TWI614798B - Processing method of laminated wafer - Google Patents

Abstract

A method for processing laminated wafers is provided. In a laminated wafer, the wafer can be divided into individual wafers even when the wafer side is attached to the adhesive sheet.

Provided is a method for processing a laminated wafer, which is characterized in that: Before the dividing step is performed, a fixing step is provided, in which a fixing agent is arranged between the adhesive sheet and the surface of the wafer in a region corresponding to the remaining peripheral region, and the remaining peripheral region of the wafer is fixed to the adhesive sheet.

Description

Processing method of laminated wafer Field of invention

The present invention relates to a method for processing a laminated wafer in which a plurality of wafers are arranged on a wafer.

Background of the invention

Conventionally, a three-dimensional structure has been known as one of the methods of integrating a plurality of semiconductor elements in one package. This three-dimensional stacking refers to a method of stacking a plurality of semiconductor element wafers in a three-dimensional direction. One of the three-dimensional stacking techniques is the CoW (Chip on wafer) method (see, for example, Patent Document 1).

In the three-dimensional configuration shown above, a laminated wafer in which wafers are laminated on a wafer is formed, and the laminated wafer is divided into individual wafers to form a laminated wafer in a state where wafers are laminated on the wafer.

As a method of dividing a laminated wafer, as disclosed in Patent Document 2, a method of performing dicing by a cutting device including a cutting blade is known.

In addition, in another method of dividing a laminated wafer, as disclosed in Patent Document 3, it is known to form a modified layer by irradiating a laser beam. Then, the wafer is divided by applying an external force to the wafer. As a method of dividing by applying an external force, for example, a dividing method using an expansion device disclosed in Patent Document 4 is known.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Publication No. 2012-209522

[Patent Document 2] Japanese Patent Laid-Open No. 2007-214201

[Patent Document 3] Japanese Patent No. 3408805

[Patent Document 4] Japanese Patent Laid-Open No. 2010-034250

Summary of invention

In one form of a laminated wafer, a laminated wafer in which a wafer-like interposer (intermediate wafer) is laminated is known. For the laminated wafer of the form shown above, in order to perform the characteristic inspection of the bumps formed in the interposer, after the division into the laminated wafer, it must be formed so that the wafer side is supported so that the divided interposer side becomes the upper side In the state of sticking flakes.

In order to achieve this, it is considered that the wafer side of the laminated wafer is adhered to the adhesive sheet, and the laminated wafer is divided while the wafer-like interposer is exposed on the upper side.

However, the wafer-like interposer is not provided with a wafer in the remaining peripheral area, and the wafer cannot pass through the wafer to cause the interposer to adhere to the adhesive sheet.

Therefore, using the expansion device disclosed in Patent Document 4, a method of dividing an adhesive sheet and applying an external force to a wafer-shaped interposer is performed. However, since the remaining area of the outer periphery is not fixed to the adhesive sheet by adhesion, an external force cannot be applied to a boundary portion between the area where the wafer is disposed and the remaining area of the peripheral area, and a problem that the boundary portion cannot be divided is generated.

This system is not only applicable to laminated wafers using wafer-like interposers, but also to laminated wafers on which element wafers are formed.

The present invention was developed by the inventor in view of the above problems, and an object thereof is to provide a method for dividing a wafer into individual wafers even if the wafer side is adhered to an adhesive sheet in a laminated wafer in which wafers are laminated. Processing method of laminated wafers.

According to the invention described in claim 1, a method for processing a laminated wafer is provided. The laminated wafer includes: a wafer; and each region of a surface of the wafer that is laminated on a predetermined area divided by a plurality of intersecting division lines. And a wafer region including a plurality of stacked wafers and a peripheral remaining region surrounding the wafer region. A step is formed between the wafer region and the remaining peripheral region. The processing method of the laminated wafer is characterized by: having: The sheet attaching step is to attach an adhesive sheet on the wafer side of the laminated wafer; the division starting point forming step is to form a wafer along a predetermined dividing line of the laminated wafer before or after the adhesive sheet attaching step is performed. The starting point of division; and the dividing step, which is to expand the adhesive sheet to give external force to the laminated wafer after the sticking sheet attaching step and the dividing start point forming step, and divide the wafer from the dividing start point, and at least perform the dividing step. Previously, there was a fixing step, which was attached to the area corresponding to the remaining area of the periphery, A fixing agent is arranged between the landing sheet and the surface of the wafer, and the remaining area of the outer periphery of the wafer is fixed to the adhesive sheet.

According to the invention described in claim 2, there is provided a method for processing a laminated wafer as described in claim 1, wherein the adhesive sheet is a pressure-sensitive sheet, and the fixing agent is made of an ultraviolet curing resin. In the fixing step, The fixing agent is located in a region corresponding to the remaining peripheral area. After the adhesive sheet and the surface of the wafer are arranged in a dotted line, the fixing agent is irradiated with ultraviolet rays through the adhesive sheet, thereby leaving the remaining peripheral area of the wafer. Fix on adhesive sheet.

According to the present invention, there is provided a method for processing a laminated wafer in which a wafer is laminated on a wafer, and the wafer can be divided into individual wafers even when the wafer side is adhered to an adhesive sheet.

Specifically, at least before expanding the adhesive sheet, a fixing step is performed, which is to arrange a fixing agent between the adhesive sheet and the surface of the wafer in a region corresponding to the remaining region of the outer periphery, and to leave the outer periphery of the wafer The area is fixed to the adhesive sheet.

As a result, the remaining portion of the outer periphery of the wafer can also be fixed to the adhesive sheet through a fixing agent, and the external force is also transmitted to the remaining portion 16 of the wafer to act as a tensile force in a radial manner. The resulting singulation starting point breaks the wafer.

1‧‧‧Laminated wafer

1A‧‧‧Chip

11‧‧‧ intermediary

11a‧‧‧ surface

11b‧‧‧Back

12‧‧‧Chip

13‧‧‧ divided scheduled line

14‧‧‧Chip area

16‧‧‧ remaining area

17‧‧‧ Modified layer

18‧‧‧ Adhesive sheet

18a‧‧‧Adhesive layer

18b‧‧‧ substrate

19‧‧‧ Junction

20‧‧‧ ring frame

20a‧‧‧ opening

22‧‧‧ Wafer Unit

30‧‧‧laser irradiation unit

32‧‧‧ Fixture

34‧‧‧ keep the platform

40‧‧‧ Fixative

41‧‧‧ Fixative

42‧‧‧ UV

43‧‧‧Gap section

44‧‧‧ ultraviolet irradiation device

50‧‧‧ split device

51‧‧‧ keep the platform

55‧‧‧Air Cylinder

56‧‧‧Frame holding member

56a‧‧‧mounting surface

S‧‧‧ Clearance

FIG. 1 is a perspective view showing the structure of a laminated wafer.

FIG. 2 is a perspective view showing a step of attaching the adhesive sheet.

Fig. 3 is a side view showing the step of applying the adhesive sheet.

FIG. 4 is a side cross-sectional view showing a laminated wafer attached to an adhesive sheet.

FIG. 5 is a side view showing the step of forming a division starting point.

FIG. 6 is a side cross-sectional view showing the fixation of the remaining peripheral area by the fixing agent.

FIG. 7 (A) is a perspective view explaining the arrangement of a gel-like fixing agent. (B) is a perspective view explaining the arrangement of the hardened fixative.

FIG. 8 is a side cross-sectional view showing a state before division in the division step.

FIG. 9 is a side cross-sectional view showing a state after the division in the division step.

FIG. 10 is a side cross-sectional view showing an example using an ultraviolet curable resin as a fixing agent.

Forms used to implement the invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a laminated wafer 1 as an example of a processing object of the present invention.

The laminated wafer 1 is formed on the surface 11 a of the interposer 11 composed of a thin plate-shaped wafer, and is arranged at a predetermined position so that a plurality of wafers 12 and 12 are aligned vertically and horizontally.

In a region between adjacent wafers 12 and 12, predetermined division lines 13 and 13 are defined, and division is performed along the division division lines 13 and 13.

In the surface 11 a of the interposer 11, a region where the wafer 12 is arranged is a wafer region 14, and a portion on the outer periphery of the wafer region 14 is configured as a remaining region 16.

Since the wafer region 14 is configured to be higher than the remaining peripheral region 16 only by the thickness of the wafer 12, a step 15 is formed at the boundary portion between the wafer region 14 and the remaining peripheral region 16. With the existence of this step 15, if the wafer region 14 of the laminated wafer 1 is adhered to the adhesive sheet 18 (FIG. 2), the remaining peripheral region 16 will float from the adhesive sheet 18.

Therefore, if the adhesive sheet 18 is to be expanded for division, no external force is applied to the peripheral remaining region 16 floating from the adhesive sheet 18, and the division between the wafer region 14 and the peripheral remaining region 16 cannot be performed.

Therefore, in this embodiment, the division of the laminated wafer 1 is performed by the following method. First, as shown in FIGS. 2 and 3, an adhesive sheet attaching step of attaching an adhesive sheet 18 to the wafer 12 side of the laminated wafer 1 is performed.

As shown in FIG. 2 and FIG. 3, in the multilayer wafer 1, the back surface 11 b of the interposer 11 is set to the upper side, and the wafer 12 (wafer region 14) is opposed to the adhesive layer 18 a of the adhesive sheet 18. The wafer 12 is attached to the adhesive layer 18a.

Here, the base material 18b (FIG. 3) of the adhesive sheet 18 can be comprised with PO (polyolefin), PVC (polyvinyl chloride), PE (polyethylene terephthalate), etc., for example. The adhesive layer 18a (paste layer) may be made of a rubber-based or acrylic resin.

In addition, a ring-shaped frame 20 having an opening 20 a having a size surrounding the laminated wafer 1 is attached to the adhesive sheet 18.

Next, as shown in FIG. 4, the adhesive sheet 18 is stored in a ring shape. The frame 20 is appropriately cut into the outer periphery of the frame 20 to form a wafer unit 22 that fixes the laminated wafer 1 to the ring-shaped frame 20 through the adhesive sheet 18.

Next, as shown in FIG. 5, before or after the adhesive sheet sticking step is performed, a dividing start point forming step of forming a dividing start point along the planned dividing line 13 of the laminated wafer 1 on the interposer 11 is performed.

In this embodiment, as shown in FIG. 5, after performing the adhesive sheet sticking step, a modified layer is formed on the interposer 11 by the laser irradiation unit 30 to form a division starting point.

In the example of FIG. 5, the ring frame 20 is held by the jig 32, and the holding platform 34 sucks and holds the laminated wafer 1 through the adhesive sheet 18.

Next, the holding platform 34 is processed and fed while facing the direction of the arrow X1, and a laser beam is irradiated to the interposer 11 by the laser irradiation unit 30. Thereby, as shown in FIG. A modified layer 17 is formed in the layer 11.

Among them, as shown in this embodiment, in addition to forming the starting point of the division (modified layer 17) by laser beam irradiation, formation of a laser processing groove by laser ablation processing, or The division starting point is formed by the formation of a cutting groove for a cutting device provided with a rotating cutter.

In addition, before the adhesive sheet sticking step is performed, a dividing starting point forming step may be performed in advance to form the modified layer 17, and then, as shown in FIG. 3, the laminated wafer 1 on which the modified sheet is formed is attached to the adhesive sheet. 18.

Next, in addition to the steps described above, it is implemented externally. A fixing agent 40 (FIG. 4) is disposed between the adhesive sheet 18 and the surface 11 a of the interposer 11 in a region corresponding to the peripheral remaining region 16, and the peripheral remaining region 16 of the interposer 11 is fixed to the fixing step of the adhesive sheet 18.

This fixing step may be performed before the division step described later is performed, and is scheduled to be performed before or after any of the above steps.

FIG. 6 shows a state in which a fixing agent 40 is disposed on the surface 11 a of the interposer 11, and the remaining sheet 16 of the interposer 11 is adhered to the adhesive sheet 18 through the fixer 40.

This fixing agent 40 is, for example, a gel-like adhesive, and it is conceivable to inject the fixing agent 40 in such a manner as to draw (border) the periphery of the interposer 11 so that the remaining area 16 and the adhesive sheet 18 of the outer periphery of the interposer 11 are injected. The gap S is supplied with the fixing agent 40.

In addition, as shown in FIG. 1, the placement system of the fixing agent 40 is performed in a state in which the surface 11 a of the interposer 11 is exposed thereon, that is, it can be performed before the adhesive sheet sticking step. Thereby, the fixing step is performed simultaneously with the adhesive sheet sticking step.

Alternatively, as shown in FIG. 4, the surface 11 a of the interposer 11 may be adhered to the adhesive sheet 18, that is, after the adhesive sheet attaching step. Alternatively, as shown in FIG. 5, it may be performed after forming a starting point for division by laser beam irradiation or the like, that is, performing after the step for forming the starting point for division.

Next, the placement of the fixing agent 40 may be performed automatically by a coating device for applying the fixing agent 40, or it may be performed manually by an operator. In addition, as shown in FIG. 7 (A), The fixing agent 40 may be used to draw (border) the periphery of the interposer 11. Alternatively, as shown in FIG. 7 (B), the fixing agent 41 may be intermittently supplied and the fixing agent 41 may be arranged in a dotted line.

The fixing agent 40 does not need to stay in the gap S (FIG. 6) between the interposer 11 and the adhesive sheet 18, and can also wrap around the outer periphery or the back surface 11 b of the interposer 11, thereby covering the back surface 11 b with the fixing agent 40.

Next, as shown in FIG. 8 and FIG. 9, a dividing step of expanding the adhesive sheet 18 to apply an external force to the laminated wafer 1 and dividing the interposer 11 from the dividing starting point (modification layer 17) is performed.

In this embodiment, a dividing device 50 having a holding platform 51 that holds the laminated wafer 1 adhered to the adhesive sheet 18 and a frame holding member 56 that holds the ring frame 20 is used.

The frame holding member 56 is driven by the air cylinder 55 to be lowered from the holding position shown in FIG. 8 to the expanded position shown in FIG. 9, and the holding platform 51 and the frame holding member 56 are relatively moved in the vertical direction.

At this time, the ring-shaped frame 20 held on the mounting surface 56 a of the frame holding member 56 is lowered, and the adhesive sheet 18 mounted on the ring-shaped frame 20 abuts on the upper end edge of the holding platform 51, mainly in the radial direction. expansion.

As a result, an external force is transmitted to the interposer 11 adhered to the adhesive sheet 18 and a tensile force is applied in a radial manner. When the intermediary layer 11 is applied in a radial manner, the tensile force is applied along the planned division line 13 (see FIG. 1). Since the modified layer 17 formed by) has a reduced strength, the modified layer 17 serves as a dividing point, and the interposer 11 is broken along the modified layer 17 and is divided into individual wafers 1A and 1A.

Next, when performing this division step, the remaining area 16 of the outer periphery of the interposer 11 is also fixed to the adhesive sheet 18 through the fixing agent 40, Therefore, the external remaining area 16 also transmits external forces and acts as a tensile force in a radial manner. The intermediate layer 11 is broken when the modified layer 17 is formed at the boundary portion 19 of the wafer area 14 and the remaining area 16.

The present invention can be implemented as above.

That is, it is formed as a processing method of a laminated wafer 1 having an interposer 11 as a wafer and layers of the interposer 11 divided by intersecting plural divided predetermined lines 13 respectively. The wafer 12 in each region of the surface includes a wafer region 14 in which a plurality of wafers 12 are laminated, and a peripheral remaining region 16 surrounding the wafer region 14. A step 15 is formed between the wafer region 14 and the peripheral remaining region 16. The processing method of circle 1 includes: an adhesive sheet attaching step of attaching an adhesive sheet 18 to the wafer 12 side of the laminated wafer 1; and before or after performing the adhesive sheet attaching step, forming an interlayer 11 along the laminated wafer The division start point formation step of the division start point of the division line 1 of 1; after performing the adhesive sheet attachment step and the division start point formation step, the adhesive sheet 18 is expanded to apply external force to the laminated wafer 1 and the intervening layer 11 is divided from the division start point. A division step of division, and at least before the division step is performed, a fixing step is provided, which is located in an area corresponding to the remaining peripheral area 16 and on the surface of the adhesive sheet 18 and the interposer 11. A fixing agent 40 is arranged between the surfaces 11 a, and the remaining area 16 of the outer periphery of the interposer 11 is fixed to the adhesive sheet 18.

By this processing method, the remaining area 16 of the outer periphery of the interposer 11 of the wafer is also fixed to the adhesive sheet 18 through the fixing agent 40. Therefore, the remaining area 16 of the outer periphery also transmits the external force and acts as a tensile force in a radial manner. The modified layer 17 formed at the boundary portion 19 of the wafer region 14 and the remaining peripheral region 16 can break the interposer 11.

In the above embodiment, the description is made by using the laminated wafer 1 using the interposer 11 as a wafer. However, the present invention can also be applied to a laminated wafer in which an element wafer is laminated with an element. .

In addition, in the embodiment shown in FIG. 7 (B), the sheet may be adhered. 18 is a pressure-sensitive sheet that is adhered by pressing, and the fixing agent 41 is made of an ultraviolet curing resin. In the fixing step, the fixing agent 41 is in a region corresponding to the remaining peripheral region 16 and the adhesive sheet 18 is After being arranged in a dotted line with the surface 11a of the interposer 11, as shown in FIG. 10, the fixing agent 41 is irradiated with ultraviolet rays 42 through the adhesive sheet 18, thereby fixing the remaining area 16 of the outer periphery of the interposer 11 to the adhesive sheet. 18.

This embodiment is a particularly suitable embodiment when a UV-curable resin is used as the curing type fixing agent 41. If it is not arranged in a dotted line, that is, it is not intermittently arranged at intervals, the expansion of the adhesive sheet 18 during the division step is hindered by the curing of the fixing agent.

In the embodiment shown in FIG. 10, the fixing agent 41 is hardened by irradiating the fixing agent 41 with the ultraviolet rays 42 from the ultraviolet irradiation device 44 from the back side of the adhesive sheet 18.

The fixing agent 41 is arranged in a dotted line in the remaining peripheral region 16 of the interposer 11. Therefore, a gap 43 is formed between the scattered fixing agents 41 (FIG. 7 (B)). The expansion of the adhesive sheet 18 can transmit an external force to the entire area of the interposer 11 and apply a radial tensile force.

1‧‧‧Laminated wafer

11‧‧‧ intermediary

11a‧‧‧ surface

11b‧‧‧Back

12‧‧‧Chip

13‧‧‧ divided scheduled line

16‧‧‧ remaining area

17‧‧‧ Modified layer

18‧‧‧ Adhesive sheet

18a‧‧‧Adhesive layer

18b‧‧‧ substrate

40‧‧‧ Fixative

S‧‧‧ Clearance

Claims (2)

A method for processing a laminated wafer. The laminated wafer includes: a wafer; and a wafer each laminated on each area of the surface of the wafer divided by a plurality of intersecting predetermined division lines. The laminated wafer includes: A wafer region of the wafer and a remaining peripheral region surrounding the wafer region form a step between the wafer region and the remaining peripheral region. The method for processing a laminated wafer is characterized by having: an adhesive sheet attaching step, It is to adhere an adhesive sheet on the wafer side of the laminated wafer; the division starting point forming step is to form the wafer along the predetermined division line of the laminated wafer before or after implementing the adhesive sheet attachment step. A starting point of division; and a dividing step, which is performed after the step of sticking the adhesive sheet and the step of forming the starting point of division, expanding the adhesive sheet to apply external force to the laminated wafer, and dividing the wafer from the starting point of division, and At least before the dividing step is performed, a fixing step is provided, which is in an area corresponding to the remaining area of the outer periphery, and on the surface of the adhesive sheet and the wafer. Disposed between the fixing agent, and the remaining region of the outer periphery of the wafer fixed to the adhesive sheet. For example, the method for processing a laminated wafer according to item 1 of the patent scope, wherein the adhesive sheet is a pressure-sensitive sheet, and the fixing agent is made of an ultraviolet curing resin. In the fixing step, the fixing agent is in contact with the outer periphery. Remaining area The area corresponding to the domain is arranged in a dotted line between the adhesive sheet and the surface of the wafer, and then the fixing agent is irradiated with ultraviolet rays through the adhesive sheet, thereby fixing the remaining area of the periphery of the wafer. At this adhesive sheet.