JP4886909B1 - Wafer holder - Google Patents

Abstract

The wafer is not damaged when the wafer is removed from the wafer holder, the cost of performing the characteristic test is low, the characteristic test can be performed at a high temperature, and the holder can be operated even if force is applied perpendicularly to the wafer surface. Provided is a wafer holder capable of easily mounting a wafer on a loading stage surface of an apparatus for performing a characteristic test without causing the wafer to be detached or damaged.
A metal sheet (12) is fixed to the holding frame (10) so as to close a hollow portion of the holding frame (10) that is provided with a hollow portion while leaving a peripheral portion in a ring shape. A perforated region 14 with a hole is formed. The wafer 30 can be disposed so as to cover a part or all of the perforated region 14, and the wafer 30 disposed on the metal sheet 12 is fixed so as not to move with respect to the metal sheet 12. A wafer fixing mechanism 20 formed of a heat resistant material is provided.
[Selection] Figure 1

Description

  The present invention relates to a holder for holding and transporting a wafer in a characteristic test process of a wafer such as a semiconductor wafer on which electronic devices, optical devices, and the like are formed.

  Wafers formed by two-dimensionally arranging multiple electronic or optical devices of the same shape are tested for their electrical or optical characteristics prior to the dicing process to separate these devices. A characteristic test is performed, and an operation for identifying a non-defective device and a defective device is performed. Several device electrical characteristic test apparatuses or electrical characteristic test methods have been disclosed (see, for example, Patent Documents 1 to 4). The optical characteristics of the device are also tested using the same apparatus and method.

  Conventionally, a method has been used in which a single wafer is mounted on a jig such as a suction arm and mounted on a loading stage of a characteristic test apparatus. The reason why such a technique can be taken is that the wafer has a sufficient thickness and has a sufficient strength that is unlikely to break even when handled by a jig such as a suction arm.

  However, recently, it has been demanded to make the wafer thinner.

  One reason for the demand for thin wafers is that it has been widely recognized that thin wafers can improve the characteristics of electronic or optical devices. In addition, even if an individual device is embedded in a card or the like to be modularized, it is required to make this device so that the embedded portion hardly changes in thickness from the other portions of the card. Is also in the background. In addition, the thinning of the wafer is effective in dissipating the heat generated from the device through the wafer to the outside of the wafer.

  As a wafer holder used to transport wafers that have become thin enough to be handled by jigs such as suction arms, so that they can be mounted on the loading stage of equipment that performs characteristic tests, A component holder is disclosed (see Patent Document 5). When this electronic component holder is used, the holding frame is arranged downward on the surface so as to surround the electronic component (wafer) facing down on the surface via a gap. Next, the peripheral part of the exposure port of the holding layer is adhered to the back surface peripheral part of the electronic component using an adhesive tape, and the holding layer is adhered to the back surface of the holding frame. Then, after holding the holding frame upside down and facing the surface upward, a holding layer that surrounds the electronic component is attached to the surface of the holding layer, and its peripheral portion interferes with the surface peripheral portion of the electronic component. And sandwiching the peripheral edge of the electronic component.

Japanese Patent Laid-Open No. 05-333098 Japanese Patent Application Laid-Open No. 07-245401 Japanese Patent Application Laid-Open No. 08-153763 JP 2005-294773 A JP 2011-23546 A

  However, the method of transporting the wafer to the loading stage of the apparatus for carrying out the characteristic test using the electronic component holder disclosed in Patent Document 5 is the method of peeling the wafer from the adhesive tape that fixes the peripheral edge of the wafer. May be damaged.

  Further, since the adhesive tape is a consumable item, it is necessary to use a new adhesive tape every time the characteristic test is performed, and a new cost is generated each time the characteristic test is performed.

  In addition, since the heat-resistant temperature of the adhesive tape is low, it is impossible to perform a characteristic test in which the wafer to be subjected to the characteristic test is set to a high temperature of about 120 ° C. or higher.

  Furthermore, the holding by the electronic component holder disclosed in Patent Document 5 is weak to the force acting perpendicular to the wafer surface, and if such force is applied, the wafer may be detached from the electronic component holder or the wafer may be damaged. There is sex.

  In addition, when the wafer held by the electronic component holder disclosed in Patent Document 5 is directly mounted on the loading stage of the apparatus for performing the characteristic test, the back surface of the wafer is lifted from the loading stage surface by the thickness of the adhesive tape. Therefore, special measures are required to place the wafer flat on the loading stage of the apparatus for performing the characteristic test.

  The inventor of this application came up with the idea of using a metal sheet functioning as a holding layer instead of sandwiching and fixing the wafer between the holding layer and the holding layer made of the above-mentioned adhesive tape. In this metal sheet, a perforated region having a plurality of fine holes is formed, and when the wafer is fixed to the loading stage of the wafer characteristic test apparatus, the wafer is sucked through the hole and fixed to the loading stage. For example, it was convinced that the above-mentioned problems could be solved as a wafer holder that was thinned and mechanical strength was weakened.

  Accordingly, an object of the present invention is to provide a wafer holder capable of easily mounting a thinly processed wafer on a loading stage surface of an apparatus for performing characteristic tests.

  Therefore, according to the gist of the present invention, a wafer holder having the following configuration is provided.

  The wafer holder of the present invention includes a holding frame, a metal sheet, and a wafer fixing mechanism. The holding frame is provided with a hollow portion leaving a peripheral portion in a ring shape, and a metal sheet is fixed so as to block the hollow portion. The metal sheet has a perforated region in which a plurality of fine holes are formed, and a wafer can be arranged so as to cover a part or all of the perforated region. And the wafer arrange | positioned on a metal sheet is fixed to this metal sheet with a wafer fixing mechanism. The wafer fixing mechanism is preferably formed of a heat resistant material.

  The perforated region is preferably provided separately in a plurality of portions of the metal sheet.

  The wafer fixing mechanism may include a wafer outer shape reference adapter plate, an adapter plate pressing cover plate, a cover plate stopper, and a screw. Then, the peripheral edge of the wafer is sandwiched between the inner peripheral edge of the hollow portion of the wafer external reference adapter plate and the metal sheet, and the adapter plate presser cover plate is stacked on the wafer external reference adapter plate, and the adapter plate presser cover plate is stacked. It is preferable to fix the wafer to the holding frame using a cover plate stopper and a screw so that the wafer is fixed to the metal sheet.

  Or it is good to form a metal sheet with a ferromagnetic metal material, and to form an adapter plate pressing cover plate using the ferromagnetic material which has magnetism. Then, the peripheral edge of the wafer is sandwiched between the inner peripheral edge of the hollow portion of the wafer external reference adapter plate and the metal sheet, and the adapter plate presser cover plate is stacked on the wafer external reference adapter plate. It is preferable that the wafer is fixed so as not to move relative to the metal sheet by being attracted to the metal sheet by magnetism.

  Alternatively, when the transport state can always be kept horizontal by a transport robot or the like, the adapter plate presser cover plate is preferably formed using a material such as a heat-resistant thin silicon rubber sheet. Then, the peripheral edge of the wafer is sandwiched between the inner peripheral edge of the hollow portion of the wafer external reference adapter plate and the metal sheet, and the adapter plate presser cover plate is stacked on the wafer external reference adapter plate. It is preferable that the wafer be fixed so that the wafer does not move relative to the metal sheet due to its own weight and weak self-adhesiveness.

  Each of the wafer outer shape reference adapter plate and the adapter plate presser cover plate is provided with a hollow portion in a ring shape leaving a peripheral portion.

  According to the wafer holder of the present invention, the metal sheet is fixed so as to block the hollow portion of the holding frame, and the wafer is disposed on the metal sheet. Therefore, even if a force is applied perpendicularly to the wafer surface, the wafer holder The wafer will not come off or be damaged.

  Further, if the holding layer for supporting the wafer is formed of a metal sheet and a wafer fixing mechanism for fixing the wafer arranged on the metal sheet is formed of a heat-resistant material, it can be used in a characteristic test at a high temperature.

  In addition, the metal sheet has a perforated region in which a plurality of fine holes are formed, and the wafer is arranged so as to cover a part or all of the perforated region. Simply place it directly, not fix it. Therefore, there is little risk that the wafer is damaged when the wafer is removed from the wafer holder.

  Furthermore, instead of adopting a configuration in which the peripheral portion of the exposure opening of the holding layer is adhered to the peripheral portion of the back surface of the wafer, the wafer holder of the present invention is a perforated region in which a plurality of fine holes are formed using a metal sheet. Since the wafer is arranged so as to cover a part or all of the wafer, when the wafer is mounted on the loading stage surface of the apparatus for performing the characteristic test, it does not float from the back loading stage surface of the wafer, The wafer can be easily mounted flat on the loading stage surface of the apparatus for performing the characteristic test.

  In addition, it is not necessary to replace the metal sheet with a new metal sheet for each characteristic test, so it can be used universally, so there is no new cost even if the number of characteristic tests is repeated, and it is economically effective. Is obtained.

  By providing the perforated area at a plurality of locations by separating the perforated area into the metal sheet, the wafer can be disposed by appropriately covering the perforated area with this wafer in accordance with the size and shape of the outer shape of the wafer.

It is a figure which shows schematic shape of the component which comprises the wafer holder of embodiment of this invention. It is a figure which shows the schematic shape of an example of the metal sheet in which the piercing | piercing area | region was provided separately in several parts. It is a figure which shows the schematic shape which looked at the wafer holder of this Embodiment of this invention assembled in the state which can fix and convey a wafer from the direction perpendicular | vertical to the surface of a wafer. (A) is the schematic which cut and showed the wafer holder of the state before fixing a wafer in the state which can fix and convey a wafer in the direction perpendicular | vertical to the surface of a wafer. (B) is a schematic view showing the wafer holder assembled in a state where the wafer can be fixed and transported, cut in a direction perpendicular to the surface of the wafer.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIGS. 1 to 4 show an example of the configuration according to the present invention, and only schematically show the arrangement relationship of each component to the extent that the present invention can be understood. It is not limited to the examples shown.

  Prior to the dicing process of a wafer such as a semiconductor wafer on which electronic devices, optical devices, and the like are formed, a characteristic test of these devices is performed. When the wafer is thinly processed, the strength is such that it cannot be directly held by a jig such as a suction arm. The wafer holder according to the present invention is used for transport for mounting such a wafer on a loading stage of a characteristic test apparatus.

  The wafer handled here is, for example, a silicon wafer having a diameter of 200 mm, and is thinned by a method such as back grinding to a thickness of 100 μm or less, and in some cases, 20 μm or less.

  A wafer to be subjected to a characteristic test is transported by a wafer holder, and is sucked and fixed to a loading stage of the wafer characteristic test apparatus. In the electrical characteristic test of a wafer, it may be necessary to pass a current from the front surface to the back surface of the wafer on which the electronic device is formed. In this case, a needle-like probe electrode is brought into contact with an electrode of an arbitrary electronic device that is an object of a characteristic test formed on the surface of the wafer, and a voltage is applied from the needle-like probe electrode to Current) from the electrode to the back.

  In order to pass a current from the front surface to the back surface of the wafer, the surface of the loading stage of the wafer characteristic test apparatus and the back surface of the wafer need to be electrically connected. For this reason, in the wafer holder of the present invention, as described below, the wafer is held by a metal sheet in which a perforated region in which a plurality of fine holes are formed is formed. With this configuration, the wafer can be adsorbed and fixed to the loading stage of the characteristic test apparatus through the hole in the perforation region. Furthermore, since the metal sheet is conductive, a state where the surface of the loading stage and the back surface of the wafer are electrically connected is realized.

  With reference to FIGS. 1-4, the structure of the wafer holder of embodiment of this invention is demonstrated. As shown in FIG. 1, the wafer holder of this embodiment includes a holding frame 10, a metal sheet 12, and a wafer fixing mechanism 20. The holding frame 10 is provided with a hollow portion in a ring shape leaving a peripheral portion. The metal sheet 12 is fixed to the holding frame 10 so as to block the hollow portion of the holding frame 10.

  The metal sheet 12 is preferably formed using a metal sheet called a shim material. A technique such as welding can be used to fix the metal sheet 12 to the holding frame 10.

  The shim material has sufficient thickness uniformity and flatness to be used for the metal sheet 12. In addition, stainless steel shim materials are resistant to rust and can be treated with gold plating for the purpose of ensuring a large electrical conductivity on the surface. It is a suitable material for the holder.

  The metal sheet 12 has a perforated region 14 in which a plurality of fine holes are formed. The wafer 30 can be arranged so as to cover a part or all of the perforated region 14. In order to form the above-described perforated region 14 in the metal sheet 12 formed of a shim material, for example, an etching technique or the like may be used as appropriate. The wafer fixing mechanism 20 can fix the wafer 30 disposed on the metal sheet 12 so as not to move with respect to the metal sheet 12. For example, in order to perform a characteristic test performed at a high temperature of 120 ° C. or higher, the wafer fixing mechanism 20 is preferably formed of a heat resistant material such as metal.

  The wafer fixing mechanism 20 includes a wafer outer shape reference adapter plate 16 and an adapter plate presser cover plate 18 that presses and fixes the plate. Then, the peripheral edge of the wafer 30 is sandwiched between the inner peripheral edge of the hollow portion of the wafer external reference adapter plate 16 and the metal sheet 12, and the adapter plate presser cover plate 18 is stacked on the wafer external reference adapter plate 16. Then, the adapter plate presser cover plate 18 is fixed to the holding frame 10. As a result, the wafer 30 is fixed so as not to move with respect to the metal sheet 12.

  By configuring the wafer fixing mechanism 20 with the wafer outer reference adapter plate 16, it becomes easy to fix the wafer 30 to the holding frame 10 regardless of the difference in the outer shape of the wafer 30.

  As shown in FIG. 2, the perforated region 14 can be provided separately in a plurality of portions (the perforated region 14-1 and the perforated region 14-2) of the metal sheet 12. Thus, by providing the perforated region separately in a plurality of portions, various wafers having different outer sizes and shapes can be fixed and transported.

  A method for fixing the wafer 30 to the metal sheet 12 by the wafer fixing mechanism 20 will be described with reference to FIGS. 3, 4A, and 4B. An embodiment of the characteristic test process for the wafer 30 will be described.

  The wafer fixing mechanism 20 includes a wafer outer shape reference adapter plate 16 and an adapter plate presser cover plate 18 that presses and fixes the plate. Then, the peripheral portion of the wafer 30 is fitted and aligned along the inner peripheral portion of the hollow portion of the wafer external reference adapter plate 16, and the adapter plate presser cover plate 18 is stacked on the wafer external reference adapter plate 16. Then, the adapter plate presser cover plate 18 is fixed to the holding frame 10 using the cover plate stopper 24 and the screw 26. As a result, the wafer 30 is sandwiched between the metal sheet 12 and the adapter plate pressing cover plate 18, and the wafer 30 is fixed so as not to move with respect to the metal sheet 12.

  In order to fix the wafer 30 to the metal sheet 12, first, the peripheral portion of the wafer 30 is fitted into the inner peripheral portion of the hollow portion of the wafer external reference adapter plate 16, and the adapter plate presser cover plate 18 is stacked. It is sandwiched between the metal sheet 12 and the adapter plate presser cover plate 18. Then, by holding the adapter plate holder cover plate 18 with the cover plate stopper 24 and fixing the screw 26 to the fixing female screw of the holding frame 10 of the wafer characteristic test apparatus, the wafer 30 is fixed to the metal sheet 12 and the adapter plate holder. It is sandwiched between the cover plate 18 and fixed.

  The wafer external reference adapter plate 16 is provided with a notch aligning portion 22 for determining the orientation flat direction of the wafer 30.

  The wafer 30 to be subjected to the characteristic test is transferred using the wafer holder according to the embodiment of the present invention and placed on the suction surface 32s of the loading stage 32 of the wafer characteristic test apparatus. When the wafer 30 is fixed to the wafer holder and placed on the loading stage 32 in this manner, the wafer 30 is sucked by the suction holes 34 provided in the loading stage 32 through the holes in the perforated region 14 of the metal sheet 12, and the wafer 30 is fixed to the wafer holder and is fixed to the loading stage 32 by suction. Since the metal sheet 12 is conductive, a state in which the suction surface 32s of the loading stage 32 and the back surface 30r of the wafer 30 are electrically connected is realized.

  Since the surface 30f of the wafer 30 is uncovered and exposed, the needle-like probe electrode is brought into contact with the electrode of an arbitrary electronic device which is the object of the characteristic test formed on the surface 30f of the wafer 30. A voltage can be applied from the probe electrode.

  When the wafer 30 is fixed to the loading stage 32 while being fixed to the wafer holder, if the diameter of a plurality of fine holes constituting the perforated region is too large, the portion directly above the hole of the wafer 30 to be adsorbed Deflection occurs due to the force that is sucked. Therefore, there is an upper limit for the diameter of the hole.

  For example, when the wafer 30 is a Si wafer having a thickness of 100 μm, it has been found that if the hole diameter is 0.2 mm or more, the wafer 30 is distorted. That is, in practice, the wafer to be transferred by the wafer holder often has a strength corresponding to a Si wafer having a thickness of 100 μm, so that the hole diameter is desirably 0.2 mm or less.

  In any case, the diameters of the plurality of fine holes constituting the perforated region are preferably set to a size that does not cause distortion in the wafer 30 when the wafer 30 is sucked and fixed to the loading stage 32 of the characteristic test apparatus. Further, if the diameter of the hole is too small, the suction force acting on the wafer 30 is weakened, which is not preferable. From these viewpoints, it is preferable to set the diameter of the hole to the maximum size that does not cause distortion in the wafer 30.

  The configuration in which the wafer fixing mechanism 20 includes the cover plate stopper 24 and the screw 26 has been described. However, the metal sheet 12 is formed of a ferromagnetic metal material, and the adapter plate presser cover plate is formed using a ferromagnetic material with magnetism. 18 can also be formed. With this configuration, the adapter plate presser cover plate 18 is attracted to the metal sheet 12 by magnetism, and the wafer 30 is fixed to the metal sheet 12.

  If the structure is fixed by magnetism, the cover plate stopper 24 and the screw 26 are not required, and it is necessary to perform troublesome work such as loosening the screw 26 when the wafer 30 is transported away from the metal sheet 12. Disappear. That is, the wafer can be easily fixed and the wafer 30 can be easily detached from the metal sheet 12 by removing the adapter plate presser cover plate 18 from the metal sheet 12.

  When measuring a magnetic device, the metal sheet 12 can be formed of a nonmagnetic metal material, and the adapter plate presser cover plate 18 can be formed using a material such as a heat-resistant thin silicon rubber sheet. If the adapter plate presser cover plate 18 is fixed to the metal sheet 12 with its own weight and weak self-adhesiveness, measurements from -50 ° C to 200 ° C are possible, wafers can be easily fixed, and the adapter If the plate presser cover plate 18 is removed so as to be peeled off from the metal sheet 12, the wafer 30 can be easily removed from the metal sheet 12.

  If the wafer outer shape reference adapter plate 16 and the adapter plate presser cover plate 18 are obstructive to the electrical characteristic test of the wafer, the wafer outer shape reference is performed while the wafer 30 is in the state of being fixed to the loading stage 32. Either one or both of the adapter plate 16 and the adapter plate presser cover plate 18 may be removed.

  When the wafer 30 is set to a low temperature or high temperature state in order to perform a low temperature or high temperature characteristic test, there is a difference between the thermal expansion of the wafer 30 and the thermal expansion of the material constituting the wafer fixing mechanism 20. Occurs. However, even if the position of the wafer 30 fluctuates due to this difference in thermal expansion, the suction fixing force by suction is not so great that the position of the wafer 30 cannot be shifted. Accordingly, it is sufficiently possible to adjust by moving the position of the wafer 30 to the optimum position where the electrical characteristic test of the wafer is possible.

  In addition, although the structure and function of the wafer holder of this invention were demonstrated on the assumption that the semiconductor wafer in which the electronic device, the optical device, etc. were formed as the wafer 30, the wafer held by this wafer holder, It is not limited to the wafer on which the device is formed. For example, a dice obtained by dicing a sapphire crystal substrate, a glass substrate, or the like may be required for use as a spacer or the like when bonding a diced electronic device. In the process of processing the dice as the spacer, the wafer holder of the present invention can be used when a sufficiently thin sapphire crystal substrate, glass substrate or the like is transported to the loading stage of the dicing apparatus.

10: Holding frame
12: Metal sheet
14: Perforated area
16: Wafer outer diameter reference adapter plate
18: Adapter plate presser cover plate
20: Wafer fixing mechanism
22: Notch alignment part
24: Cover plate stopper
26: Screw
30: Wafer
32: Loading stage
34: Suction hole

Claims (2)

A holding frame provided with a hollow part leaving a peripheral part in a ring shape;
A metal sheet having a perforated region with a plurality of fine holes, which is fixed to the holding frame so as to block the hollow portion;
A wafer fixing mechanism for fixing a wafer disposed on the metal sheet so as to cover a part or all of the perforated region ,
The metal sheet is formed using a metal sheet called shim material, and a plurality of fine holes opened in the perforated region are formed by an etching technique ,
The wafer fixing mechanism is formed of a heat resistant material,
Wafer outline reference adapter plate in which a hollow part is provided leaving a peripheral part in a ring shape,
The wafer outer shape reference adapter plate is pressed and fixed, an adapter plate presser cover plate provided with a hollow portion leaving a peripheral portion in a ring shape,
A cover plate stopper for fixing the adapter plate presser cover plate to the holding frame;
With
The peripheral edge portion of the wafer is sandwiched between the inner peripheral edge portion of the hollow portion of the wafer outer shape reference adapter plate and the metal sheet, and the adapter plate presser cover plate is stacked on the wafer outer shape reference adapter plate. A wafer holder, wherein a plate holder cover plate is fixed to the holding frame using the cover plate stopper so that the wafer does not move relative to the metal sheet . Corresponding to the size and shape of the wafer, the perforation region is provided by separating it into a plurality of portions of the metal sheet so that the wafer can be disposed by appropriately covering the perforation region with the wafer. The wafer holder according to claim 1 , wherein the wafer holder is provided.