JP2005286106A - Heater unit and device loading the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heater unit, in which temperature distribution of a heater can be made uniform from start of cooling to termination of cooling and cooling speed is further improved. <P>SOLUTION: The heater unit is provided with a heater substrate in which a heating element circuit and an insulating film protecting the heating element circuit are formed at a rear face, and which loads an object to be heated on a main face opposite to the rear face and heats it and a cooling block that can abut on/be detached from the rear face of the heater substrate. The sum total of the flatness of an abutment face of the heater substrate and the cooling block is not more than 0.8 mm. It is the same as the heater substrate, where the heating element circuit is formed in the inside. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heater unit including a substrate to be heated and heat-treated, a cooling block for cooling the heater substrate, and an apparatus including 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, or a flat display panel manufacturing / inspection 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. Further, further improvement in the cooling rate is also required.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a heater unit that can make the temperature distribution of the heater from the start of cooling to the end of cooling more uniform and further improve the cooling rate, and a device equipped with the heater unit.

  As a result of studying the technique of Patent Document 1 or Patent Document 2 to further uniform the temperature distribution of the heater from the start of cooling to the end of cooling and further improve the cooling speed, the inventors have found that the cooling block and the heater unit It was found that the flatness of the contact surface affects the temperature distribution and cooling rate of the heater.

  For example, as shown in FIG. 4, if the gap between the heater block 2 having the heating element circuit 22 and the insulating layer 23 protecting the heating element circuit formed on the back surface and the cooling block 3 is large, the temperature of the heater It has been found that the distribution is non-uniform and the cooling rate is slow. Further, as shown in FIG. 5, the same applies to the heater substrate 2 in which the heating element circuit 22 is formed.

  That is, in the heater unit of the present invention, a heater substrate on which a heating element circuit and an insulating film for protecting the heating element circuit are formed on the back surface, and an object to be heated is mounted on the main surface opposite to the back surface. In addition, in the heater unit having the cooling block that can contact and be separated from the back surface of the heater substrate, the total flatness of the contact surfaces of the heater substrate and the cooling block is 0.8 mm or less.

  Alternatively, a heater circuit in which a heating element circuit is formed and a heating target is mounted on the main surface and heat-treated, and a cooling block that can be in contact with and separated from the back surface opposite to the main surface of the heater substrate The total flatness of the contact surfaces of the heater substrate and the cooling block is 0.8 mm or less.

  In the heater unit, the surface roughness of the contact surface between the heater substrate and the cooling block is preferably 5 μm or less in terms of Ra. Further, in the case of a heater substrate having a heating element circuit and an insulating film for protecting the heating element circuit formed on the back surface, the thickness of the insulating film for protecting the heating element circuit is 15 μm or more and 500 μm or less, and is insulated. The difference between the maximum value and the minimum value of the film thickness is preferably 200 μm or less.

  It is preferable that the main component of the ceramic heater is at least one selected from the group consisting of aluminum nitride, silicon carbide, aluminum oxide, and silicon nitride, and more preferably aluminum nitride.

  A semiconductor manufacturing / inspection device equipped with such a heater unit or a flat display panel manufacturing / inspection device can improve the cooling rate and make the heater temperature distribution more uniform than conventional devices. As a result, the throughput is greatly improved, and the characteristics and yield, reliability, integration, and image quality of the semiconductor and flat display panel can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the heater unit which can make temperature distribution of a heater more uniform from a cooling start to a cooling end can be provided. Semiconductor manufacturing / inspection equipment equipped with such a heater unit or flat display panel manufacturing / inspection equipment has a more uniform heater temperature distribution than conventional equipment, so the characteristics and yield of semiconductors and flat display panels In addition, reliability, integration degree and image quality can be improved. Further, since the cooling rate is improved, the heat treatment time can be shortened in the apparatus, and the productivity can be improved.

  An embodiment of the present invention will be described with reference to FIG. FIG. 2 is an example of an embodiment of the present invention, in which a heating element circuit 22 and an insulating layer 23 for protecting the heating element circuit are formed on the back surface of the ceramic substrate 21 and contact with the cooling block 3 of the heater substrate 2. The surface 4 is flattened so that the sum of the flatness of the surface 4 and the flatness of the contact surface 5 with the heater substrate of the cooling block is 0.8 mm or less. More preferably, the total flatness is 0.4 mm or less.

  Conventionally, it has been proposed to improve the flatness and surface roughness of the heater substrate main surface on which the object to be heated is mounted, and to make the temperature distribution of the object to be heated uniform, but in the heater unit having a cooling block, There has been no proposal to improve the flatness of the contact surfaces of the heater substrate and the cooling block to make the temperature distribution uniform and to improve the cooling rate.

  By flattening both the flatness of the contact surface 4 of the heater substrate 2 with the cooling block 3 and the flatness of the contact surface 5 of the cooling block with the heater substrate, the heater substrate and the cooling block are made uniform over the entire surface. Since the contact between them and the adhesion between the two is further improved, the heat transfer rate is improved, and when the cooling block is brought into contact with the heater substrate, the cooling rate is improved and the entire back surface of the heater substrate is uniformly distributed. Since it is cooled, the uniformity of the temperature distribution of the heater substrate during cooling is improved.

  Even if only one of the flatness of the contact surface 4 with the cooling block 3 of the heater substrate 2 and the flatness of the contact surface 5 with the heater substrate of the cooling block is flattened, the above effect cannot be obtained. The said effect can be acquired by making the sum total of both flatness into 0.8 mm or less.

  Further, as shown in FIG. 3, even in the case of the heater substrate 2 in which the heating element circuit 22 is formed and the object to be heated is mounted on the main surface, the heater substrate 2 is similarly applied. By making the total of the flatness of the contact surface 4 with the cooling block 3 and the flatness of the contact surface 5 with the heater substrate of the cooling block 0.8 mm or less, the uniformity of temperature distribution and cooling The effect of improving the speed can be obtained. Also in this case, it is more preferable that the sum of the flatness of both is 0.4 mm or less.

  In order to flatten the contact surfaces of the heater substrate and the cooling block, a known lapping method or a processing method such as grinding with a grindstone can be employed. The surface roughness after processing is preferably 5 μm or less in terms of Ra. By making the surface roughness of the contact surfaces of the heater substrate and the cooling block 5 Ra or less in Ra, the adhesion between the heater substrate and the cooling block is improved, and the uniformity of the temperature distribution of the heater substrate and the cooling rate are improved. .

  In particular, when the surface roughness of the contact surface of the heater substrate is improved to approach a mirror surface state, the radiation rate of the surface decreases. When the emissivity is lowered, the amount of heat released from the surface is reduced, which is preferable because it saves power for heating the heater substrate. In addition, when the heater substrate is ceramic, if the surface roughness is rough, the ceramic particles fall off due to friction when contacting the cooling block, which becomes particles and adversely affects the quality of the object to be heated. give. The surface roughness Ra is more preferably 1 μm or less.

  In addition, in the case of the heater substrate 2 in which the heating element circuit 22 and the insulating layer 23 for protecting the heating element circuit are formed on the back surface as shown in FIG. 2, in order to flatten the contact surface with the cooling block, If it is too much, the thickness of the insulating layer becomes thin, and in some cases, the heating element circuit is exposed, and there is a possibility of causing a short circuit accident. In order to prevent this, the thickness of the insulating layer may be increased. However, since the insulating layer often has a low thermal conductivity, the thicker the thickness, the higher the thermal resistance and the slower the cooling rate. Therefore, the thickness of the insulating layer is preferably 15 μm or more and 500 μm or less after planarization.

  Also, if the thickness of the insulating layer after planarization varies, the thermal resistance changes and the cooling rate varies, so the temperature distribution of the heater substrate tends to be non-uniform. Therefore, the thickness of the insulating layer after planarization is desirably uniform, and the difference between the maximum value and the minimum value of the insulating layer is preferably 200 μm or less.

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

  For example, as shown in FIG. 1, the cooling block 3 is installed in the container by elevating means 7 such as an air cylinder, and can contact and separate from the heater substrate 2 as necessary. FIG. 1 shows a state where the cooling block 3 is separated. The cooling block 3 is provided with a through-hole for passing through an insert 6 such as an electrode for supplying power and a temperature measuring means.

  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.

  Further, the back surface opposite to the main surface is processed to be flat. The flatness is such that the sum of the flatness of the contact surfaces of the cooling blocks to be combined is 0.8 mm or less.

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, press molding, degreasing in a nitrogen atmosphere at 700 ° C., and sintering in a nitrogen atmosphere at 1850 ° C., the aluminum nitride sintered body 21 shown in FIG. 2 was created. 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 12 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. Thereafter, degreasing was performed in a nitrogen atmosphere at 900 ° C., and firing was performed at 1800 ° C. in a nitrogen atmosphere to form a heating element circuit 22 having a thickness of 20 μm. A ZnO—B ₂ O ₃ —Al ₂ O ₃ based glass paste was applied to the surface on which the heating element circuit was formed, except for the power feeding portion, and fired at 700 ° C. in a nitrogen atmosphere, and an insulating layer having a thickness of 80 μm. 23 was formed. In addition, after polishing an insulating layer to be described later, a tungsten terminal was attached to the power feeding portion by screwing, and a nickel electrode was screwed to the tungsten terminal to complete the heater substrate 2.

  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. 2 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.

  The respective contact surfaces of the heater substrate and the cooling block were polished so as to have the flatness shown in Table 1. In addition, both surface roughness was Ra1.0micrometer.

  As shown in FIG. 1, the heater substrate and the cooling block are assembled using the support 9 and the lifting / lowering means 7 and the like, and the feeding electrode and the thermocouple penetration 6 are attached through the through holes of the cooling block. The heater can be heated by energization. As shown in FIG. 1, a bottomed cylindrical heat shield 8 having an inner surface height of 30 mm, an inner diameter of 333 mm, and a thickness of 1.5 mm (but the bottom surface thickness is 3 mm) is also attached to complete the heater unit 1. I let you.

  The heater substrate was heated up to 180 ° C. as measured by a thermocouple and then held at 180 ° C. for 90 seconds to stabilize the temperature. During this time, the cooling block was separated from the heater substrate, 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 substrate, and the heater substrate was cooled to 50 ° C.

  The temperature variation ΔT of the heater substrate when the temperature of the thermocouple reached 120 ° C. during cooling was measured. 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. The cooling time required for cooling from 180 ° C. to 50 ° C. was also measured. These results are shown in Table 1. The flatness in Table 1 is a result of measuring the contact surface at a pitch of 10 mm using a probe-type three-dimensional shape measuring instrument.

  As can be seen from Table 1, the total flatness is 0.8 μm or less, the cooling time can be within 8 minutes, and the temperature variation ΔT at 120 ° C. can also be within 1.0 ° C.

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, press molding, degreasing in a nitrogen atmosphere at 700 ° C., and sintering at 1850 ° C. in a nitrogen atmosphere, two aluminum nitride sintered bodies were produced. 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 12 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 one of the processed aluminum nitride sintered bodies. Thereafter, degreasing was performed in a nitrogen atmosphere at 900 ° C., and firing was performed at 1800 ° C. in a nitrogen atmosphere to form a heating element circuit having a thickness of 20 μm. An aluminum nitride paste is applied to the surface on which the heating element circuit pattern is formed, degreased at 700 ° C. in a nitrogen atmosphere, and then the other processed aluminum nitride sintered body is superposed and fired at 1850 ° C. in a nitrogen atmosphere. Then, the heater substrate 2 having the heating element circuit 22 inside as shown in FIG. 2 was prepared. In addition, a through-hole for attaching a power feeding terminal was processed in advance in the aluminum nitride sintered body superposed later. In addition, after polishing an insulating layer, which will be described later, a tungsten terminal was attached to the power supply portion with a gold solder, and a nickel electrode was screwed to the tungsten terminal to complete the heater substrate 2.

  Next, the same cooling block as in Example 1 was prepared, and the contact surfaces of the heater substrate and the cooling block were polished so as to have the flatness shown in Table 2. In addition, both surface roughness was Ra1.0micrometer.

  The heater substrate and the cooling block were assembled as shown in FIG. 1 in the same manner as in Example 1 to complete the heater unit 1, and the temperature variation ΔT and the cooling time were measured as in Example 1. These results are shown in Table 2.

  As can be seen from Table 2, the total flatness is 0.8 μm or less, the cooling time can be within 8 minutes, and the temperature variation ΔT at 120 ° C. can also be within 1.0 ° C.

  No. of Example 1 1 and No. 11 and No. 2 of Example 2. 17 and No. The contact surface of the cooling block 27 was further polished to obtain a surface roughness (Ra) as shown in Table 3, and the temperature variation ΔT and the cooling time at 120 ° C. were set as in Example 1. It was measured. These results are shown in Table 3.

  As can be seen from Table 3, the cooling time can be shortened if the surface roughness of the contact surface of the cooling block is 5 μm or less in terms of Ra.

In the same manner as in Example 1, a heating element circuit was formed on an aluminum nitride sintered body with a W paste, and a ZnO—B ₂ O ₃ —Al ₂ O ₃ based glass paste was used on the surface on which the heating element circuit was formed, The insulating layer 23 was formed by coating except for the power feeding portion and baking at 700 ° C. in a nitrogen atmosphere. Table 4 shows the average thickness (film thickness) of the insulating layer and the difference between the maximum value and the minimum value (film thickness variation). Thereafter, a tungsten terminal and a nickel electrode were attached in the same manner as in Example 1 to complete the heater substrate.

  The same cooling block as in Example 1 was prepared, and the contact surfaces of the heater substrate and the cooling block were polished so that the flatness was 0.2 mm. In addition, both surface roughness was Ra micrometer. The heater substrate and the cooling block were assembled as shown in FIG. 1 in the same manner as in Example 1 to complete the heater unit 1, and the temperature variation ΔT at 120 ° C. and the cooling time were measured as in Example 1. These results are shown in Table 4.

  The thickness of the insulating layer was measured as follows. First, the shape of the back surface of the aluminum nitride sintered body is measured with a three-dimensional shape measuring instrument, and when the heating element circuit is formed and the insulating layer is formed, the insulating layer is formed on a part of the back surface of the heater substrate. The insulating layer was formed in such a manner that, after firing, the surface shape of the insulating layer and the shape of the surface where the insulating layer was not formed were measured with a three-dimensional shape measuring instrument, and the thickness of the insulating layer was measured.

  As shown in Table 4, when the film thickness was 10 μm, the heater current began to be disturbed at around 150 ° C. during the temperature increase, and the temperature increase could not be continued. When the temperature was lowered and examined, a pinhole was present in a part of the insulating layer, and the heating element circuit was short-circuited.

  Further, as can be seen from Table 4, when the film thickness exceeds 500 μm, the cooling time becomes longer. It seems that the insulation layer became thick and the heat insulation effect appeared. On the other hand, when the film thickness variation exceeds 200 μm, the temperature variation at 120 ° C. increases. This is also because the heat insulation effect appears in the thick part and it is difficult to cool.

  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. As in Example 1, a cooling block was attached, and the temperature variation ΔT of the heater substrate at 120 ° C. was measured as in Example 1.

  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 5.

  As can be seen from Table 5, 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 substrate and the cooling block used in Example 1 were mounted on a resist heat treatment apparatus, and photolithography was performed. The total flatness and surface roughness of the contact surfaces of the heater substrate and the cooling block were those in Table 6. The surface roughness was the same for the heater substrate and the cooling block. 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.

  For comparison, a conventional heater unit that does not process the contact surface between the heater substrate and the cooling block was similarly mounted on the resist heat treatment apparatus, and the line width variation was measured. The results are shown in Table 6.

  As can be seen from Table 6, when the cooling block of the present invention is used, the temperature distribution of the heater becomes much more uniform than in the prior art, and it has been found 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.

  ADVANTAGE OF THE INVENTION According to this invention, the heater unit which can make temperature distribution of a heater more uniform from a cooling start to a cooling end can be provided. 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 cross-sectional schematic diagram which shows an example of the heater unit of this invention. It is a cross-sectional schematic diagram of the principal part of the heater unit of this invention. It is a cross-sectional schematic diagram of the principal part of the other heater unit of this invention. It is a cross-sectional schematic diagram of the principal part of the conventional heater unit. It is a cross-sectional schematic diagram of the principal part of the other conventional heater unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heater unit 2 Heater board 3 Cooling block 4 Contact surface of heater board 5 Contact surface of cooling block 6 Insert 7 Lifting means 8 Container 9 Support body 21 Ceramic base body 22 Heating element circuit 23 Insulating layer

Claims (8)

  A heating element circuit and an insulating film for protecting the heating element circuit are formed on the back surface, a heater substrate on which a heated object is mounted on the main surface opposite to the back surface, and a heat treatment is applied to the back surface of the heater substrate. A heater unit having a cooling block that can be contacted and separated, wherein the total flatness of the contact surfaces of the heater substrate and the cooling block is 0.8 mm or less.   A heater circuit in which a heating element circuit is formed and a heating target is mounted on the main surface and heat-treated, and a cooling block that comes into contact with and can be separated from the back surface opposite to the main surface of the heater substrate. The heater unit according to claim 1, wherein the total flatness of the contact surfaces of the heater substrate and the cooling block is 0.8 mm or less.   3. The heater unit according to claim 1, wherein the surface roughness of the contact surface between the heater substrate and the cooling block is Ra of 5 μm or less.   4. The thickness of the insulating film for protecting the heating element circuit is 15 μm or more and 500 μm or less, and the difference between the maximum value and the minimum value of the winning insulating film is 200 μm or less. The heater unit described in 1.   5. The heater unit according to claim 1, wherein the main component of the ceramic heater is at least one selected from the group consisting of aluminum nitride, silicon carbide, aluminum oxide, and silicon nitride.   The heater unit according to any one of claims 1 to 4, wherein a main component of the ceramic heater is aluminum nitride.   A semiconductor manufacturing / inspection apparatus comprising the heater unit according to claim 1. A flat panel display manufacturing / inspecting apparatus comprising the heater unit according to claim 1.

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