JP5067050B2 - Wafer holder for wafer prober and wafer prober mounted therewith - Google Patents

Description

  The present invention relates to a wafer holder used in a wafer prober for inspecting electrical characteristics of a semiconductor wafer placed on a wafer placement surface, and a wafer prober on which the wafer holder is placed.

  Conventionally, in a semiconductor inspection process, a heat treatment is performed on a semiconductor substrate (wafer) that is an object to be processed. That is, the wafer is heated to a temperature higher than the normal use temperature, and semiconductor chips that may become defective are accelerated and removed, and burn-in is performed to prevent the occurrence of defects after shipment. . Specifically, after a semiconductor circuit is formed on a semiconductor wafer and before cutting into individual chips, the electrical performance of each chip is measured while the wafer is heated to remove defective products. In this burn-in process, reduction of process time is strongly demanded in order to improve throughput.

  In such a burn-in process, a heater is provided on the chuck top to hold the semiconductor wafer on the wafer mounting surface of the chuck top and to heat the semiconductor wafer when measuring electrical characteristics of the semiconductor wafer. Conventional chuck tops and heaters are made of metal because the entire back surface of the wafer needs to be in contact with the ground electrode.

  However, when a wafer is inspected, a probe called a probe card having a large number of energizing electrode pins is pressed against the probe with a force of several tens of kgf to several hundred kgf, so that the metal chuck top and heater are deformed if they are thin. As a result, a contact failure may occur between the wafer and the probe pins. For this reason, a thick metal plate having a thickness of 15 mm or more is used for the purpose of maintaining the rigidity of the chuck top and the heater. However, it takes a long time to raise and lower the temperature of the heater, which is a great obstacle to improving the throughput.

  In the burn-in process, electricity is passed through the chip to measure the electrical characteristics. With the recent increase in chip output, the chip generates a lot of heat when measuring the electrical characteristics, and in some cases, the chip self-heats. May destroy. Therefore, it is required to cool rapidly after the measurement. In addition, it is required to be as uniform as possible during the measurement. Therefore, copper (Cu) having a high thermal conductivity of 403 W / mK has been generally used as the metal material.

  On the other hand, in Japanese Patent Laid-Open No. 2001-033484, instead of the above-described thick metal plate, a thin metal layer is formed on the surface of a ceramic substrate that is thin but has high rigidity and is not easily deformed. A wafer prober with a small chuck top has been proposed. This chuck top is said to be capable of raising and lowering temperature in a short time because it has high rigidity and does not cause poor contact and has a small heat capacity. And it is supposed that an aluminum alloy, stainless steel, etc. can be used as a support stand for installing this chuck top.

  However, as described in Japanese Patent Application Laid-Open No. 2001-033484, when only the outermost peripheral portion of the chuck top is supported by a bottomed cylindrical support, the chuck top may be warped by pressing of the probe card. . Therefore, it is necessary to devise not only support with a bottomed cylindrical support but also support a chuck top by providing a larger number of support columns.

  In recent years, with the miniaturization of semiconductor processes, the load per unit area at the time of probing increases, and the accuracy of alignment between the probe card and the wafer prober is also required. The wafer prober normally repeats the operation of heating the wafer to a predetermined temperature, moving to a predetermined position during probing, and pressing the probe card. At this time, in order to move the wafer prober to a predetermined position, high positional accuracy is also required for the drive system.

  However, in the conventional wafer prober, when the wafer held on the chuck top is heated to a predetermined temperature, that is, about 100 to 200 ° C., the heat is transmitted from the chuck top to the drive system, and the metal parts of the drive system are There is a problem in that it expands thermally, which impairs accuracy.

  Furthermore, due to an increase in load during probing, the rigidity of the chuck top itself on which the wafer is placed has been required. That is, if the chuck top itself is deformed by the load during probing, the pins of the probe card cannot be uniformly contacted with the wafer, so that inspection cannot be performed or the wafer is damaged. Therefore, the size of the chuck top is increased in order to suppress deformation, and the weight thereof is increased. As a result, there is a problem in that the accuracy of the drive system is affected. Further, along with the increase in size of the chuck top, there has been a problem that the temperature and cooling time of the wafer prober become very long and the throughput is lowered.

  Furthermore, in order to improve the throughput, a cooling mechanism is provided to increase the temperature raising / lowering speed of the wafer prober. However, conventionally, the cooling mechanism is air-cooled, or a cooling plate is provided directly below the metal heater. Therefore, in the former case, there is a problem that the cooling rate is slow, and in the latter case, since the cooling plate is a metal, there is a problem that the cooling plate is easily deformed by the pressure of the probe card during probing.

  In order to solve these problems, a ceramic chuck top has been recently used as described in JP-A-2001-033484. However, when the chuck top is ceramic, when the wafer is heated to a predetermined temperature of about 100 to 200 ° C., a large load is applied to the chuck top due to a difference in thermal expansion between the bottomed cylindrical support and the chuck top. . For this reason, there is a problem that the chuck top is deformed and the pins of the probe card cannot be uniformly contacted with the wafer, the chuck top itself is broken, or the wafer is damaged in the worst case.

  In order to solve these problems, Japanese Patent Application Laid-Open No. 2001-135681 discloses a method for preventing warping and cracking of a ceramic chuck top by forming a large number of support columns in a bottomed cylindrical support container. Proposed. It is described that the above-mentioned support columns are preferably arranged in a grid pattern at intervals of 1 to 10 mm, and are preferably supported at a number of locations.

  However, when supporting with a large number of support pillars, heat tends to flow into the support container from the chuck top heated to a temperature of about 100 to 200 ° C. via the support pillar, and the influence of the warp generated in the support container remains. The problem of chuck top warping has not been solved. It is possible to interpose a heat insulating material as a countermeasure against this heat inflow, but if the heat insulating material is a heat insulating resin, etc., there is a concern that the rigidity will be lowered, and for ceramics, there is a concern that the chuck top will be damaged due to concentration of load, and for metals, The heat insulation effect cannot be obtained. In the first place, it is indispensable to secure high-accuracy heat insulating materials of 1 to 2 μm level for a large number of support pillars and support containers, so it is difficult to control the flatness of the heat insulating materials, and it becomes very expensive. The assembly itself is expected to be difficult.

JP 2001-033484 A JP 2001-135682 A

  In view of the above-described conventional circumstances, the present invention can realize a highly accurate temperature distribution during temperature rise and cooling, and can prevent deformation and breakage of the chuck top even during rapid temperature rise and cooling. In addition, it is possible to prevent deformation and breakage of the chuck top against pressing by probing, reduce the load on the drive system and cut off the inflow of heat, and can be used repeatedly An object of the present invention is to provide a wafer holder for a wafer prober capable of realizing accurate and highly accurate measurement, and a wafer prober apparatus equipped with the wafer holder.

In order to achieve the above object, a wafer holder for a wafer prober provided by the present invention includes a chuck top having a chuck top conductor layer on the surface and a heating body, a plurality of support bars for supporting the chuck top, and a support. Each support rod partially supports the back side of the chuck top, and the plurality of support rods are arranged concentrically with respect to the chuck top or chucked. Concentric and centrally arranged with respect to the top, the thermal expansion coefficients of the plurality of support rods are larger as the outer concentric support rods, and when arranged at the central portion, the central support rods The support rods arranged concentrically are larger than the support rods . Moreover, it is preferable that the total support area in which the support rod supports the chuck top is 20% or less of the total area of the back surface of the chuck top.

In the wafer prober wafer holder of the present invention, the outermost support bars of the prior SL concentrically arranged support bars, that is on a concentric circle of the more than half of the diameter of the chuck top diameter Is preferred.

  In the wafer holder for a wafer prober according to the present invention, the chuck top may include a cooling module together with a heating body. In that case, it is preferable that the heating body and the cooling module do not contact the support rod. Moreover, it is preferable that a part of the heat generating part of the heating body or a part of the flow path of the cooling module is also present outside the outermost support rod arranged concentrically.

  In the wafer holder for a wafer prober of the present invention, the diameter of the heating body is preferably 90 to 110% of the diameter of the chuck top. The diameter of the cooling module is preferably 90 to 110% of the diameter of the chuck top.

In the wafer holder for a wafer prober of the present invention, the support bar is preferably separated from the chuck top and the bottom substrate. Moreover, it is preferable that the said support rod is a columnar body or a cylindrical body. Furthermore, it is preferable that the chuck top and the bottom substrate are fastened with a screw via the support rod, and the difference in thermal expansion coefficient between the support rod and the screw is 5 × 10 ⁻⁶ / K or less.

  The present invention also provides a heater unit for a wafer prober comprising the wafer holder for a wafer prober of the present invention described above. The present invention further provides a wafer prober comprising the above-described heater unit of the present invention.

  According to the present invention, it is possible to achieve both high rigidity and high heat insulation by controlling the arrangement and total support area of the plurality of support rods that partially support the chuck top. Highly accurate temperature distribution can be realized, there is no deformation or breakage of the chuck top even during rapid heating, cooling and probing pressing, maintaining the chuck top flatness and reducing the load on the drive system In addition, it is possible to provide a wafer holder for a wafer prober capable of performing accurate and highly accurate measurement even after repeated use by blocking heat inflow.

  Furthermore, a heating element and a cooling module can be provided, and these can be enlarged to almost the same size as the outer diameter of the chuck top, so that excellent temperature uniformity characteristics can be obtained even when the temperature is raised or lowered compared to the conventional case. . Compared to conventional thick and heavy support pillars with the same outer diameter as the conventional chuck top, and a cylindrical support with a bottom that supports the outer periphery of the chuck top in a ring shape, the weight can be reduced rapidly. And can increase the throughput of the inspection process. Moreover, since the contact area between the chuck top and the bottom substrate can be reduced, the heat insulation effect is high, heat transfer to the bottom drive system can be cut off, and high-precision measurements can be realized even when used repeatedly. It becomes.

  Therefore, by using the wafer holder of the present invention, there is no risk of warping or breakage, high thermal conductivity of the wafer mounting surface, excellent thermal uniformity, and rapid heating and cooling are possible. It is possible to provide a simple heater unit and a semiconductor inspection apparatus such as a wafer prober, a handler apparatus, or a tester apparatus equipped with the heater unit.

  A wafer holder for a wafer prober according to the present invention will be described with reference to FIG. The wafer holder 1 of the present invention is provided with a chuck top 2 having a chuck top conductor layer 3 and a heating body 4, a plurality of support bars 5 that partially support the chuck top 2, and the support bars 5. Bottom substrate 6. A gap 7 exists between the chuck top 2, the support bar 5, and the bottom substrate 6, and the heat insulation effect can be enhanced by the gap 7. The shape of the gap 7 is not particularly limited, and may be a shape that suppresses as much as possible the amount of heat or cold generated in the chuck top 2 transmitted to the support bar 5.

  A plurality of support bars 5 are installed on a flat bottom substrate 6 and partially support the back side of the chuck top 2 at a plurality of locations. Therefore, the chuck top 2 supported by the plurality of support bars 5 can suppress deformation when the probe card is pressed. Further, the contact area between the chuck top 2 and the support bar 5 can be reduced, and at the same time, the gap 7 can be easily formed between the chuck top 2 and the support bar 5. By forming such a gap 7, most of the space between the chuck top 2 and the support rod 5 becomes an air layer, and in combination with the small contact area, an efficient heat insulating structure can be achieved.

  The support bar 5 that supports the chuck top 2 may be integrated with the bottom substrate 6 or may be separated. However, if the support bar 5 and the bottom substrate 6 are separated, the contact interface can be increased not only between the chuck top 2 and the support bar 5 but also between the support bar 5 and the bottom substrate 6. This is preferable because efficient heat insulation can be achieved.

  The wafer holder of the present invention for supporting the chuck top 2 with the plurality of support bars 5 has a hollow structure having the gap 7 between the chuck top 2 and the support bar 5 as described above. The weight can be reduced as compared with a wafer holder provided with a support column made of a columnar plate equivalent to the outer diameter of the top or a cylindrical support with a bottom that supports the outer periphery of the chuck top in a ring shape. . This weight reduction makes it possible to rapidly increase or decrease the temperature and increase the throughput of the inspection process.

  As for the arrangement of the support rods with respect to the chuck top, a plurality of support rods are arranged concentrically with respect to the chuck top, or a plurality of support rods are arranged concentrically with respect to the chuck top and one support rod is centered. It is preferable to arrange in the part. In any case, the thermal expansion coefficient of each support rod is larger in the support rod arranged concentrically than the support rod arranged in the center, and the outer side of the support rod arranged concentrically. It is preferable to arrange so as to be large.

  For example, as shown in FIG. 2, the support bar 5 a may be disposed at the center of the chuck top 2, and a plurality of support bars 5 c may be disposed concentrically. As shown in FIG. 3, it is also possible to arrange a plurality of support bars 5b concentrically without arranging a support bar at the center. Further, as shown in FIG. 4, a plurality of support bars 5 b and 5 c may be arranged concentrically with a plurality of diameters with respect to the chuck top 2. Furthermore, as shown in FIG. 5, the support bar 5a can be arranged at the center, and a plurality of support bars 5b and 5c can be arranged concentrically with a plurality of diameters.

  Further, when the support rods are arranged in a plurality of concentric circles, for example, in the case of FIG. 4, the outermost support rod 5 c is preferably arranged on a concentric circle having a diameter of ½ or more of the diameter of the chuck top 2. . If the diameter of the support rod arranged concentrically on the outermost circumference is less than half of the diameter of the chuck top, the deformation amount of the chuck top (deflection amount) when the end of the chuck top is pressed by pressing during probing ) Increases and proper probing cannot be performed. More preferably, the outermost support rod is on a concentric circle having a diameter of 2/3 or more of the diameter of the chuck top.

  The number of support rods arranged in a plurality of concentric circles is preferably three or more for each concentric circle, and more preferably six or more for the outermost concentric circle. When there are two or less support rods for one concentric circle, the distance between the support rods increases, so that when pressing during probing, the amount of deformation (deflection) of the chuck top increases and proper probing can be performed. It may not be possible.

  The larger the number of support rods, the more advantageous is the bending during probing load. However, if the number of support rods is too large, the contact area between the chuck top and the support rod becomes too large. Since it is transmitted to the bottom substrate and further to the drive system, the measurement accuracy is lowered. Preferably, the total support area (contact area between the chuck top and the support bar) for supporting the chuck top of the support bar is set to 20% or less, more preferably 15% or less of the total area of the back surface of the chuck top. High measurement accuracy can be maintained due to the effect.

  In general, a wafer prober has a driving device mounted underneath, and in the probing operation at the time of inspection, movement in the X, Y, and Z directions is repeatedly performed with an acceleration of about 0.5 G. Therefore, it is necessary to fix the chuck top and the bottom substrate via a support bar so as to withstand vibration during movement.

For example, as shown in FIG. 6, the chuck top 2 can be fixed to the bottom substrate 6 fastened to a lower driving device (not shown) using screws 8 or the like. When the chuck top and the bottom substrate are fastened with screws through the support rods as described above, it is preferable that the difference in thermal expansion coefficient between the support rods and the screws is 5 × 10 ⁻⁶ / K or less. When the difference in thermal expansion coefficient between the support rod and the screw is larger than 5 × 10 ⁻⁶ / K, the flatness of the chuck top is deteriorated at the time of temperature rise and cooling, and the worst is not preferable because it leads to damage of the chuck top. . In FIG. 6, the screw 8 is passed through the inside of the support bar 5, but it is also possible to insert the screw in a place different from the support bar 5.

  The shape of the support bar is not particularly limited, and may be a columnar body, a cone or a pyramid, or a cylindrical body. In particular, if the support bar is a cylindrical body, as shown in FIG. 7, the chuck top 1 and the bottom substrate 6 can be fixed with screws through the through holes 5 a of the support bar 5. . In this way, if the support rod is a cylindrical body having a through hole, it is not necessary to insert a screw in a different place from the support rod, and therefore the avoidance hole of the heating body and the cooling module can be minimized. Therefore, an efficient heating body and cooling channel can be designed.

  In recent semiconductor probing, the chuck top is provided with a heating element because it is necessary to heat the wafer to a temperature of 100 to 200 ° C. As the heating element, one in which a resistance heating element is sandwiched between insulators such as mica is preferable because the structure is simple. When attaching a heating element to the chuck top, place the heating element on the back side of the chuck top (opposite side of the wafer mounting surface) and fix it with a mechanical method such as screwing using a metal holding plate. Can do.

  As the resistance heating element, a metal material can be used. For example, nickel, stainless steel, silver, tungsten, molybdenum, chromium, and alloys of these metals are preferable. Of these metals, stainless steel and nichrome are preferred. When stainless steel or nichrome is processed into the shape of a resistance heating element, the foil can be formed in a predetermined circuit pattern with relatively high accuracy by a technique such as etching. In addition, since it is inexpensive and has oxidation resistance, it can withstand long-term use even when the use temperature is high.

  The insulator that sandwiches the resistance heating element is not particularly limited as long as it is a heat-resistant insulator. For example, in addition to mica, silicon resin, epoxy resin, phenol resin, or the like can be used. Further, when the resistance heating element is sandwiched between insulating resins, the heat generated by the resistance heating element is smoothly transferred to the chuck top, so that the heat conduction of the resin can be enhanced by dispersing the filler in the resin. The filler material dispersed in the resin is not particularly limited as long as there is no reactivity with the resin. For example, boron nitride, aluminum nitride, alumina, silica, or the like can be used.

  Further, the chuck top can include a cooling module together with the above-described heating body. In general, in a wafer holder equipped with a heating element and a cooling module, if it is not possible to prevent the heat of the heating element or the low temperature of the cooling module from being transmitted to the support rod, the bottom substrate where the support rod is installed and the bottom substrate bottom Heat and low temperature are transmitted to the drive system, and the mechanical accuracy is shifted due to the difference in thermal expansion of each component, which causes the flatness and parallelism of the wafer mounting surface of the chuck top to be significantly deteriorated.

  In the wafer holder of the present invention, since the chuck top is locally supported only by a plurality of support rods, the contact area between the chuck top and the bottom substrate can be reduced, and further, since the gap is provided, the heat insulation effect is increased, and the chuck The flatness and parallelism of the top are not deteriorated. Furthermore, the heating body and the cooling module are arranged so as not to contact the support rod. For example, by providing an avoidance hole in the heating body and the cooling module and inserting the support rod into the avoidance hole, the heat insulation effect can be further enhanced. it can.

  In addition, when supporting the back surface outer peripheral part of a chuck | zipper top in a ring shape using a bottomed cylindrical support body, it is necessary to make the outer diameter of a heating body and a cooling module smaller than the internal diameter of a support body. For this reason, at the time of temperature rise, the heat dripping of the outer peripheral portion is large, and there is a limit to the improvement of the heat uniformity. Further, since the refrigerant flow path cannot be extended to the outer periphery of the chuck top even during cooling, there is a limit to the improvement in cooling heat uniformity.

  On the other hand, since the wafer holder of the present invention has a structure in which the back surface of the chuck top is partially supported by a plurality of support rods, a heating body and a cooling module having the same outer diameter as the chuck top should be mounted. Can do. For this reason, it is possible to further improve the thermal uniformity during temperature rise and cooling while maintaining the flatness and rigidity of the chuck top. In particular, if a part of the heat generating part of the heating body or a part of the flow path of the cooling module is also present outside the outermost support rod, the thermal uniformity can be further improved. When the cooling module is formed of a metal such as Cu or Al having high thermal conductivity, the cooling module itself acts as a soaking plate, and an effect of improving the soaking property can be obtained.

  The diameter of the heating body is preferably 90 to 110% of the diameter of the chuck top. If the diameter of the heating body is less than 90% of the diameter of the chuck top, the temperature distribution of the chuck top at the time of temperature rise is lowered. If the diameter of the heating element is larger than the chuck top, the temperature distribution of the chuck top can be improved, but in practice it is inappropriate to make it larger than 110% of the diameter of the chuck top in order to make the apparatus size as small as possible. There are often.

  As for the size of the cooling module, the diameter of the cooling module is preferably 90 to 110% of the diameter of the chuck top as in the case of the heating body. If the diameter of the cooling module is less than 90% of the diameter of the chuck top, heat inflow from the outer peripheral portion becomes significant, and the temperature distribution of the chuck top during cooling is deteriorated, which is not preferable. In addition, when the cooling module diameter is larger than the chuck top, the temperature distribution of the chuck top during cooling can be improved. However, in practice, it is more than 110% of the chuck top diameter due to the restriction of making the apparatus size as small as possible. Increasing the size is often inappropriate.

  It is preferable that a metal layer for shielding (shielding) electromagnetic waves is formed between the chuck top and the heating body. This electromagnetic shield electrode layer plays a role of blocking electromagnetic waves generated by a heating body or the like, or noise that affects the probing of the wafer such as an electric field. Although this noise does not have a great influence on the measurement of normal electrical characteristics, it particularly affects the measurement of the high frequency characteristics of the wafer. As the electromagnetic shield electrode layer, for example, a metal foil can be inserted between the heating body and the chuck top, and the chuck top and the heating body need to be insulated. Although there is no restriction | limiting in particular as metal foil to be used, Since a heating body becomes the temperature of about 200 degreeC, metal foil which consists of stainless steel, nickel, aluminum, etc. is preferable.

  An insulating layer is required between the chuck top and the electromagnetic shield electrode layer. When the chuck top is an insulator, between the chuck top conductor layer formed on the wafer mounting surface of the chuck top, and when the chuck top is a conductor, the chuck top itself and the electromagnetic shield layer In the meantime, a capacitor is formed on the electric circuit, and this capacitor component may affect noise when probing the wafer. Therefore, by forming an insulating layer between the electromagnetic shield electrode layer and the chuck top, the above noise can be reduced. Can be reduced.

  Moreover, it is preferable to provide a guard electrode layer through an insulating layer between the chuck top and the electromagnetic shield electrode layer. Further, by covering the support rod with a conductor (metal layer), it is possible to reduce the influence of noise during measurement of wafer characteristics due to high frequency. Further, by connecting the guard electrode layer to the metal layer formed on the support rod, it is possible to further reduce the noise that affects the high frequency characteristics of the wafer.

  For the bottom substrate, the Young's modulus is preferably 200 GPa or more. When the Young's modulus of the bottom substrate is less than 200 GPa, the thickness of the bottom substrate cannot be reduced, so that a sufficient volume of voids cannot be secured and a sufficient heat insulating effect cannot be expected. In addition, a sufficient space for mounting the cooling module cannot be secured. More preferably, the Young's modulus of the bottom substrate is 300 GPa or more. Use of a material having a Young's modulus of 300 GPa or more is particularly preferable because deformation of the bottom substrate can be significantly reduced, and the bottom substrate can be further reduced in size and weight.

  The thermal conductivity of the bottom substrate is preferably 40 W / mK or less. If the thermal conductivity of the bottom substrate exceeds 40 W / mK, the heat applied to the chuck top is easily transferred to the bottom substrate, which affects the accuracy of the drive system, which is not preferable. In recent years, since a high temperature of 150 to 200 ° C. is required as a temperature during probing, the thermal conductivity of the bottom substrate is more preferably 10 W / mK or less, and particularly preferably 5 W / mK or less. This is because the amount of heat transferred from the support rod to the drive system is significantly reduced when the thermal conductivity is at this level.

  The material of the bottom substrate that satisfies these conditions is preferably mullite, alumina, a composite of mullite and alumina (mullite-alumina composite), or the like. Mullite is preferable in that it has a low thermal conductivity and a large heat insulating effect. Alumina is preferable in terms of high Young's modulus and high rigidity. The mullite-alumina composite is a generally preferable material because it has a thermal conductivity smaller than that of alumina and a Young's modulus larger than that of mullite.

  Regarding the material of the support rod, it is necessary to consider the thermal expansion coefficient. That is, when the chuck top is heated by the heating body, the center of the chuck top is always warped in a concave shape because heat is transmitted from the lower heating body. On the other hand, the bottom substrate always warps in a convex shape due to the heat from the upper heating body. In addition, since the prober driving device is connected to the lower part of the bottom substrate, the structure is very rigid. Therefore, the support rod at the center of the chuck top is applied with a force downward from the chuck top and upward from the bottom substrate as compared to the outer peripheral portion, and is also stretched by its own thermal expansion. It will be pushed up from the bottom.

  At this time, the chuck top itself deforms into a concave shape due to thermal expansion, and therefore, the center of the chuck top has a force pushed up from below by the support rod and a force that warps downward due to its own thermal expansion. It will be stored as internal stress. Further, during probing, since a probing pressure is applied from the wafer mounting surface side of the chuck top, a force in the direction of increasing internal stress is applied. For this reason, if the thermal expansion coefficient of the support rod that supports the center of the chuck top is larger than that of the support rod that supports the outer periphery, the support portion itself will be further stretched. In the worst case, the chuck top will crack. Probing may not be continued. Even if it is initially okay, if the temperature rise and cooling are repeated and the probing operation is repeated, there is a greater risk of eventually leading to chuck top cracking.

  In order to avoid this situation, it is better to eliminate the support rod that supports the center of the chuck top, but if it is eliminated, the deformation of the chuck top due to the probing pressure (chuck top deflection) will increase, and probing will be poor. . Therefore, the internal stress applied to the chuck top can be reduced by controlling the thermal expansion coefficient of the support rod supporting the central portion to be equal to or less than the thermal expansion coefficient of the support rod supporting the outer peripheral portion, and the temperature rise and cooling Even if the process is repeated or the probing operation is repeated, the chuck top can be prevented from cracking.

  The same applies to cooling. When a cooling module and a heating body are provided at the lower part of the chuck top, for example, when cooling to −60 ° C., the chuck top has a temperature distribution in which the upper wafer mounting surface side is warm and the lower side is cold. The center part warps in a convex shape. On the other hand, the bottom substrate is warped concavely at the center due to a temperature distribution in which the upper side is cold and the lower side is warm. Therefore, also in this case, the force applied to the chuck top can be reduced by reducing the thermal expansion coefficient of the support rod supporting the center portion of the chuck top to be equal to or less than the thermal expansion coefficient of the support rod supporting the outer peripheral portion. Even if the cooling is repeated or the probing operation is repeated, a chuck top without cracks can be realized.

  Furthermore, the Young's modulus of the support rod is preferably 100 GPa or more. When the Young's modulus of the support rod is less than 100 GPa, it is necessary to arrange a large number of support rods. If a large number of support bars are arranged, it is necessary to increase the number of avoidance holes provided in the heating body and the cooling module, and the heating capacity and cooling capacity are impaired, which is not preferable. A more preferable Young's modulus is 200 GPa or more.

  The thermal conductivity of the support rod is preferably 40 W / mK or less, like the bottom substrate. If the thermal conductivity of the support rod exceeds 40 W / mK, the heat applied to the chuck top is easily transferred to the bottom substrate, which affects the accuracy of the drive system, which is not preferable. In recent years, since a high temperature of 150 to 200 ° C. is required as a temperature during probing, the thermal conductivity of the support rod is more preferably 10 W / mK or less, and particularly preferably 5 W / mK or less. This is because the amount of heat transferred from the support rod to the drive system is significantly reduced when the thermal conductivity is at this level.

  As a specific material of the support rod, a material having a smaller coefficient of thermal expansion than the bottom substrate is preferable. Therefore, when the bottom substrate is mullite, alumina, mullite-alumina composite, mullite-alumina composite, silicon nitride, cordierite, Glass or the like is preferable. Mullite-alumina composite and silicon nitride are preferable in that they have a small coefficient of thermal expansion and high rigidity. Cordierite and glass are preferable in that they have a small coefficient of thermal expansion.

  Although there is no restriction | limiting in particular as a magnitude | size of a support rod, It is preferable that an outer diameter is 5 mm or more. When the outer diameter is less than 5 mm, the support effect is not sufficient, and the support rod is easily deformed. Moreover, it is preferable that the outer diameter of a support rod is 20 mm or less. When it has the outer diameter exceeding this, a contact area becomes large and the heat insulation effect is not acquired. In addition, when the cooling module is provided, it is necessary to provide a large avoidance hole for avoiding the support rod in the cooling module, which is not preferable because the cooling capacity is impaired.

  In addition, the shape of the support rod is not particularly limited, such as a columnar shape, a triangular prism shape, a quadrangular prism shape, a conical shape, or a pyramid shape. In the case where the support bar is separated from the bottom substrate, there are no particular restrictions on the method for fixing both, but brazing with active metal, glassing, screwing, and the like can be given. Among these, screwing is particularly preferable. By screwing, the attachment and detachment is facilitated, and further, since heat treatment is not performed at the time of fixing, deformation of the support rod and the bottom substrate due to heat treatment can be suppressed. In particular, if the support rod is a cylindrical body as described above, a screw can be inserted into a through hole inside the support rod so that the support rod can be fixed to the chuck top and the bottom substrate.

  The surface roughness of the contact portion between the support bar and the chuck top or the bottom substrate is preferably 0.1 μm or more in terms of Ra. When the surface roughness Ra is less than 0.1 μm, the contact area between the support portion, the chuck top and the bottom substrate increases, and the gap between the two becomes relatively small, so that Ra is 0.1 μm or more. This is not preferable because the amount of heat transfer becomes larger than the case. There is no particular upper limit on the surface roughness, but if Ra is 5 μm or more, the cost for treating the surface may increase.

  As a method for setting the surface roughness to Ra of 0.1 μm or more, a polishing process or a process such as sand blasting can be performed. In this case, it is necessary to optimize the polishing conditions and blasting conditions so that Ra is 0.1 μm or more. Moreover, since the contact interface can be increased by separating the support bar from the bottom substrate, the amount of heat transfer can be reduced.

  Similarly, the surface roughness of the bottom of the bottom substrate is preferably 0.1 μm or more in terms of Ra. Since the surface roughness of the bottom portion of the bottom substrate is rough, the amount of heat transferred to the drive system can also be reduced. In this way, by forming an interface in each member and setting the surface roughness of the interface to Ra of 0.1 μm or more, the amount of heat transferred to the bottom of the bottom substrate can be reduced. In addition, the amount of power supplied to the resistance heating element can be reduced.

  The perpendicularity between the contact surface of the support rod with the chuck top or the contact surface of the support rod with the bottom substrate and the support rod is preferably 10 mm or less in terms of a measurement length of 100 mm. For example, when the squareness exceeds 10 mm, it is not preferable because the support rod itself is likely to be deformed when the pressure applied to the chuck top is applied to the support rod.

  A metal layer is preferably formed on the surface of the bottom substrate. Electric fields and electromagnetic waves generated from the heating body for heating the chuck top, the prober drive unit, and the surrounding equipment, etc., affect noise when inspecting the wafer, but a metal layer is formed on the bottom substrate. It is preferable because this electromagnetic wave can be blocked. The method for forming the metal layer is not particularly limited. For example, a conductive paste obtained by adding glass frit to a metal powder such as silver, gold, nickel, or copper may be applied and baked with a brush or the like.

  Alternatively, a metal layer can be formed by spraying a metal such as aluminum or nickel. It is also possible to form a metal layer on the surface by plating. Further, these methods can be combined. That is, after applying and baking a conductor paste, a metal such as nickel may be plated, or plating may be formed after thermal spraying. Of these methods, plating or thermal spraying is particularly preferable. Plating is preferable because it has high adhesion strength and high reliability. Thermal spraying is preferable because a metal film can be formed at a relatively low cost.

  The metal layer may include a conductor on at least a part of the surface of the bottom substrate. The material to be used is not particularly limited as long as it is a conductor, and for example, stainless steel, nickel, aluminum or the like can be used. As a method of providing a conductor, a ring-shaped conductor can be attached to the side surface of the bottom substrate. A metal foil of the above material can be formed into a ring shape with a size larger than the outer diameter of the bottom substrate, and can be attached to the side surface of the bottom substrate. By making this conductor ring larger than the outer diameter of the chuck top, the entire side surface from the bottom of the bottom substrate to the top surface of the chuck top can be covered without contacting the chuck top.

  Moreover, you may attach metal foil or a metal plate to the bottom face part of a bottom board | substrate, and the effect (guard effect) which interrupts electromagnetic waves can be heightened by connecting with the metal foil attached to the side surface. A metal foil or a metal plate may be attached to the upper surface of the bottom substrate, and the guard effect can be enhanced by connecting it to the metal foil attached to the side surface and the bottom surface. By adopting such a method, it is preferable because the guard effect can be obtained at a relatively low cost compared to the case of applying plating or conductive paste. Although there is no restriction | limiting in particular regarding the fixing method of metal foil and a metal plate, and a bottom board | substrate, For example, metal foil and a metal plate can be attached to a bottom board | substrate using a metal screw. Moreover, it is preferable to integrate the metal foil and the metal plate of the bottom surface portion and the side surface portion of the bottom substrate.

  It is not preferable that the warping of the chuck top is 30 μm or more because the prober probe at the time of probing causes contact with one piece and the characteristics cannot be evaluated, or it is erroneously evaluated as a defective determination due to poor contact. Further, even if the parallelism between the surface of the chuck top conductor layer and the bottom surface of the bottom of the support bar is 30 μm or more, contact failure is similarly caused, which is not preferable. Even when the warp and parallelism of the chuck top are good at 30 μm or less at room temperature, the case where the warp and parallelism is 30 μm or more at the time of probing at 200 ° C. is not preferable as above. The same applies to probing at -60 ° C. That is, it is preferable that both the warpage and the parallelism are 30 μm or less over the entire temperature range in which probing is performed.

It is preferable that the heating body, the electromagnetic shield electrode layer, the guard electrode layer, and the like that are insulated from each other by the insulating layer are mechanically fixed to the chuck top using screws or the like by a pressing plate. In that case, it is desirable that the difference between the thermal expansion coefficient of the pressing plate and the thermal expansion coefficient of the chuck top is 5 × 10 ⁻⁶ / K or less. When the difference in thermal expansion coefficient between the pressing plate and the chuck top is in the above relationship, both the warpage and the parallelism can be 30 μm or less over the entire temperature range in which probing is performed.

  When the thermal expansion coefficient of the holding plate is larger than 5 ppm / K as a difference from the thermal expansion coefficient of the chuck top, when the temperature is raised to 100 to 200 ° C., it is disposed below the chuck top due to the bimetal effect. Since the holding plate is larger than the chuck top, stress is applied so that the central portion of the chuck top becomes concave, the flatness of the chuck top is deteriorated, and the warp and parallelism of the chuck top at room temperature are good at 30 μm or less. However, it is not preferable because warpage and parallelism are 30 μm or more during probing at 200 ° C. Furthermore, when a support bar is arranged at the center of the chuck top, probing becomes impossible due to the support bar pushing up the center of the chuck top whose center is deformed into a concave shape. Or damage.

On the other hand, when the difference in thermal expansion coefficient is smaller than 5 × 10 ⁻⁶ / K, the pressing plate disposed on the lower side of the chuck top is smaller than the chuck top when the temperature is raised, so that the central portion of the chuck top is convex. Stress is applied, the flatness of the chuck top is deteriorated, and even when the warp and parallelism of the chuck top are good at 30 μm or less at room temperature, the warp and parallelism are 30 μm when probing at −60 ° C. Since it becomes the above, it is not preferable.

  The wafer holder of the present invention can include a cooling module on the chuck top. By flowing an antifreeze refrigerant cooled separately by a chiller through the cooling module, the chuck top can be rapidly cooled. Further, when heating the chuck top, it is desirable that the cooling module is movable so that the cooling module is separated from the heating body provided at the lower part of the chuck top and the temperature is increased efficiently. Further, by using a thermocouple or a platinum resistor embedded in the cooling module or the chuck top and cooling while controlling the temperature or controlling the heat generation amount of the heating body, fine temperature control during cooling can be performed. At this time, by using a highly heat conductive material such as Cu or Al as the cooling module, the cooling module can be used as a soaking plate to achieve high soaking.

  As shown in FIG. 8, the cooling module 9 is fixed on the opposite side (back surface) of the wafer mounting surface 2a of the chuck top 2, and a resistance heating element is sandwiched between the lower surface thereof with an insulator. There is a method of fixing the heating body 4 having a structure. At this time, a soft material such as Si resin having deformability and heat resistance and high thermal conductivity can be inserted between the back surface of the chuck top and the cooling module. By providing a soft material between the chuck top and the cooling module that can reduce the flatness and warpage of each other, the contact area can be increased, the cooling capacity inherent to the cooling module can be demonstrated, and the cooling rate can be increased. Can be increased.

  As another fixing form, as shown in FIG. 9, a heating body 4 having a structure in which a resistance heating element is sandwiched between insulators is installed on the back surface of the chuck top 2, and the cooling module 9 is fixed to the lower surface thereof. Can do. Furthermore, as shown in FIG. 10, a cooling module 9 can be arranged on the bottom substrate 6 and can be made movable by using an elevating means 10 such as an air cylinder. It is preferable to make the cooling module movable because the heating rate and cooling rate of the chuck top can be greatly improved and the throughput can be increased. In addition, the movable type is preferable because no pressure is applied to the probe card at the time of probing on the cooling module, so that the cooling module is not deformed by pressure, and the cooling capacity is higher than that of air cooling.

  In the wafer holder of the present invention, the chuck top is supported only by a plurality of support bars, and the cooling module is fixed to the chuck top, so that there is no contact between the support bar and the bottom substrate and the cooling module, and structural force is reduced. Does not work. Therefore, unlike the structure in which the cooling module of the same size as the conventional chuck top is supported by the support bar and the structure in which the cooling module / chuck top made of metal and provided with the internal flow path is supported by the support bar, In the present invention, the probe card pressure at the time of probing does not work on the cooling module itself, and it is preferable that the cooling module is not deformed even if it is used repeatedly.

  In any of the above methods, there is no particular limitation on the method for fixing the cooling module, but it can be fixed by a mechanical method such as screwing or clamping. Also, when fixing the chuck top, cooling module, and heating element with screws, the number of screws is 3 or more, and further 6 or more improves the adhesion between them, further improving the cooling capacity of the chuck top. Therefore, it is preferable.

  For example, as shown in FIG. 8, in the case of a method in which the cooling module 9 is directly installed on the back side of the chuck top 2 and the heating element 4 having a structure in which a resistance heating element is sandwiched between insulators on the lower surface, The body 4 can be fixed to the chuck top 2 with screws or the like with a pressing plate (not shown). At this time, it is desirable that the thermal expansion coefficient of the holding plate is equal to or less than the thermal expansion coefficient of the cooling module. If the thermal expansion coefficient of the holding plate is larger than the thermal expansion coefficient of the cooling module, the central part of the chuck top warps in a concave shape due to the bimetal effect of the cooling module and the holding plate when the temperature is raised to 200 ° C. The force that warps in a concave shape works more strongly and deteriorates the flatness of the chuck top. Even if the warp and parallelism of the chuck top are good at 30 μm or less at room temperature, it is not preferable if the warp and parallelism is 30 μm or more when probing at 200 ° C.

  When the thermal expansion coefficients of the holding plate and the cooling module are the same, there is a heating body on the lower side of the cooling module, so that when the temperature is raised to 200 ° C., the central portion also warps in a concave shape. That is, the force which makes the center part of a chuck | zipper top bend | curve into a concave shape acts more like the above, and will deteriorate the flatness of a chuck | zipper top. By making the thermal expansion coefficient of the pressing plate smaller than the thermal expansion coefficient of the cooling module, bimetal between the cooling module and the pressing plate can be prevented, and the flatness of the chuck top when the temperature is raised by 200 ° C. can be kept good.

  The same applies to cooling. If the coefficient of thermal expansion of the retainer plate is greater than the coefficient of thermal expansion of the cooling module, the central part warps in a convex shape due to the bimetal effect, and this causes the central part of the chuck top to warp in a convex shape. Works more strongly and deteriorates the flatness of the chuck top. Even if the warp and parallelism of the chuck top are good at 30 μm or less at room temperature, it is not preferable that the warp and parallelism become 30 μm or more during probing at −60 ° C. Thus, by setting the thermal expansion coefficient of the holding plate to be equal to or less than the thermal expansion coefficient of the cooling module, both warpage and parallelism can be set to 30 μm or less over the entire temperature range in which probing is performed.

  In the wafer holder of the present invention, the cooling module may be mounted in the gap between the chuck top, the support bar, and the bottom substrate, or the cooling module is mounted on the support bar, and the chuck top is mounted thereon. You may make it the structure which mounts. In any method, since the chuck top and the cooling module are fixed, the cooling rate can be increased as compared with the movable type. Further, since the cooling module is mounted on the support rod, the contact area of the cooling module with the chuck top increases, and the chuck top can be cooled more quickly.

  Thus, when fixing a cooling module with respect to a chuck | zipper top, it is also possible to heat up, without flowing a refrigerant | coolant to a cooling module. Further, since the refrigerant does not flow into the cooling module, the heat generated by the heating body is not lost to the refrigerant and escapes out of the system, so that the temperature can be increased more efficiently. However, even in this case, the chuck top can be efficiently cooled by flowing the coolant through the cooling module during cooling.

  Further, the chuck top and the cooling module can be integrated. In this case, the material of the chuck top and the cooling module used for integration is not particularly limited, but it is necessary to form a flow path for flowing a coolant in the cooling module. It is preferable that the difference in thermal expansion coefficient of the cooling module portion is small, and it is natural that the same material is most preferable.

  As a material used in this case, ceramics described as the material of the chuck top or a composite of ceramics and metal can be used. In this case, a chuck top conductor layer is formed on the wafer mounting surface side, a coolant channel is formed on the opposite surface side, and a substrate made of the same material as the chuck top is brazed, for example. A wafer holder can be manufactured by integrating by a technique such as glass attachment. As a matter of course, the flow path may be formed on the side of the substrate to be attached, or the flow path may be formed on both substrates. It is also possible to integrate by screwing.

  In this way, by integrating the chuck top and the cooling module, the chuck top can be cooled more quickly than when the cooling module is fixed to the chuck top as described above.

  The material of the cooling module is not particularly limited, but aluminum, copper, and alloys thereof are preferable because they have a relatively high thermal conductivity and can quickly take away the heat of the chuck top. Further, stainless steel, magnesium alloy, nickel, and other metal materials can be used. Further, in order to impart oxidation resistance to the cooling module, a metal film having oxidation resistance such as nickel, gold, and silver can be formed using a technique such as plating or thermal spraying.

  Ceramics can also be used as the material for the cooling module. The material in this case is not particularly limited, but aluminum nitride and silicon carbide are preferable because they have a relatively high thermal conductivity and can quickly remove heat from the chuck top. Silicon nitride and aluminum oxynitride are preferable because they have high mechanical strength and excellent durability. Oxide ceramics such as alumina, cordierite, and steatite are preferable because they are relatively inexpensive.

  As described above, since the material of the cooling module can be variously selected, the material may be selected depending on the application. Among these, aluminum plated nickel and copper plated nickel are excellent in oxidation resistance, have high thermal conductivity, and are relatively inexpensive. preferable.

  It is also possible to flow a coolant through the cooling module. By flowing the refrigerant, the heat transmitted from the heating body to the cooling module can be quickly removed, so that the cooling rate of the heating body can be further improved. As the refrigerant flowing in the cooling module, water, fluorinate, ethylene glycol, or the like can be selected, and there is no particular limitation.

  As a suitable example for forming the flow path in the cooling module, two aluminum plates are prepared, and the flow path is formed on one of the aluminum plates by machining or the like. And in order to improve corrosion resistance and oxidation resistance, nickel plating is given to the whole surface. This is pasted with another nickel-plated aluminum plate. At this time, for example, an O-ring or the like is inserted so that water does not leak around the flow path, and the two aluminum plates are bonded together by screwing or welding.

  Alternatively, two copper (oxygen-free copper) plates are prepared, and a flow path is formed on one of the copper plates by machining or the like. The other copper plate and a stainless steel pipe serving as the refrigerant inlet / outlet are simultaneously brazed to the copper plate. Nickel plating is applied to the entire surface of the joined cooling plates in order to improve corrosion resistance and oxidation resistance. Furthermore, as another form, it can be set as a cooling module by attaching the pipe | tube which flows a refrigerant | coolant to cooling plates, such as an aluminum plate or a copper plate. In this case, the cooling efficiency can be further increased by forming a counterbore groove having a shape close to the cross-sectional shape of the pipe in the cooling plate and bringing the pipe into close contact with each other. Moreover, in order to improve the adhesiveness of a cooling pipe and a cooling plate, you may insert thermally conductive resin, ceramics, etc. as an intervening layer.

  A chuck top conductor layer is formed on the wafer mounting surface of the chuck top. The purpose of forming the chuck top conductor layer is to protect the chuck top from corrosive gases, acids, alkali chemicals, organic solvents, water, and the like that are normally used in semiconductor manufacturing. Further, the chuck top conductor layer has a role of dropping to the ground in order to block electromagnetic noise from below the chuck top between the wafer and the wafer placed on the chuck top.

  The method for forming the chuck top conductor layer is not particularly limited, and examples thereof include a method in which a conductor paste is applied by screen printing and then fired, a technique such as vapor deposition or sputtering, or a technique such as spraying or plating. Of these, thermal spraying and plating are particularly preferable. These thermal spraying and plating methods do not involve heat treatment when forming the conductor layer, so the warp due to heat treatment does not occur on the chuck top itself, and the cost is relatively low. A simple conductor layer can be formed.

  In particular, it is particularly preferable to form a sprayed film on the chuck top and form a plating film thereon. The sprayed film has better adhesion with ceramics or metal-ceramics than the plated film. The reason why the sprayed film is excellent in adhesion is that the material to be sprayed, such as aluminum or nickel, forms some oxide, nitride or oxynitride at the time of spraying, so the formed compound is the surface layer of the chuck top. It is because it can react and adheres firmly.

  However, since the sprayed film contains these compounds, the conductivity of the film is lowered. On the other hand, since plating can form a substantially pure metal, the adhesion strength with the chuck top is not as high as that of the sprayed film, but a conductor layer having excellent conductivity can be formed. Therefore, when a sprayed film is formed as a base and a plated film is formed thereon, the plated film has a good adhesion strength with respect to the sprayed film because the sprayed film is a metal, and also has a good electrical conductivity. It is particularly preferable because it can also be imparted.

  Further, the surface roughness of the chuck top conductor layer is preferably 0.5 μm or less in terms of Ra. When the surface roughness exceeds 0.5 μm in Ra, when measuring a device with a large calorific value, the heat generated by the device itself during probing cannot be dissipated from the chuck top, and the device itself rises. It may be heated and destroyed by heat. A surface roughness Ra of 0.02 μm or less is more preferable because heat can be radiated more efficiently.

  When the chuck top heating element is heated, for example, when probing at 200 ° C., the temperature of the lower end surface of the support bar is preferably 100 ° C. or less. If the temperature exceeds 100 ° C, the prober drive system at the bottom of the support rod will be distorted due to the difference in thermal expansion coefficient, and the accuracy will be lost. As a result, the device cannot be evaluated accurately. Further, when measuring room temperature after measuring temperature rise at 200 ° C., it takes time to cool from 200 ° C. to room temperature, and throughput is lowered.

  The Young's modulus of the chuck top is preferably 250 GPa or more. If the Young's modulus is less than 250 GPa, the chuck top bends due to the load applied to the chuck top during probing, and the flatness and parallelism of the upper surface of the chuck top are significantly deteriorated. For this reason, poor contact of the probe pins occurs, an accurate inspection cannot be performed, and the wafer may be damaged. For this reason, the Young's modulus of the chuck top is preferably 250 GPa or more, and more preferably 300 GPa or more.

  The thermal conductivity of the chuck top is preferably 15 W / mK or more. When the thermal conductivity is less than 15 W / mK, the temperature distribution of the wafer placed on the chuck top is deteriorated, which is not preferable. For this reason, if the thermal conductivity is 15 W / mK or more, it is possible to obtain heat uniformity so as not to hinder probing. An example of such a material having thermal conductivity is alumina having a purity of 99.5% (thermal conductivity 30 W / mK). The heat conductivity of a particularly preferable chuck top is 170 W / mK or more.

  The thickness of the chuck top is preferably 8 mm or more. If the thickness is less than 8 mm, the chuck top is deflected by a load applied to the chuck top during probing, and the flatness and parallelism of the upper surface of the chuck top are significantly deteriorated. Therefore, an accurate inspection cannot be performed due to poor contact of the probe pins, and the wafer may be damaged. For this reason, the thickness of the chuck top is preferably 8 mm or more, and more preferably 10 mm or more.

  The material forming the chuck top is preferably a metal-ceramic composite, ceramic, or metal. As the metal-ceramic composite, an aluminum-silicon carbide composite, a silicon-silicon carbide composite, or an aluminum-silicon-silicon carbide composite, which has a relatively high thermal conductivity and is easy to obtain thermal uniformity when the wafer is heated. It is preferably one of the body. Of these, the silicon-silicon carbide composite is particularly preferable because it has a particularly high Young's modulus and a high thermal conductivity.

  In addition, since these composite materials have conductivity, as a method of forming the heating body, for example, an insulating layer is formed on the back surface opposite to the wafer mounting surface by a method such as thermal spraying or screen printing. By heating the conductor layer on the screen or forming the conductor layer in a predetermined pattern by a technique such as vapor deposition, a heating body can be obtained.

  Moreover, metal foils, such as stainless steel, nickel, silver, molybdenum, tungsten, chromium, and these alloys, can be made into a predetermined pattern by an etching, and can be used as a heating body. In this method, the insulation with the chuck top can be formed by the same method as described above. For example, an insulating resin sheet can be inserted between the chuck top and the heating body. This is preferable because the insulating layer can be easily formed at a lower cost than the above method. Examples of the resin that can be used in this case include mica, epoxy resin, polyimide resin, phenol resin, and silicon resin from the viewpoint of heat resistance. Among these, mica is particularly preferable because it is excellent in heat resistance and electrical insulation, is easy to process, and is inexpensive.

  Further, ceramics as the material of the chuck top is relatively easy to use because it is not necessary to form an insulating layer as described above. As a method for forming the heating element in this case, the same method as described above can be selected. Among ceramics, alumina, aluminum nitride, silicon nitride, mullite, and alumina-mullite composite are preferable. These materials are preferable because of their relatively high Young's modulus and small deformation due to the pressing of the probe card. Of these, alumina is particularly excellent because of its relatively low cost and excellent electrical characteristics at high temperatures.

  Moreover, it is also possible to apply a metal as the material of the chuck top. In this case, tungsten or molybdenum having a particularly high Young's modulus and alloys thereof can be used. Specific examples of the alloy include an alloy of tungsten and copper and an alloy of molybdenum and copper. These alloys can be produced by impregnating copper into tungsten or molybdenum. Since the metal chuck top is also a conductor like the ceramic-metal composite, the above method is applied as it is to form the chuck top conductor layer, and the heating body is formed as the chuck top. Can be used.

  When a load of 3.1 MPa is applied to the chuck top, the amount of deflection is preferably 30 μm or less. Since many pins for wafer inspection are pressed onto the chuck top from the probe card from the wafer, the pressure also affects the chuck top, and the chuck top is bent at least. If the amount of deflection at this time exceeds 30 μm, the pins of the probe card cannot be uniformly pressed against the wafer, so that the wafer cannot be inspected. More preferably, the amount of bending when the pressure is applied is 10 μm or less.

  The wafer holder for a wafer prober of the present invention can be suitably used for heating and inspecting an object to be processed such as a wafer. For example, if it is applied to a wafer prober, a handler device, or a tester device, it is particularly preferable because the characteristics of high rigidity and high thermal conductivity can be utilized.

[Example 1]
Two alumina substrates having a diameter of 305 mm and a thickness of 10 mm were prepared. Concentric grooves and through holes for vacuum chucking the wafer were formed on the wafer mounting surface of the alumina substrate. Further, nickel plating was applied to the wafer mounting surface and the back surface to form a chuck top conductor layer and a guard electrode layer. Then, the chuck top conductor layer and the guard electrode layer on the back surface were polished to make the total warpage amount 10 μm, and the surface roughness Ra finished to 0.02 μm to obtain a chuck top.

  Next, a copper cooling module having a channel formed therein was prepared. Under this cooling module, a heating element having a structure in which a resistance heating element is sandwiched between insulators is disposed, and the cooling module is fixed to the back surface of the chuck top with screws. As a result, the temperature can be raised and lowered, and the refrigerant was not flown through the cooling module at the time of temperature rise, but was cooled by flowing a refrigerant whose temperature was controlled by a chiller only when cooling.

Further, the cooling module was attached to the guard electrode layer surface of the chuck top via a silicon resin sheet to ensure insulation of the guard electrode layer and 1 × 10 ¹⁰ Ω or more and used as an electromagnetic shield layer. The resistance heating element was manufactured by etching a stainless foil with a predetermined pattern. Moreover, the outer diameter of the cooling module and the heating body was 305 mm.

  Further, an alumina substrate having a diameter of 310 mm and a thickness of 20 mm was prepared as a bottom substrate. A cylindrical guard plate made of SUS having a diameter of 311 mm, an inner diameter of 310 mm, and a height of 50 mm was fixed to the outer periphery of the bottom substrate, and connected to the guard electrode layer of the chuck top. A plurality of cylindrical alumina-mullite composites having an outer diameter of 15 mm and an inner diameter of 10 mm were prepared as support rods, and all were processed to a height of 20 mm.

  One support bar was placed at the center of the bottom substrate, and 12 support bars were placed at concentric positions with a diameter of 280 mm. On these support rods, the above-mentioned cooling module and chuck top to which a heating body was attached were mounted to obtain a wafer holder for a wafer prober of the present invention.

  Regarding the wafer holder for a wafer prober of the present invention, the outside diameter of the cooling module and the heating body was changed as shown in Table 1 below, and the temperature was kept at 200 ° C. using a wafer thermometer adsorbed on the chuck top. 30 minutes later, and 30 minutes after cooling to −50 ° C., the wafer temperature distribution of the chuck top (CT) was measured. The obtained results are also shown in Table 1 below as a soaking range.

  The determination of the soaking range is shown on the right side of each column of 200 ° C. temperature rise and −50 ° C. cooling. That is, in the determination of the soaking range at the 200 ° C. temperature rising keep, ± 1% or less is ◎, ± 2% or less is ◯, and more than ± 2% is Δ with respect to the center value of the wafer temperature. The determination of the soaking range during the -50 ° C. cooling keep was defined as ◎ for ± 3% or less, ◯ for ± 4% or less, and Δ for greater than ± 4% with respect to the center value of the wafer temperature.

  As can be seen from the above results, the heat distribution of the chuck top can be improved by setting the outer diameter of the cooling module and the heating body to 90% or more, preferably 95% or more of the outer diameter of the chuck top. .

  Next, as a comparative example, a wafer holder including a bottomed cylindrical support was produced. That is, one columnar alumina having a diameter of 310 mm and a thickness of 40 mm was prepared and subjected to counterboring with an inner diameter of 295 mm and a depth of 20 mm. A cylindrical guard plate made of SUS having a diameter of 311 mm, an inner diameter of 310 mm, and a height of 50 mm was fixed to the outer peripheral side surface of the bottomed cylindrical support and connected to the guard electrode layer of the chuck top.

  A through-hole for connecting an electrode that supplies power to the heating heat body was formed in the bottomed cylindrical support. In addition, a copper cooling module with a flow path formed inside is mounted, and a heating element with a resistance heating element sandwiched between insulators is placed under the cooling module, and the cooling module is fixed to the chuck top with screws. did. Thus, a structure capable of raising and lowering the temperature was provided, and at the time of raising the temperature, the refrigerant was not supplied to the cooling module, but only when the refrigerant was cooled, the refrigerant was cooled by flowing the refrigerant whose temperature was controlled.

Further, the cooling module was attached to the guard electrode layer surface of the chuck top via a silicon resin sheet to ensure insulation of the guard electrode layer and 1 × 10 ¹⁰ Ω or more and used as an electromagnetic shield layer. The resistance heating element was manufactured by etching a stainless foil with a predetermined pattern. Moreover, the outer diameter of the cooling module and the heating body was 280 mm.

  One support rod of the mullite-alumina composite was disposed near the center of the bottomed cylindrical support, and a cooling module and a heating body were attached on the bottomed cylindrical support and the support rod. A chuck top was mounted to obtain a wafer holder for a wafer prober of a comparative example.

  With respect to the wafer holder for the wafer prober of this comparative example, the wafer temperature distribution was measured in the same manner as described above. When the results were compared with Table 1 above, the wafer holder for a wafer prober of the present invention compared to the conventional wafer holder for a wafer prober of the comparative example, both when heated at 200 ° C. and cooled at −50 ° C. The soaking range was halved.

[Example 2]
An alumina substrate having a diameter of 305 mm and a thickness of 10 mm was prepared. Concentric grooves and through holes for vacuum chucking the wafer are formed on the wafer mounting surface of the alumina substrate, nickel plating is applied to the wafer mounting surface and the back surface, respectively, and the chuck top conductor layer and the guard electrode layer are formed. Formed. Thereafter, the chuck top conductor layer and the guard electrode layer on the back surface were polished, the total warpage amount was 10 μm, and the surface roughness was finished to 0.02 μm with Ra to obtain a chuck top.

  In addition, a copper cooling module with a flow path formed inside is prepared, and a heating element having a structure in which a resistance heating element is sandwiched between insulators is arranged on the lower surface thereof. Fixed. Thus, a structure capable of raising and lowering the temperature was provided, and the refrigerant was not flown through the cooling module at high temperatures, but was cooled by flowing a refrigerant whose temperature was controlled by a chiller only when cooling.

Further, the cooling module was attached to the guard electrode layer surface of the chuck top via a silicon resin sheet to ensure insulation of the guard electrode layer and 1 × 10 ¹⁰ Ω or more and used as an electromagnetic shield layer. The resistance heating element was manufactured by etching a stainless foil with a predetermined pattern. Moreover, the outer diameter of the cooling module and the heating body was 304 mm.

  Further, an alumina substrate having a diameter of 310 mm and a thickness of 20 mm was prepared as a bottom substrate. A cylindrical guard plate made of SUS having a diameter of 311 mm, an inner diameter of 310 mm, and a height of 50 mm was fixed to the outer periphery of the bottom substrate, and connected to the guard electrode layer of the chuck top.

  Also, as support rods, a plurality of cylindrical SUSs having a diameter of 15 mm and an inner diameter of 10 mm, alumina, alumina-mullite composite, Si-SiC, Kovar, silicon nitride, cordierite, and quartz glass were prepared, each having a height of 20 mm. It was processed into. Table 2 below shows the thermal expansion coefficient, Young's modulus, and thermal conductivity of the material used as the support rod.

  Next, on the bottom substrate, support rods of the above materials are arranged in the arrangements A to E shown in Table 3 below, and a chuck top to which a cooling module and a heating body are attached is mounted thereon, and a wafer is mounted. A wafer holder for a prober was obtained.

In addition, the arrangement | positioning of the support rod shown in Table 3 is as follows.
A: Three equally arranged on a concentric circle having a diameter of 100 mm B: Six equally arranged on a concentric circle having a diameter of 270 mm C: One in the center and six equally arranged on a concentric circle having a diameter of 270 mm D: 100 mm in diameter Equally three on a concentric circle and six equally on a 270 mm diameter concentric circle E: One at the center, three equally on a 100 mm diameter concentric circle, and six equally on a 270 mm diameter concentric circle

  Table 3 below shows the results of probing the wafer holder for wafer probers by heating the wafer to 200 ° C. by energizing the heater. That is, as an initial evaluation, “good” indicates good probing over the entire surface of the wafer, and “poor” indicates some defective. Furthermore, for those with good initial evaluation, continuous probing for 24 hours was carried out.

  Further, the warpage of the chuck top (CT) when the temperature was raised at 200 ° C. was measured, and 30 μm or less was evaluated as “◯” and 20 μm or less as “◎”. Further, the CT deflection when a load of 100 kg / diameter 20 mm was applied was measured, and 50 μm or less was indicated as Δ, 30 μm or less as ◯, and 20 μm or less as ◎. Further, after 24 hours of continuous probing, the temperature of the bottom substrate was measured, and a temperature of 170 ° C. or lower was evaluated as Δ, a temperature of 150 ° C. or lower as ◯, and a temperature of 130 ° C. or lower as ◎.

[Example 3]
A wafer holder for a wafer prober was produced in the same manner as in Example 1 except that the bottom substrate was produced from a mullite-alumina composite. When this wafer holder was subjected to probing similar to that in Example 1, the same results as in Example 1 were obtained.

[Example 4]
A wafer holder for a wafer prober was produced in the same manner as in Example 1 except that the chuck top was made of a Si—SiC composite. When this wafer holder was subjected to probing similar to that in Example 1, the same results as in Example 1 were obtained.

[Example 5]
A wafer holder for a wafer prober was produced in the same manner as in Example 1 except that the chuck top was made of AlN. When this wafer holder was subjected to probing similar to that in Example 1, the same results as in Example 1 were obtained.

It is a schematic sectional drawing which shows one specific example of the wafer holder for wafer probers by this invention. FIG. 3 is a schematic plan view showing an arrangement example of support bars in a wafer holder for a wafer prober of the present invention. It is a schematic top view which shows the other example of arrangement | positioning of the support bar in the wafer holder for wafer probers of this invention. It is a schematic top view which shows another example of arrangement | positioning of the support bar in the wafer holder for wafer probers of this invention. FIG. 5 is a schematic plan view showing still another example of arrangement of support bars in a wafer holder for a wafer prober of the present invention. It is a schematic sectional drawing which shows the fastening state of the chuck | zipper top and bottom board | substrate and support bar in the wafer holder for wafer probers of this invention. It is a schematic sectional drawing which shows the fastening state by the screw using the cylindrical support rod in the wafer holder for wafer probers of this invention. It is a schematic sectional drawing which shows the other specific example of the wafer holder for wafer probers by this invention. It is a schematic sectional drawing which shows another specific example of the wafer holder for wafer probers by this invention. It is a schematic sectional drawing which shows another specific example of the wafer holder for wafer probers by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wafer holder for wafer probers 2 Chuck top 2a Wafer mounting surface 3 Chuck top conductor layer 4 Heating body 5, 5a, 5b, 5c Support rod 6 Bottom substrate 7 Gap 8 Screw 9 Cooling module 10 Lifting means

Claims (13)

The chuck top has a chuck top conductor layer on the surface and is provided with a heating body, a plurality of support bars for supporting the chuck top, and a bottom substrate on which the support bars are installed. The plurality of support bars are arranged concentrically with respect to the chuck top, or are arranged concentrically and in the center with respect to the chuck top, and the plurality of support bars The outer concentric support rod has a larger coefficient of thermal expansion, and when it is arranged at the center, the support rod arranged concentrically is larger than the support rod at the center. Prober wafer holder.   2. The wafer holder for a wafer prober according to claim 1, wherein a total support area in which the support bar supports the chuck top is 20% or less of a total area of the back surface of the chuck top. 3. The wafer prober according to claim 1, wherein an outermost support rod among the support rods arranged concentrically is on a concentric circle having a diameter of ½ or more of a chuck top diameter. 4. Wafer holder. The chuck top, characterized in that it comprises a cooling module with the heating body, a wafer prober wafer holder according to any one of claims 1-3. 5. The wafer holder for a wafer prober according to claim 4 , wherein the heating body and the cooling module do not contact the support rod. Part of the flow path of the part or the cooling module of the heat generating portion of the heating body, characterized in that also present outside the support rods of the outermost periphery disposed in the concentrically to claim 4 or 5 A wafer holder for a wafer prober as described. The wafer holder for a wafer prober according to any one of claims 4 to 6 , wherein a diameter of the heating body is 90 to 110% of a diameter of the chuck top. The wafer holder for a wafer prober according to any one of claims 4 to 7 , wherein the cooling module has a diameter of 90 to 110% of a diameter of the chuck top. The support rod is characterized by separating the chuck top and bottom substrates, wafer prober wafer holder according to any one of claims 1-8. Characterized in that said support rod is columnar body or a cylindrical body, a wafer prober wafer holder according to any one of claims 1-9. Wherein the chuck top and the bottom substrate via a support rod is fastened with screws, and wherein the thermal expansion coefficient difference of the support rod and the screw is not more than 5 × 10 -6 ^{/ K,} according to claim 10 Wafer holder for wafer probers. A heater unit for a wafer prober comprising the wafer holder for a wafer prober according to any one of claims 1 to 11 . A wafer prober comprising the heater unit according to claim 12 .

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