JP6329782B2 - Attaching the protective tape - Google Patents

Description

  The present invention relates to a method for adhering a protective tape for adhering a protective tape to the back side of a wafer, and particularly to a method for adhering a protective tape to a MEMS wafer.

  In the manufacturing process of MEMS (Micro Electro Mechanical Systems) devices such as acceleration sensors and pressure sensors, a fine three-dimensional structure called a MEMS device is built in each region of the wafer surface partitioned in a grid pattern by dividing lines. A rare MEMS wafer is formed. In order to facilitate handling of the wafer, the MEMS wafer is carried into a processing apparatus with a protective tape attached to the back surface of the wafer and supported by the annular frame via the protective tape. In the processing apparatus, the MEMS wafer is cut along a division planned line to be divided into individual MEMS devices (see, for example, Patent Document 1).

JP 2009-076823 A

  By the way, when sticking a protective tape on the back surface of a wafer by a tape mounter, the front surface side of the wafer is held on a table, and the protective tape is stuck from the end to the back surface of the wafer by a roller. However, in the case where a fine three-dimensional structure is formed on the surface side as in the MEMS wafer of Patent Document 1, the protective tape with the surface side of the MEMS wafer in contact with the table in the tape mounter described above. If it is attached, the MEMS device may be damaged. Although it is conceivable to simply place the MEMS wafer on the protective tape, there is a problem that air bubbles remain between the wafer and the protective tape.

  This invention is made in view of such a point, and while protecting the damage | damage of the device formed in the surface, the sticking method of the protective tape which can adhere | attach a protective tape on the back surface of a wafer favorably The purpose is to provide.

The method for adhering the protective tape of the present invention is an adhesive tape adhering method for adhering a protective tape to the back surface of a wafer having a plurality of devices formed on the surface, and the protective tape is softened by heating and is highly It is made of a material that makes it easy for air to pass through the gaps in the molecular chain, and the entire wafer surface can be aspirated after the wafer placement step that places the back side of the wafer on the adhesive layer side of the protective tape and the wafer placement step. In addition, the back surface side of the wafer is placed on a suction table having a heatable holding surface through a protective tape, and the entire back surface of the wafer is heated and sucked and held between the back surface of the wafer and the adhesive layer of the protective tape. and a protective tape heating sucking step of protective tape to the wafer back surface is adhered with invading bubbles are removed by passing through the gap of the polymer chains of the protective tape And wherein the door.

  According to this configuration, after the back surface of the wafer is placed on the adhesive layer of the protective tape, the entire back surface of the wafer is sucked and held by the suction table. At this time, the protective tape is softened by heating and the gap between the polymer chains of the protective tape is easily expanded, and the air in the air bubbles left between the wafer and the protective tape is drawn into the gap between the polymer chains by suction. . The air in the bubbles passes through the gap between the polymer chains of the softened protective tape and is sucked to the suction table side, and finally all the air in the bubbles is removed. Thereby, bubbles remaining between the protective tape and the wafer are removed, and the protective tape and the wafer are brought into close contact with each other. Thus, even if it is a case where the back surface side of a wafer is mounted with respect to a protective tape in order to prevent damage to a device, a protective tape can be favorably stuck to a wafer.

  According to the present invention, by sucking while heating the entire back surface of the wafer through the protective tape, the protective tape can be satisfactorily adhered to the back surface of the wafer while preventing damage to the device formed on the front surface. it can.

It is a figure which shows an example of the wafer mounting step which concerns on this Embodiment. It is sectional drawing of the wafer of the state in which the protective tape which concerns on this Embodiment was affixed. It is a figure which shows an example of the protection tape heating suction step which concerns on this Embodiment.

  Hereinafter, a method for attaching a protective tape according to the present embodiment will be described with reference to the accompanying drawings. In the method for attaching a protective tape according to the present embodiment, air bubbles remaining between the protective tape and the wafer due to the wafer being placed on the protective tape are removed from between the protective tape and the wafer. FIG. 1 is a diagram illustrating an example of a wafer placement step according to the present embodiment. FIG. 2 is a cross-sectional view of the wafer in a state where the protective tape according to the present embodiment is attached. FIG. 3 is a diagram showing an example of the protective tape heating and sucking step according to the present embodiment.

  2A shows a sectional view of the entire wafer, and FIG. 2B shows a partially enlarged view of FIG. 2A. FIG. 3A shows a heated and sucked state of the entire wafer, and FIGS. 3B and 3C show partially enlarged views of FIG. 3A. In addition, the method for attaching the protective tape according to the present embodiment is not limited to the following configuration as long as it is configured to remove bubbles left between the wafer and the protective tape by heat suction.

  As shown in FIG. 1, first, a wafer mounting step is performed. In the wafer mounting step, the wafer W is positioned above the protective tape 14 attached to the annular frame 17, and the back surface 11 of the wafer W is mounted on the adhesive layer 16 (see FIG. 2B) side of the protective tape 14. The wafer W is formed in a substantially disc shape, and the surface 10 of the wafer W is partitioned in a lattice shape by a plurality of division lines (not shown). A fine three-dimensional structure called a MEMS device (device) 12 is disposed in each region partitioned by the division lines. A notch 13 indicating a crystal orientation is formed on the outer edge of the wafer W.

  The protective tape 14 has a UV curable adhesive layer 16 laminated on the upper surface of a tape base material 15 made of a synthetic resin such as polyolefin (PO) (see FIG. 2B). As shown in FIG. 2A, when the wafer W is placed on the protective tape 14, the wafer W is supported on the annular frame 17 via the protective tape 14, and handling properties at the time of transporting the wafer W are improved. Thus, in the wafer placement step, the protective tape 14 is attached to the back surface 11 of the wafer W without bringing the front surface 10 of the wafer W on which the MEMS device 12 is formed into contact with a table or the like.

  However, as shown in FIG. 2B, when the wafer W is placed on the protective tape 14, the air escape path is blocked, so that an infinite number of spaces are formed between the back surface 11 of the wafer W and the adhesive layer 16 of the protective tape 14. Bubbles 18 are left. The infinite number of bubbles 18 deteriorates the adhesion between the back surface 11 of the wafer W and the adhesive layer 16 of the protective tape 14, which may cause a problem in the subsequent process. In the present embodiment, before the wafer W is processed in the subsequent process, the bubbles 18 between the wafer W and the adhesive layer 16 of the protective tape 14 are removed in the protective tape heating suction step.

  In the present embodiment, a MEMS wafer in which the MEMS device 12 (see FIG. 1) is formed on the surface 10 as the wafer W will be described as an example. However, the present invention is not limited to this configuration. The wafer W may be, for example, a CMOS wafer having a CMOS formed as a solid-state imaging device on the surface. The wafer W may be a semiconductor wafer in which devices such as IC and LSI are formed on a semiconductor substrate such as silicon or gallium arsenide, or an optical device such as LED is formed on a ceramic, glass or sapphire inorganic material substrate. An optical device wafer may be used.

  Note that the tape base material 15 and the adhesive layer 16 of the protective tape 14 are formed of a material that is softened by heating so that air can easily pass through the gaps between the polymer chains constituting the tape base material 15 and the adhesive layer 16. Just do it. Further, the wafer mounting step may be performed manually or automatically by a tape mounter (not shown).

  As shown in FIG. 3A, after the wafer placement step, a protective tape heating and sucking step is performed. In the protective tape heating and sucking step, the wafer W attached to the annular frame 17 via the protective tape 14 is placed on the holding surface 23 of the suction table 2, and the annular frame 17 around the wafer W is held by the clamp portion 27. Fixed. The holding surface 23 of the suction table 2 is formed on the upper surface of the porous plate 22 fitted in the circular recess 21 of the table body 20, and is connected to the suction source 26 via the suction path 25 in the suction table 2. Yes. In the suction table 2, the wafer W is sucked and held by the negative pressure generated on the holding surface 23 of the porous plate 22.

  In addition, a heater 24 is embedded in the porous plate 22 to heat the entire back surface 11 of the wafer W held on the holding surface 23 via the protective tape 14. The heater 24 is provided over the entire porous plate 22 so that the back surface 11 of the wafer W can be uniformly heated. When the protective tape 14 is heated by the heater 24, the protective tape 14 is softened, and the passage of fine air in the tape is easily spread. The entire back surface 11 of the wafer W is heated by the heater 24, and the entire back surface 11 of the wafer W is sucked by the holding surface 23, whereby air bubbles between the back surface 11 of the wafer W and the adhesive layer 16 of the protective tape 14. 18 (refer to FIG. 3B) makes it easy for air to escape.

  More specifically, as shown in FIG. 3B, when the back surface 11 of the wafer W is heated and sucked, the gap between the polymer chains of the adhesive layer 16 and the tape base material 15 is easily expanded by heating, and the pressure in the bubbles 18 is increased. And the air in the bubbles 18 easily leaks to the outside. Further, the air in the bubbles 18 is drawn into the gap between the polymer chains of the protective tape 14 by the suction by the holding surface 23, and the air flows out to the holding surface 23 through any gap through which air can pass. In this way, the air of the bubbles 18 left (invaded) between the wafer W and the protective tape 14 causes fine gaps between the polymer chains of the adhesive layer 16 and the tape base material 15 to the lower pressure side. It begins to come out little by little to the holding surface 23 side.

  Then, as shown in FIG. 3C, the air in the bubbles 18 escapes toward the holding surface 23, so that the bubbles 18 between the wafer W and the protective tape 14 are gradually reduced. When the air is completely removed from the bubbles 18 and the bubbles 18 remaining between the protective tape 14 and the wafer W are removed, the adhesive layer 16 of the protective tape 14 is brought into close contact with the back surface 11 of the wafer W. Thus, even when the back surface 11 side of the wafer W is placed on the protective tape 14 in order to prevent the MEMS device 12 from being damaged, the protective tape 14 is adhered to the wafer W well.

  Even if the bubbles 18 between the protective tape 14 and the wafer W are not completely removed by the heat suction, if the air is released from the bubbles 18 and the vacuum state is maintained, the suction holding on the wafer W is released. When done, the bubble 18 is removed. That is, the bubbles 18 in a vacuum state are crushed by the atmospheric pressure outside the protective tape 14, and the adhesive layer 16 of the protective tape 14 is in close contact with the back surface 11 of the wafer W. In addition, since invisible bubbles contained between the protective tape 14 and the wafer W are also removed, the adhesion of the protective tape 14 to the wafer W can be improved.

  Here, the present applicant uses a protective tape 14 in which a polyolefin (PO) is coated with a UV curable adhesive, and the temperature of the holding surface 23 is kept at 60 ° C., while the entire back surface 11 of the wafer W is used. Was sucked for about 15 minutes and a heated suction step was performed. As a result, good adhesion of the protective tape 14 to the wafer W was confirmed.

  As described above, according to the method for attaching the protective tape 14 according to the present embodiment, after the back surface 11 of the wafer W is placed on the adhesive layer 16 of the protective tape 14, the wafer W is absorbed by the suction table 2. The entire back surface 11 is sucked and held while being heated. At this time, the protective tape 14 is softened by heating and the gap between the polymer chains of the protective tape 14 is easily widened, and the air in the bubbles 18 left between the wafer W and the protective tape 14 by suction is polymer chains. It is drawn into the gap. The air in the bubbles 18 passes through the gap between the polymer chains of the softened protective tape 14 and escapes to the suction table 2 side. Finally, all the air in the bubbles 18 is removed. Thereby, the bubbles 18 remaining between the protective tape 14 and the wafer W are removed, and the protective tape 14 and the wafer W are brought into close contact with each other. Thus, even if it is a case where the back surface 11 side of the wafer W is mounted with respect to the protective tape 14 in order to prevent the damage of the MEMS device 12, the protective tape 14 can be stuck on the wafer W satisfactorily. it can.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the above-described embodiment, the wafer W supported by the annular frame 17 via the protective tape 14 has been described as an example, but the present invention is not limited to this configuration. The present invention is applicable to the wafer W to which the protective tape 14 is attached, and the wafer W may not be supported by the annular frame 17.

  Further, in the above-described embodiment, the adsorption table 2 is configured to embed the heater 24 in the porous plate 22 and perform heat suction, but is not limited to this configuration. The suction table 2 only needs to be able to heat and suck the protective tape 14 and the wafer W, and may be configured to heat and suck by arranging a heater 24 on the lower surface of the porous plate 22.

  In the embodiment described above, the wafer W is placed on the suction table 2 after the wafer W is placed on the protective tape 14 in the wafer placing step. However, the present invention is not limited to this configuration. The wafer placement step may be performed on the suction table 2. For example, the protective tape 14 may be sucked and held on the holding surface 23 with the adhesive layer 16 facing upward, and the wafer W may be placed on the adhesive layer 16 of the protective tape 14 in this state.

  As described above, the present invention has the effect of preventing damage to the device formed on the front surface and satisfactorily adhering the protective tape to the back surface of the wafer. In particular, the MEMS device is disposed. It is useful for a method of attaching a protective tape for attaching a protective tape to the back side of the wafer.

W wafer 10 Wafer surface 11 Wafer back surface 12 MEMS device (device)
DESCRIPTION OF SYMBOLS 14 Protective tape 15 Tape base material 16 Adhesive layer 18 Bubble 2 Adsorption table 23 Holding surface 24 Heater

Claims (1)

A method of attaching a protective tape, wherein a protective tape is attached to the back surface of a wafer having a plurality of devices formed on the surface,
The protective tape is formed of a material that is softened by heating so that air can easily pass through the gaps between the polymer chains.
A wafer mounting step of mounting the back surface of the wafer on the adhesive layer side of the protective tape;
After performing the wafer mounting step, the back surface of the wafer is mounted on the suction table having a holding surface capable of suctioning and heating the entire wafer surface, and the entire back surface of the wafer is heated via the protective tape. At the same time, air bubbles that have entered between the wafer back surface and the adhesive layer of the protective tape are removed by passing through the gap between the polymer chains of the protective tape, and the protective tape is attached to the back surface of the wafer. A protective tape heating suction step;
A method for attaching a protective tape comprising:

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