JP5056228B2 - Heater unit and semiconductor device manufacturing / inspection apparatus having the same - Google Patents

Description

  The present invention relates to a heater unit mainly used for heating a semiconductor substrate or a flat display panel substrate, particularly to a heater unit used in a photolithography process, a prober inspection process or a final inspection process, and a manufacturing / inspection apparatus equipped with the heater unit. It is.

  Many devices have been developed that can be heated and loaded with an object to be heated. Of these, the uniformity of the temperature distribution of the object to be heated (also referred to as soaking) is particularly required. In manufacturing or inspection, there is a heater unit used for heat treatment of a semiconductor substrate or a glass substrate. This heater unit is used, for example, for heating and drying a resist solution applied on a substrate in a lithography process, or for raising a temperature for performing inspection of a substrate at a desired temperature.

  The semiconductor devices and flat display panels are competing to reduce the price of products through mass production through continuous operation, and thus these manufacturing / inspection apparatuses are required to shorten the tact time. Therefore, in order to obtain a high throughput with one manufacturing / inspection apparatus, not only the processing time of the object to be processed during the temperature maintenance time but also the time required for changing the heater temperature accompanying the change of the processing conditions (temperature increase) Time, cooling time) must be shortened.

  As a heater unit for this purpose, Japanese Patent Application Laid-Open No. 2004-014655 describes a heater unit in which a cooling plate having a desired heat capacity is movably installed with respect to the heater plate. As shown in FIG. 1, the heater unit includes a heater plate 1 having a resistance heating element, a movable cooling plate 2a for quickly cooling the heater plate 1, and heat is not easily transmitted to the manufacturing / inspection apparatus. It consists of a container 3 for storing a heater plate 1 and a cooling plate 2a for shielding. Note that a thermometer 4 or a temperature sensor is connected to monitor the heater temperature.

  As shown in FIG. 1, in the heater unit having the movable cooling plate 2a, the cooling plate 2a is installed so as to be driven up and down by an elevating mechanism such as an air cylinder. By separating from, rapid temperature rise becomes possible. Further, the temperature of the object to be heated placed on the placement surface can be lowered in a short time by bringing the cooling plate 2a into contact with the heated heater plate 1 during cooling.

  Another specific example of the heater unit is shown in FIG. In this heater unit, the heater plate 1 and the cooling plate 2 b are supported by a bottomed cylindrical support member 5. The cooling plate 2b shown in FIG. 2 is fixed to the opposite side of the mounting surface of the heater plate 1 by a pressing plate (not shown) or the like, but the gap between the heater plate 1 and the bottomed cylindrical support member 5 is fixed. It is also possible to use a movable type that moves up and down in the unit and contacts or separates from the heater plate 1.

  In the conventional heater unit described above, the heater plate includes a ceramic mounting table 6 on which a semiconductor substrate or the like is mounted, for example, as shown in FIG. 3, and resistance heat is generated on the opposite side (back surface) of the mounting surface of the mounting table 6. A body 7 is disposed, a flexible insulating sheet 8 is interposed, a presser plate 9 having a relatively high strength is further provided, and a connecting screw 10 between the presser plate 9 and the mounting table 6 is specifically used. It is mechanically joined and fixed using rivets, bolts and nuts. In some cases, a resistance heating element is disposed on the back surface of the mounting table, and then an electric insulating film is coated thereon to form a heater plate.

Further, a metal or ceramic block is used as the cooling plate. Cooling efficiency can be further improved by forming a coolant channel in the cooling plate and allowing the coolant to flow through the channel. The cooling plate is fixed to the heater plate 1 with a holding plate or the like as shown in the specific example of FIG. 3 and the movable cooling plate 2a that can contact or separate from the heater plate 1 as shown in the specific example of FIG. There is a thing.
JP 2004-014655 A

  In the conventional heater unit described above, as a method for maintaining the in-plane thermal uniformity of the wafer, a high heat conductive material such as copper is used for the mounting table, or the temperature of the heating element is increased by increasing the thickness of the mounting table. The only way to cope with this was to eliminate unevenness or to control the heating element in multiple zones to balance partial heat generation. On the other hand, in the case of a heater that requires a high temperature rise, the mounting table needs to be made of a material with a low density or a reduced thickness. In addition, in order to improve the throughput, it is necessary to improve the heating rate and the cooling rate while maintaining the temperature distribution in the wafer surface, and it is very difficult to achieve both in-plane temperature uniformity. It was.

  The present invention has been made in view of such conventional problems, and it is possible to increase the temperature increase / decrease rate while maintaining or further improving the temperature uniformity within the wafer surface, An object is to provide a heater unit which is not damaged by thermal stress and has excellent reliability.

  In order to achieve the above object, the present inventors reduce the heat capacity by reducing the thickness of the mounting table in a heater unit in which two or more plate-like members including the mounting table are mechanically connected by screws. In order to increase the rate of temperature increase and decrease in temperature, even if the thickness of the mounting table is reduced, we have conducted intensive research on a method that can prevent the temperature uniformity from being lowered and the plate-shaped member from being damaged. It was.

  In general, in a heater unit in which two or more plate-like members are mechanically connected with screws, the constituent materials of the plate-like members are different from each other. However, the amount of thermal expansion may differ depending on the temperature difference between the plate-like members. Therefore, in a heater unit in which two or more plate-like members are mechanically fixed with screws or the like, stress concentration occurs in the screw portion due to a difference in thermal expansion, and the flatness changes due to bending of the plate-like member including the mounting table. May occur, resulting in a decrease in in-plane temperature uniformity, or deformation or breakage of the plate-like member or screw.

  Therefore, in the present invention, when two or more plate-like members are mechanically connected with screws, a bearing mechanism is provided on the connecting screws, so that an excellent axial heat is applied in the vertical direction. In order to absorb the difference in thermal expansion in the lateral direction, the bearing mechanism is slid to prevent the occurrence of changes in flatness due to the mutual thermal expansion difference and to ensure temperature uniformity within the wafer surface. .

That is, manufacturing and inspection equipment for the heater unit of the semiconductor device provided by the present invention, in the manufacturing and inspection equipment for the heater unit of the semiconductor device for heat treatment equipped with a wafer on the mounting table, two containing table The plate-like member described above is mechanically connected by a connecting screw, the connecting screw has a bearing mechanism, and a threaded portion of the connecting screw is fixed to the plate-like member by an adhesive. To do.

Also, one specific example of the heater unit for semiconductor device manufacturing / inspection apparatus provided by the present invention includes a mounting table for mounting a wafer and performing heat treatment, a resistance heating element for heating the mounting table, and a resistance And a pressing plate for mechanically pressing the heating element against the mounting table, and these plate-like members are mechanically connected by a connecting screw having a bearing mechanism, and the threaded portion of the connecting screw is the plate It is fixed to the shaped member with an adhesive . In the case of this heater unit, a movable cooling plate that contacts or separates from the pressing plate can be further provided.

Furthermore, another specific example of the heater unit for semiconductor device manufacturing / inspection apparatus provided by the present invention includes a mounting table for mounting a wafer and performing heat treatment, a resistance heating element for heating the mounting table, A cooling plate for cooling the mounting table, and these plate-like members are mechanically connected by a connecting screw having a bearing mechanism, and a threaded portion of the connecting screw is attached to the plate-like member. It is fixed by . In the case of this heater unit, a pressing plate is further provided outside the cooling plate, and the mounting table and the pressing plate can be mechanically connected by the connecting screw.

Further, in the manufacturing and inspection equipment for the heater unit of the semiconductor device according to the present invention, it is preferable to arrange the pre-Symbol connecting screw 4 or more places.

In the heater unit for semiconductor device manufacturing / inspection apparatus according to the present invention, the bearing mechanism is provided on either the seating surface of the male screw head of the connection screw or the surface of the plate-like member facing the seating surface. The bearing groove is provided and a bearing ball held in the bearing groove, and the depth of the bearing groove is equal to or less than the diameter of the bearing ball.

In this semiconductor device manufacturing / inspection device heater unit, it is preferable to use three or more bearing balls per one connecting screw. The sphericity of the bearing ball is preferably 30 μm or less. The diameter of the bearing ball is preferably 4 mm or less. Furthermore, it is preferable that the material of the bearing ball is any one selected from ceramics, stainless steel, iron, and nickel.

In the heater unit for manufacturing / inspecting a semiconductor device according to the present invention, it is desirable that at least two of the plate-like members are made of materials having different coefficients of thermal expansion. In this case, it is preferable that the difference in coefficient of thermal expansion between the two plate-shaped members is 1.0 × 10 ⁻⁹ / ° C. or more.

In the heater unit for manufacturing / inspecting a semiconductor device according to the present invention, the mounting table is mainly composed of at least one selected from aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, copper, aluminum, nickel, and silicon. It is preferable that The pressing plate preferably contains at least one selected from aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, copper, aluminum, nickel, silicon, and stainless steel as a main component.

The present invention also provides a manufacturing and inspection equipment for the semiconductor device, characterized in that mounting the manufacturing and inspection equipment for the heater unit of the semiconductor device of the present invention described above.

  According to the present invention, by providing a bearing mechanism to a connecting screw that mechanically connects a plurality of plate-like members, an axial force is applied in the vertical direction to maintain good heat transfer, while thermal expansion is performed in the horizontal direction. Since the difference can be absorbed by the bearing mechanism, the change in the flatness of the mounting table is eliminated while suppressing the generation of particles, the temperature uniformity within the wafer surface is maintained better or improved than before, and the temperature rises. -A heater unit capable of increasing the temperature drop rate can be provided.

  Therefore, by using the heater unit of the present invention, particularly in the manufacturing process of a semiconductor device or a flat display panel, the heating process under the following conditions can be performed immediately after the temperature conditions on the temperature rising side and the temperature lowering side are changed. The time required for the change can be further shortened. In addition, since high in-plane temperature uniformity can be achieved, in the semiconductor process, for example, variations in film thickness and line width in the photoresist process can be reduced. Further, in the inspection process, constant heat uniformity and probing can always be ensured by the prober device. As a result, the productivity, performance, yield, and reliability of the manufactured semiconductor device and flat display panel can be improved.

  The heater unit of the present invention includes a bearing mechanism on a connection screw that mechanically connects a plurality of plate-like members such as a mounting table, a resistance heating element, and a pressing plate. Therefore, in order to maintain good heat transfer by applying axial force in the vertical direction with the connecting screw, at the same time, the bearings in the horizontal direction are prevented from changing the flatness of the mounting table due to the difference in thermal expansion of each plate-like member. The thermal expansion difference can be absorbed by sliding the mechanism.

  Therefore, by maintaining such good flatness, the thickness of the mounting table is reduced in order to increase or decrease the temperature rising speed and temperature decreasing speed while maintaining or improving the uniformity of the in-plane temperature. Thus, the heat capacity can be reduced. Further, the bearing structure can suppress the thermal expansion difference due to the temperature difference between two or more plate-like members, or the friction due to the difference in thermal expansion at the portion where the plate-like members of different materials are fixed, so that the above-mentioned soaking performance is improved In addition, it is possible to prevent the generation of particles that are essential in semiconductor manufacturing apparatuses and inspection apparatuses.

The effects of the present invention relating to the flatness, particles, thermal uniformity, etc. described above are that each plate-like member is made of a different material in a combination of a mounting table and a holding plate or a mounting table and a cooling plate, and therefore has a different coefficient of thermal expansion. When it has, it appears prominently. In particular, when the difference in coefficient of thermal expansion between the two plate-like members is 1.0 × 10 ⁻⁹ / ° C. or more, the heater unit of the present invention provided with a bearing mechanism on the connecting screw is extremely effective.

  It is preferable that a connecting screw used for connecting two or more plate-like members is fixed to the plate-like member with an adhesive. The normal screw is fixed by utilizing a frictional force when the seat surface (collar portion) of the screw contacts the plate-like member. On the other hand, when the bearing mechanism is provided on the seat surface of the screw, it will loosen even if it is tightened with the recommended screw torque recommended for that screw, and sufficient frictional force to keep the screw fixed over time is obtained. It's hard to be done. Therefore, in the present invention, an appropriate amount of adhesive is applied to the threaded portion of the connection screw and fixed to the plate-like member, thereby preventing the connection screw from loosening with time. The adhesive to be used is not particularly limited as long as it can withstand the use temperature and can follow the difference in thermal expansion.

  Moreover, it is preferable to arrange | position the connection screw provided with the bearing mechanism in four or more places in a heater unit. If the number of connecting screws is small, the balance cannot be achieved, and the axial force of the connecting screws is not applied in the vertical direction with respect to the mounting table and the holding plate, so that it is difficult to exert the effect of the bearing mechanism. By arranging four or more connecting screws in the heater unit, the bearing effect is sufficiently exerted when the heater temperature rises, and the flatness of the mounting table and the pressing plate can be prevented from being lowered. The number of connecting screws is more preferably 7 or more.

  Next, a specific example of the heater unit of the present invention will be described with reference to FIG. This heater unit is a plate-like member having a mounting table 6 for mounting a heated object, a resistance heating element 7 for heating the mounting table 6, a resistance heating element 7 and a holding plate 9. And a pressing plate 9 for mechanically pressing the resistance heating element 7 against the mounting table 6. The mounting table 6 and the pressing plate 9 are mechanically connected by a connecting screw 10 with the insulating sheet 8 and the resistance heating element 7 interposed therebetween, and the connecting screw 10 is provided with a bearing mechanism.

  The heater unit shown in FIG. 4 does not include a cooling plate, and the heater plate is configured by the mounting table 6, the resistance heating element 7, the insulating sheet 8, and the pressing plate 9. Although not shown, wiring for supplying power to the resistance heating element 7 and a temperature sensor for monitoring the heater temperature are connected. Furthermore, in the case of this heater unit, a movable cooling plate can be provided below the heater plate. The movable cooling plate can be driven up and down by an elevating mechanism such as an air cylinder to abut or separate from the holding plate 9.

  As shown in FIG. 4A, the bearing mechanism provided on the connection screw is composed of a bearing groove 11a on the seat surface of the male screw head of the connection screw 10 and a bearing ball 12 held in the bearing groove 11a. Composed. Further, as shown in FIG. 4B, a bearing groove 11b is provided on the surface of the holding plate 9 facing the seat surface of the male screw head of the connection screw 10, and the bearing ball 12 is held in the bearing groove 11b. You can also In any case, the depth of the bearing grooves 11 a and 11 b is set to be equal to or smaller than the diameter of the bearing ball 12.

  Thus, by providing a bearing groove on either the seat surface of the male screw head of the connecting screw or the surface of the holding plate facing the seat surface, and holding the bearing ball in the groove, Drop-out can be prevented, and an inexpensive and simple bearing mechanism can be made. When the bearing groove is formed on the surface of the pressing plate, it is desirable that the remaining plate thickness of the pressing plate is 0.5 mm or more. If the remaining plate thickness is less than 0.5 mm, it is not preferable because local deformation of the pressing plate may gradually occur due to a long heat cycle history.

  In the heater unit of the present invention, the configuration of the plurality of plate-like members connected by the connecting screws is not limited to the case of the heater plate shown in FIG. 4, but a mounting table, a resistance heating element, a pressing plate, and insulation as necessary. A sheet | seat and a pressing board can be comprised combining suitably. For example, as shown in FIG. 5A, an insulating sheet 8 is interposed on the back surface of the mounting table 6 with respect to the mounting surface as necessary, and stainless steel or nickel-chromium foil is etched, for example, in a spiral shape. A resistance heating element 7 is disposed, a flexible insulating sheet 8 is interposed on the back side thereof, and a relatively strong presser plate 9 is combined on the back side to form a heater plate.

  Further, a cooling plate can be combined with the mounting table, the resistance heating element, the pressing plate, and if necessary, the insulating sheet and the pressing plate. For example, as shown in FIG. 5 (b), there is a combination in which a resistance heating element 7 is disposed on the back surface of the mounting table 6, the cooling plate 2b is stacked on the back surface side, and a pressing plate 9 is disposed on the back surface. Furthermore, as shown in FIG.5 (c), the flexible insulating sheets 8 and 8 can also be interposed on the both sides of the resistance heating element 7 in the combination of FIG.5 (b).

  A specific example of the heater unit of the present invention incorporating these cooling plates is shown in FIG. In FIG. 6A, a resistance heating element 7 is disposed on the back surface of the mounting table 6 with respect to the mounting surface through an insulating sheet 8 as necessary, and the cooling plate 2b is interposed on the back surface side through the insulating sheet 8. Are stacked and mechanically connected by a connecting screw 10 having a bearing mechanism in combination with a pressing plate 9 on the back surface. Moreover, as shown in FIG.6 (b), the mounting base 6 and the cooling plate 2b can also be mechanically connected with the connection screw 10 which the bearing mechanism provided, without using a pressing plate. In FIG. 6A, a bearing groove 11a is provided in the seat surface of the male screw head of the connection screw 10, and in FIG. 6A, the cooling plate 2b facing the seat surface of the male screw head of the connection screw 10 is provided. A bearing groove 11b is provided on the surface.

  As the insulating sheet, it is desirable to use a sheet having a high thermal conductivity as much as possible. Further, it is preferable to use an insulating material having a thermal expansion curve approximate to the thermal expansion curve of the mounting table, for example, crystallized glass or glaze glass, or an organic material having heat resistance. The stacking order of the resistance heating element and the insulating sheet is not particularly limited between the mounting table and the pressing plate or between the mounting table and the cooling plate. The cooling plate is made of a metal or ceramic block. Further, the cooling efficiency can be further improved by forming a coolant channel in the cooling plate and allowing the coolant to flow through the channel.

  In the heater unit of the present invention, in the bearing mechanism described above and illustrated in FIGS. 4 and 6, it is preferable to use three or more bearing balls, more preferably five or more, for each connecting screw. By having three or more bearing balls per connecting screw, the bearing balls are likely to roll in the expansion direction as the plate-shaped member such as the mounting table and the holding plate expands, so each plate-shaped member is restrained by the connecting screw. It can expand freely and can maintain each good flatness. Further, a bearing mechanism in which a plurality of bearing balls are mounted in advance may be used.

  The sphericity of the bearing ball is desirably 30 μm or less. When the sphericity of the bearing ball exceeds 30 μm, the bearing ball does not roll smoothly when the plate-shaped member such as the mounting table and the pressing plate expands, and the mounting table and the pressing plate are restrained by friction. This is because the difference in displacement between the members increases and the flatness of the mounting table deteriorates.

  The diameter of the bearing ball is desirably 4 mm or less. If the diameter of the bearing ball is larger than 4 mm, it is necessary to enlarge the bearing surface (collar part) that holds the bearing ball of the connecting screw. It is necessary to provide a large counterbore on the movable cooling plate to be installed. As a result, when the cooling plate is brought into contact and cooled, the unevenness of the temperature occurs on the wafer mounting surface due to the influence of the counterbore portion, and the in-plane temperature distribution of the wafer is deteriorated.

  The material of the bearing ball is preferably any one of ceramics, stainless steel, iron, and nickel. If the material of the bearing ball is aluminum, copper, brass, resin, etc., the strength at the time of thermal expansion is not sufficient, and the sphericity cannot be maintained, so that the effect of the bearing mechanism cannot be sufficiently exhibited.

  The mounting table of the heater unit is preferably composed mainly of at least one selected from the group consisting of aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, copper, aluminum, nickel, and silicon. Among these, a ceramic mounting table is preferable. This is because, when a metal mounting table is used, there is a problem that particles that are avoided in the microfabrication process of the semiconductor device manufacturing process are generated and adhere to the wafer.

  As the ceramic constituting the mounting table, aluminum nitride or silicon carbide having high thermal conductivity is preferable if importance is attached to the uniformity of temperature distribution. Further, if reliability is important, silicon nitride is preferable because it has high strength and is resistant to thermal shock. If importance is attached to the cost, aluminum oxide is preferable. Among these ceramics, aluminum nitride is preferable in consideration of performance and balance. Further, considering flatness and high rigidity in prober applications, silicon nitride or ceramics mainly composed of silicon nitride is preferable.

  The pressing plate preferably contains at least one selected from aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, copper, aluminum, nickel, silicon, and stainless steel as a main component. In addition, it is preferable that the flatness of the contact surface of the pressing plate and the cooling plate is 300 μm or less. Further, as the material of the connecting screw, stainless steel, nickel, titanium, Kovar, or the like can be used.

Next, a method for manufacturing the mounting table for the heater unit will be described in detail by taking the case of aluminum nitride (AlN) as an example. The AlN raw material powder preferably has a specific surface area of 2.0 to 5.0 m ² / g. Specific and surface area decrease sinterability of aluminum nitride is less than 2.0 m 2 / ^g, handling since the powder agglomeration is very strong difficult exceeds 5.0 m 2 / ^g. Further, the amount of oxygen contained in the raw material powder is preferably 2 wt% or less. When the amount of oxygen exceeds 2 wt%, the thermal conductivity of the sintered body decreases. The amount of metal impurities other than aluminum contained in the raw material powder is preferably 2000 ppm or less. When the amount of metal impurities exceeds 2000 ppm, the thermal conductivity of the sintered body decreases. In particular, group 4 elements such as Si as metal impurities and iron group elements such as Fe have a high effect of lowering the thermal conductivity of the sintered body, and therefore the content is preferably 500 ppm or less.

  Since aluminum nitride is a hardly sinterable material, it is preferable to add a sintering aid to the AlN raw material powder. As the sintering aid to be added, a rare earth element compound is preferable. The rare earth element compound reacts with the aluminum oxide or aluminum oxynitride present on the surface of the AlN powder particles during sintering to promote the densification of the aluminum nitride and to increase the thermal conductivity of the aluminum nitride sintered body. Since it also has a function of removing oxygen that causes the decrease, the thermal conductivity of the obtained aluminum nitride sintered body can be improved.

  In addition, as the rare earth element compound of the sintering aid, oxides, nitrides, fluorides, stearic acid compounds, and the like can be used. Of these, oxides are preferable because they are inexpensive and easily available. In addition, since the stearic acid compound has high affinity with the organic solvent, mixing the AlN raw material powder and the sintering aid with the organic solvent is particularly preferable because the mixing property becomes high.

  The rare earth element compound is preferably an yttrium compound that is particularly effective in removing oxygen, and the amount added is preferably 0.01 to 5 wt%. When the addition amount is less than 0.01 wt%, it is difficult to obtain a dense sintered body, and the thermal conductivity of the sintered body is lowered. Moreover, when the addition amount exceeds 5 wt%, a sintering aid exists at the grain boundaries of the aluminum nitride sintered body. When used in a corrosive atmosphere, the sintering aid present at the grain boundaries is Etching causes degranulation and particles. Furthermore, the preferable amount of addition of the sintering aid is 1 wt% or less. In this case, since the sintering aid does not exist at the triple point of the grain boundary, the corrosion resistance is improved.

  Next, a predetermined amount of a solvent, a binder and, if necessary, a dispersant and a glaze are added to and mixed with the AlN raw material powder and the sintering aid powder. As a mixing method, ball mill mixing, ultrasonic mixing, or the like is possible. By such mixing, a raw material slurry of aluminum nitride can be obtained.

  An aluminum nitride sintered body can be manufactured by molding and sintering the obtained slurry. For example, granules are produced from the slurry by a technique such as a spray dryer, and the granules are inserted into a predetermined mold and subjected to press molding. The pressing pressure at this time is desirably 9.8 MPa or more. When the pressure is less than 9.8 MPa, the strength of the molded body is often not sufficiently obtained, and is easily damaged during handling.

Moreover, although the density of a molded object changes with content of a binder, and the addition amount of a sintering auxiliary agent, it is preferable that it is 1.5 g / cm < ³ > or more. When the density of the compact is less than 1.5 g / cm ³ , the distance between the raw material powder particles becomes relatively large, so that the sintering is difficult to proceed. Further, if the density of the molded body exceeds 2.5 g / cm ³ , it is difficult to sufficiently remove the binder in the molded body by the degreasing process in the next step, and thus it becomes difficult to obtain a dense sintered body. The density of the molded body is preferably 2.5 g / cm ³ or less.

  Next, the molded body is heated in a non-oxidizing atmosphere to perform a degreasing treatment. When the degreasing treatment is performed in an oxidizing atmosphere such as the air, the surface of the AlN powder is oxidized, so that the thermal conductivity of the obtained sintered body is lowered. As the non-oxidizing atmosphere gas, nitrogen or argon is preferable. The amount of carbon remaining in the molded body after the degreasing treatment is preferably 1.0 wt% or less. If carbon exceeding 1.0 wt% remains, sintering is inhibited, and a dense sintered body cannot be obtained.

  The heating temperature in the degreasing treatment is preferably 500 ° C. or higher and 1000 ° C. or lower. When the temperature is less than 500 ° C., the binder cannot be sufficiently removed, and therefore, excessive carbon remains in the molded body after the degreasing treatment, and sintering in the subsequent sintering step is hindered. Further, at a temperature exceeding 1000 ° C., the amount of remaining carbon becomes too small, so that the ability to remove oxygen from the oxide film present on the surface of the AlN powder is lowered, and the thermal conductivity of the obtained sintered body is lowered. .

  Thereafter, the degreased shaped body is sintered. Sintering is performed at a temperature of 1700 to 2000 ° C. in a non-oxidizing atmosphere such as nitrogen or argon. The moisture contained in the atmosphere gas such as nitrogen used is preferably −30 ° C. or less in terms of dew point. When it contains more moisture, AlN reacts with moisture in the atmospheric gas during sintering to form oxynitrides, which may reduce the thermal conductivity of the sintered body. Moreover, it is preferable that the oxygen amount in atmospheric gas is 0.001 vol% or less. If the amount of oxygen is large, the surface of AlN may be oxidized and the thermal conductivity may be reduced.

  Furthermore, a boron nitride (BN) compact is suitable as a jig used during sintering. This BN compact has sufficient heat resistance to the above sintering temperature of 1700 to 2000 ° C., and its surface has solid lubricity, so that a jig for contracting the compact during sintering Since the friction with the molded body can be reduced, a sintered body with less distortion can be obtained.

  The obtained AlN sintered body is processed as necessary to obtain a mounting table. The surface roughness of the mounting surface on which the workpiece is mounted is preferably 5 μm or less in terms of Ra. If the surface roughness is more than 5 μm in Ra, the AlN degranulation may increase due to the friction between the mounting surface and the workpiece. The degranulated particles become particles and adversely affect the processing such as film formation or etching on the object to be processed. Further, it is more preferable that the surface roughness of the mounting surface is 1 μm or less in terms of Ra.

  The mounting table is mechanically connected by a connecting screw having a bearing mechanism after combining a resistance heating element, a pressing plate, and an insulating sheet and a pressing plate as necessary. This is accommodated in a container and supported by a rod or the like, or is supported by a bottomed cylindrical support. Further, if necessary, a movable cooling plate can be installed and brought into contact with or separated from the holding plate with an air cylinder or the like.

  Next, a procedure for heat-treating an object to be heated using the heater unit of the present invention will be described. First, the heater plate is heated by energizing the resistance heating element of the heater plate in a low temperature state. Thereafter, an object to be heated such as a wafer is mounted on the mounting surface, and the object to be heated is heated for about 60 to 180 seconds. When the processing is completed, the object to be heated is taken out and the next object to be heated is mounted on the placement surface. After the necessary amount of heat treatment is completed, the temperature condition is changed for another heat treatment.

  When changing the temperature condition, when changing to a higher temperature side, the temperature can be easily changed by changing the energization condition as it is. On the other hand, in the case of changing to a lower temperature side, after energizing the heater unit is temporarily stopped, the cooling plate is raised and brought into contact with the back surface of the heater plate, or the heater plate is used by using the built-in cooling plate. The heat of the heater plate is released to the cooling plate, so that the temperature of the heater plate and thus the heated object is rapidly lowered. At this time, a coolant such as cooling water flows through the coolant flow path of the cooling plate, and the heat transmitted to the cooling plate is absorbed by the coolant, so that the heat can be effectively exhausted outside the unit.

  Thereafter, when it is detected that the temperature measuring thermometer or temperature sensor for controlling the heater has almost reached the set temperature, the resistance heating element is again energized to maintain the set temperature. Thus, throughput can be improved by changing the temperature condition during cooling in a short time.

  The heater unit according to the present invention is preferably mounted on a semiconductor manufacturing / inspection apparatus or a flat display panel manufacturing / inspection apparatus. The manufacturing / inspection apparatus equipped with the heater unit according to the present invention can raise and lower the temperature at a higher speed than the conventional one, and a stable in-plane temperature uniformity (thermal uniformity) can be obtained. Therefore, not only can the performance, yield, and reliability of semiconductor devices and flat display panels be improved, but the time required for the heat treatment process is shortened compared to conventional devices, and the productivity of semiconductor devices and flat display panels is improved. Can be achieved.

[Example 1]
AlN powder and a sintering aid were mixed, a binder and a solvent were mixed, granules were produced by spray drying, and then press molded. The compact was degreased in a nitrogen atmosphere and sintered at 1850 ° C. in a nitrogen atmosphere to obtain a sintered body. The AlN powder used has an average particle size of 0.6 μm and a specific surface area of 3.4 m ² / g. The obtained AlN sintered body was processed into an AlN mounting table having a diameter of 330 mm and a thickness of 6 mm. Further, a mounting table made of Al ₂ O ₃ was also produced in the same manner as described above except that the material was Al ₂ O ₃ .

For each of the AlN and Al ₂ O ₃ mounting tables, a resistance heating element of a spiral circuit pattern made of SUS foil or Ni-Cr foil on the back surface opposite to the wafer mounting surface, and if necessary The insulating sheet and the pressing plate (Al, Cu) are superposed in this order, and are joined by a conventional connecting screw (without a bearing mechanism) that has been used in the past. A plate was made. In addition, a Kovar terminal having substantially the same thermal expansion coefficient was attached to the power supply portion of the resistance heating element, and the power supply wiring was connected to enable energization. A temperature sensor was embedded to monitor the temperature.

  Further, using the AlN mounting table, a resistance heating element of a spiral circuit pattern made of SUS foil or Ni-Cr foil on the back surface opposite to the wafer mounting surface, and an insulating sheet as required Sample plate 3 is an example of the present invention. The pressing plates (Al, Cu, SUS) are superposed in this order, and are joined by four (one at the center, three at the outer periphery) connecting screws provided with a bearing mechanism. ~ 5 heater plates were prepared. The bearing mechanism of the connecting screw is one in which ten bearing balls having a diameter of 2 mm and a sphericity of 10 μm are held in a bearing groove having a depth of 1.5 mm provided on the seating surface of the male screw head. Moreover, the connecting screw fixed the screwing part to the mounting base etc. with the adhesive agent. The installation of the power supply wiring and temperature sensor was the same as described above.

  As a possible cooling plate, two aluminum alloy plates having a diameter of 330 mm and a thickness of 10 mm were prepared, and a surface that contacted one of the heater plates was manufactured by machining so that the flatness was 200 μm. The contact surface was provided with Ni cermet (metal foam) having a thickness of 1.5 mm so as to prevent partial contact and uniformly contact the entire surface. Further, each of the two aluminum alloy plates was provided with through holes for inserting a power supply wiring, a temperature sensor, and a rod supporting the heater plate.

  Further, a phosphorus deoxidized copper pipe having a diameter of 6 mm and an inner diameter of 4 mm was bent to form a flow path through which cooling water can flow. At both ends of the flow path, an inlet and an outlet for supplying and discharging cooling water were formed. This pipe was placed between the two aluminum alloy plates and fixed by screwing to produce a cooling plate having a flow path inside. The cooling plate is movable up and down by an elevating mechanism such as an air cylinder, and can contact or separate from the heater plate.

  The container was made of stainless steel (SUS), the side wall was 30 mm high, the inner diameter was 337 mm, the thickness was 1.5 mm, and the bottom wall was 3 mm thick. This container is provided with an opening for fastening a power supply wiring, a temperature sensor, and a rod for supporting the heater plate and the cooling plate to the container. In this SUS container, each heater plate of Samples 1 to 5 and a movable cooling plate were assembled by using a rod, an elevating mechanism or the like to complete a heater unit.

  Table 1 below shows the types of the mounting table and the pressing plate, the thermal expansion coefficient, and the presence or absence of the bearing mechanism of the connecting screw for each of the heater units of Samples 1 to 5. Moreover, about each heater unit, using a well-known electric micrometer, the height of 2 points | pieces of the center part and outer periphery part on a mounting base in normal temperature, and 2 point heights when a heater is heated up to 200 degreeC. Each was measured, and the difference in displacement between these two points was determined. The obtained results are shown in Table 2 below.

Sample 1 of the comparative example uses an AlN mounting table and an Al holding plate and uses a conventional connecting screw without a bearing mechanism, but the displacement of the central portion and outer peripheral portion of the mounting table when heated at 200 ° C. The difference in quantity was as large as 22.1 μm. Further, in the sample 2 in which the mounting table is made of Al ₂ O ₃ and the pressing plate is made of Cu for the purpose of reducing the difference in thermal expansion coefficient between the mounting table and the pressing plate without the conventional bearing mechanism. The difference in displacement between the central part and the outer peripheral part of the mounting table during heating at 200 ° C. was 18.3 μm.

  On the other hand, in the case of Samples 3 to 5 of the example of the present invention having the bearing mechanism on the connecting screw, regardless of the difference in thermal expansion coefficient between the mounting table and the pressing plate, and regardless of the material of the pressing plate, The difference in displacement between the central part and the outer peripheral part kept a small value of 10 μm or less, and the deterioration of the flatness of the mounting surface could be suppressed.

[Example 2]
In the same manner as in Example 1, a heater plate was fabricated using a connecting screw having an AlN mounting table, a Cu pressing plate, and a bearing mechanism. At that time, the number of bearing balls per connecting screw was changed as shown in Table 3 below. About each heater unit of the obtained samples 6-9, it calculated | required similarly to the said Example 1, and calculated | required the displacement amount of the center part and outer peripheral part of a mounting base at the time of 200 degreeC heating, and the difference of the displacement amount The results are shown in Table 3 below.

  In the sample 6 having one bearing ball per connection screw, the connection screws are not balanced, and the axial force of the connection screws is not applied to the mounting table and the holding plate in the vertical direction. It turned out that an effect is not demonstrated. On the other hand, in the samples 7 to 9 having three or more bearing balls per connecting screw, the bearing balls roll in the expansion direction along with the thermal expansion of the mounting table and the pressing plate, and the mounting table and the pressing plate are Since it expands freely without being constrained by the connecting screw, the difference in the displacement amount could be suppressed to 10 μm or less.

[Example 3]
In the same manner as in Example 1, a heater plate was fabricated using a connecting screw having an AlN mounting table, a Cu pressing plate, and a bearing mechanism. At that time, the sphericity of the bearing ball used was changed as shown in Table 4 below. About each heater unit of the obtained samples 10-15, it obtained by calculating | requiring the difference of the displacement amount of the center part and outer periphery part of the mounting base at the time of 200 degreeC heating similarly to the said Example 1, and the displacement amount. The results are shown in Table 4 below.

  If the sphericity of the bearing ball exceeds 30 μm, the bearing ball does not roll smoothly when the mounting table or the pressing plate expands, and the mounting table and the pressing plate are restrained by friction. It has been found that the difference in displacement between the central portion and the outer peripheral portion increases, and the flatness of the mounting table deteriorates.

[Example 4]
In the same manner as in Example 1, a heater plate was fabricated using a connecting screw having an AlN mounting table, a Cu pressing plate, and a bearing mechanism. At that time, the number of connecting screws used for coupling the mounting table and the like was changed as shown in Table 5 below so as to be evenly arranged. About each heater unit of the obtained samples 16-20, it calculated | required similarly to the said Example 1, and calculated | required the displacement amount of the center part and outer periphery part of the mounting base at the time of 200 degreeC heating, and the difference of the displacement amount The results are shown in Table 5 below.

  Sample 16 has one connecting screw only at the center of the heater, and sample 17 has three connecting screws arranged at equal intervals on the outer periphery, both of which are located at the center and outer periphery of the mounting table when heated at 200 ° C. The difference in displacement was extremely large. On the other hand, in the sample 18 with one connecting screw and three outer peripheral parts, the sample 19 with one central part and six outer peripheral parts, the sample 20 with one central part, three intermediate parts and six outer peripheral parts, In either case, the difference in displacement between the central portion and the outer peripheral portion of the mounting table during heating at 200 ° C. could be suppressed to 10 μm or less.

[Example 5]
In the same manner as in Example 1, a heater plate was fabricated using a connecting screw having an AlN mounting table, a Cu pressing plate, and a bearing mechanism. At that time, the diameter of the used bearing ball was changed as shown in Table 6 below. In addition, the depth of the bearing groove was appropriately changed in accordance with the diameter of each bearing ball so that it could be held.

  About each heater unit of the obtained samples 21 to 26, the in-plane temperature distribution immediately after the cooling plate was brought into contact with the heater plate kept at 180 ° C. and cooled from 180 ° C. to 130 ° C. was 17 points. Measurements were taken with a temperature measuring Si wafer, and the results obtained are also shown in Table 6 below. Further, in the same manner as in Example 1, the amount of displacement between the central portion and the outer periphery of the mounting table during heating at 200 ° C. and the difference between the amounts of displacement were determined.

  As a result, regardless of the diameter of the bearing ball, the difference in displacement between the central portion and the outer peripheral portion of the mounting table was 10 μm or less. However, as can be seen from Table 6, when the diameter of the bearing ball exceeds 4 mm, the in-plane thermal uniformity during cooling is significantly reduced. This is because if the bearing ball diameter exceeds 4 mm, the seating surface of the connecting screw for providing the bearing groove becomes large. Therefore, the counterbore depth and the counterbore diameter provided on the movable cooling plate so as to escape the large seating surface are large. Therefore, unevenness occurs in the cooling degree of the cooling plate, and the heat uniformity during cooling is significantly deteriorated.

[Example 6]
In the same manner as in Example 1, a heater plate was fabricated using a connecting screw having an AlN mounting table, a Cu pressing plate, and a bearing mechanism. At that time, in Samples 27 to 28, no adhesive was applied to the threaded portion of the connection screw, and in Samples 29 to 31, the adhesive shown in Table 7 below was applied to bond and fix the connection screw. Sample 27 used a normal connection screw without a bearing mechanism, but sample 28 used a connection screw having the same bearing mechanism as sample 3 of Example 1 above.

  About each heater unit of samples 27-31, the torque management of 20 cN * m was performed and the connecting screw was tightened. Then, after repeating the heat cycle to normal temperature and 200 degreeC 10 times, the return torque of the connection screw was measured, and the obtained result was combined with following Table 7, and was shown.

  Samples 29 to 31 in which the connecting screws having the bearing mechanism were fixed with an adhesive had a high return torque of 10 cN · m or more. However, it was found that in the sample 27 in which the connecting screw having the bearing mechanism is not fixed with an adhesive, the return torque becomes very small, and there is a high risk that the connecting screw is loosened during use. In addition, it can be seen that the sample 28 using a normal connection screw having no bearing mechanism has a sufficient return torque even if it is not fixed with an adhesive, and the risk of screw loosening is small.

It is a schematic sectional drawing which shows one specific example of a heater unit. It is a schematic sectional drawing which shows the other specific example of a heater unit. It is general | schematic sectional drawing which shows one specific example of the heater plate using the conventional connection screw. It is a schematic sectional drawing which shows the specific example of the heater plate which connected the some plate-shaped member using the connection screw provided with the bearing mechanism of this invention. It is a schematic sectional drawing which shows the combination of a some plate-shaped member. It is general | schematic sectional drawing which shows the specific example which connected the some plate-shaped member containing a cooling plate using the connection screw provided with the bearing mechanism of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heater plate 2a Movable cooling plate 2b Cooling plate 3 Container 5 Support body 6 Mounting base 7 Resistance heating element 8 Insulation sheet 9 Holding plate 10 Connecting screw 11a, 11b Bearing groove 12 Bearing ball

Claims (16)

In a heater unit for a semiconductor device manufacturing / inspection apparatus for mounting and heating a wafer on a mounting table, two or more plate-like members including the mounting table are mechanically connected by a connecting screw, and the connection A heater unit for a semiconductor device manufacturing / inspection apparatus , wherein a screw includes a bearing mechanism, and a threaded portion of the connection screw is fixed to the plate-like member with an adhesive . These plate-like members are provided with a mounting table for mounting and heating the wafer , a resistance heating element for heating the mounting table, and a pressing plate for mechanically pressing the resistance heating element against the mounting table. For a semiconductor device manufacturing / inspection device , wherein the connecting screw is mechanically connected with a connecting screw having a bearing mechanism, and a threaded portion of the connecting screw is fixed to the plate-like member with an adhesive . Heater unit. The heater unit for a semiconductor device manufacturing / inspection device according to claim 2, further comprising a movable cooling plate that contacts or separates from the pressing plate. A mounting table for mounting and heating a wafer , a resistance heating element for heating the mounting table, and a cooling plate for cooling the mounting table, these plate-like members having a bearing mechanism A heater unit for manufacturing / inspecting a semiconductor device, wherein the heater unit is mechanically connected with a screw, and a threaded portion of the connecting screw is fixed to the plate-like member with an adhesive . The semiconductor device manufacturing / inspection according to claim 4, further comprising a pressing plate outside the cooling plate, wherein the mounting table and the pressing plate are mechanically connected by the connecting screw. Heater unit for equipment . The heater unit for a semiconductor device manufacturing / inspection apparatus according to claim 1 , wherein four or more connecting screws are arranged. The bearing mechanism includes a bearing groove provided on either the seat surface of the male screw head of the connection screw or the surface of the plate-like member facing the seat surface, and a bearing ball held in the bearing groove. The heater unit for a semiconductor device manufacturing / inspection device according to claim 1 , wherein the depth of the bearing groove is equal to or less than the diameter of the bearing ball. 8. The heater unit for a semiconductor device manufacturing / inspecting device according to claim 7 , wherein three or more bearing balls are used per one connecting screw. 9. The heater unit for manufacturing / inspecting a semiconductor device according to claim 7 , wherein the sphericity of the bearing ball is 30 [mu] m or less. The heater unit for a semiconductor device manufacturing / inspection device according to any one of claims 7 to 9 , wherein a diameter of the bearing ball is 4 mm or less. The heater unit for a semiconductor device manufacturing / inspection device according to any one of claims 7 to 10 , wherein a material of the bearing ball is any one selected from ceramics, stainless steel, iron, and nickel. . 12. The heater unit for a semiconductor device manufacturing / inspection device according to claim 1 , wherein at least two of the plate-like members are made of materials having different coefficients of thermal expansion. 13. The heater unit for manufacturing / inspecting a semiconductor device according to claim 12 , wherein a difference in coefficient of thermal expansion between the two plate-like members is 1.0 × 10 ⁻⁹ / ° C. or more. The mounting table according to any one of claims 1 to 13 , wherein the mounting table is mainly composed of at least one selected from aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, copper, aluminum, nickel, and silicon. A heater unit for a semiconductor device manufacturing / inspection device according to 1 . 6. The pressing plate according to claim 2 or 5 , wherein the pressing plate is mainly composed of at least one selected from aluminum nitride, silicon carbide, aluminum oxide, silicon nitride, copper, aluminum, nickel, silicon, and stainless steel. A heater unit for manufacturing / inspecting apparatus of the semiconductor device described. 16. A semiconductor device manufacturing / inspection apparatus comprising the semiconductor device manufacturing / inspection apparatus heater unit according to claim 1 .

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