TW201709290A - Method of manufacturing device chips - Google Patents

Abstract

The objective of the present invention is to provide a method to manufacture device chips, capable of continuously arranging a plurality of devices in one line without a gap. The method to manufacture device chips manufactures the device chips from a device wafer having a device in each area of a surface which is partitioned by a plurality of planned division lines intersected with each other and having a predetermined width. According to the present invention, the method comprises: a modified layer formation step of placing, in the inside of a device wafer, a focusing point of a laser beam of a wavelength having transmittance with respect to the device wafer, and irradiating the laser beam from the rear surface of the device wafer along both edges of a lateral direction of the planned division line, so as to vertically form a plurality of two lines of parallel modified layers; and a division step of applying external force to the device wafer after carrying out the modified layer formation step, so as to divide the device wafer into a plurality of device chips by using the modified layer as a cut starting point. In the modified layer formation step, the modified layer of the rear surface side is formed in a position recessed towards a device side from the modified layer of a surface side, and a surface side is most projected out on a side surface of the device chip cut along the modified layers.

Description

Method for manufacturing component wafer

The present invention relates to a method of manufacturing an element wafer for use in a long line sensor or LED printer head.

The electronic component of the component wafer obtained by dividing the component wafer such as a semiconductor wafer or an optical element wafer is an electronic component such as a long line sensor or an LED printer head.

As a feature of these electronic components, electronic components in which a plurality of components are arranged neatly are formed in such a manner that the manufactured component bus bar wafers are arranged in one row without leaving a gap, and the interval between the component wafers is reduced to the limit.

In order to prevent the omission of the sensing or the omission of the printing, it is important that the components are arranged without gaps as much as possible. When manufacturing the component wafer, the component wafer is divided as much as possible without leaving the dividing line of the component wafer. It is important.

Further, when the wafers are arranged in one row, it is important that the adjacent elements are not separated from each other, and that no convex portion remains on the side surface of the wafer. In order to satisfy the demand, the proposal is inclined obliquely. The cutting blade is a method of processing the two sides of the width direction of the dividing line to cut the predetermined line (for example, refer to Japanese Laid-Open Patent Publication No. 2010-073821 or JP-A-2007-273743).

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-073821

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-273743

However, in the conventional method using a cutting insert, it is necessary to prepare a dedicated cutting device for tilting the cutting insert, and it is necessary to cause chipping due to chipping, in order to prevent the component from collapsing. It is necessary to have a margin for the distance between the component and the cutting insert, so there is a limit to arranging a plurality of components in a row.

The present invention has been made in view of such problems, and an object thereof is to provide a method for manufacturing an element wafer in which a plurality of elements can be continuously arranged in one line without leaving a gap.

According to the present invention, there is provided a method of fabricating an element wafer which is formed from a component crystal of an element in a field of a surface which is defined by a plurality of predetermined dividing lines having a specified width intersecting each other. Round, manufacturing a component wafer; characterized by comprising: a holding step of holding a component wafer on a surface side of the component wafer opposite to a holding surface of the chuck bed; and modifying the layer forming step to perform the holding After the step, the condensing point of the lightning ray beam having a wavelength transparent to the component wafer is placed inside the component wafer, and the lightning ray beam is taken from the back surface of the component wafer along the width direction of the dividing line. Irradiating both edges, forming two modified layers in which a plurality of layers are parallel to each other in the vertical direction; and dividing step, after performing the reforming layer forming step, applying an external force to the element wafer to the modified layer Dividing the component wafer into a plurality of component wafers for breaking the starting point; in the reforming layer forming step, forming the modified layer on the back side to a position on the component side from the modified layer on the surface side; The side surface of the element wafer which is broken by the modified layer of the plurality of layers is the most prominent on the surface side.

According to the method for fabricating an element wafer of the present invention, a plurality of layers of modified layers are formed inside the element wafer by a lightning beam to break the element wafer into individual element wafers, and are formed along the dividing line on the surface side. The two modified layers are formed toward the center from both edges of the dividing line, and a modified layer is formed along both edges on the back side.

Therefore, in the element wafer in which the element wafer is divided, the side surface of the wafer is inclined from the surface toward the obliquely lower side (the wafer center side), and when the wafers are connected to each other, the wafers adjacent to each other on the element surface side are not formed. gap. Therefore, when a plurality of component wafers are arranged in one row, a plurality of component wafers can be arranged into one with almost no gap between adjacent components. Column.

Further, the reforming layer formed on the element wafer is divided into a plurality of element wafers from the breaking starting point, and no breakage occurs, and the portion which is as close as possible to the edge portion of the dividing line can be broken. The effect of the component wafer.

10‧‧‧Clip bed

11‧‧‧Semiconductor wafer

13, 13a, 13b‧‧‧ dividing line (cutting lane)

14‧‧‧ concentrator

15‧‧‧ components

20‧‧‧Splitting device

21‧‧‧Modified layer

22‧‧‧Expansion roller

23‧‧‧Component chip

24‧‧‧Box keeping means

25‧‧‧Cut Department

26‧‧‧Box holding member

27‧‧‧ line sensor

FIG. 1 is a front side perspective view of a semiconductor wafer.

FIG. 2 is a perspective view showing a state in which the surface side of the semiconductor wafer is attached to an extending tape of an adhesive tape attached to the annular frame as an outer peripheral portion.

Fig. 3 is a partial cross-sectional side view showing the step of forming a modified layer.

4 is an enlarged partial view showing a back side of a semiconductor wafer at a position where a reforming layer is formed in a reforming layer forming step.

Fig. 5 (A) is a cross-sectional view showing a method of forming a modified layer according to a first embodiment of the present invention, and Fig. 5 (B) is a cross-sectional view showing a method of forming a modified layer according to a second embodiment.

6(A) and 6(B) are partial cross-sectional side views showing a dividing step, and Fig. 6(C) is an enlarged view of a portion A of Fig. 6(B).

Fig. 7 is a cross-sectional view showing a line sensor in which a plurality of element wafers are arranged in a row.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to Fig. 1, there is shown a perspective view of a semiconductor wafer (element wafer). The element wafer 11 shown in FIG. 1 is made of, for example, a tantalum wafer having a thickness of 300 μm, and a plurality of predetermined dividing lines (cutting lines) 13 are formed in a lattice shape on the surface 11a, and are divided by a plurality of strips. Each of the areas defined by the predetermined line 13 forms an element 15 such as a CCD or a CMOS.

The semiconductor wafer 11 thus configured is provided with an element region 17 in which a plurality of elements 15 are formed, and an outer peripheral region 19 surrounding the element region 17 on the surface 11a. 11b is the back surface of the semiconductor wafer 11.

The wafer to be processed by the method of manufacturing the element wafer of the present invention is not limited to the semiconductor wafer 11 shown in FIG. 1, and includes an epitaxial layer (light-emitting layer) in which gallium nitride or the like is formed on the sapphire substrate. An element wafer such as a photo-component wafer.

In the method of manufacturing an element wafer according to an embodiment of the present invention, before processing, as shown in FIG. 2, the surface 11a of the element wafer 11 is attached to the adhesive tape which is attached to the ring frame F by the outer peripheral portion. The stretch tape T is formed. Thereby, the back surface 11b of the element wafer 11 is exposed at the time of processing.

In the method of manufacturing an element wafer of the present embodiment, first, a holding step is performed to hold the element wafer 11 on the surface 11a side of the element wafer 11 and the holding surface of the chuck bed of the laser processing apparatus.

That is, as shown in FIG. 3, the chuck bed 10 of the laser processing apparatus is used to suck the holding element wafer 11 via the stretch tape T, and the back surface 11b side of the element wafer 11 is exposed upward. Next, the ring frame F is held by the clamp 12 and fixed.

In a state in which the element wafer 11 is held by the chuck bed 10, a reforming layer forming step is performed by using the concentrator 14 of the lightning beam generating unit to have a wavelength transparent to the element wafer 11 (for example, The light collecting point of the pulsed laser beam of 1064 nm is positioned inside the wafer 11 corresponding to the dividing planned line 13, and the beam of thunder rays is irradiated from the side of the back surface 11b of the wafer 11, while the chuck bed 10 is directed to the arrow X1. The feed is fed in the direction or the X2 direction, and a plurality of modified layers 21 are formed inside the wafer.

The position of the reforming layer formed in the reforming layer forming step will be described with reference to FIG. In Fig. 4, a predetermined dividing line for the side where the elements are closely arranged is referred to as 13a, and a dividing line for dividing the side where the elements are not closely arranged is referred to as 13b.

In the division planned line 13a, two modified layers 21 are formed inside the wafer 11 along both edges in the width direction of the division planned line 13a. The reforming layer 21 in this direction is formed by forming a plurality of layers in the thickness direction of the wafer 11.

Regarding the division planned line 13b, one modified layer 21 is formed inside the wafer along the outline center of the division planned line 13b. The formation of the reforming layer 21 in this direction also forms a plurality of layers in the thickness direction of the wafer 11.

Refer to Figure 5 for further details on the reforming layer formation steps. Explain it. Fig. 5(A) is a cross-sectional view showing a step of forming a modified layer according to the first embodiment. In the reforming layer forming step of the first embodiment, first, two mutually parallel modifications are formed on the side closer to the center side of the predetermined distance from the both edges of the dividing line 13a on the side closer to the surface 11a of the element wafer 11. Mass layer 21.

Then, at the position where the condensed spot P of the ray beam condensed by the concentrator 14 is raised to the side of the back surface 11b of the wafer 11, two edges which are parallel to each other are formed along the both edges of the dividing line 13a. Mass layer 21. Further, the spot P of the lightning beam is positioned to the side of the back surface 11b of the wafer 11, and two reforming layers 21 which are parallel to each other are formed so as to overlap the reforming layer 21 formed a little earlier in the up and down direction. . The same two modified layers 21 are formed in a plurality of layers along the adjacent planned dividing line 13a so as to feed the wafer 11 by the indexing.

Further, in the embodiment shown in FIG. 5(A), the modified layer 21 on the side close to the surface 11a of the wafer 11 is formed, and the modified layer 21 on the side of the back surface 11b in which the two layers overlap in the vertical direction is formed. However, the number of layers of the modified layer 21 is not limited thereto, and the modified layer 21 on the surface 11a side of two or more layers may be formed, and the modified layer 21 on the side of the back surface 11b of only one layer may be formed in three or more layers.

Regarding the division planned line 13b, it is not necessary to closely align the sides of the elements, so that the modified layer 21 of a plurality of layers is formed so as to overlap the center of the division planned line 13b in the vertical direction.

Referring to Fig. 5(B), there is shown a cross-sectional view showing a step of forming a modified layer according to a second embodiment of the present invention. Modification layer in the present embodiment In the forming step, the reforming layer 21 on the surface 11a side of the wafer 11 is overlapped with the reforming layer 21 formed next in the thickness direction of the wafer 11.

The length of the overlap is preferably about 30 μm. As described above, the formation of the modified layer 21 was carried out, and it was confirmed that a desired crack which propagated from the reforming layer 21 can be surely formed.

The processing conditions in the reforming layer forming step can be set, for example, as follows.

Light source: LD excitation Q switcher Nd: YVO4 pulse laser

Wavelength: 1064nm

Average output: 0.2W

Repeat frequency: 80kHz

Converging spot diameter: Φ1μm

Processing feed rate: 100nm/s

After the reforming layer forming step is performed, the dividing step is performed to apply an external force to the element wafer 11, and the element wafer 11 is divided into a plurality of element wafers by using the modified layer 21 as a breaking starting point.

Refer to Figure 6 for the division step. Referring to FIG. 6(A), the dividing device 20 includes an expansion drum 22 and a frame holding means 24 that holds the ring frame F. The expansion drum 22 has an inner diameter smaller than the inner diameter of the annular frame F and larger than the outer diameter of the wafer 11 attached to the expanded tape T attached to the annular frame F.

The frame holding means 24 utilizes an annular frame holding member 26. A plurality of clamps 28 as fixing means disposed on the outer periphery of the frame holding member 26. The upper surface of the frame holding member 26 is formed with a mounting surface 26a on which the annular frame F is placed, and the annular frame F is placed on the mounting surface 26a.

Next, the annular frame F placed on the placing surface 26a is fixed to the frame holding member 26 by the clamp 28. The frame holding means 24 thus configured is coupled to the piston rod 32 of the cylinder 30, and the frame holding member 26 is moved in the vertical direction by actuating the cylinder 30.

The wafer dividing step using the dividing device 20 configured as described above will be described with reference to FIGS. 6(A) to 6(C). As shown in FIG. 6(A), the annular frame F that supports the wafer 11 via the stretch tape T is placed on the mounting surface 26a of the frame holding member 26, and is fixed to the frame holding member by the clamp 28. 26. At this time, the frame holding member 26 is positioned at a position where the placement surface 26a is at a position substantially the same as the upper end of the expansion drum 22.

Next, the cylinder 30 is driven to lower the frame holding member 26 to the expanded position as shown in Fig. 6(B). As a result, the annular frame F fixed to the mounting surface 26a of the frame holding member 26 also descends, and the extension tape T attached to the annular frame F abuts against the upper end edge of the expansion roller 22, and is mainly expanded. In the radial direction.

As a result, a radial tension acts on the wafer 11 attached to the stretch tape T. As described above, when the radial tension is applied to the wafer 11, the wafer 11 is broken by the modified layer 21 as a breaking starting point, and is divided into the element wafers 23 one by one.

In the method of manufacturing the element wafer of the present embodiment, the predetermined dividing line 13a on the side of the side where the elements are closely arranged is formed with two modified layers 21 at the same height along the respective dividing lines 13a, on the wafer 11. A plurality of modified layers 21 are formed in the thickness direction.

Further, the modified layer 21 is formed closer to the side of the element 15 than the one of the surface 11a closest to the wafer 11 to the modified layer 21, and closer to the side of the element 15, as shown in Fig. 6(B). The enlarged view of the A portion is also shown in Fig. 6(C), and the side surface of the element wafer 23 obtained after the wafer 11 is divided is inclined obliquely from the surface of the forming element 15 toward the wafer center side. Further, the scribe line portion 25 remains between the adjacent element wafers 23.

In particular, the predetermined dividing line 13b orthogonal to the dividing line 13a extending in the first direction is formed as shown in Fig. 4, and a modified layer is formed at a substantially central portion of the dividing line 13b. For the reason of 21, when the dividing step shown in Fig. 6 is carried out, the side faces of the element wafers 23 are perpendicular to the elements 15 formed on the surface.

According to the method of manufacturing an element wafer of the above-described embodiment, it is necessary to closely align the sides of the element, and the side surface of the wafer is inclined obliquely from the surface toward the wafer center side, so that a plurality of element wafers 23 are connected, for example, In the case where the line sensor 27 is constructed as shown in Fig. 7, the adjacent elements 15 can be arranged with the element wafer 23 aligned almost without gaps.

In the above embodiment, an image sensor of a CCD, a CMOS or the like is manufactured by applying the element wafer of the present invention to a semiconductor wafer. Although the example of the wafer has been described, the manufacturing method of the present invention is not limited thereto, and the method of manufacturing the LED wafer by applying the division of the optical element wafer in which a plurality of LEDs are formed on the surface is also applicable.

10‧‧‧Clip bed

11‧‧‧Semiconductor wafer

11a‧‧‧ surface

11b‧‧‧Back of semiconductor wafer 11

13a‧‧‧ dividing line (cutting lane)

14‧‧‧ concentrator

15‧‧‧ components

21‧‧‧Modified layer

P‧‧‧ spotlight

T‧‧‧Extension tape

Claims (1)

A method for manufacturing an element wafer, wherein an element wafer is formed from a component wafer in which an element is formed in each of a surface of a surface defined by a plurality of predetermined dividing lines having a specified width crossing each other; Having a holding step of holding the component wafer on the surface side of the component wafer opposite to the holding surface of the chuck bed; the reforming layer forming step is performed on the component wafer after performing the holding step The light-converging point of the thunder beam having a transparent wavelength is positioned inside the element wafer, and the lightning beam is irradiated from the back surface of the element wafer along both edges in the width direction of the dividing line, in the up and down direction Forming two modified layers in which a plurality of layers are parallel to each other; and a dividing step of applying an external force to the component wafer after the reforming layer forming step is performed, and dividing the component wafer by using the modified layer as a breaking starting point a plurality of component wafers; in the reforming layer forming step, the modified layer on the back side is formed to be displaced from the modified layer on the surface side to the component side; and is broken along the modified layer of the plurality of layers The side surface of the component wafer is the most prominent on the surface side.