JP2005209981A - Cooling block, heater unit and apparatus mounting same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling block which makes the temperature distribution of a heater more uniform until the cooling end from the cooling start, a heater unit having a heater combined with the cooling block, and an apparatus mounting the same. <P>SOLUTION: The cooling block has a refrigerant passage the return way of which is disposed along the forward way thereof. The forward and return ways are preferably disposed on approximately the same plane and the spacing between both ways is preferably 15 mm or less. The chiller block is preferably made of a material having a thermal conductivity of 30 W/mK or higher. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cooling block, a heater unit in which the cooling block and a heater substrate for performing heat treatment are combined, and an apparatus equipped with the heater unit. In particular, etching apparatus, sputtering apparatus, plasma CVD apparatus, low pressure plasma CVD apparatus, metal CVD apparatus, insulating film CVD apparatus, low dielectric constant film (low-K) CVD apparatus, MOCVD apparatus, degas apparatus, ion implantation apparatus, coater developer The present invention relates to a semiconductor manufacturing apparatus, a semiconductor inspection apparatus, a flat display panel manufacturing / inspection apparatus, and a photoresist heat treatment apparatus.

  Conventionally, in a semiconductor manufacturing process, various processes such as a film formation process and an etching process are performed on a semiconductor substrate (wafer) that is an object to be processed. In a semiconductor manufacturing apparatus that performs processing on such a semiconductor substrate, a ceramic heater for holding the semiconductor substrate and heating the semiconductor substrate is used.

  For example, in the photolithography process, a resist film pattern is formed on the wafer. In this process, the wafer is cleaned, heat-dried, cooled, coated with a resist film on the wafer surface, mounted on a ceramic heater in a photolithography processing apparatus, dried, and then subjected to processing such as exposure and development. Applied. In this photolithography process, since the temperature at which the resist is dried greatly affects the quality of the coating film, the temperature uniformity during the processing of the ceramic heater is important.

  In the CVD process, after cleaning and drying the wafer, the wafer is mounted on a ceramic heater in the CVD apparatus, and an insulating film or a metal film is formed on the wafer surface by a chemical reaction. Since the temperature during this chemical reaction greatly affects the quality of the insulating film and the metal film, the temperature uniformity of the ceramic heater is also important.

  Further, these wafer processes are required to be completed in as short a time as possible in order to improve the throughput. For this reason, the inventors have studied a semiconductor manufacturing apparatus having a cooling means in order to cool the heated heater in a short time. For example, Patent Document 1 proposes a semiconductor manufacturing apparatus including a cooling block that can be contacted and separated on the surface of the heater opposite to the wafer mounting surface.

Patent Document 2 proposes a semiconductor manufacturing apparatus in which a cooling liquid flow path is formed in a cooling block to further improve the cooling rate and to maintain uniformity of the heater temperature from the start of cooling to the end of cooling. did.
Japanese Patent Application No. 2002-163747 Japanese Patent Application No. 2003-387741

  In recent semiconductor manufacturing processes such as electronic devices, further uniformity of the temperature distribution of the heater is required, and the temperature distribution of the heater from the start of cooling to the end of cooling as well as during heating and holding is further increased. High uniformity is required.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cooling block that can make the temperature distribution of the heater more uniform from the start to the end of cooling, a heater unit that combines the cooling block and the heater, and an apparatus equipped with the same. It is.

  The inventors have studied to further uniform the temperature distribution of the heater from the start of cooling to the end of cooling in the technique of Patent Document 2, and as a result, the arrangement of the flow path of the cooling medium formed in the cooling block is It was found to affect the temperature distribution. That is, the cooling block of the present invention has a refrigerant flow path, and the return path of the refrigerant flow path is disposed along the forward path. It has been found that by arranging the refrigerant flow path in this way, the uniformity of the temperature distribution of the heater from the start of cooling to the end of cooling is improved. It is preferable that the forward path and the return path of the refrigerant flow path are disposed on substantially the same plane.

  The distance between the forward path and the return path of the refrigerant flow path is preferably 15 mm or less, the cooling block is preferably made of a material having a thermal conductivity of 30 W / mK or more, and the thermal conductivity is 100 W / mK. More preferably, it consists of the above materials.

  The surface of the cooling block is preferably nickel-plated. Furthermore, the material of the cooling block is preferably aluminum, and the surface of the cooling block is preferably anodized.

  Furthermore, the heater unit of the present invention comprises a heater substrate on which an object to be heated is placed and heat-treated, and any one of the cooling blocks. It is preferable that the cooling block is bonded to the heater substrate or has means for contacting and separating from the heater substrate.

  The main component of the heater is preferably aluminum nitride, aluminum oxide, silicon carbide, or silicon nitride, and particularly preferably aluminum nitride.

  A semiconductor manufacturing / inspection apparatus equipped with such a heater unit, a flat display panel manufacturing / inspection apparatus, or a photoresist heat treatment apparatus has a more uniform heater temperature distribution than conventional apparatuses. The characteristics, yield, reliability, integration degree, and image quality of the flat display panel can be improved.

  According to the present invention, it is possible to provide a cooling block that can make the temperature distribution of the heater more uniform from the start of cooling to the end of cooling, and a heater unit that combines the cooling block and the heater. A semiconductor manufacturing / inspection apparatus equipped with such a heater unit, a flat display panel manufacturing / inspection apparatus, or a photoresist heat treatment apparatus has a more uniform heater temperature distribution than conventional apparatuses. The characteristics, yield, reliability, integration degree, and image quality of the flat display panel can be improved.

  An embodiment of the present invention will be described with reference to FIG. FIG. 1 is an example of an embodiment of the present invention, and shows a schematic plan view of a refrigerant flow path 2 of a circular cooling block 1. A schematic plan view in the case of a rectangle is shown in FIG. The cooling block 1 is formed with a refrigerant flow path 2, and the forward path 2 a of the refrigerant flow path is disposed from the outer peripheral portion to the inner peripheral portion of the cooling block, and is folded at a folding portion 2 c near the center of the cooling block. It is connected to the return path 2b. The return path 2b of the refrigerant flow path is disposed on substantially the same plane along the forward path 2a.

  The cooling medium is introduced from the cooling medium inlet 3 to the forward path 2a of the cooling medium flow path, passes through the folded portion 2c, and goes out of the cooling block from the outlet 4 via the return path 2b. When the cooling block cools the heater in contact with the heater, for example, the cooling medium receives a substantially constant amount of heat per unit time from the entrance to the exit.

  Therefore, the temperature of the cooling medium begins to rise after entering the inlet, and the temperature rises in proportion to the length of the flow path. At this time, if the inlet and the outlet are arranged at substantially the same position of the cooling block and are arranged along the forward path and the return path of the refrigerant flow path, the lengths of the forward path and the return path become substantially the same, and the length of the refrigerant flow path Regardless of this, the average temperature on the forward and return paths is constant. Therefore, it has been found that the uniformity of the temperature distribution of the cooling block is improved. If the uniformity of the temperature distribution of the cooling block is improved, the uniformity of the temperature distribution of, for example, a heater cooled by the cooling block is improved.

  1 or 2, when the length of the forward path 2a is L, the temperature of the cooling medium at the inlet 3 is Tin, and the temperature rise of the cooling medium per unit length in the refrigerant channel is ΔT, The temperature of the cooling medium in the forward path at the distance x is Tin + ΔT · x. The temperature of the cooling medium in the return path at the same position is Tin + ΔT · (2L−x) because the length of the return path is the same as the length of the forward path.

  Therefore, the average temperature of the cooling medium in the forward path and the return path at the distance x from the inlet is Tin + ΔT · L, and is constant regardless of the position of the flow path of the cooling medium. Here, the positional relationship between the inlet 3 and the outlet 4 is preferably arranged so that the inlet is located on the center side of the cooling block as shown in FIGS. This is because the cooling effect of the entire cooling block is enhanced by setting the inlet having the lowest temperature of the cooling medium to the center side of the cooling block.

  When the distance between the forward path and the return path is wide, the effect of making the average temperature of the cooling medium constant becomes small, and the average temperature varies depending on the position of the flow path of the cooling medium. The uniformity of the temperature distribution of the cooling block is further improved when the distance between the forward path and the return path is 15 mm or less. Furthermore, when a material having a thermal conductivity of 30 W / mK or more is used as the material of the cooling block, the uniformity of the temperature distribution of the cooling block is further improved. For applications that require even higher uniformity, it is desirable to use one having a thermal conductivity of 100 W / mK or more.

  The material of the cooling block is preferably the one having the thermal conductivity, but considering workability and cost, it is more preferably a metal. Specific examples include pure aluminum, aluminum casting, chromium nickel steel, nickel steel, and pure iron. It is desirable that rust or the like does not occur on the abutting surface that abuts against a heater or the like that is an object to be cooled of the cooling block. When the material of the cooling block is made of metal, although there is a difference in degree, the abutment surface is somewhat altered as it is used. When the contact surface of the cooling block changes in quality, the cooling efficiency is lowered.

  Therefore, in order to suppress this surface alteration, it is desirable to nickel-plat at least the contact surface of the cooling block. Among the nickel platings, electroless nickel plating called so-called Kanisen plating is preferable. This is because electroless nickel plating is excellent in corrosion resistance, wear resistance, adhesion, thickness uniformity, and the like. When the material of the cooling block is aluminum, the surface may be anodized.

  The cooling block can be formed by engraving the coolant flow path on one plate with a drill or the like. However, in consideration of workability and cost, it is preferable to manufacture the cooling block by processing grooves on the two plates. For example, as shown to Fig.3 (a), the groove | channel used as a refrigerant | coolant flow path is processed and formed in both of two boards, and two boards are joined. Further, as shown in FIG. 3 (b), a groove serving as a coolant channel may be processed only in one plate. Further, as shown in FIG. 3C, grooves serving as the forward path and the return path of the refrigerant flow path may be processed in each plate. Furthermore, as shown in FIG. 3 (d), the forward and backward paths of the refrigerant flow path can be along the vertical direction using three plates.

  In any case, when joining the plates by screwing or the like, it is preferable to seal at least the outer peripheral portion with an O-ring or the like, because there is no possibility that the cooling medium leaks out of the cooling block. .

  A heater unit can be obtained by combining the above cooling block with a heater. As shown in FIG. 4, the cooling block may be joined to the heater 5 by a method such as screwing. In addition, as shown in FIG. 5, a cooling block may be installed using elevating means 6 such as an air cylinder so that the heater 5 can be brought into contact with and separated from the heater 5. 5A shows a state where the cooling block is in contact with the heater, and FIG. 5B shows a state where the cooling block is separated from the heater.

  It is preferable that the outer diameter shapes of the cooling block and the heater are substantially the same. If they are not substantially the same, even if the temperature distribution of the cooling block is uniform, the ability to cool the heater is uneven in the heater surface, and the temperature distribution of the heater being cooled becomes non-uniform.

  For example, in the case of a substantially circular heater, if the diameter of the cooling block is made larger than the diameter of the heater, the outer periphery of the heater is further cooled during cooling and the temperature falls below the center. The temperature difference increases. Conversely, when the diameter of the cooling block is made smaller than that of the heater, the temperature near the center of the heater is lowered, and the temperature difference between the center and the outer periphery of the heater is also increased. In the case of a substantially circular heater, the difference in diameter between the heater and the cooling block is preferably within ± 25%. In the case of a substantially rectangular heater, the difference in side length is preferably within ± 25%.

  By installing the above heater unit in the container, a semiconductor manufacturing / inspection apparatus, a flat display panel manufacturing / inspection apparatus, or a photoresist heat treatment apparatus can be obtained.

  For example, as shown in FIG. 6, the cooling block 1 is installed in the container 10 by elevating means 6 such as an air cylinder, and can contact and separate from the heater 5 as necessary. FIG. 6 shows a state where the cooling block 1 is separated. The cooling block 1 is provided with a through-hole for penetrating an insert such as an electrode 7 for supplying power and a temperature measuring means 8. These inserts and the container 10 may be hermetically sealed with a sealing material 9.

  When heating the heater or holding it at a high temperature, for the purpose of preventing a decrease in the heating rate and reducing power consumption, the cooling medium should not be flowed and the cooling medium should be flowed only when the heater is cooled. preferable. In addition, as shown in FIG. 6, when the cooling block is installed so that it can be contacted and separated, it is preferable that the cooling block is separated when the heater is heated or kept at a high temperature and is contacted during cooling. The cooling rate can be shortened by starting to flow the cooling medium before the contact. In addition, it is preferable on handling that the cooling medium is a liquid.

  The material of the heater of the present invention is preferably ceramic. Use of metal is not preferable because there is a problem that particles adhere to the wafer. As the ceramic, aluminum nitride or silicon carbide having high thermal conductivity is preferable if importance is attached to the uniformity of temperature distribution. If importance is placed on reliability, silicon nitride is preferable because it is strong and resistant to thermal shock. If importance is attached to the cost, aluminum oxide is preferable.

  Among these ceramics, aluminum nitride (AlN) is preferable in consideration of the balance between performance and cost. Below, the manufacturing method of the heater of this invention is explained in full detail in the case of AlN.

The raw material powder of AlN preferably has a specific surface area of 2.0 to 5.0 m ² / g. When the specific surface area is less than 2.0 m ² / g, the sinterability of aluminum nitride is lowered. On the other hand, if it exceeds 5.0 m ² / g, the aggregation of the powder becomes very strong, so that handling becomes difficult. Furthermore, 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 this range, the thermal conductivity of the sintered body decreases. In particular, group IV elements such as Si and iron group elements such as Fe as metal impurities have a high effect of reducing the thermal conductivity of the sintered body, and therefore the content is preferably 500 ppm or less.

  Since AlN is a hardly sinterable material, it is preferable to add a sintering aid to the AlN raw material powder. The sintering aid to be added is preferably a rare earth element compound. The rare earth element compound reacts with the aluminum oxide or aluminum oxynitride existing on the surface of the aluminum nitride powder particles during the sintering to promote the densification of the aluminum nitride and the thermal conductivity of the aluminum nitride sintered body. Therefore, the thermal conductivity of the aluminum nitride sintered body can be improved.

  The rare earth element compound is preferably an yttrium compound that is particularly effective in removing oxygen. The addition amount is preferably 0.01 to 5 wt%. If it is less than 0.01 wt%, it is difficult to obtain a dense sintered body, and the thermal conductivity of the sintered body decreases. If it exceeds 5 wt%, a sintering aid exists at the grain boundaries of the aluminum nitride sintered body. Therefore, when used in a corrosive atmosphere, the sintering aid present at the grain boundaries is etched. , Cause degranulation and particles. Furthermore, the amount of the sintering aid added is preferably 1 wt% or less. If it is 1 wt% or less, the sintering aid is not present at the triple point of the grain boundary, so that the corrosion resistance is improved.

  As the rare earth element compound, an oxide, nitride, fluoride, stearic acid compound, or the like can be used. Of these, oxides are preferable because they are inexpensive and readily available. In addition, since the stearic acid compound has a high affinity with an organic solvent, when the aluminum nitride raw material powder and the sintering aid are mixed with the organic solvent, the mixing property is particularly preferable.

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

  An aluminum nitride sintered body can be obtained by molding and sintering the obtained slurry. There are two types of methods, a cofire method and a post metallization method.

  First, the post metallization method will be described. Granules are prepared from the slurry by a technique such as spray drying. The granules are inserted into a predetermined mold and press-molded. At this time, the press pressure 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 by handling.

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. If it is less than 1.5 g / cm ³ , the distance between the raw material powder particles becomes relatively large, so that sintering does not proceed easily. Moreover, it is preferable that a molded object density is 2.5 g / cm < ³ > or less. If it exceeds 2.5 g / cm ³ , it will be difficult to sufficiently remove the binder in the molded body by the degreasing process in the next step. For this reason, it becomes difficult to obtain a dense sintered body as described above.

  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 sintered body is lowered. As the non-oxidizing atmosphere gas, nitrogen or argon is preferable. The heating temperature for 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 laminated body after the degreasing treatment, which inhibits sintering in the subsequent sintering step. Further, at a temperature exceeding 1000 ° C., the amount of remaining carbon becomes too small, so that the ability of the oxide film present on the surface of the AlN powder to remove oxygen is lowered, and the thermal conductivity of the sintered body is lowered.

  Moreover, it is preferable that the carbon amount which remains in the molded object after a degreasing process is 1.0 wt% or less. If carbon exceeding 1.0 wt% remains, sintering is inhibited, and a dense sintered body cannot be obtained.

  Next, sintering is performed. Sintering is performed at a temperature of 1700 to 2000 ° C. in a non-oxidizing atmosphere such as nitrogen or argon. At this time, it is preferable that the moisture contained in the atmosphere gas such as nitrogen used is −30 ° C. or less in terms of dew point. In the case of containing more moisture than this, AlN reacts with moisture in the atmospheric gas during sintering to form oxynitrides, which may reduce the thermal conductivity. 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 for the jig used during sintering. Since this BN compact has sufficient heat resistance to the sintering temperature and has a solid lubricating property on its surface, the friction between the jig and the laminate when the laminate shrinks during sintering. Therefore, a sintered body with less distortion can be obtained.

  The obtained sintered body is processed as necessary. When screen-printing the conductive paste in the next step, the surface roughness of the sintered body is preferably 5 μm or less in terms of Ra. If the thickness exceeds 5 μm, defects such as pattern bleeding and pinholes are likely to occur when a circuit is formed by screen printing. The surface roughness Ra is more preferably 1 μm or less.

  When polishing the above surface roughness, it is natural to screen print on both sides of the sintered body, but even when screen printing is performed only on one side, the surface opposite to the screen printed side is also polished. It is better to apply. When only the surface to be screen printed is polished, the sintered body is supported by the surface that is not polished during screen printing. At this time, there may be protrusions and foreign matters on the surface that has not been polished, so that the fixing of the sintered body becomes unstable, and the circuit pattern may not be drawn well by screen printing.

  At this time, the parallelism of both processed surfaces is preferably 0.5 mm or less. When the parallelism exceeds 0.5 mm, the thickness of the conductive paste may vary greatly during screen printing. The parallelism is particularly preferably 0.1 mm or less. Furthermore, the flatness of the screen printing surface is preferably 0.5 mm or less. Even in the case of flatness exceeding 0.5 mm, the variation in the thickness of the conductive paste may increase. A flatness of 0.1 mm or less is particularly suitable.

  A conductive paste is applied by screen printing to the polished sintered body to form an electric circuit. The conductive paste can be obtained by mixing metal powder, oxide powder as necessary, binder and solvent. The metal powder is preferably tungsten, molybdenum or tantalum from the viewpoint of matching the thermal expansion coefficient with ceramics.

In order to increase the adhesion strength with AlN, an oxide powder can also be added. The oxide powder is preferably an oxide of a IIa group element or a IIIa group element, Al ₂ O ₃ , SiO ₂ or the like. In particular, yttrium oxide is preferable because it has very good wettability to AlN. The addition amount of these oxides is preferably 0.1 to 30 wt%. When the content is less than 0.1 wt%, the adhesion strength between the metal layer, which is the formed electric circuit, and AlN is lowered. Moreover, when it exceeds 30 wt%, the electrical resistance value of the metal layer which is an electric circuit will become high.

  The thickness of the conductive paste is preferably 5 μm or more and 100 μm or less after drying. When the thickness is less than 5 μm, the electrical resistance value becomes too high and the adhesion strength also decreases. Moreover, also when exceeding 100 micrometers, adhesive strength falls.

  In addition, when the circuit pattern to be formed is a heater circuit (a heating element circuit), the pattern interval is preferably 0.1 mm or more. If the interval is less than 0.1 mm, when a current is passed through the heating element, a leakage current is generated depending on the applied voltage and temperature, resulting in a short circuit. In particular, when used at a temperature of 500 ° C. or higher, the pattern interval is preferably 1 mm or more, more preferably 3 mm or more.

  Next, the conductive paste is degreased and fired. Degreasing is performed in a non-oxidizing atmosphere such as nitrogen or argon. The degreasing temperature is preferably 500 ° C. or higher. If the temperature is less than 500 ° C., the binder in the conductive paste is not sufficiently removed, and carbon remains in the metal layer, and metal carbide is formed when baked, so that the electrical resistance value of the metal layer becomes high.

  Firing is preferably performed at a temperature of 1500 ° C. or higher in a non-oxidizing atmosphere such as nitrogen or argon. When the temperature is less than 1500 ° C., the particle growth of the metal powder in the conductive paste does not proceed, so that the electric resistance value of the fired metal layer becomes too high. The firing temperature should not exceed the sintering temperature of the ceramic. When the conductive paste is fired at a temperature exceeding the sintering temperature of the ceramic, the sintering aid contained in the ceramic begins to evaporate, and further, the grain growth of the metal powder in the conductive paste is promoted, and the ceramic and the metal layer. The adhesion strength of the is reduced.

Next, in order to ensure the insulation of the formed metal layer, an insulating coat can be formed on the metal layer. The material of the insulating coat is not particularly limited as long as the reactivity with the electric circuit is small and the difference in thermal expansion coefficient from AlN is 5.0 × 10 ⁻⁶ / K or less. For example, crystallized glass or AlN can be used. These materials can be formed, for example, by pasting them into a paste, performing screen printing with a predetermined thickness, degreasing as necessary, and firing at a predetermined temperature.

  Next, a ceramic substrate can be further laminated as required. Lamination is preferably performed via a bonding agent. The bonding agent is obtained by adding a IIa group element compound or a group IIIa element compound and a binder or a solvent to aluminum oxide powder or aluminum nitride powder, and applying the paste to the bonding surface by a method such as screen printing. Although there is no restriction | limiting in particular in the thickness of the bonding agent to apply | coat, it is preferable that it is 5 micrometers or more. When the thickness is less than 5 μm, bonding defects such as pinholes and bonding unevenness easily occur in the bonding layer.

  The ceramic substrate coated with the bonding agent is degreased at a temperature of 500 ° C. or higher in a non-oxidizing atmosphere. Thereafter, the ceramic substrates to be stacked are superposed, a predetermined load is applied, and the ceramic substrates are bonded together by heating in a non-oxidizing atmosphere. The load is preferably 5 kPa or more. When the load is less than 5 kPa, sufficient bonding strength cannot be obtained, or the above-described bonding defect is likely to occur.

  The heating temperature for bonding is not particularly limited as long as the ceramic substrates are sufficiently adhered to each other through the bonding layer, but is preferably 1500 ° C. or higher. If it is less than 1500 degreeC, sufficient joint strength is hard to be obtained and it will be easy to produce a joint defect. Nitrogen or argon is preferably used for the non-oxidizing atmosphere during the degreasing and bonding.

  As described above, a ceramic laminated sintered body serving as a heater can be obtained. For example, if the electric circuit is a heater circuit without using a conductive paste, for example, a molybdenum wire (coil), an electrostatic adsorption electrode or an RF electrode, a mesh of molybdenum or tungsten (network) It is also possible to use.

  In this case, the molybdenum coil and mesh are incorporated in the AlN raw material powder, and can be manufactured by a hot press method. The hot press temperature and atmosphere may be in accordance with the sintering temperature and atmosphere of AlN, but the hot press pressure is preferably 0.98 MPa or more. If it is less than 0.98 MPa, a gap may be formed between the molybdenum coil or mesh and AlN, and the performance of the heater may not be achieved.

  Next, the cofire method will be described. The raw material slurry described above is formed into a sheet by a doctor blade method. Although there is no restriction | limiting in particular regarding sheet shaping | molding, As for the thickness of a sheet | seat, 3 mm or less is preferable after drying. If the thickness of the sheet exceeds 3 mm, the amount of drying shrinkage of the slurry increases, so that the probability of cracking in the sheet increases.

  A metal layer to be an electric circuit having a predetermined shape is formed on the above-described sheet by applying a conductive paste by a technique such as screen printing. The same conductive paste as that described in the post metallization method can be used. However, in the cofire method, there is no problem even if the oxide powder is not added to the conductive paste.

  Next, the sheet on which the circuit is formed and the sheet on which the circuit is not formed are stacked. In the laminating method, each sheet is set at a predetermined position and overlapped. At this time, a solvent is applied between the sheets as necessary. In the state of being overlaid, heat as necessary. When heating, it is preferable that heating temperature is 150 degrees C or less. When heated to a temperature exceeding this, the laminated sheets are greatly deformed. Then, the stacked sheets are integrated by applying pressure. The applied pressure is preferably in the range of 1 to 100 MPa. If the pressure is less than 1 MPa, the sheets may not be sufficiently integrated and may peel during the subsequent steps. Further, when a pressure exceeding 100 MPa is applied, the deformation amount of the sheet becomes too large.

  This laminated body is degreased and sintered in the same manner as the above-described post metallization method. The degreasing treatment and sintering temperature, the amount of carbon, etc. are the same as in the post metallization method. When the conductive paste is printed on a sheet as described above, a heater circuit, an electrostatic adsorption electrode, etc. are printed on a plurality of sheets, respectively, and these are stacked to facilitate an energizing heat generating heater having a plurality of electric circuits. It is also possible to create it. In this way, a ceramic laminated sintered body serving as a heater can be obtained.

  In addition, when an electric circuit such as a heating element circuit is formed in the outermost layer of the ceramic laminate, in order to protect the electric circuit and ensure insulation, the electric circuit An insulating coating can be formed thereon.

  The obtained ceramic laminated sintered body is processed as necessary. Usually, in the sintered state, the accuracy required for a semiconductor manufacturing apparatus is often not reached. As for the processing accuracy, for example, the flatness of the workpiece mounting surface is preferably 0.5 mm or less, more preferably 0.1 mm or less. When the flatness exceeds 0.5 mm, a gap is likely to be formed between the workpiece and the ceramic heater, and the heat of the ceramic heater is not transmitted uniformly to the workpiece, and the temperature unevenness of the workpiece is likely to occur. Become.

  The surface roughness of the workpiece mounting surface is preferably 5 μm or less in terms of Ra. When the Ra exceeds 5 μm, AlN may be shed more frequently due to friction between the energizing heater and the workpiece. At this time, the shed particles become particles and have an adverse effect on processes such as film formation and etching on the object to be processed. Further, the surface roughness is preferably 1 μm or less in terms of Ra.

Mix 100 parts by weight of aluminum nitride powder and 0.6 parts by weight of yttrium stearate powder, mix 10 parts by weight and 5 parts by weight of polyvinyl butyral as a binder and dibutyl phthalate as a solvent. After the production, it was press-molded, degreased in a nitrogen atmosphere at 700 ° C., and sintered at 1850 ° C. in a nitrogen atmosphere to produce an aluminum nitride sintered body. The aluminum nitride powder used had an average particle size of 0.6 μm and a specific surface area of 3.4 m ² / g. The aluminum nitride sintered body was processed to have a diameter of 330 mm and a thickness of 15 mm.

Also, a W paste was prepared using 100 parts by weight of W powder having an average particle size of 2.0 μm, 1 part by weight of Y ₂ O ₃ , 5 parts by weight of ethyl cellulose as a binder, and butyl carbitol as a solvent. did. A pot mill and three rolls were used for mixing. The W paste was screen-printed to form a heating element circuit pattern on the processed aluminum nitride sintered body. Then, it degreased in 900 degreeC and nitrogen atmosphere, and baked at 1800 degreeC in nitrogen atmosphere. A ZnO—B ₂ O ₃ —Al ₂ O ₃ glass paste was applied to the surface on which the heating element circuit pattern was formed, applied to a thickness of 100 μm, excluding the power feeding portion, and baked at 700 ° C. in a nitrogen atmosphere. . In addition, a tungsten terminal was attached to the power feeding portion with a gold solder, and a nickel electrode was screwed to the tungsten terminal to complete the heater.

  Next, a pure aluminum plate having a diameter of 330 mm, a thickness of 12 mm, and 7 mm was prepared as a cooling block. The thermal conductivity of the pure aluminum plate is 200 W / mK. Among these, a flow path as shown in FIG. 1 for flowing a cooling medium having a width of 5 mm and a depth of 5 mm was formed by machining on an aluminum plate having a thickness of 12 mm. Further, a groove having a width of 2 mm and a depth of 1 mm for inserting an O-ring was formed on the outer periphery of the flow path. In addition, through holes were formed at the entrance and exit of the cooling medium. These two aluminum plates were fixed with screws by inserting an O-ring. In these aluminum plates, three through holes were formed so that the power supply electrode and thermocouple penetrated.

  Moreover, the cooling block of chromium nickel steel, nickel steel, pure iron, and aluminum casting was similarly prepared. Furthermore, in the cooling block of each material, the flow path of the cooling medium is formed on the center side from the position 10 mm from the outer periphery of the cooling block, and the total area of the flow path is 15% of the area of the contact surface of the cooling block, The distance between the forward path and the return path was set as shown in Table 1. In addition, this space | interval is a wall surface space | interval of each flow path of an outward path and a return path. Further, the surface roughness of the flow path where the cooling medium contacts is Ra 0.2 μm.

  Further, the warpage of the contact surface of the cooling block made of each material was 0.02 mm or less, and the outer peripheral corner portion of the contact surface was chamfered to 100 μm. For comparison, a cooling block having a conventional flow path pattern as shown in FIG. 7 was also made of each material. Except for the flow path pattern, it was finished in the same manner as in the example. In the flow path pattern of FIG. 7, there is no interval between the forward path and the return path, so in Table 1, it is described as a comparative example in the interval column.

  These heaters and a cooling block were attached to a container of a semiconductor manufacturing apparatus as shown in FIG. 6, and further, a power supply electrode and a thermocouple were attached through the through holes of the cooling block so that the heater could be heated by energization. At this time, the angle between the contact surface of the cooling block and the contact surface of the heater was set to be within 5 degrees.

  The heater was heated up to 400 ° C. as measured by a thermocouple and then held at 400 ° C. for 30 minutes to stabilize the temperature. During this time, the cooling block was separated from the heater, and the cooling medium was not flowed. Thereafter, the energization was stopped, the cooling block in which water was passed as a cooling medium was brought into contact with the heater, the heater was cooled, and the temperature variation ΔT when 250 ° C. was reached was measured. These results are shown in Table 1. The cooling water flow rate was 1000 cc / min.

  Note that a wafer thermometer was used to measure the temperature variation. A wafer thermometer was placed on the wafer mounting surface of the heater, and the difference between the maximum value and the minimum value of the measured value of the wafer thermometer was regarded as the temperature variation of the heater.

  As can be seen from Table 1, the cooling block of the present invention has small temperature variation and excellent uniformity of the heater temperature distribution. Further, it can be seen that the distance between the forward path and the return path is less than 15 mm when the temperature variation is small, and when this distance is 30 mm, the temperature variation approaches that when a conventional cooling block is used. It can also be seen that the temperature variation is smaller when the material of the cooling block is a thermal conductivity of 30 W / mK or more, and the temperature variation is further reduced when the material is 100 W / mK or more.

  The same aluminum nitride heater and pure aluminum cooling block as in Example 1 were prepared. Moreover, the surface of the cooling block made of pure aluminum was prepared by nickel plating and the surface subjected to alumite treatment. The distance between the forward path and the return path of the cooling block flow path was 15 mm. These aluminum nitride heater and cooling block were assembled in a container of a semiconductor manufacturing apparatus in the same manner as in Example 1.

  As in Example 1, the heater was heated up to 400 ° C. as measured by a thermocouple and held at 400 ° C. for 30 minutes to stabilize the temperature. Then, the energization was stopped and cooling was performed by flowing water as a cooling medium. The cycle in which the block is brought into contact with the heater, the heater is cooled to 50 ° C., and the temperature is raised again to 400 ° C. is repeated 1000 times, and the temperature variation ΔT when the temperature reaches 250 ° C. as in Example 1 is It was measured at the 1000th time. The results are shown in Table 2.

  As can be seen from Table 2, when the surface of the cooling block is not treated, the uniformity of the heater temperature deteriorates after 1000 repetitions, whereas when the nickel plating or alumite treatment is applied, the heater temperature is reduced. The uniformity of was almost unchanged even after 1000 times of repetition.

  When the contact surface with the heat of the cooling block after repeating 1000 times was observed, the contact surface with the heater of the cooling block subjected to nickel plating and alumite treatment maintained a metallic luster, but no treatment In the cooling block, innumerable protrusions such as white spots were generated. When this protrusion was analyzed, it was aluminum oxide. This is considered that pure aluminum was thermally oxidized. It is considered that since the protrusions are generated, the contact state between the cooling block and the heater is changed, and the uniformity of the heater temperature is deteriorated.

  The heater made from aluminum nitride of Example 1 and the cooling block made from pure aluminum were prepared. In addition to the cooling block prepared in Example 1, as shown in FIGS. 3 (a) and 3 (c), both 12 mm and 7 mm thick pure aluminum plates were grooved. Got ready. Further, three pure aluminum plates of 3 mm, 8 mm and 8 mm were prepared by performing groove processing as shown in FIG. The flow path for flowing the cooling medium had the same shape as that of Example 1, and was finished to a width of 5 mm and a depth of 5 mm when assembled in the cooling block. The distance between the forward path and the return path was 10 mm.

  These cooling block and aluminum nitride heater were assembled in a container of a semiconductor manufacturing apparatus in the same manner as in Example 1. In the same manner as in Example 1, the temperature variation ΔT when the temperature reached 250 ° C. was measured. The results are shown in Table 3.

  As can be seen from Table 3, the temperature variation in FIG. 3 (a) or FIG. 3 (b) where the forward path and the return path are formed on the same plane is the smallest, and in FIG. The variation was large, and the temperature variation of FIG. 3D, which was not on the same plane, was the largest.

  In the same manner as in Example 1, three types of heaters of aluminum oxide, silicon carbide, and silicon nitride were prepared. Four types of heaters were used in which the aluminum nitride heater prepared in Example 1 was added. The cooling block was made of pure aluminum, and the cooling block prepared in Example 1 with the distance between the forward path and the return path being 15 mm was assembled in the container in the same manner as in Example 1. Then, similarly to Example 1, the temperature variation ΔT of the heater at 250 ° C. was measured.

  In addition, after heating the heater to 400 ° C. as measured by a thermocouple, the temperature was stabilized by maintaining the temperature at 400 ° C. for 30 minutes, and when the energization was stopped, the cooling block in which cooling water was passed was brought into contact with the heater. The operation of cooling the heater to 50 ° C. and raising the temperature again was repeated 1000 times at maximum, and the number of times until the heater was damaged was examined. The results are shown in Table 4.

  As can be seen from Table 4, aluminum nitride and silicon carbide are superior in temperature uniformity. In addition, it can be seen that other than aluminum oxide does not break in the cycle test and is highly reliable. Furthermore, it has been found that aluminum nitride is excellent in both temperature uniformity and reliability.

  The aluminum nitride heater used in Example 1 and a cooling block with a distance of 10 mm between the forward path and the return path were mounted on a resist heat treatment apparatus, and photolithography was performed. The resist used was an ultra-high resolution resist for KrF excimer laser steppers with a wavelength of 248 nm, pre-baked at 130 ° C. for 90 seconds and exposed at 130 ° C. for 90 seconds, and the line width variation (3σ) at 130 nm node was measured.

  As a result, the line width variation was 8 nm. On the other hand, when the same line width variation was measured using the cooling block of the flow path pattern of FIG. 7 used in Example 1, it was 13 nm. Thus, it has been found that the use of the cooling block of the present invention makes the temperature distribution of the heater much more uniform than in the prior art, so that the line width variation can be greatly reduced.

  The fact that the line width variation can be greatly reduced means that, for example, a transistor which is a semiconductor device includes elements such as an electrode wiring, an insulating film, and an impurity diffusion layer. Since the dimensions of these elements are very fine, from submicron meters to around 100 nm in recent years, high dimensional accuracy is required.

  These elements are formed through various heating-related processes such as ultra-thin chemical vapor deposition, etching, and photolithography processes. At this time, if the heating temperature varies within the surface of the semiconductor substrate that is the object to be processed, the dimensions of those elements vary. If there is little variation in the heating temperature and the temperature is uniform, the variation in the dimensions of those elements will be reduced, and the yield will be improved.

  Further, if the dimensional accuracy of these elements is improved, the design with finer dimensions becomes possible, and the degree of integration can be improved. That is, the characteristics of the semiconductor device can be improved. Also in a flat display panel, it is possible to improve characteristics such as yield improvement, uniformity of pixel characteristics over the entire panel surface, and high-definition image by pixel miniaturization.

  Therefore, if a semiconductor manufacturing / inspection apparatus equipped with the heater unit of the present invention, a flat display panel manufacturing / inspection apparatus, or a photoresist heat treatment apparatus is used, the characteristics, yield, reliability, or integration degree of the semiconductor or flat display panel will be described. And image quality can be improved.

  According to the present invention, it is possible to provide a cooling block that can make the temperature distribution of the heater more uniform from the start of cooling to the end of cooling, and a heater unit that combines the cooling block and the heater. A semiconductor manufacturing / inspection apparatus equipped with such a heater unit, a flat display panel manufacturing / inspection apparatus, or a photoresist heat treatment apparatus has a more uniform heater temperature distribution than conventional apparatuses. The characteristics, yield, reliability, integration degree, and image quality of the flat display panel can be improved.

It is a plane schematic diagram which shows an example of the refrigerant flow path of the cooling block of this invention. It is a plane schematic diagram which shows another example of the refrigerant flow path of the cooling block of this invention. It is a cross-sectional schematic diagram which shows the formation form of the refrigerant flow path of the cooling block of this invention. It is a cross-sectional schematic diagram which shows an example of a structure of the heater unit of this invention. It is a cross-sectional schematic diagram which shows an example of the other structure of the heater unit of this invention. It is a cross-sectional schematic diagram which shows an example of a structure of the apparatus of this invention. It is a plane schematic diagram which shows the refrigerant | coolant flow path of the conventional cooling block.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling block 2 Refrigerant flow path 3 Cooling medium inlet 4 Cooling medium outlet 5 Heater 6 Lifting means 7 Feed electrode 8 Temperature measuring means 9 Sealing material 10 Container

Claims (13)

  A cooling block having a refrigerant flow path, wherein the return path of the refrigerant flow path is disposed along the forward path.   The cooling block according to claim 1, wherein the forward path and the return path of the refrigerant flow path are arranged on substantially the same plane.   The cooling block according to claim 1 or 2, wherein an interval between the forward path and the return path of the refrigerant flow path is 15 mm or less.   The cooling block according to any one of claims 1 to 3, wherein the cooling block is made of a material having a thermal conductivity of 30 W / mK or more.   The cooling block according to claim 1, wherein a surface of the cooling block is plated with nickel.   The cooling block according to any one of claims 1 to 4, wherein a material of the cooling block is aluminum, and a surface of the cooling block is anodized.   A heater unit comprising: a heater substrate on which an object to be heated is placed and heat-treated; and the cooling block according to any one of claims 1 to 6.   The heater unit according to claim 7, wherein the cooling block has means for contacting and separating from the heater substrate.   The heater unit according to any one of claims 1 to 8, wherein a main component of the heater is any one of aluminum nitride, aluminum oxide, silicon carbide, and silicon nitride.   The heater unit according to any one of claims 1 to 8, wherein a main component of the heater is aluminum nitride.   A semiconductor manufacturing / inspection apparatus equipped with the heater unit according to claim 7.   11. A flat display panel manufacturing / inspection apparatus on which the heater unit according to claim 7 is mounted. A photoresist heat treatment apparatus equipped with the heater unit according to claim 7.

Images