JP2007128993A - Adhesive tape for semiconductor substrate and adhesive tape feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent electrostatic breakdown of an element due to electrification of an adhesive tape. <P>SOLUTION: The adhesive tape 25 has a first conductor layer 31 formed on a tape base 27, and a second conductor layer 32 formed on a release sheet 28; and also has an adhesive layer exposed part 37 formed at one of ends 25A of the tape base 27, where the release sheet 28 is partially peeled off. An adhesive layer 26 and the second conductor layer 32 of the release sheet 28 are simultaneously brought into contact with an outer peripheral surface of a core 29 for taking up and supporting the adhesive tape 25. By keeping the core 29 electrically connected with ground potential, the electrification of the adhesive layer 26 in peeling the release sheet 28 is effectively prevented to avoid the electrostatic breakdown of the element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an adhesive tape for a semiconductor substrate and an adhesive tape supply device used in a wafer dicing process, a wafer back grinding process, and the like.

  In recent years, due to the demand for downsizing and thinning of electronic devices, the thinning of the semiconductor chip, which is a component, has become an indispensable condition for future product development. Conventionally, a semiconductor chip is thinned by a back grinding process of a semiconductor wafer on which elements are formed.

  With reference to FIG. 5 and FIG. 6, various processes from the production of a thin semiconductor chip to the mounting will be described. Adhesive protective tape 8 is affixed to the surface (element formation surface) of semiconductor wafer 10 on which elements are formed (FIG. 5A), and then the back surface of semiconductor wafer 10 is ground using grinding device 1 (FIG. 5B). Then, after peeling off the protective tape 8 from the surface of the semiconductor wafer 10 using the auxiliary tape 2 for peeling (FIG. 5C), the semiconductor wafer 10 is mounted on the ring frame 3 via the adhesive dicing tape 9 ( 5D), the semiconductor wafer 10 is separated into pieces by the dicing saw 4 (FIG. 6E). After the dicing process, the semiconductor chip 11 is pushed up by the needle 5 and simultaneously adsorbed by the collet 6 (FIG. 6F), and mounted on the lead frame 7 using the mounter 12 (FIG. 6G).

  As described above, the protective tape 8 and the dicing tape 9 are used to support the semiconductor wafer 10 in the back surface grinding process and the dicing process of the semiconductor wafer 10. As the protective tape 8 and the dicing tape 9, an adhesive tape 15 having a configuration as shown in FIG. 7 is usually used.

  As shown in FIG. 7, the conventional adhesive tape 15 includes an adhesive layer 16, a tape base material 17 that supports the adhesive layer 16, and a release sheet 18 that is releasably coated on the adhesive layer 16. ing. The adhesive layer 16 is made of, for example, an acrylic adhesive material, and the tape base material 17 is made of polyolefin, vinyl chloride, or the like. As the release sheet 18, a resin sheet such as polyester or polypropylene is used, and a configuration in which a release process is performed on the attachment surface is common.

  The adhesive tape 15 having the above configuration is used in a rolled state as shown in FIG. 8, and is automatically attached to the front or back surface of the semiconductor wafer using an adhesive tape supply device in the production line. As shown in FIG. 9, the winding side end 15 </ b> A of the adhesive tape 15 is joined to an insulating core (core) 19 made of paper or resin via an adhesive tape 20. Further, as shown in FIG. 10, the tape base material 17 (and the adhesive layer 16) is preliminarily processed by a notch 21 so that the adhesive tape 15 has a size corresponding to the wafer diameter of the applied semiconductor wafer. In some cases, it may be automatically attached to a semiconductor wafer by a non-adhesive tape supply device.

  Since the adhesive layer 16, the tape base material 17, and the release sheet 18 are all insulating materials, the adhesive tape 15 inherently tends to generate static electricity. In particular, the amount of static electricity generated when the release sheet 18 is peeled to expose the adhesive layer 16 is very large (maximum of about 6000 V). For this reason, the charged tape base material 17 is affixed on the front surface or the back surface of the semiconductor wafer, and adversely affects the device such as electrostatic breakdown of the circuit and mechanical deformation of the MEMS (Micro-Electro-Mechanical System) structure. There's a problem. In addition, dust and dust in the air are sucked in and become a factor of reducing the device yield.

  On the other hand, various types of pressure-sensitive adhesive tapes with antistatic measures have been proposed. For example, in Patent Document 1 below, an antistatic treatment layer 22 is provided on the surface of a tape substrate 17 as shown in FIG. 11A. A configuration is disclosed. As another conventional technique, an antistatic treatment layer 22 is formed at the interface between the adhesive layer 16 and the tape substrate 17 (FIG. 11B), or an adhesive layer 23 in which the antistatic treatment layer is kneaded is provided. (FIG. 11C).

Japanese Utility Model Publication No. 6-20442

  However, in the structure shown in FIGS. 11A and 11B, the charging of the tape base material 17 can be suppressed, but the charge charged on the release sheet 18 cannot be lost. Therefore, charges are accumulated in the adhesive layer 16 when the release sheet 18 is peeled off, and the charged adhesive layer is attached to the semiconductor wafer, causing electrostatic breakdown of the element.

  In addition, as shown in FIG. 11C, in the structure in which the antistatic agent is kneaded into the adhesive layer, the antistatic agent kneaded into the adhesive layer bleeds, contaminates the semiconductor wafer and deteriorates the device performance. There is a risk of causing. In particular, when the pressure-sensitive adhesive tape is used as a protective tape for the back grinding process, since the pressure-sensitive adhesive layer is attached to the element forming surface of the semiconductor wafer, the problem of element contamination becomes significant.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an adhesive tape for a semiconductor substrate and an adhesive tape supply device that can prevent electrostatic breakdown of an element due to charging of the adhesive tape without contaminating the semiconductor wafer. .

  In solving the above problems, the adhesive tape for a semiconductor substrate of the present invention has a first conductor layer formed on a tape base material and a second conductor layer formed on the release sheet, and a tape base material. The release sheet is partially peeled and removed from one end side.

  In the present invention, the first conductor layer is formed at the interface between the tape base material and the adhesive layer, but may be formed on the surface of the tape base material. Moreover, the said 2nd conductor layer is formed in the surface of the side which does not oppose the adhesion layer of a peeling sheet.

  Further, in the present invention, a metal core that is bonded to one end side of the tape base material through an adhesive layer and supports the tape base material in a roll shape is provided, and an adhesive tape is provided on the outer peripheral surface of the core. The adhesive layer and the release sheet are in contact with each other at the same time.

  With the above configuration, at one end of the tape, the tape base material and the release sheet come into contact with the metal core via the first conductor layer and the second conductor layer, respectively. By connecting this core to the ground potential, the charge charged on the tape base material and the release sheet at the time of peeling of the release sheet is removed via the above-described core. Thereby, electrostatic breakdown of the semiconductor element due to charging of the adhesive layer can be prevented. Further, the element is not contaminated by the antistatic agent.

  As described above, according to the present invention, it is possible to prevent electrostatic breakdown of the element due to charging of the adhesive tape, and to improve productivity and yield.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing a configuration of an adhesive tape for a semiconductor substrate (hereinafter simply referred to as “adhesive tape”) 25 according to an embodiment of the present invention. The pressure-sensitive adhesive tape 25 of this embodiment includes a pressure-sensitive adhesive layer 26, a tape base material 27 that supports the pressure-sensitive adhesive layer 26, and a release sheet 28 that is detachably coated on the pressure-sensitive adhesive layer 26.

  The adhesive layer 26 is made of, for example, an acrylic adhesive material, and has a characteristic that the adhesive component does not remain on the semiconductor wafer when the tape is peeled off while firmly holding the semiconductor wafer (semiconductor substrate) during back grinding or dicing. Yes. The tape base material 27 is made of a resin material such as polyolefin or vinyl chloride.

  The release sheet 28 functions as a protective sheet for the adhesive layer 26 and is peeled from the adhesive layer 26 when the adhesive tape 25 is used. As the release sheet 28, a resin sheet such as polyester or polypropylene is used, and a release treatment is applied to the attachment surface.

  In the adhesive tape 25 of the present embodiment, the first conductor layer 31 is formed on the tape base material 27, and the second conductor layer 32 is formed on the release sheet 28. As will be described later, the first conductor layer 31 and the second conductor layer 32 are electrically connected to the ground potential (ground potential) via the adhesive tape supply device 36, thereby releasing the release sheet from the adhesive layer 26. This prevents charging of the adhesive layer 26, the tape base material 27, and the release sheet 28 when peeling 28.

The first conductor layer 31 and the second conductor layer 32 are made of a coating film of a conductive composite material obtained by kneading a conductive material in a resin binder, or a metal film formed by a film forming method such as vapor deposition. As the first and second conductor layers 31 and 32, for example, those having a surface resistance of, for example, 10 ¹⁰ Ω / sq or less are used. The first conductor layer 31 is formed on the surface of the tape base material 27 on the adhesive layer 26 side, and the second conductor layer 32 is formed on the surface of the release sheet 28 that does not face the adhesive layer 26.

  FIG. 2 shows a schematic configuration of the adhesive tape supply device 36 according to the present invention. The adhesive tape supply device 36 is used in a process of attaching the adhesive tape 25 to the front or back surface of the semiconductor wafer W, such as a wafer back surface grinding process or a dicing process.

  The supply roller (supply unit) 38 of the adhesive tape supply device 36 includes a core 29 that winds and supports the adhesive tape 25 in a roll shape, and the adhesive tape 25 is rotated by rotating the core 29. It is paid out. The adhesive tape 25 fed out from the supply roller 38 is supplied onto the work table 33 on which the semiconductor wafer W is placed after the release sheet 28 is peeled off. The release sheet 28 is wound around the winding core 30 of the take-up roller (release sheet collecting unit) 39 and collected. In the vicinity of the work table 33, there are provided a pressing roller 34 for pressing the supplied adhesive tape against the front surface (or the back surface) of the semiconductor wafer W, a cutter unit 35 for cutting off excess tape, and the like. In addition, the tape base material 27 may be processed into an external shape corresponding to the wafer diameter in advance, and only a necessary part may be attached on the wafer.

  In the adhesive tape supply device 36 having the above-described configuration, the adhesive tape 25 supplied from the supply roller 38 is likely to be charged when the tape base material 27 (adhesive layer 26) and the release sheet 28 are peeled off. If the tape substrate 27 is attached to the semiconductor wafer W in a charged state, there is a concern about electrostatic breakdown of elements formed on the semiconductor wafer W.

  Therefore, in the present invention, in order to prevent the adhesive tape 25 from being charged, the first conductor layer 31 and the second conductor layer 32 of the adhesive tape 25 are electrically grounded via the adhesive tape supply device 36. Specifically, the supply roller 38 that supports the adhesive tape 25, the winding roller 39 that collects the release sheet 28, the work table 33 that supports the semiconductor wafer W, and the like are electrically grounded.

  3 and 4 show the grounding structure of the adhesive tape 25 in the supply roller 38. FIG.

  FIG. 3A shows the configuration of the end of the adhesive tape 25 on the supply roller 38 side. As shown in the drawing, the one end 25A side of the adhesive tape 25 includes an adhesive layer exposed portion 37 from which the release sheet 28 is partially peeled and removed. By directly attaching the adhesive layer exposed portion 37 to the outer peripheral surface of the core 29 of the supply roller 38, the first conductor layer 31 is connected to the electrically grounded core 29 via the adhesive layer 26. The Thereby, the charge removal of the adhesive layer 26 or the tape base material 27 is promoted. Moreover, the adhesive tape 20 (FIG. 9) for joining the adhesive tape 25 to the core 29 becomes unnecessary.

  On the other hand, as shown in FIG. 3B, the adhesive tape 28 fixed to the core 29 via the adhesive layer exposed portion 37 has the second conductor layer 32 formed on the release sheet 28 at the beginning of the winding. Contact the outer peripheral surface. As a result, the charge charged on the release sheet 28 is guided to the core 29 via the second conductor layer 32, and the release sheet 28 is neutralized.

  The formation length of the adhesive layer exposed portion 37 is not particularly limited, but the adhesive tape 25 can be adhered to the core 29 with an appropriate adhesive force, and the second conductor layer 32 of the release sheet 28 is attached to the outer peripheral surface of the core 29. May be of a size that allows contact with the adhesive layer 26 simultaneously. Specifically, although depending on the diameter of the core 29, the formation length of the adhesive layer exposed portion 37 is, for example, about 3 cm to 5 cm.

  4A and 4B are cross-sectional views illustrating an example of the configuration of the supply roller 38. FIG. The winding core 39 is attached via a core fixing bar 41 to a shaft 40 that is rotationally driven by a gear 41. In this example, the core fixing bar 41 is fixed to the shaft 40 by, for example, screwing. Each of the core 39, the shaft 40, and the core fixing bar 41 is made of a metal such as aluminum or a conductive material such as carbon, and the shaft 40 is electrically connected to the ground potential.

  In the pressure-sensitive adhesive tape supply device 36 of the present embodiment configured as described above, the pressure-sensitive adhesive tape 25 (the pressure-sensitive adhesive layer 26, the tape base material 27, and the release sheet 28) includes the winding core 29, the core fixing bar 41, and the shaft 40. Therefore, the adhesive tape 25 can be prevented from being charged when the release sheet 28 is peeled off. Further, since the release sheet 28 is also in contact with the core 30 of the winding roller 39 via the second conductor layer 32, the release sheet 28 is against the ground potential electrically connected to the core 30. It is possible to release the electric charge charged in 28.

  Therefore, according to the present embodiment, it is possible to effectively prevent the adhesive layer 26 from being charged when the release sheet 28 is peeled from the adhesive tape 25 fed from the supply roller 38. Thereby, the electrostatic breakdown of the element formed in the semiconductor wafer W can be avoided.

  In addition, since the adhesive tape 25 can be prevented from being charged, dust or the like in the working atmosphere is not attracted to the tape, and the yield and productivity can be improved. Furthermore, since the antistatic agent is not used, the device is not contaminated by bleeding of the antistatic agent.

  The embodiment of the present invention has been described above. Of course, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

  For example, in the above embodiment, the adhesive layer exposed portion 37 formed on the one end portion 25A of the adhesive tape 25 is directly adhered to the core 29 of the supply roller 38 to prevent the adhesive layer 26 from being charged. Instead of this, for example, a configuration may be employed in which a slit is formed on the peripheral surface of the core 29 and the adhesive layer exposed portion 37 is sandwiched in the slit.

  Moreover, although the above embodiment demonstrated the example which applied this invention to the protective tape for wafer back surface grinding, or the dicing tape as the adhesive tape 25 which concerns on this invention, not only this but charging of the adhesion layer is carried out. The present invention is applicable to all semiconductor manufacturing processes to be suppressed.

It is sectional drawing which shows the structure of the adhesive tape 25 for semiconductor substrates by embodiment of this invention. It is a schematic block diagram of the adhesive tape supply apparatus 36 by embodiment of this invention. It is sectional drawing which shows one end part 25A of the adhesive tape 25, A has shown the tape single-piece | unit state, B has shown the joining form to the core 29. FIG. It is a figure which shows schematic structure of the supply roller 38 in an adhesive tape supply apparatus, A is a longitudinal cross-sectional view, B is a cross-sectional view. It is a process flow figure explaining one manufacturing process of a semiconductor chip. It is a process flow figure explaining one manufacturing process of a semiconductor chip. It is sectional drawing which shows the structure of the conventional adhesive tape for semiconductor substrates. It is a roll side view explaining the usage pattern of the conventional adhesive tape. It is a perspective view which shows the roll winding start end of the conventional adhesive tape. It is a top view of the tape base material externally processed corresponding to the wafer diameter. It is sectional drawing explaining the structure of the adhesive tape in which the conventional antistatic measures were taken.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 25 ... Adhesive tape for semiconductor substrates, 26 ... Adhesive layer, 27 ... Tape base material, 28 ... Release sheet, 29 ... Core of supply part, 30 ... Core of release sheet collection | recovery part, 31 ... 1st conductor layer, 32 ... second conductor layer, 33 ... work table, 34 ... pressing roller, 35 ... cutter unit, 36 ... adhesive tape supply device, 37 ... adhesive layer exposed part, 38 ... supply roller (supply part), 39 ... winding roller ( Release sheet collecting part), 40 ... shaft, 41 ... core fixing bar, W ... semiconductor wafer (semiconductor substrate)

Claims (6)

Affixed to the front or back of the semiconductor substrate,
In an adhesive tape for a semiconductor substrate comprising an adhesive layer, a tape base material that supports the adhesive layer, and a release sheet that is releasably coated on the adhesive layer,
While having a first conductor layer formed on the tape substrate and a second conductor layer formed on the release sheet,
The adhesive tape for a semiconductor substrate, wherein the release sheet is partially peeled and removed from one end side of the tape base material. The adhesive tape for a semiconductor substrate according to claim 1, wherein the first conductor layer is formed at an interface between the tape base material and the adhesive layer. The adhesive tape for a semiconductor substrate according to claim 1, wherein the second conductor layer is formed on a surface of the release sheet that does not face the adhesive layer. It is bonded to one end side of the tape base material via the adhesive layer, and includes a metal core that supports the tape base material in a roll shape. The adhesive tape for a semiconductor substrate according to claim 1, wherein the release sheet is in contact with the release sheet simultaneously. An adhesive tape supply device for supplying an adhesive tape for a long semiconductor substrate wound in a roll,
The pressure-sensitive adhesive tape includes a pressure-sensitive adhesive layer, a tape base material that supports the pressure-sensitive adhesive layer, a release sheet that is releasably coated on the pressure-sensitive adhesive layer, a first conductor layer formed on the tape base material, And having a second conductor layer formed on the release sheet, the release sheet is partially peeled off at one end of the tape base material,
The supply unit for supplying the adhesive tape includes a metal core that is bonded to the one end side of the tape base material via the adhesive layer and supports the tape base material in a roll shape. An adhesive tape supply device, wherein the core is electrically connected to a ground potential. 6. A release sheet collecting unit that winds and collects a release sheet peeled from the adhesive tape, and a winding shaft of the release sheet collecting unit is electrically connected to a ground potential. The adhesive tape supply apparatus of description.

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