JP2009031117A - Heating/cooling module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating/cooling module which will not be damaged, even if it is heated or cooled in a short time, whereby a heating amount of a heater for heating a semiconductor chip mounted thereon can be increased. <P>SOLUTION: This heating/cooling module comprises a ceramics heater 1 for heating an object to be processed mounted thereon, a cooling mechanism 3 for cooling the ceramics heater 1, and a support body 2 placed between the ceramics heater 1 and the cooling mechanism 3. The support body 2 is so configured that a heater-side support body 2a and a cooling mechanism-side support body 2b, made of different materials, are combined. Interposer layers 4, 4 which is to be constituted of a soft material with thermal conductivity of 1 W/mK or larger are, preferably, interposed in between the heater-side support body 2a and the cooling mechanism-side support body 2b and in between the cooling mechanism-side support body 2b and the cooling mechanism 3, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus for heating or cooling and inspecting an object to be processed, and more particularly to a heating and cooling module used in a tester for inspecting a semiconductor chip.

  Conventionally, various devices have been proposed as devices for heating and cooling a semiconductor chip. In particular, in recent years, the amount of heat generated during operation tends to increase as the capacity, function, and speed of semiconductor chips increase. Further, improvement in throughput is also demanded, and it is necessary for a semiconductor chip inspection apparatus, for example, a tester, to heat a semiconductor chip in as short a time as possible and perform an electrical test, and then rapidly cool it.

As such a semiconductor chip heating / cooling device, various structures such as a burn-in device described in JP-A-2005-265665 have been proposed. However, if a large amount of electric power is applied to the heating element of the heating / cooling device in order to rapidly heat the semiconductor chip, there is a problem that the heating / cooling device is damaged. Even if the cooling is attempted rapidly, there is a limit to the cooling rate that can be obtained due to structural limitations between the cooling mechanism and the semiconductor chip.
JP 2005-265665 A

  In view of the above-described conventional circumstances, the present invention mounts and heats an object to be processed such as a semiconductor chip, so that the heating value of the heater can be increased, and heating that does not break even if heated or cooled in a short time. An object is to provide a cooling module.

  In order to achieve the above object, a heating / cooling module provided by the present invention includes a ceramic heater for mounting and heating a workpiece, a cooling mechanism for cooling the ceramic heater, and between the ceramic heater and the cooling mechanism. In the heating / cooling module having a support body, it is possible to rapidly raise the temperature and cool by suitably selecting two or more different materials as the support body on the heater side and the cooling mechanism side.

  Generally, in order to perform rapid temperature rise or cooling, it is desirable to join a ceramic heater and a support. However, if the thermal expansion coefficients of the ceramic heater and the support are significantly different, the support or ceramic heater is likely to crack during bonding, and even if it can be joined without cracking, it will crack during use. As a device, there is a problem that the service life is short.

Therefore, in the heating and cooling module of the present invention, at least the heater side support and the cooling mechanism side support are made of different materials. Specifically, the material of the heater-side support is desirably a material having a difference in thermal expansion coefficient within 2 × 10 ⁻⁶ / ° C. with that of the ceramic heater. The material of the cooling mechanism side support is preferably a material having a difference in thermal expansion coefficient within 10 × 10 ⁻⁶ / ° C. from the thermal expansion coefficient of the cooling module. The thermal conductivity of the support (the heater side support and the cooling mechanism side support) is preferably 100 W / mK or more. When the support has a thermal conductivity of 100 W / mK or more, rapid temperature increase and cooling are possible.

  The joining of the ceramic heater and the heater side support is preferably brazed. As the brazing material to be used, a material having a relatively high thermal conductivity such as Ag, Cu, Au, Si, or Sn can be used. These brazing materials have relatively high thermal conductivity, and if the brazing material thickness is several tens of μm or less, the thermal resistance between the ceramic heater and the support can be reduced, and the heat generated by the ceramic heater can be smoothened. Since it can transmit to a support body, it becomes possible to cool a ceramic heater efficiently and rapidly.

  Further, it is preferable that an intermediate layer of a soft material having a thermal conductivity of 1 W / mK or more, easy deformation, and excellent fillability is provided between the heater side support and the cooling mechanism side support. It is preferable to have a similar intervening layer also between the cooling mechanism side support and the cooling module. By having the intervening layer, heat transfer between the supports or the interface between the support and the cooling module is improved, and rapid temperature increase or cooling is possible.

  When brazing the ceramic heater to the heater side support, the material of the heater side support is preferably close to that of the ceramic heater and high in thermal conductivity. For example, an AlN heater is used. In this case, W, Mo, Cu—W, Cu—Mo, and the like are preferable, and W having the same thermal expansion coefficient is particularly preferable. In addition, the heater-side support preferably has a thickness of 1 mm or more and has a larger outer shape than the AlN heater in order to promote transient heat exchange and increase the heat capacity. Moreover, it is desirable to have an intervening layer between the heater side support and the cooling mechanism side support. Moreover, it is desirable to have an intervening layer also between the cooling mechanism side support and the cooling mechanism. By selecting a soft material with good heat transfer as the intervening layer, rapid temperature rise and cooling are possible.

The thermal expansion coefficient of the heater-side support is preferably about the same as that of the ceramic heater. When AlN (thermal expansion coefficient 4 × 10 ⁻⁶ / ° C.) is selected for the ceramic heater, the support has a thermal expansion coefficient of It is desirable to select a material in the range of 2-6 × 10 ⁻⁶ / ° C. The thermal expansion coefficient of the cooling mechanism side support is an intermediate value (4 to 17 × 10 ⁻⁶ ) between the thermal expansion coefficient of the heater side support and the thermal expansion coefficient of the material (for example, Cu) used for the cooling mechanism. / ° C) is desirable.

  According to the present invention, there is provided a heating / cooling module suitable for a semiconductor chip tester, which can increase the heat generation amount of the heater, has excellent temperature rising / falling characteristics, and does not break even if heated or cooled in a short time. Can be provided.

  As shown in FIG. 1, a conventional general heating / cooling module has a support 2 on the lower surface of a ceramic heater 1 such as aluminum nitride, and a cooling mechanism 3 below the support 2. With the heating / cooling module having such a configuration, a semiconductor chip is mounted on a ceramic heater, heated to a predetermined temperature, and necessary inspection is performed. Thereafter, the semiconductor chip can be cooled by reducing or reducing the output of the ceramic heater to zero and cooling the ceramic heater through the support by the cooling mechanism.

On the other hand, in the heating / cooling module of the present invention, as shown in FIG. 2, the support 2 arranged between the ceramic heater 1 and the cooling mechanism 3 is composed of a heater-side support 2a and a cooling-mechanism-side support that are made of different materials. The structure is a combination of 2b. The material of the heater-side support 2a is preferably a material having a difference in thermal expansion coefficient within 2 × 10 ⁻⁶ / ° C. from that of the ceramic heater 1. Moreover, as a material of the cooling mechanism side support body 2b, it is desirable to use a material having a difference between the thermal expansion coefficient of the cooling module 3 and a thermal expansion coefficient within 10 × 10 ⁻⁶ / ° C.

  As described above, by using the heater-side support 2a having the same thermal expansion coefficient as the ceramic heater 1 and the cooling mechanism-side support 2b having the same thermal expansion coefficient as the cooling mechanism 3 as the support 2, In addition to excellent thermal conductivity, the transmission of thermal stress can be reduced. That is, in the normal structure as shown in FIG. 1, if the thermal conductivity is increased and the temperature is rapidly raised and lowered, a large thermal stress may be generated and the ceramic heater may break. However, the configuration of the present invention can transmit the thermal stress. It can be made smaller to prevent cracking of the heater.

  In the heating / cooling module having this structure, heat exchange associated with heating and cooling is performed between the ceramic heater and the support and between the support and the cooling mechanism in the process of heating and cooling described above. For this reason, as shown in FIG. 2, it is preferable to insert the intervening layer 4 with high thermal conductivity in these interfaces. As shown in FIG. 2, the intervening layer 4 can be inserted between the heater-side support 2a and the cooling mechanism-side support 2b, between the cooling mechanism-side support 2b and the cooling mechanism 3, or both. it can.

  The intervening layer needs to be a soft material that is flexible, easily deformed, and excellent in filling properties so as to be in close contact with the ceramic heater, the support, and the cooling mechanism. That is, since the ceramic heater, the support body, and the cooling mechanism are all hard materials, when the surfaces are brought into contact with each other, a gap is generated between them. Since air exists in this gap, heat transfer is greatly hindered. In order to fill this gap, by inserting an intervening layer of a soft material that can follow the shape of each abutting surface, unevenness in heat transfer can be eliminated, and uniform and smooth heat transfer can be achieved.

  As a material for such an intervening layer, there is no particular problem as long as it has heat resistance in the operating temperature range, and for example, a heat-resistant resin, a soft metal, graphite or the like can be selected. As the heat resistant resin, since the maximum temperature of the heater is about 300 ° C., an epoxy resin, a polyimide resin, a silicon resin, or a phenol resin can be selected. As the soft metal, a metal such as indium, copper, aluminum, or an alloy thereof can be used. Moreover, carbon materials, such as graphite, a foam metal, etc. can also be used. Since these materials are all soft materials having deformability, heat transfer can be made smooth by inserting them between the members.

  Further, the intercalation layer preferably has a higher thermal conductivity, and specifically, the thermal conductivity is particularly preferably 1 W / mK or more. When the heat resistant resin is used as the intervening layer, the thermal conductivity can be increased by adding BN, alumina, silica, AlN, metal powder, or the like. By providing the intervening layer having a high thermal conductivity in this way, the thermal stress generated during rapid temperature rise and fall can be released to the intervening layer, so that the ceramic heater can be more reliably prevented from cracking.

  In addition, as described above, by adopting a structure comprising two or more layers of the support, the thermal stress caused by the dimensional variation due to the temperature difference between the ceramic heater and the cooling mechanism is caused between the heater side support and the cooling mechanism side support. And can be relaxed by an intervening layer made of a soft material having deformability. Thereby, generation | occurrence | production of the curvature of a ceramic heater and damage can be avoided.

  The material of the ceramic heater is preferably aluminum nitride. In semiconductor chip inspection, the temperature of the ceramic heater is repeatedly raised and lowered in a short time, and thermal stress is applied. Therefore, if the heater is made of ceramics with low thermal conductivity such as alumina, the effect of thermal shock etc. As a result, the ceramic heater may crack and be damaged. Aluminum nitride generally has a thermal conductivity of 70 W / mK or more and is more resistant to thermal shock than alumina or the like, and therefore is suitable as a material for a ceramic heater.

The ceramic heater is provided with at least one resistance heating element for heating the semiconductor chip. Although it is possible to form the resistance heating element on the surface of the ceramic substrate, it is preferable to embed the resistance heating element inside because it is not necessary to ensure insulation from the support and the cooling mechanism. The heating capacity of the ceramic heater is preferably 10 W / cm ² or more.

  It is preferable to form a plurality of the resistance heating element layers. For example, if a two-layer resistance heating element is used, twice the power can be input to the heating element circuit compared to the case of one layer, so that the temperature rise rate can be increased and the throughput is improved. can do. Further, the size of the ceramic heater is about 20 to 25 mm square, and in order to flow a large electric power to the heater of this size, it can be easily handled by forming a multilayer heating element layer. That is, as the resistance heating element layer is increased, the amount of electric power applied to the heater can be increased. Specifically, the amount of electric power to be input is usually about several tens of watts to 200 W, but the heating / cooling module having the structure of the present invention can input up to about 1 kW at maximum.

  The thickness of the ceramic heater is preferably 0.3 mm or more. If the thickness is smaller than this, it may be damaged by mechanical impact, which is not preferable. On the other hand, if the thickness exceeds 5 mm, the heat capacity of the heater increases, and it takes time for cooling, which is not preferable. The most preferable thickness is 0.5 to 2 mm. A thickness within this range is particularly preferable because the heat capacity is relatively small, the cooling rate is high, and no damage is caused by mechanical impact.

  The thermal conductivity of the support existing between the ceramic heater and the cooling mechanism is preferably 100 W / mK or more. The support supports the heater and also serves to transfer the temperature of the cooling mechanism to the heater and quickly take away the heat of the heater. For this reason, it is preferable that the support has a high thermal conductivity, and particularly preferably 100 W / mK or more.

The heater-side support preferably has the same thermal expansion coefficient as that of a ceramic heater material, for example, aluminum nitride (2 to 6 × 10 ⁻⁶ / ° C.). It is preferable that it is ^x10 < ^-6 > / degrees C or less. Suitable examples of the material include tungsten and its alloys.

It is preferable that the cooling mechanism side support has a thermal expansion coefficient of about an intermediate value (4 to 17 × 10 ⁻⁶ ) between the material used for the cooling mechanism and the heater side support. Specific examples of the material include copper and its alloys such as Cu-W and Cu-Mo. Further, aluminum and its alloys, silver, gold or the like can also be used. Furthermore, ceramics such as aluminum nitride and silicon carbide, and composites such as Al—SiC, Si—SiC, and Al—AlN can also be used. Since these materials are exposed to a high temperature, a heat resistant film may be formed on the surface thereof. Examples of the heat resistant film include nickel, silver, gold, platinum, and the like, and these can be formed by a technique such as sputtering or vapor deposition, or a technique such as plating.

  Although there is no restriction | limiting in particular about a cooling mechanism, It can be set as the structure which forms the flow path through which a refrigerant | coolant passes in a metal plate, and covers with another metal plate. The material of the cooling mechanism is not particularly limited, but a material having high thermal conductivity is preferable. For example, the same material as that of the support can be used, and a metal material such as stainless steel can also be used. In addition, the refrigerant flowing through the flow path is not particularly limited, and a compound such as water, air, or florinate may be used depending on the use temperature.

  There are no particular restrictions on the method of forming the flow path. For example, a metal pipe may be attached to the surface opposite to the surface on which the metal plate support is mounted, and the coolant may flow inside the pipe. Moreover, there is no restriction | limiting in particular about the cross-sectional shape of a metal pipe, It can be set as various shapes, such as circular and a square. Since the pipe through which the refrigerant passes needs to be in close contact with the metal plate, the pipe is fixed to the metal plate by a method such as screwing. Can be secured. Furthermore, effective cooling can be realized by inserting and filling the soft material described above between the pipe and the metal plate.

  In the heating / cooling module of the present invention, the number of ceramic heaters, supports, and cooling mechanisms is usually configured so that one support and one ceramic heater are mounted on one cooling mechanism. It is preferable. However, other configurations are possible. For example, four, eight, sixteen or more supports and an aluminum nitride heater can be mounted on one cooling mechanism.

  Moreover, regarding the connection of the ceramic heater, the support and the cooling mechanism, a method which does not hinder mutual heat transfer is preferable. For example, for the connection between the ceramic heater and the support, a technique such as brazing can be used to improve heat transfer by suitably selecting the thermal expansion coefficient. The connection between the heater side support and the cooling mechanism side support and the connection between the cooling mechanism side support and the cooling mechanism can be fixed by a mechanical method such as screwing.

  In the case of the connection by screwing, a through hole larger than the diameter of the screw is formed in the support or the ceramic heater, the screw is inserted into the through hole, and the screw can be screwed into the female screw formed in the cooling mechanism. The reason why the through-holes larger than the diameter of the screw are formed is to prevent these members from being damaged or deformed even when the temperature rises due to the heating of the heater and thermal expansion occurs. The material of the screw used here is not particularly limited, but stainless steel, Kovar, or the like can be used.

Next, a method for manufacturing a ceramic heater will be described by taking the case of aluminum nitride (AlN) as an example. The raw material powder of aluminum nitride (AlN) used 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 the specific surface area exceeds 5.0 m ² / g, the aggregation of the powder becomes very strong and handling becomes difficult.

  The amount of oxygen contained in the raw material powder is preferably 2 wt% or less. When the amount of oxygen exceeds 2 wt%, the thermal conductivity of the sintered body decreases. The amount of metal impurities other than aluminum contained in the raw material powder is preferably 2000 ppm or less. When the amount of metal impurities exceeds 2000 ppm, the thermal conductivity of the sintered body decreases. In particular, as a metal impurity, a group 4 element such as Si or an iron group element such as Fe has 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 present 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.

  As the rare earth element compound as the sintering aid, oxides, nitrides, fluorides, stearic acid compounds and the like can be used. Of these, oxides are preferable because they are inexpensive and readily available. Further, since the stearic acid compound has a high affinity with an organic solvent, mixing the aluminum nitride raw material powder with a sintering aid or the like with an organic solvent is particularly preferable because the mixing property becomes high. Of the rare earth element compounds, an yttrium compound having a particularly remarkable function of removing oxygen is preferable, and yttrium oxide is particularly preferable.

  The addition amount of the sintering aid 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 preferable addition amount of the sintering aid is 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.

  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 a 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 produced from the slurry by a technique such as spray drying. The granules are inserted into a predetermined mold and press-molded. The pressing pressure at this time is desirably 9.8 MPa or more. When the pressure is less than 9.8 MPa, the strength of the molded body is often not sufficiently obtained, and is easily damaged by handling or the like.

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 1.5-2.5 g / cm < ³ >. 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. On the other hand, when the density of the molded body exceeds 2.5 g / cm ³ , it becomes 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.

  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. If the temperature is less than 500 ° C., the binder cannot be removed sufficiently and carbon remains excessively, which hinders sintering in the subsequent sintering step. Further, at a temperature exceeding 1000 ° C., the amount of remaining carbon becomes too small, so 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. The amount of carbon remaining in the molded body after the degreasing treatment is preferably 1.0 wt% or less. If carbon exceeding 1.0 wt% remains, sintering is inhibited and a dense sintered body cannot be obtained.

  Next, the molded body after the degreasing treatment is sintered. Sintering is performed at a temperature of 1700 to 2000 ° C. in a non-oxidizing atmosphere such as nitrogen or argon. The moisture contained in the atmospheric gas such as nitrogen used at this time is preferably −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. This BN compact has sufficient heat resistance with respect to the sintering temperature, and its surface has solid lubricity, so that the friction with the jig is reduced when the compact shrinks during sintering. And a sintered body with less distortion can be obtained.

  The obtained AlN sintered body is processed as necessary. For example, when the conductive paste in the next step is screen-printed, the surface roughness of the sintered body is preferably 5 μm or less in Ra, and therefore the polishing process is performed so that the surface of the sintered body has the above surface roughness. If the surface roughness of the sintered body exceeds 5 μm in Ra, defects such as pattern bleeding and pinholes are likely to occur when a circuit is formed by screen printing. The surface roughness is more preferably 1 μm or less in terms of Ra.

  When polishing the 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, not only the surface to be screen printed but also the opposite side It is better to perform polishing. 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.

  Moreover, it is preferable that the parallelism of both process surfaces of a sintered compact is 0.5 mm or less. If 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. When the flatness exceeds 0.5 mm, the thickness of the conductive paste may vary greatly. The flatness is particularly preferably 0.1 mm or less.

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

In addition, an oxide powder can be added to the conductive paste in order to increase the adhesion strength with the AlN sintered body. As the oxide powder, oxides of 2A group elements and 3A group elements, Al ₂ O ₃ , SiO _{2 and the} like are preferable. 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. On the other hand, when the thickness exceeds 100 μm, the adhesion strength decreases, which is not preferable.

  In addition, when the circuit pattern to be formed is a heater circuit (resistance 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 may occur depending on the applied voltage and temperature, resulting in a short circuit. In particular, when used at a temperature of 200 ° C. or higher, the pattern interval is preferably 1 mm or more, and more preferably 2 mm or more. When a plurality of resistance heating element layers are formed, a plurality of substrates are prepared by the same method as described above, and a heating element circuit is formed on each of them.

  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. When the degreasing temperature is less than 500 ° C., the binder in the conductive paste is not sufficiently removed, carbon remains in the metal layer, and metal carbide is formed when fired. Get higher.

  The conductive paste is preferably baked 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 preferably does not exceed the sintering temperature of the ceramic. When the conductive paste is baked 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. Adhesion strength with 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 preferably the same material as the ceramic on which the metal layer is formed. If the materials of the ceramic and the insulating coating are significantly different, problems such as warping after sintering occur due to the difference in thermal expansion coefficient. For example, in the case of AlN, a predetermined amount of group 2A element or group 3A element oxide or carbonate is added to the AlN powder as a sintering aid and mixed, and a binder or solvent is added to this to form a paste. The paste can be applied on the metal layer by screen printing.

  The amount of sintering aid added at this time is preferably 0.01 wt% or more. When the amount of the sintering aid is less than 0.01 wt%, the insulating coat is not densified, and it is difficult to ensure the insulating property of the metal layer. Moreover, it is preferable that the amount of sintering aid does not exceed 20 wt%. If it exceeds 20 wt%, an excessive sintering aid penetrates into the metal layer, and the electrical resistance value of the metal layer may change. Although there is no restriction | limiting in particular in the thickness to apply | coat, It is preferable that it is 5 micrometers or more. This is because if it is less than 5 μm, it is difficult to ensure insulation.

  Next, another sintered body substrate is laminated on the sintered body substrate on which the circuit is formed with the circuit interposed therebetween. Lamination is preferably performed via a bonding agent. The bonding agent to be used is a paste obtained by adding a group 2A element compound, a group 3A element compound, a binder, or a solvent to aluminum oxide powder or aluminum nitride powder, and is applied to the bonding surface by a technique 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 substrate coated with the bonding agent is degreased at a temperature of 500 ° C. or higher in a non-oxidizing atmosphere. Thereafter, the substrates to be stacked are overlapped, a predetermined load is applied, and the substrates are bonded together by heating in a non-oxidizing atmosphere. The applied load is preferably 5 kPa or more. When the load is less than 5 kPa, sufficient bonding strength cannot be obtained or bonding defects are likely to occur.

  The heating temperature for bonding is not particularly limited as long as the substrates are sufficiently adhered to each other via 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, argon, or the like is preferably used for the non-oxidizing atmosphere during the degreasing and bonding described above. As described above, an aluminum nitride heater can be obtained.

  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.

  By applying a conductive paste on the sheet by a method such as screen printing, a metal layer that forms an electric circuit having a predetermined shape is formed. 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. A plurality of sheets on which circuit formation has been performed can be laminated. 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 where the sheets are overlapped, heating is performed as necessary. When heating, it is preferable that heating temperature is 150 degrees C or less. Heating to a temperature exceeding this is not preferable because 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.

  The obtained laminate is degreased and sintered in the same manner as the above-described post metallization method. The degreasing and sintering temperatures, the amount of residual carbon, and the like are the same as in the post metallization method. When printing the above-described conductive paste on a sheet, an aluminum nitride heater having one or more layers of circuits is manufactured by printing heater circuits on one or more sheets and laminating them. It is also possible to do.

  The obtained aluminum nitride heater is processed as necessary. Usually, the required accuracy is often not achieved in the sintered state. As processing accuracy, for example, the flatness of the workpiece mounting surface is preferably 0.1 mm or less, and more preferably 0.05 mm or less. When the flatness exceeds 0.5 mm, a gap is likely to be generated between the object to be processed (semiconductor chip) and the aluminum nitride heater, and the heat of the aluminum nitride heater is not transmitted uniformly to the semiconductor chip, resulting in uneven temperature of the semiconductor chip. Is likely to occur.

  The surface roughness of the workpiece mounting surface of the aluminum nitride heater 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 aluminum nitride heater and the semiconductor chip. In particular, the surface roughness Ra is more preferably 1 μm or less.

[Example 1]
5 parts by weight of yttrium oxide (Y ₂ O ₃ ) was added to 95 parts by weight of aluminum nitride (AlN) powder, an acrylic binder and an organic solvent were added, and mixed for 24 hours in a ball mill to prepare an AlN slurry. Using this slurry, an AlN sheet was produced by a doctor blade method. 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.

For forming a resistance heating element, 0.5 wt% of Y ₂ O ₃ was added to W powder having an average particle diameter of 2.0 μm, and a binder and a solvent were added and mixed to prepare a W paste. A pot mill and three rolls were used for mixing. By screen printing this W paste, a heater circuit pattern was formed on the AlN sheet.

  An AlN sheet on which the heater circuit was printed and a sheet on which the heater circuit was not printed were stacked and thermocompression bonded to produce a sheet molded body. The sheet compact was degreased at 800 ° C. in a nitrogen atmosphere and then sintered at 1850 ° C. in a nitrogen atmosphere to produce a 20 mm square AlN heater. Further, in order to increase the heater output, the number of stacked heaters was set to 3 and the thickness was set to 2 mm. When the number of stacked heaters is 1, the heater output can only be increased up to about 200 W, and the temperature rise time is three times or more as compared with the case where the number of stacked heaters is 3.

  As a cooling mechanism, a copper plate having a thickness of 2 mm and a size of 80 mm square and a copper plate having a thickness of 4 mm and a size of 80 mm square were prepared. On the copper plate having a thickness of 4 mm, a flow path for flowing the cooling refrigerant was formed by spot facing. The surfaces of these copper plates were plated with nickel, and then a 2 mm thick copper plate and a 4 mm thick copper plate were brazed with silver brazing to provide a cooling mechanism having a flow path inside.

  Next, nine types of materials A to I shown in Table 1 below were prepared as supports (heater-side support and cooling mechanism-side support). The sizes of the supports are all 20 × 20 × 5 mm in thickness.

  The AlN heater and the heater-side support were brazed, and the heater-side support, the cooling mechanism-side support and the cooling mechanism were screwed to complete the heating / cooling module shown in Table 2 below. At that time, silicon resin (Si resin) or Si resin added with alumina is used as an intervening layer, and between both the heater side support and the cooling mechanism side support and between the cooling mechanism side support and the cooling mechanism, A heating / cooling module in which the intervening layer shown in Table 2 was inserted was also produced. The thickness of the intervening layers is all 0.1 mm.

  A semiconductor chip was mounted on these heating / cooling modules, the temperature was raised from room temperature (25 ° C.) to 200 ° C., the characteristics of the semiconductor chip were evaluated, the chip was removed, and then cooled to room temperature. The cooling mechanism was made to flow fluorinate as a refrigerant and the temperature was set to −60 ° C. The temperature rising time from room temperature to 200 ° C. and the cooling time from 200 ° C. to room temperature were measured, and the results are shown in Table 2 below together with the configuration of the heating and cooling module. In addition, the cracking situation at the time of temperature rise of the brazed AlN heater is also shown in Table 2 below.

  As can be seen from Table 2, the cooling time can be particularly shortened if intervening layers are inserted between the heater side support and the cooling mechanism side support and between the cooling mechanism side support and the cooling mechanism. In addition, when a heater-side support having a large thermal expansion coefficient was combined, the AlN heater brazed at the time of temperature increase was cracked, and the temperature could not be increased.

  As a comparative example, instead of the aluminum nitride heater, an alumina heater (thickness 2 mm) was used to fabricate a heating / cooling module having the same configuration as above, and when heated and cooled in the same manner, the alumina heater was damaged during heating. .

It is general | schematic sectional drawing which shows the conventional general heating-cooling module. It is a schematic sectional drawing which shows the heating-cooling module by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic heater 2 Support body 2a Heater side support body 2b Cooling mechanism side support body 3 Cooling mechanism 4 Intervening layer

Claims (8)

  A heating / cooling module including a ceramic heater for mounting and heating an object to be processed, a cooling mechanism for cooling the ceramic heater, and a support disposed between the ceramic heater and the cooling mechanism. A heating / cooling module having a structure in which a heater-side support and a cooling-mechanism-side support are different from each other.   2. The heating and cooling module according to claim 1, further comprising an intervening layer made of a soft material having a thermal conductivity of 1 W / mK or more between the heater side support and the cooling mechanism side support.   The heating / cooling module according to claim 1, wherein an intervening layer made of a soft material having a thermal conductivity of 1 W / mK or more is provided between the cooling mechanism side support and the cooling mechanism. The heating / cooling module according to claim 1, wherein the ceramic heater has two or more resistance heating element layers therein and has a heating capacity of 10 W / cm ² or more. The thermal conductivity of the support is 100 W / mK or more, and the difference in thermal expansion coefficient between the heater-side support and the ceramic heater is 2 × 10 ⁻⁶ / ° C. or less. The heating-cooling module in any one of -4.   The heating / cooling module according to claim 1, wherein the ceramic heater and the heater-side support are brazed.   The heating / cooling module according to claim 1, wherein the heater-side support and the cooling mechanism-side support are mechanically fixed. The ceramic heater is an aluminum nitride heater having a heating capacity of 10 W / cm ² or more, wherein the support has a thermal conductivity of 100 W / mK or more and the interstitial layer has a thermal conductivity of 1 W / mK or more. The heating and cooling module according to any one of claims 1 to 7.

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