the support and the heating block so that the temperature measured by the temperature measurement means becomes a preset temperature. adjust. Further, the control means adjusts the distance between the semiconductor substrate held on the support and the heating block so that the temporal change rate of the measured temperature calculated from the temperature measured by the temperature measuring means is constant. May be.

  Further, as the position adjusting means, for example, by adopting a configuration including a fixing screw fixed to the heating block and a motor that rotationally drives the fixing screw, the pedestal and the heat conducting plate can be configured with a simple and inexpensive configuration. The contact pressure with can be adjusted. Furthermore, it is preferable that a plurality of the heating blocks are arranged at positions facing the semiconductor substrate, and each of the plurality of heating blocks includes the heater, the temperature measuring unit, and the position adjusting unit.

  According to the present invention, since the temperature transmission speed can be controlled in a very short time, it is possible to make the in-plane temperature distribution extremely uniform when the temperature of the semiconductor substrate rises and falls when the semiconductor substrate is heat-treated. it can. In addition, since more control items are required than in the prior art, more accurate wafer in-plane temperature uniformity can be realized. As a result, not only the baking temperature during the heat treatment but also the integrated temperature can be precisely controlled, and the quality of the semiconductor device can be improved.

  In particular, according to the present invention, since the temperature uniformity range within the semiconductor substrate surface can be controlled to ± 0.05 ° C. or less, the progress of the reaction in the chemically amplified resist film during the heat treatment is uniform and constant. Can be. Therefore, the pattern dimensional accuracy after development can be improved, and a fine resist pattern can be stably formed even in a semiconductor manufacturing process of 65 nm node and 45 nm node.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the semiconductor substrate processing apparatus of the present invention is embodied as a wafer heating apparatus.

(First embodiment)
FIG. 1 is a longitudinal sectional view showing a wafer heating apparatus according to the first embodiment of the present invention, and FIG. 2 is a transverse sectional view showing a pedestal portion of the apparatus. In FIG. 1 and FIG. 2, the same code | symbol is attached | subjected to the component corresponding or equivalent to the prior art shown in FIG.

  As shown in FIG. 1, the wafer heating apparatus of the present embodiment includes a disk-shaped pedestal 4 having an outer diameter slightly larger than a semiconductor substrate 1 to be processed (hereinafter referred to as a wafer 1), A disk-shaped heat conduction plate 5 having an outer diameter substantially the same as that of the pedestal 4 is provided in contact with the upper surface of the pedestal 4. The heat conductive plate 5 and the pedestal 4 are configured separately, but both can be formed of a material such as aluminum, copper, and stainless steel. In this embodiment, the thickness of the base 4 is 1-5 cm, and the thickness of the heat conductive plate 5 is about 0.5-3 cm.

  A plurality of ring-shaped heaters 6 formed of nichrome wire or the like for baking the wafer 1 (heating process) are built in the pedestal 4. A thermometer 9 made of a thermocouple or a resistance thermometer is embedded in the heat conduction plate 5 at a position facing each heater 6. As shown in FIG. 2, in the present embodiment, nine heaters 6 are arranged at equal intervals around the axis position of the base 4 and its axis. 2 is a cross-sectional view in a plane including the heater 6 of FIG. 1, and the pedestal 4 shows only the outer shape.

  As shown in FIG. 1, a plurality of columnar supports 7 (hereinafter referred to as gap pins 7) are arranged concentrically with the heat conductive plate 5 at the peripheral edge of the upper surface of the heat conductive plate 5. The wafer 1 is placed on the gap pins 7 with the back surface substantially in point contact. In addition, a gap of about 0.1 to 0.5 mm is secured between the wafer 1 supported by the gap pins 7 and the heat conducting plate 5, and substantially heat radiation and heat via air existing in the gap are secured. The wafer 1 is heated by conduction. The gap pins 7 may be any number and shape as long as they can support the wafer 1 in parallel with the surface of the heat conducting plate 5.

  The periphery of the base 4 and the heat conductive plate 5 is covered with a hot plate cover 8 made of stainless steel or aluminum. The distance between the surface of the wafer 1 and the inner surface of the hot plate cover 8 is about 1 to 3 cm. In the wafer heating apparatus of the present embodiment, air is supplied from the base 4 and the gap 11 between the heat conducting plate 5 and the hot plate cover 8 and passes over the surface of the wafer 1, so that the hot plate cover 8 Air is discharged to the outside from the opening 12 formed in the center. This air flow is used for adjusting the amount of radiant heat from the hot plate cover 8 to the wafer 1 and for cooling when changing the temperature of the wafer heating device to a low temperature.

  Furthermore, in this wafer heating apparatus, a fixing screw 2 connected to the rotating shaft of the motor 3 and the motor 3 is provided corresponding to each heater 6. The motor 3 and the fixing screw 2 constitute contact pressure adjusting means for adjusting the contact pressure between the base 4 and the heat conducting plate 5. Each fixing screw 2 is screwed into a screw hole formed through the ring center of the heater 6 and the pedestal 4, and reaches the inside of the heat conducting plate 5. An enlarged diameter portion 2a having an increased diameter is provided. The enlarged diameter portion 2 a is loosely fitted in the heat conducting plate 5. This prevents the fixed diameter portion 2a of the fixing screw 2 from coming off from the heat conducting plate 5 and rotates the motors 3 to give a fixed torque to the fixing screw 2 so that the pedestal 4 and the heat conducting plate can be provided. 5 can be fastened together. Further, by adjusting the torque applied to the fixing screw 2, the contact pressure between the pedestal 4 and the heat conducting plate 5 can be adjusted, and when the torque of the fixing screw 2 is loosened, the pedestal 4 and the heat conducting plate 5 It is also possible to form a gap between them. In the present embodiment, the positions of the base 4 and the motor 3 are fixed by a fixing member (not shown).

  The baking process of the wafer 1 using the wafer heating apparatus having the above-described configuration is performed as follows. When the wafer 1 is placed on the gap pins 7 and the baking process is started, first, the temperature control unit 10 supplies power to the heater 6. And the temperature control unit 10 acquires the temperature measured by each thermometer 9 arrange | positioned inside the heat conductive board 5, for example at the predetermined time interval set beforehand. At this time, the temperature control unit 10 compares a set temperature stored in an internal memory (not shown) with the acquired measured temperature.

  As a result, when the measured temperature at a specific location of the heat conducting plate 5 is lower than the set temperature, the temperature control unit 10 supplies electric power (voltage or current) to be applied to the heater 6 at the position corresponding to the thermometer 9. Increase the temperature of the specific part of the pedestal 4. At the same time, the temperature control unit 10 drives the motor 3 installed corresponding to the heater 6 at the specific location to increase the tightening of the fixing screw 2, and the pedestal 4 and the heat conduction plate 5 at the specific location are connected. Increase contact pressure. Thereby, since the heat from the heater 6 is more efficiently conducted to the heat conducting plate 5, the temperature of the wafer 1 rises more quickly.

  On the other hand, when the measured temperature at a specific location of the heat conducting plate 5 is higher than the set temperature, the temperature control unit 10 supplies electric power (voltage or current) to be applied to the heater 6 at the position corresponding to the thermometer 9. Decrease or shut off and lower the temperature at that particular location on the pedestal 4. At the same time, the motor 3 installed corresponding to the heater 6 at the specific location is driven to loosen the fixing screw 2 and the contact pressure between the base 4 and the heat conducting plate 5 at the specific location is reduced. As a result, heat from the heater 6 is less likely to be conducted to the heat conducting plate 5, and the temperature of the wafer 1 is lowered more quickly.

  In this way, it is mounted on the gap pin 7 by heat radiation from the heat conduction plate 5 through the contact portion between the base 4 and the heat conduction plate 5, heat conduction through the air in the gap, and radiation heat from the heat plate cover 8. The temperature of the placed wafer 1 is controlled. Although not particularly limited, in this embodiment, the contact surface between the pedestal 4 and the heat conducting plate 5 is formed by a rough surface (for example, the surface roughness Ra is 2 μm or more and 20 μm or less). Thereby, the control range of the temperature transmission speed can be widened.

  As described above, in this embodiment, when controlling the temperature of the wafer 1, in addition to controlling the amount of power input to the heater 6 provided on the pedestal 4, the motor 3 adjusts the rotational torque of the fixing screw 2. The contact pressure between the base 4 and the heat conducting plate 5 is controlled. For this reason, compared with the case where only the control of the power input amount to the heater 6 is performed, the amount of heat transferred from the pedestal 4 to the heat conducting plate 5 (heat transfer speed from the pedestal 4 to the heat conducting plate 5) is reduced in a short time. Can be controlled within. As a result, it is possible to realize temperature control that is constant within the wafer surface even to transient characteristics in temperature control such as temperature increase rate and temperature decrease rate, and the temperature uniformity of the wafer 1 is improved as compared with the conventional case. The integrated temperature can also be precisely controlled.

  As a result of examining the temperature characteristics of the wafer implemented by this wafer heating apparatus, for example, the range of temperature uniformity within the wafer surface is ± 0.05 ° C., and the temperature rise rate at the center of the wafer is 2 ° C. When the temperature was 0.5 ° C./second, the rate of temperature rise at the outer periphery of the wafer was 2.4 ° C./second. From this, it can be understood that according to the configuration of the present embodiment, the transient characteristics at the time of raising and lowering the temperature are improved as compared with the conventional configuration shown in FIG.

  If the wafer heating apparatus of this embodiment is applied to a baking process after exposing a chemically amplified resist applied on a wafer, the progress of the reaction in the resist during baking becomes uniform and constant, and 65 nm after development. A fine resist pattern of 45 nm can be stably obtained. That is, as a specific process step in the photolithography process, first, a chemically amplified resist having photosensitivity to the wavelength of exposure light, for example, for KrF or ArF excimer lithography, is applied to the wafer and baked at a predetermined temperature. (Pre-baking) is performed. Next, the semiconductor integrated circuit pattern is exposed on the wafer. After the exposure, the wafer is set in the wafer heating apparatus according to the present invention, and the baking is performed for a certain period of time while controlling the temperature by the above method. The acid generated in the exposed resist and the hydroxyl group of the resin constituting the resist The dehydration reaction proceeds with the part. Then, after this baking, development processing is performed to form a resist pattern.

(Second Embodiment)
FIG. 3 is a longitudinal sectional view of a wafer heating apparatus according to the second embodiment of the present invention, and FIG. 4 is a transverse sectional view of a heating block of the apparatus. 3 and 4, the same reference numerals are given to the components corresponding to or corresponding to those of the first embodiment shown in FIGS. 1 and 2.

  As shown in FIG. 3 and FIG. 4, the wafer heating apparatus of the present embodiment is uniformly arranged along one periphery of the heating block having a circular shape in plan view arranged in the center. A total of nine heating blocks 14 comprising eight fan-shaped heating blocks in plan view are provided. Since each heating block 14 is configured to be movable up and down as will be described later, a cylindrical assembly for positioning and consolidating the heating blocks 14 is provided at the outermost peripheral portion of each heating block 14. A body 13 is arranged. 4 is a cross-sectional view in a plane including the heater 6 of FIG. 3, and the heating block 14 (pedestal 4) and the aggregate 13 show only the outer shape. The gap pins 7 provided on the aggregate 13 support the wafer 1 at a certain height. The gap pins 7 only need to be able to support the wafer 1 in parallel with the surface of the heating block 14 (the surface of the heat conductor 5), and the number and shape thereof are arbitrary.

  Each heating block 14 is integrally joined with a pedestal 4 and a heat conducting plate 5 provided in contact therewith. Each pedestal 4 contains a ring-shaped heater 6 formed of nichrome wire or the like for baking the wafer 1. Further, a thermometer 9 made of a thermocouple or a resistance thermometer is embedded in each heat conduction plate 5 at a position facing each heater 6.

  Furthermore, a fixing screw 2 connected to the rotating shaft of the motor 3 and the motor 3 is provided for each heating block 14. The motor 3 and the fixing screw 2 constitute position adjusting means for moving the position of the heating block 14 with respect to the wafer 1. Each fixing screw 2 is screwed into a screw hole formed through the ring center of the heater 6 and the pedestal 4, and reaches the inside of the heat conducting plate 5. An enlarged diameter portion 2a having an increased diameter is provided. The pedestal 4 and the heat conductive plate 5 constituting each heating block 14 are fastened and mechanically fixed by the fixing screws 2 with substantially equal torque. Therefore, by rotating each motor 3, each heating block 14 moves up and down as a whole, and the height relative to the wafer 1 can be finely adjusted (for example, about 0.1 to 1 mm). Other configurations are the same as those of the wafer heating apparatus according to the first embodiment shown in FIGS. 1 and 2, and detailed description thereof is omitted here. In the present embodiment, the position of the motor 3 is fixed by a fixing member (not shown). Although not particularly limited, in the present embodiment, unlike the first embodiment, the contact surface between the base 4 and the heat conducting plate 5 is not roughened.

  The baking process of the wafer 1 using the wafer heating apparatus having the above-described configuration is performed as follows. When the wafer 1 is placed on the gap pins 7 and the baking process is started, first, the temperature control unit 10 supplies power to the heater 6. And the temperature control unit 10 acquires the temperature measured by each thermometer 9 arrange | positioned inside the heat conductive board 5, for example at the predetermined time interval set beforehand. At this time, the temperature control unit 10 compares a set temperature stored in an internal memory (not shown) with the acquired measured temperature.

  As a result, when the measured temperature at a specific location on the heat conducting plate 5 is lower than the set temperature, the temperature control unit 10 supplies electric power (voltage or current) to be applied to the heater 6 at the position corresponding to the thermometer 9. Increase the temperature of the pedestal 4. At the same time, the motor 3 installed corresponding to the heater 6 at that specific location is driven to rotate the fixing screw 2 to raise the heating block 14, and the front surface of the heat conducting plate 5 and the back surface of the wafer 1. Reduce the distance. As a result, the amount of heat radiation from the heat conducting plate 5 increases, and the temperature of the wafer 1 rises more quickly.

  On the other hand, when the measured temperature at a specific location of the heat conducting plate 5 is higher than the set temperature, the temperature control unit 10 supplies electric power (voltage or current) to be applied to the heater 6 at a position corresponding to the thermometer 9. Decrease or shut off and lower the temperature of the pedestal 4. At the same time, the motor 3 installed corresponding to the heater 6 at the specific location is driven to rotate the fixing screw 2 to lower the heating block 14, and the surface of the heat conducting plate 5 and the back surface of the wafer 1 Increase the distance. As a result, the amount of heat radiation from the heat conducting plate 5 decreases, and the temperature of the wafer 1 decreases more quickly. FIG. 3 shows a state where the temperature is lowered to control the temperature of the central heating block 14.

  As described above, the temperature of the wafer 1 placed on the gap pin 7 is controlled by heat radiation from the heat conduction plate 5 and heat conduction through the air in the gap and radiation heat from the heat plate cover 8. Is done.

  As described above, in the present embodiment, when controlling the temperature of the wafer 1, in addition to the control for adjusting the power input amount to the heater 6 provided on the pedestal 4 of the heating block 14, it is connected to the rotating shaft of the motor 3. The fixing screw 2 is rotated to control the distance between the front surface of the heat conduction plate 5 of the heating block 14 and the back surface of the wafer 1. For this reason, it is possible to control the amount of heat transferred from the heat conducting plate 5 to the wafer 1 within a short period of time compared to the case where only the amount of power input to the heater 6 is controlled. As a result, similar to the configuration of the first embodiment, it is possible to realize temperature control that is constant within the wafer surface even for transient characteristics in temperature control such as temperature increase rate and temperature decrease rate. The temperature uniformity of the wafer 1 is improved, and the integrated temperature can be precisely controlled.

  As a result of examining the temperature characteristics of the wafer 1 implemented using this wafer heating apparatus, for example, the range of temperature uniformity within the wafer surface is ± 0.05 ° C., and the temperature at the center of the wafer When the rising speed was 2.5 ° C./second, the temperature rising speed of the wafer outer peripheral portion was 2.4 ° C./second. From this, it can be understood that according to the configuration of the present embodiment, the transient characteristics at the time of raising and lowering the temperature are improved as compared with the conventional configuration shown in FIG.

  In the above description, the heating block 14 is composed of the pedestal 4 and the heat conducting plate 5. However, in the present embodiment, the heating block 14 is not necessarily divided into the pedestal 4 and the heat conducting plate 5. , May be formed integrally.

(Third embodiment)
In the first and second embodiments, the configuration has been described in which, during the wafer temperature control process, the rate of change at the time of temperature rise and fall at the temperature measurement position in the heat conducting plate 5 can be made constant. That is, in the first embodiment, the contact pressure between the pedestal 4 and the heat conduction plate 5 is used, and in the second embodiment, the distance between the surface of the heat conduction plate 5 of the heating block 14 and the back surface of the wafer 1 is designated as the heat conduction plate. The temperature was adjusted based on the temperature measured by the thermometer 9 embedded in 5.

  However, if the temperature control of the wafer 1 is limited to the temperature control of temperature increase / decrease, the above-described adjustment can be performed based on a physical quantity other than the measurement temperature. Therefore, in the present embodiment, a configuration in which the above-described adjustment is performed based on the change speed per unit time of the temperature measured by the thermometer 9 will be described.

  In the present embodiment, for example, the measurement unit 10 of the wafer heating apparatus having the configuration shown in FIGS. 1 and 2 is based on the measurement temperature continuously input from each thermometer 9 to the temperature control unit 10. Then, the temperature change rate per unit time is calculated, and the temperature control is performed so that the change rate at each location is the same. For such temperature control, for example, a set value (temperature gradient) of the rate of change at the time of temperature rise and fall is stored in advance in the temperature control unit 10, and the rate of change of the measured temperature is controlled based on the set value, Or it is realizable by controlling the time change of the measurement temperature of another location on the basis of the time change of the measurement temperature in a predetermined position like the center part of a heat conduction board.

  Specifically, in the wafer heating apparatus having the configuration shown in the first embodiment (FIGS. 1 and 2), the temporal change rate of the temperature in the region including each thermometer 9 is the same. The contact pressure between the pedestal 4 and the heat conducting plate 5 is adjusted. For example, if the temperature control unit 10 calculates that the temperature rise rate at the wafer center is 2.5 ° C./second and the temperature rise rate at the wafer outer periphery is 2.0 ° C./second, the temperature increase rate at the wafer outer periphery is Therefore, the temperature control unit 10 increases the contact pressure between the pedestal 4 and the heat conducting plate 5 by changing the tightening torque of the wafer outer periphery from 10 N · m to 15 N · m, and increases the temperature increase rate of the wafer outer periphery. Increase.

  As a result of examining the temperature characteristic of the wafer 1 in which the temperature transient characteristic is controlled to be constant within the wafer surface by this method, for example, when the temperature rise rate at the center of the wafer is 2.5 ° C./second, The temperature rising rate of the part was 2.4 ° C./second. The range of temperature uniformity within the wafer surface was ± 0.05 ° C.

  Further, in the wafer heating apparatus having the configuration shown in the second embodiment (FIGS. 3 and 4), the temperature change rate with time in each heating block 14 including the heat conducting plate 5 is the same. The height position of the heating block 14, that is, the distance between the back surface of the wafer 1 and the surface of the heat conductive plate 5 is adjusted. For example, if the temperature control unit 10 calculates that the temperature rise rate at the wafer center is 2.5 ° C./second and the temperature rise rate at the wafer outer periphery is 2.0 ° C./second, the temperature increase rate at the wafer outer periphery is Since the distance to the heat conduction plate 5 on the outer periphery of the wafer 1 is changed from 0.2 mm to 0.1 mm, the distance between the back surface of the wafer 1 and the surface of the heat conduction plate 5 is shortened. Increase the rate of temperature rise.

  As a result of examining the temperature characteristic of the wafer 1 in which the temperature transient characteristic is controlled to be constant within the wafer surface by this method, for example, when the temperature rise rate at the center of the wafer is 2.5 ° C./second, The temperature rising rate of the part was 2.4 ° C./second. The range of temperature uniformity within the wafer surface was ± 0.05 ° C.

  As described above, according to the present invention, the temperature transmission speed can be controlled in a very short time, so that the in-plane temperature distribution at the time of temperature rise and temperature drop of the semiconductor substrate when the semiconductor substrate is heat-treated can be obtained. It can be made extremely uniform. In addition, since more control items are required than in the prior art, more accurate wafer in-plane temperature uniformity can be realized. As a result, not only the baking temperature during the heat treatment but also the integrated temperature can be precisely controlled, and the quality of the semiconductor device can be improved. In particular, according to the present invention, since the temperature uniformity range within the semiconductor substrate surface can be controlled to ± 0.05 ° C. or less, the progress of the reaction in the chemically amplified resist film during the heat treatment is uniform and constant. Can be. Therefore, the pattern dimensional accuracy after development can be improved, and a fine resist pattern can be stably formed even in a semiconductor manufacturing process of 65 nm node and 45 nm node.

  The embodiments described above do not limit the technical scope of the present invention, and various modifications and applications other than those already described are possible within the scope of the present invention. For example, in each of the above-described embodiments, the wafer heating apparatus applied mainly to the resist pattern forming technique using the chemically amplified resist of the lithography technique has been described. However, the present invention is limited only to such a lithography technique. Instead, the present invention can also be applied to a semiconductor substrate processing apparatus having a heater for heating, for example, a heat treatment furnace.

  INDUSTRIAL APPLICABILITY The present invention can improve the temperature transient characteristics at the time of raising and lowering the temperature of the semiconductor substrate and the temperature uniformity within the substrate surface, and is useful as a semiconductor device manufacturing method and a semiconductor substrate processing apparatus.

1 is a longitudinal sectional view showing a wafer heating apparatus according to a first embodiment of the present invention. 1 is a cross-sectional view of a pedestal portion of a wafer heating apparatus according to a first embodiment of the present invention. FIG. 5 is a longitudinal sectional view showing a wafer heating apparatus according to a second embodiment of the present invention. Cross-sectional view of the heating block of the wafer heating apparatus in the second embodiment of the present invention Vertical section of a conventional wafer heating device

Explanation of symbols

1 Wafer (semiconductor substrate)
2 Fixing screws (contact pressure adjusting means, position adjusting means)
3 Motor (contact pressure adjusting means, position adjusting means)
4 Pedestal 5 Heat conduction plate 6 Heater 7 Gap pin (support)
8 Hot plate cover 9 Thermometer 10 Temperature control unit (control means)
14 Heating block

Claims (19)

Forming a resist film on the surface of the semiconductor substrate;
Exposing the resist film with a predetermined pattern;
Placing the exposed semiconductor substrate parallel to the surface of the heat conduction plate at a certain distance from the heat conduction plate installed on the surface of the pedestal containing the heater;
By adjusting the contact pressure between the heat conductive plate and the pedestal based on the temperature of the heat conductive plate at a position corresponding to the heater, the amount of heat transferred from the heater to the semiconductor substrate is adjusted and the semiconductor substrate is Heating, and
Developing the resist film after the heating and forming a resist pattern;
A method for manufacturing a semiconductor device, comprising:   The method of manufacturing a semiconductor device according to claim 1, wherein in the heating step, a contact pressure between the pedestal and the heat conducting plate is adjusted so that the measured temperature becomes a preset temperature.   3. The semiconductor according to claim 1, wherein, in the heating step, the contact pressure between the pedestal and the heat conducting plate is adjusted so that a temporal change rate of the measured temperature calculated from the measured temperature is constant. Device manufacturing method.   The temperature of the heat conduction plate is measured at a plurality of different locations in a plane parallel to the semiconductor substrate, and the pedestal at the position corresponding to each temperature measurement location and the heat conduction according to each measured temperature. The method for manufacturing a semiconductor device according to claim 1, wherein the contact pressure with the plate is adjusted. Forming a resist film on the surface of the semiconductor substrate;
Exposing the resist film with a predetermined pattern;
Arranging the exposed semiconductor substrate parallel to the surface of the heating block at a certain distance from the surface of the heating block having a built-in heater;
Adjusting the distance between the semiconductor substrate and the heating block by moving the heating block based on the temperature of the heating block between the semiconductor substrate and the heater at a position corresponding to the heater. Adjusting the amount of heat transferred from the heater to the semiconductor substrate and heating the semiconductor substrate;
Developing the resist film after the heating and forming a resist pattern;
A method for manufacturing a semiconductor device, comprising:   6. The method of manufacturing a semiconductor device according to claim 5, wherein, in the heating step, a distance between the semiconductor substrate and the heating block is adjusted so that the measured temperature becomes a preset temperature.   The distance between the said semiconductor substrate and the said heating block is adjusted to the state in which the time change rate of the measured temperature calculated from the measured temperature becomes constant in the said heating process. A method for manufacturing a semiconductor device.   A plurality of the heating blocks are arranged at positions facing the semiconductor substrate, and a distance between the semiconductor substrate and each heating block is adjusted according to each temperature measured in each heating block. A manufacturing method of a semiconductor device given in any 1 paragraph.   The method for manufacturing a semiconductor device according to claim 1, wherein the resist film is a chemically amplified resist film. A semiconductor substrate processing apparatus for heating and heat-treating a semiconductor substrate,
A pedestal with a built-in heater for heating the semiconductor substrate;
A heat conduction plate installed on the surface of the pedestal;
Temperature measuring means built in the heat conducting plate corresponding to the heater;
A support that holds the semiconductor substrate parallel to the surface of the heat conducting plate at a certain distance from the surface of the heat conducting plate;
Contact pressure adjusting means for adjusting the contact pressure between the pedestal and the heat conducting plate;
Control means for controlling the contact pressure adjusting means based on the temperature measured by the temperature measuring means;
A semiconductor substrate processing apparatus comprising:   The semiconductor substrate processing apparatus according to claim 10, wherein the control unit adjusts a contact pressure between the pedestal and the heat conducting plate so that a temperature measured by the temperature measuring unit becomes a preset temperature.   The said control means adjusts the contact pressure of the said base and the said heat conductive board in the state in which the temporal change rate of the measurement temperature calculated from the temperature measured by the said temperature measurement means becomes fixed. 11. The semiconductor substrate processing apparatus according to 11. The contact pressure adjusting means is
A fixing screw screwed onto the pedestal;
A motor for rotationally driving the fixing screw;
The semiconductor substrate processing apparatus of any one of Claims 10-12 provided with these.   11. The temperature measuring means is distributed and arranged at a plurality of locations on a surface facing the semiconductor substrate, and the heater and the contact pressure adjusting means are provided corresponding to each of the plurality of temperature measuring means. 14. The semiconductor substrate processing apparatus according to any one of 1 to 13. A semiconductor substrate processing apparatus for heating and heat-treating a semiconductor substrate,
A heating block with a built-in heater for heating the semiconductor substrate;
A support that holds the semiconductor substrate parallel to the surface of the heating block at a certain distance from the surface of the heating block;
Corresponding to the heater, temperature measuring means built in the heating block between the semiconductor substrate held on the support and the heater;
Position adjusting means for changing the distance between the semiconductor substrate held on the support and the heating block by moving the position of the heating block;
Control means for controlling the position adjusting means based on the temperature measured by the temperature measuring means;
A semiconductor substrate processing apparatus comprising:   The said control means adjusts the distance between the semiconductor substrate hold | maintained at the said support body and the said heating block in the state by which the temperature measured by the said temperature measurement means becomes preset temperature. Semiconductor substrate processing equipment.   The control means is provided between the heating block and the semiconductor substrate held by the support so that the temporal change rate of the measured temperature calculated based on the temperature measured by the temperature measuring means is constant. The semiconductor substrate processing apparatus of Claim 15 or 16 which adjusts the distance of. The position adjusting means is
A fixing screw fixed to the heating block;
A motor for rotationally driving the fixing screw;
The semiconductor substrate processing apparatus of any one of Claim 15 to 17 provided with these.   The heating block is arranged in a plurality at positions facing the semiconductor substrate, and each of the heating blocks includes the heater, the temperature measuring unit, and the position adjusting unit. The semiconductor substrate processing apparatus of description.

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