JP4878329B2 - Sheet sticking device and sticking method - Google Patents

Description

  The present invention relates to a sheet sticking apparatus and a sticking method, and more particularly, to a sheet sticking apparatus and a sticking method suitable for sticking an adhesive sheet to a semiconductor wafer having protrusions such as bumps.

In general, a semiconductor wafer (hereinafter simply referred to as a “wafer”) is bonded to a circuit surface using a sheet sticking apparatus and processed in each step.
Patent Document 1 discloses an adhesive sheet pasting device. The apparatus forms two decompression chambers separated by an elastic sheet, generates a differential pressure between the decompression chambers, displaces the surface position of the elastic sheet, and attaches the adhesive sheet to the wafer by the displacement of the elastic sheet. It is the composition to do.
Japanese Patent Laid-Open No. 10-233430

  However, in the sheet sticking device of Patent Document 1, every time the type of the adhesive sheet is changed, the set value of the decompression control on the elastic sheet side must be changed, and when the pressing force is insufficient, There is an inconvenience that the pressure reduction control must be performed again, which makes the operation troublesome. Further, when a strong pressing force must be applied, the elastic sheet is ruptured, so that the pressing force cannot be sufficiently applied. In particular, when an adhesive sheet for underfill is bonded to a flip chip wafer having a bump or other protrusion on the circuit surface of the conductive surface, if the pressing force is insufficient, the bump is underfilled. The adhesive layer of the adhesive sheet for use cannot be penetrated, resulting in poor electrical conduction after flip chip.

[Object of invention]
The present invention has been devised by paying attention to the above-mentioned disadvantages, and does not require a troublesome work for pressure reduction control, and can provide a sufficient pressing force and a sheet sticking apparatus and sticking method. Is to provide.

In order to achieve the above object, the present invention provides a sheet sticking apparatus for sticking an adhesive sheet in which an adhesive layer is laminated on a sheet base material on the bump forming surface side as an adherend to a semiconductor wafer provided with bumps ,
A sticking means for sticking the adhesive sheet to the semiconductor wafer by adjusting the pressure in the vacuum chamber including a vacuum comprises a table capable of holding the semiconductor wafer, with provided separately from this sticking means, the sticking Press means for applying a pressing force to the adhesive sheet affixed to the semiconductor wafer by means ,
The pressing means includes a pressing force adjusting means, and adopts a configuration in which the bump penetrates the adhesive layer and the pressing force is applied to the adhesive sheet to such an extent that the tip of the bump bites into the base sheet. Yes.

  In the present invention, the adhesive sheet may have a band shape, and may further include a cutting unit that cuts the adhesive sheet in accordance with the size of the adherend before applying the pressing force by the pressing unit. .

  Further, it is preferable that the pressing means is constituted by a press roller, and the press roller is supported via a pressing force adjusting means.

Furthermore, the present invention relates to a sheet sticking method for sticking an adhesive sheet in which an adhesive layer is laminated on a sheet base material to the bump forming surface side as an adherend to a semiconductor wafer provided with bumps ,
While holding the semiconductor wafer on the table and placing the semiconductor wafer in a decompression chamber containing a vacuum, supplying the adhesive sheet to a position facing the semiconductor wafer ,
After sticking the adhesive sheet to the semiconductor wafer by adjusting the pressure in the decompression chamber, the bumps penetrate the adhesive layer through a pressing means, and the tip of the bumps bites into the base sheet. A method of applying a pressing force to the adhesive sheet is employed.

According to the present invention, since the adhesive sheet is attached to an adherend such as a semiconductor wafer by adjusting the pressure in the decompression chamber, the adhesive sheet is further pressed and attached by pressing means, and therefore the type of the adhesive sheet is different. It is not necessary to change the pressure control conditions every time. That is, even if a pressing force shortage due to the sticking means occurs, it is possible to compensate for the shortage of the pressing force because the pressing force is subsequently applied by the pressing means.
Furthermore, when a flip chip adhesive sheet is attached to the circuit surface of a semiconductor wafer having bumps or other protrusions on the circuit surface side, the bumps may penetrate the adhesive layer to expose the apexes of the bumps. As a result, it is possible to prevent contact failure and the like when the semiconductor wafer is diced and then flip-chipped onto the lead frame.
Moreover, according to the structure provided with the cutting means, it becomes possible to cut the adhesive sheet according to the size of the adherend while supplying the belt-like adhesive sheet, and the size of the adherend is different. The applicability of can be expanded.
Furthermore, since the press roller which comprises a press means is the structure supported via a pressing force adjustment means, it can adjust pressing force according to the kind of an adhesive sheet or a to-be-adhered body. Therefore, the troublesome work of changing the pressure adjustment in the decompression chamber according to the type of the adhesive sheet is not required.

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

  FIG. 1 shows a schematic front view of the sheet sticking apparatus according to the present embodiment, and FIG. 2 shows a schematic right side view in which a part of FIG. 1 is omitted. In these drawings, the sheet sticking device 10 is placed on the opposite side of the sticking means 11 placed in the center of FIG. 1, the sheet supply means 12 placed on the left side of the sticking means 11 in the figure. The pressing means 13 and the winding means 14 and the cutting means 16 disposed on the front side (left side in FIG. 2) of the sticking means 11 are provided.

  The sheet supply means 12 includes a heat-sensitive adhesive sheet S in which an adhesive layer A is provided on a peeling sheet base material BS, and an adhesive sheet S, as shown in an enlarged view of part P in FIG. The raw fabric sheet R including the temporarily attached release sheet RL is supplied. The sheet supply means 12 is supported by the frame F and supports a roll 20 so as to be able to feed out the original sheet R wound in a roll shape. A peel sheet take-up roller 21 for taking up the sheet RL, and a peel plate 23 provided substantially horizontally between the support roller 20 and the release sheet take-up roller 21 so that the front end faces the sticking means 11 side. And a linear motion motor 24 that supports the height position of the peel plate 23 in an adjustable manner. A driving roller 26 and a pinch roller 27 are disposed between the support roller 20 and the peel plate 23, while a driving roller 29 and a pinch roller 30 are also disposed between the release sheet winding roller 21 and the peel plate 23. Is arranged. These drive rollers 26 and 29 are respectively driven by motors M1 and M2 provided on the back side of the frame F, and the release sheet take-up roller 21 is provided from a pulley, a belt, etc. (not shown) disposed between the motors M2. The release sheet RL is rotationally driven in the direction of winding the release sheet RL through the interlocking mechanism.

  As shown in FIG. 3, the sticking means 11 is disposed in a lower case 32, which includes a lower case 32 whose upper end is opened, and an upper case 33 that opens and closes the upper end of the lower case 32. A table 35 and a pressing force applying sheet 37 made of an elastic sheet attached so as to close the lower end side of the cylindrical portion 36 disposed in the upper case 33 are included. The lower case 32 includes a bottom wall 38 and a side wall 39 connected to the periphery of the bottom wall 38, and a through hole 39 </ b> A to which a hose of a decompression pump (not shown) is connected is formed in the side wall 39. On the other hand, the upper case 33 includes a top wall 40 and a peripheral wall 41 connected to the top wall 40. The top wall 40 is formed with a through hole 40A to which a hose of the decompression pump is connected. The upper case 33 is fixed to the arm 42, and one end (the lower end in FIG. 2) of the arm 42 is fixed to the rotating shaft 45 supported by the rotating bearing 43. The rotating shaft 45 is fixed by the motor M3. By being driven, the upper case 33 opens and closes the upper opening of the lower case 32. Further, a groove 41A extending in the circumferential direction is formed on the lower end surface in FIG. 3 of the peripheral wall 41 of the upper case 33, and a seal ring 44 is mounted in the groove 41A. In the case 34, a first decompression chamber C1 is formed by the pressing force imparting sheet 37, the cylindrical portion 36, and the top wall 40, while the first decompression chamber C1 is closed with the case 34 closed. The excluded space is formed as a second decompression chamber C2.

  The table 35 is not particularly limited, but is provided in a size that substantially corresponds to the size of the wafer W in this embodiment. The table 35 is provided so as to be able to hold the wafer W, and is provided so as to be able to be moved up and down via a single-axis robot 46, and includes heating means (not shown).

  As shown in FIG. 2, the pressing means 13 is constituted by a press roller 48 supported between the frames F1 arranged to face each other. The press roller 48 is provided so that the outer peripheral surface of the pinch roller 49 can be contacted and separated. The axial position of the press roller 48 and the pinch roller 49 is moved up and down by a linear motion motor 50 as a pressing force adjusting means. It is provided as possible.

  The winding means 14 includes a driving roller 52 rotatably supported by a frame F1 on one side and rotatable by a motor M4, and a winding roller 53 urged to contact the outer peripheral surface of the driving roller 52. including. The winding roller 53 is supported in a cantilevered manner on the other end of the support arm 54 supported at one end by the frame F1, and a tension spring 56 is interposed between the middle of the support arm 54 and the frame F1. Has been. With such a configuration, an unnecessary adhesive sheet portion S <b> 1 to be described later is wound up by the winding roller 53 following the driving roller 52 while being sandwiched between the driving roller 52 and the winding roller 53. .

  The frames F1 that support the pressing means 13 and the winding means 14 are provided on the slider 57 of the linear motor 58, respectively. These linear motion motors 58 extend in the left-right direction of the lower case 32 in FIG. 1, so that the pressing means 13 and the winding means 14 pass through the upper part of the lower case 32 and move in the left-right direction in FIG. It is movable.

  The cutting means 16 includes an articulated robot 70 and a cutter blade 71 held by the articulated robot 70. The articulated robot 70 and the cutter blade 71 are substantially the same as those described in Japanese Patent Application No. 2006-115106 already filed by the present applicant, and therefore detailed description thereof is omitted here. .

  Next, the sheet sticking method according to the present embodiment will be described with reference to FIG.

  In the initial setting, the lead end of the raw sheet R supported by the support roller 20 is pulled out by a predetermined length, and the release sheet RL is peeled from the adhesive sheet S at the tip position of the peel plate 23, and the lead end of the release sheet RL is removed. Fix to release sheet take-up roller 21. On the other hand, the adhesive sheet S from which the release sheet RL has been peeled is drawn so as to cross over the lower case 32, passes between the press roller 48 and the pinch roller 49, and then fixed to the take-up roller 53. In a state where the initial setting is completed in this manner, a certain space is formed between the lower case 32 and the adhesive sheet S on the lower case 32, and the wafer is transferred by a transfer arm (not shown). Space required for setting W on the table 35 is secured.

  When the wafer W is set on the table 35, the linear motors 24 and 50 are lowered so that the adhesive sheet S comes into contact with the upper surface of the lower case 32 (the upper end surface of the side wall 39). Next, the upper case 33 closes the case 34 by the rotation of the motor M3 so that the adhesive sheet S is sandwiched between the upper and lower cases 32 and 33, and the single-axis robot 46 is driven so that the upper surface of the wafer W adheres to the adhesive sheet S. The wafer W is raised to a position close to the lower surface of the wafer. In this state, the first and second decompression chambers C1 and C2 are set to a predetermined decompression state while being controlled to be substantially the same decompression state. Next, while the second decompression chamber C2 is kept in a predetermined decompression state, the decompression state only on the first decompression chamber C1 side is gradually opened (approached to atmospheric pressure).

  When the first decompression chamber C1 is decompressed and released, the adhesive force applying sheet 37 is elastically deformed by the pressure difference of the decompression chamber C2, and the surface position is pushed downward. It will be pasted on W. At this time, the adhesive sheet S is heated and pasted by a heating means (not shown) provided on the table 35.

  After the application of the sheet S is completed in this way, the first and second decompression chambers C1 and C2 are both controlled to be at atmospheric pressure, the upper case 33 is opened, and the case 34 is opened (FIG. 2). Reference), the robot 70 of the cutting means 16 moves the cutter blade 71 according to a preset teaching trajectory, and cuts the adhesive sheet S in a closed loop shape so as to match the size of the wafer W. By this sheet cutting, the outer peripheral area excluding the adhesive sheet S attached to the wafer W becomes a winding target as an unnecessary adhesive sheet portion S1.

  Next, pressing force is applied to the adhesive sheet S again by moving the press roller 48 of the pressing means 13 from the right side to the left side of the wafer W in FIG. At this time, the position of the wafer W is controlled by the single-axis robot 46 so that the upper surface thereof is equal to or higher than the upper surface of the lower case (the upper end surface of the side wall 39). As a result, as shown in FIG. 4, the adhesive sheet S is affixed in a state where the bump W1 existing between the wafer W and the adhesive sheet S surely penetrates the adhesive layer A, and the apex of the bump W1 is the base. It is enough to bite into the material sheet BS. When the press roller 48 rotates and moves to the left on the wafer W, the driving roller 52 is driven so that the unnecessary adhesive sheet portion S1 is sequentially wound by the winding roller 53.

  When the application of the pressing force by the press roller 48 is completed, that is, when the application of the adhesive sheet S is completed, the wafer W is transferred by a transfer device (not shown), a dicing process, a process of peeling the base sheet BS, a flip chip process, etc. It is conveyed to. At the same time as the frame F1 returns to the initial position, the original sheet R is pulled out in preparation for adhering to the next wafer, and the press roller 48 and the peel plate 23 return to the initial height position.

  Therefore, according to such an embodiment, after the adhesive sheet S is attached to the wafer W using the reduced pressure, the adhesive sheet S is attached to the wafer W by further applying a pressing force by the press roller 48. Therefore, the effect that the adhesion failure of the adhesive sheet S can be prevented in advance is obtained. In particular, as shown in the above embodiment, the bump W1 penetrates the adhesive layer A and the adhesive sheet S is stuck to such an extent that the apex bites into the base sheet BS, so that the wafer W is separated into chips. When the base sheet BS is peeled off in order to flip-chip, the apex portion of the bump W1 can be surely exposed from the adhesive layer A, thereby preventing the electrical conduction failure of the chip reliably. it can.

The best configuration, method and the like for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this.
That is, the invention has been illustrated and described with particular reference to particular embodiments, but it should be understood that the above-described embodiments are not deviated from the technical idea and scope of the invention. On the other hand, various modifications can be made by those skilled in the art in shape, quantity, and other detailed configurations.
Therefore, the description limited to the shape disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded one part or all part is included in this invention.

  For example, in the above-described embodiment, the case where the adhesive sheet S is a heat-sensitive adhesive sheet for underfill has been described. However, the present invention is not limited to this, and the heat-sensitive adhesive adhesive for die bonding is used. Other adhesive sheets such as sheets, pressure sensitive adhesive sheets for dicing and wafer protection can be applied.

  The case 34 constituting the attaching means attaches the adhesive sheet S to the wafer W by reducing the pressure in the first and second decompression chambers C1 and C2 and then generating a differential pressure. This includes the case where the differential pressure is formed after the state is formed.

  In addition, the adherend is not limited to the wafer W, but can also be a plate member having no other bump such as a glass plate, a steel plate, or a resin plate. The semiconductor wafer is a silicon wafer or a compound wafer. It may be.

  Furthermore, the pressing means is not limited to a roller, and may be composed of other members capable of applying pressure.

The schematic front view of the sheet sticking apparatus which concerns on this embodiment. The schematic right view which abbreviate | omitted a part of FIG. The schematic sectional drawing which shows the state by which an adhesive sheet is affixed on a wafer by the affixing means. Sectional drawing which shows the state in which a pressing force is further given to an adhesive sheet with a press roller.

Explanation of symbols

10 Sheet Pasting Device BS Sheet Base Material A Adhesive Layer S Adhesive Sheet W Semiconductor Wafer (Substrate)
C1 first room (decompression room)
C2 Second room (decompression room)
DESCRIPTION OF SYMBOLS 11 Sticking means 13 Press means 48 Press roller W1 Bump 16 Cutting means 50 Cylinder (pressing force adjusting means)

Claims (3)

In a sheet affixing device for affixing an adhesive sheet in which an adhesive layer is laminated on a sheet base material to the bump forming surface side as an adherend to a semiconductor wafer provided with bumps
A sticking means for sticking the adhesive sheet to the semiconductor wafer by adjusting the pressure in the vacuum chamber including a vacuum comprises a table capable of holding the semiconductor wafer, with provided separately from this sticking means, the sticking Press means for applying a pressing force to the adhesive sheet affixed to the semiconductor wafer by means ,
The pressing means includes a pressing force adjusting means, and the bump penetrates the adhesive layer, and the pressing force is applied to the adhesive sheet to such an extent that the tip of the bump bites into the base sheet. Pasting device. The adhesive sheet without a strip, before applying a pressing force by the pressing means, according to claim 1, wherein further comprising cutting means for cutting the adhesive sheet along the periphery of the adherend Sheet pasting device. In the sheet sticking method of sticking an adhesive sheet in which an adhesive layer is laminated on a sheet base material to the bump forming surface side as an adherend with a semiconductor wafer provided with bumps ,
While holding the semiconductor wafer on the table and placing the semiconductor wafer in a decompression chamber containing a vacuum, supplying the adhesive sheet to a position facing the semiconductor wafer ,
After sticking the adhesive sheet to the semiconductor wafer by adjusting the pressure in the decompression chamber, the bumps penetrate the adhesive layer through a pressing means, and the tip of the bumps bites into the base sheet. A sheet sticking method, wherein a pressing force is applied to an adhesive sheet.

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