JP3276506B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a semiconductor device manufacturing technique.
In particular, the present invention relates to a breaking technique for dividing a semiconductor wafer to which a wafer fixing sheet is attached into a plurality of semiconductor pellets (hereinafter, referred to as pellets). For example, in a semiconductor device manufacturing process, a semiconductor wafer is divided into a plurality of pellets. It relates to technology that is effective to use for dividing.

[0002]

2. Description of the Related Art The manufacturing process of a semiconductor device includes a pre-process in which a semiconductor integrated circuit and an optical semiconductor circuit are formed on the surface (upper surface) of a semiconductor wafer, and a process in which the semiconductor wafer is divided into pellets to form a lead frame. It is roughly divided into a post-process in which the assembled pellets are electrically connected to each other to perform resin sealing and the like. Generally, in a post-process of the semiconductor device manufacturing process, a dividing process of dividing a semiconductor wafer into individual pellets is performed by the following operation.

First, a wafer fixing sheet made of synthetic resin is attached to the back surface (lower surface) of a semiconductor wafer in order to prevent the divided pellets from being separated. Next, a notch is formed on the division line between the pellets on the surface of the semiconductor wafer as follows. Using a diamond blade, a notch is formed by the following or another method. A half dicing method in which a cut is made to about half the thickness of a semiconductor wafer. A semi-full dicing method that leaves a slight cut in the thickness direction of the semiconductor wafer. Full dicing method that cuts and separates completely.

Alternatively, a notch is formed by the following method using a diamond tool. A scribing method in which a relatively shallow notch is linearly added to a semiconductor wafer surface.

In the above method, the full dicing method does not require a breaking step. However, this method has a disadvantage that the cutting time is longer than other methods, and in fact, other methods are still frequently used.

Next, starting from the notch added to the surface of the semiconductor wafer by the above-described method, a breaking operation is performed in which the space between the pellets of the semiconductor wafer is cleaved in the crystal axis direction and separated for each pellet.

Conventionally, in this braking operation, a semiconductor wafer is placed on a stage having an appropriate hardness with its cutout side down, and a roller made of a material such as rubber is pressed from the back side of the semiconductor wafer. This is done by rubbing while applying a great pressure.

[0008] Japanese Patent Publication No. 2-59636 and Japanese Patent Publication No. 2-60076 describe examples of this type of braking method.

[0009]

However, the inventors have found that the following problems occur in the conventional braking method.

[0010] Since the stage for breaking the semiconductor wafer is in surface contact with the surface of the semiconductor wafer on which electronic circuits and the like are formed, the surface of the semiconductor wafer may be damaged during the braking operation. Further, at the time of cleavage, conductive debris generated from the semiconductor wafer adheres to the surface of the semiconductor wafer.

Conventionally, in order to solve the above problems, it has been necessary to interpose a sheet-shaped protective tape between a stage for breaking a semiconductor wafer and the surface of the semiconductor wafer. It is desirable to omit this protective tape from the viewpoint of workability and economy.

When the semiconductor wafer is turned upside down and pressed against the roller from the back side of the semiconductor wafer to cleave the semiconductor wafer, it is necessary to align the notch direction on the surface of the semiconductor wafer with the direction in which the roller is cut at a right angle. However, since the notch of the semiconductor wafer cannot be seen, it is difficult to accurately match the roller running direction.

In the method of cleaving with a roller, the force is not efficiently transmitted to the notch to which a true force is to be applied, so that the pellet may be damaged by applying an excessive force.

[0014] The above tendency is remarkable because the roller is pressed over a plurality of pellets as the pellet size decreases, and in some cases, cracks remain. If rollering is continued to completely divide the pellets, the already broken pellets come into contact with each other, and the damage such as chipping and cracking tends to occur frequently.

The notch due to dicing or scribing is usually added in a lattice shape to the surface of the semiconductor wafer, and after performing cleavage in one direction by a roller, an operator turns the wafer exactly 90 ° to perform cleavage. It is necessary to cleave in another direction. However, there was no small decrease in yield due to the misalignment.

An object of the present invention is the accuracy and workability and economical efficiency brake down Holdings Rukoto without damaging the pellets.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0018]

The outline of a typical invention among the inventions disclosed in the present application is as follows.

That is, it is formed on the surface of the semiconductor wafer.
To form a notch along on the division line between the pellets
And holding the semiconductor wafer by a wafer fixing sheet attached to the back surface of the semiconductor wafer
And the wafer around a location where the semiconductor wafer is cleaved.
(C) vacuum-adsorbing the fixing sheet;
To the notch position of the semiconductor wafer
The corresponding back surface is pushed up by a push-up member to
Cleaving the body wafer.
You .

[0020]

According to the above-mentioned means, since the semiconductor wafer is fixed by vacuum-adsorbing the peripheral portion of the wafer fixing sheet attached to the semiconductor wafer, the stage for fixing the wafer can be omitted. As a result, the surface of the semiconductor wafer does not come into surface contact with the stage as in the related art,
Scratches and adhesion of conductive foreign matter to the semiconductor surface can be prevented, and a conventionally used protective tape can be omitted.

The unnecessary position of the semiconductor wafer is detected by detecting the notch position added to the surface of the semiconductor wafer and accurately aligning the position of the push-up member of the push-up means for cleaving the semiconductor wafer with the notch position. It is possible to cleave accurately without applying extra force to the substrate.

[0022]

FIG. 1 shows a semiconductor device according to an embodiment of the present invention.
3A and 3B illustrate a semiconductor wafer breaking device used in the manufacturing method, wherein FIG. 3A is a plan view and FIG. 3B is a cross-sectional view taken along line bb of FIG. FIG. 2 is an enlarged partial view at the time of braking.

The semiconductor wafer is manufactured in the preceding process by the following operation. First, the semiconductor wafer 30 (only the upper half of the semiconductor wafer is shown in FIG. 1A) is formed in a substantially disk shape, and each pellet 31 is formed.
Each time, a transistor, a diode, a semiconductor integrated circuit, an optical semiconductor circuit, or the like is manufactured.

Next, a wafer fixing sheet 32 is attached to the back surface of the semiconductor wafer 30. The wafer fixing sheet 32 is made of a material having elasticity such as a synthetic resin.
It is formed in a circular thin film shape larger in diameter than the semiconductor wafer 30, and an appropriate adhesive is applied to one surface. As the sheet base material, for example, a vinyl chloride sheet, a polyester sheet and the like are generally used.

Subsequently, a notch 33 is formed on the dividing line between the pellets 31 on the surface of the semiconductor wafer 30 by using a method such as dicing or scribing. In the present embodiment, the depth of the notch 33 is set to approximately half the thickness of the semiconductor wafer 30.

Next, an apparatus for breaking the semiconductor wafer 30 will be described. The breaking device includes a wafer holding unit 1, and the unit main body 2 is formed of an annular disk member. A plurality of vacuum suction holes 3 are formed in the unit body 2 at equal intervals in the circumferential direction so as to penetrate in the thickness direction, and these holes 3 are connected to a vacuum source 4. . A suction pad 5 is annularly buried and fixed on the lower surface of the unit main body 2, and a portion of the wafer fixing sheet 32 around the semiconductor wafer 30 is vacuum-sucked through the suction pad 5. I have. The wafer holding unit 1 is supported by a suitable rotation support device (not shown) so as to be rotatable by 90 °.

At an upper position in the wafer holding unit 1,
A light reflection type sensor 6 is provided. The two sensors 6 are provided at regular intervals, and are configured to detect a notch 33 formed in a straight line on the surface of the semiconductor wafer 30. Note that these sensors 6 are configured to move in parallel.

A push-up unit 7 is provided below the wafer holding unit 1, and the push-up unit 7 has a push-up member 8. This push-up member 8
Has a main body 8a and a push-up plate 8b vertically supported by the main body 8a. The tip of the upper end of the push-up plate 8b has a V-shaped cross section over the entire length in the longitudinal direction.
It is formed in a pointed shape having a character shape, and the length of the peak is set to be slightly longer than the length of the notch 33 of the semiconductor wafer 30. The push-up member 8 is adjusted in advance so that the peak of the push-up plate 8 b is parallel to a line connecting the centers of the optical axes of the two sensors 6.

The periphery of the push-up member 8 is closed by a rectangular tubular guide body 9, and the push-up member 8 is configured to be vertically movable by appropriate means (not shown) while being guided by the guide body 9. . A vacuum suction hole 11 is formed in the side wall of the guide body 9, and this hole 11 is connected to a vacuum source 10 independent of the vacuum source 4 connected to the wafer holding unit 1. Accordingly, the guide body 9 is configured to be evacuated by the vacuum source 10 through the suction hole 11. A suction pad 12 is annularly embedded and fixed on the upper surface of the guide body 9, and a portion of the wafer fixing sheet 32 of the semiconductor wafer 30 around the push-up member 8 is vacuum-sucked through the suction pad 12. Have been. At the time of breaking by the push-up member 8, it is preferable that the periphery of the notch 33 to be cleaved of the semiconductor wafer 30 is sucked and held, and in this embodiment, the width of the guide body 9 is about twice the width of the pellet 31. The length is formed slightly longer than the outer diameter of the semiconductor wafer 30.

The push-up unit 7 is mounted on a movable table 13, and is configured to be able to move on the straight line in the width direction of the push-up plate 8b by the movable table 13. Then, the push-up unit 7 corrects the positional deviation from the position of the notch 33 of the semiconductor wafer 30 based on the detection signal of the light reflection type sensor 6 by feedback control means, and the tip of the push-up plate 8 b of the push-up member 8 is moved. The moving table 13 is configured to be moved so as to be disposed immediately below the notch 33 of the semiconductor wafer 30.

Next, an embodiment of the present invention will be described in which the semiconductor wafer braking device having the above-described configuration is used to divide the semiconductor wafer 30 as a work manufactured as described above into individual pellets 31. Method for manufacturing semiconductor device
The method of breaking the semiconductor wafer in the above will be described.

First, the semiconductor wafer 30 is disposed on the lower surface of the wafer holding unit 1 with the notch 33 facing upward, and the wafer fixing sheet 32 around the semiconductor wafer 30 is provided.
The portion is vacuum-sucked to the lower surface of the wafer holding unit 1 via the suction pad 5.

Next, each of the pair of light reflection type sensors 6 is arranged so as to detect the notch 33 of the semiconductor wafer 30. Subsequently, the wafer holding unit 1 is rotated based on the detection of both sensors 6, and the θ alignment is performed. At this time, the moving table 13 on which the push-up unit 7 is mounted is controlled based on the output of the light reflection type sensor 6 so that the tip of the push-up plate 8b of the push-up member 8 is located immediately below the notch 33 of the semiconductor wafer 30. To be moved and aligned.

In this alignment state, the semiconductor wafer 30
A portion of the wafer fixing sheet 32 corresponding to the periphery of the notch 33 to be cleaved is vacuum-sucked to the push-up unit 7 via the suction pad 12 on the upper surface of the guide body 9 of the push-up unit 7.

Then, as shown in FIG. 2, the push-up member 8 of the push-up unit 7 is raised, and the tip of the push-up plate 8b pushes up the notch 33 of the semiconductor wafer 30 from the back surface of the semiconductor wafer 30. . At this time, the tip of the push-up plate 8b is raised to about half the thickness of the semiconductor wafer 30. By pushing up the push-up member 8, the semiconductor wafer 30 is cleaved from the position of the notch 33 as a starting point.

If the pushing-up amount of the pushing-up member 8 is excessive, the cleaved pellet 31 comes into contact with an adjacent pellet, thereby causing chipping. Also,
If the amount of thrust is insufficient, it will not be cleaved. When the semiconductor wafer is pushed up, the area to be pushed up is vacuum-sucked to the push-up unit 7, so that the relationship between the semiconductor wafer 30 to be pushed up and the push-up member 8 is always kept constant between each push-up operation. , Quantitative control can always be ensured.

Next, the push-up member 8 is lowered, and after the vacuum suction by the push-up unit 7 is released, the push-up unit 7 is moved to the cutout position in the next row. At this time, the push-up unit 7 is moved by detecting the position of the notch 33 by the light reflection type sensor 6 so that the push-up member 8 is disposed immediately below the notch 33 in the next row. By repeating the above operation, the semiconductor wafer 30 is cleaved from the position of the notch 33 as a starting point.

After all of the notches 33 in the same direction are cleaved, the wafer holding unit 1 is rotated by 90 °, and the group of notches 33 in the other direction is sequentially cleaved in the same manner as described above.

As described above, the semiconductor wafer 30 is cleaved starting from all the notches 33 and divided into individual pellets 31.

According to the above embodiment, the following effects can be obtained. By vacuum-sucking the wafer fixing sheet attached to the semiconductor wafer in the peripheral portion of the semiconductor wafer, the stage for fixing the semiconductor wafer can be omitted, so that the surface of the semiconductor wafer does not come into surface contact with the stage. . This can prevent abrasion on the surface of the semiconductor wafer and adhesion of conductive foreign matter.

Further, since a conventionally used protective tape can be omitted, workability and economy can be improved.

Since the notch position of the semiconductor wafer is detected, and the push-up member is arranged immediately below the notch of the semiconductor wafer based on the detection signal, cleavage at a desired notch position can be performed accurately. No extra force is applied to the pellet. Therefore, cracking or chipping of the pellet can be prevented, and the yield can be improved.

FIG. 3 shows another embodiment 2 of the present invention. The second embodiment is different from the first embodiment as follows, and the other points are the same as the first embodiment.

The push-up unit 17 is mounted on the XY moving table 23, and is configured to be able to move along the direction of each of the notches 33 orthogonal to the semiconductor wafer 30. The push-up member 18 of the push-up unit 17 includes a main body 18a and a push-up needle 18b vertically supported by the main body 18a, and the tip of the upper end of the push-up needle 18b is pointed. The guide body 19 around the push-up member 18 is formed in an oval cylindrical shape. The suction pad 2 is provided on the upper surface of the guide body 19.
2 is buried and fixed in a ring shape, and a hole 21 connected to the vacuum source 10 is opened in the side wall.

When the semiconductor wafer 30 is cleaved, the push-up unit 17 is moved in accordance with the output of the light reflection type sensor 6 and is moved around one end of the notch 33 arranged at one end of the semiconductor wafer 30. The corresponding portion of the wafer fixing sheet 32 is vacuum-sucked to the push-up unit 17 via the suction pad 22 on the upper surface of the guide body 19 of the push-up unit 17.

Then, the push-up member 18 of the push-up unit 17 is raised, and the tip of the push-up needle 18 b locally pushes up one end of the notch 33 of the semiconductor wafer 30 from the back surface of the semiconductor wafer 30. At this time, the tip of the push-up needle 18b is raised to about half the thickness of the semiconductor wafer 30. From this state, the push-up unit 17 is moved along the notch 33 of the semiconductor wafer 30, and the push-up needle 18 b of the push-up unit 17 moves while rubbing the back surface of the semiconductor wafer 30. By the operation of the push-up needle 18b, the semiconductor wafer 30 is cleaved starting from the position of the notch 33.

Then, the push-up unit 17 is moved to one end of the notch 33 in the next row, and the semiconductor wafer 30 is cleaved starting from the notch 33 in the same manner as described above.

After all of the notches 33 in the same direction are cleaved, the notches 3 in the other direction are processed in the same manner as described above.
The semiconductor wafer 30 is also cleaved for No. 3.

As described above, the semiconductor wafer 30 is cleaved starting from all the notches 33 and divided into individual pellets 31 .

In the second embodiment, the push-up needle 18b is once pushed up and moved along the notch 33 while rubbing the back surface of the semiconductor wafer 30 in this state, so that the semiconductor wafer 30 is cleaved. However, the push-up needle 18b may be operated so as to push up a plurality of portions of the notch 33 at intervals.

FIG. 4 shows still another embodiment 3 of the present invention. The third embodiment is an example in which the guide body is omitted from the configuration of the first embodiment. This example can be used when the size of the pellet 31 is relatively large. That is, when the pellet 31 is large, even if the semiconductor wafer 30 slightly escapes upward due to the flexibility of the wafer fixing sheet 32 as the pushing-up member 8 is pushed up, the moment force starting from the notch 33 acts greatly. Therefore, the semiconductor wafer 30
Can be cleaved sufficiently. Therefore, when breaking a large pellet, the guide body 9 in the push-up unit 7 can be omitted.

Although the invention made by the present inventors has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the invention. Needless to say.

For example, the tip of the push-up plate 8b may be formed in a smooth circular arc shape in the width direction, or the tip of the push-up needle 18b may be formed in a smooth spherical shape.

As means for detecting the notch 33, a non-contact type position detecting means such as an image recognition device may be used instead of the light reflection type sensor.

In the above embodiment, the push-up units 7 and 17 are configured to move with respect to the wafer holding unit 1, but the wafer holding unit 1 is configured to move with respect to the push-up units 7 and 17. You can also.

In the above description, the invention made by the present inventor has been mainly described with respect to the case where a circular semiconductor wafer is divided vertically and horizontally, which is the field of application as the background. It is effective to use for dividing a semiconductor wafer on which the following pellets are formed.

[0057]

The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.

[0058] Since the surface of the semi-conductor wafer is held in a non-contact state, abrasions and to the surface of the semiconductor wafer, along with the deposition of the conductive foreign matter can be prevented, omit the protective tape which is conventionally used Can improve workability and economic efficiency. In addition, since an appropriate braking pressure can be applied to the cutout position of the semiconductor wafer, the semiconductor wafer can be divided well for each pellet.

[Brief description of the drawings]

FIG. 1 is a method for manufacturing a semiconductor device according to an embodiment of the present invention;
Shows a semiconductor wafer braking device used for
(A) is a top view, (b) is a bb line sectional view of (a).

FIG. 2 is an enlarged partial view at the time of braking.

Figure 3 shows a braking apparatus for a semiconductor wafer according to another embodiment of the present invention, (a) is a plan view, (b) is (a)
FIG. 3 is a sectional view taken along line bb of FIG.

Figure 4 shows a braking apparatus for a semiconductor wafer according to still another embodiment of the present invention, a line b-b sectional view of (a) is a plan view, (b) (a).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wafer holding unit, 2 ... Unit body, 3, 1
1, 21: holes, 4, 10: vacuum source, 5, 12, 22: suction pad, 6: light reflection sensor, 7, 17: push-up unit, 8, 18: push-up member, 8a, 18a: body, 8b ... thrust plate, 18b ... thrust needle, 9,
19: guide body, 13, 23: moving table, 30: semiconductor wafer, 31: pellet, 32: wafer fixing sheet, 33: notch.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/301

Claims (1)

(57) [Claims] 1. A step of forming a notch along a dividing line between pellets formed on a surface of a semiconductor wafer.
When the a step of holding the semiconductor wafer by a wafer fixing sheet which is attached to the back surface of the semiconductor wafer, the solid said wafer around the location where cleaving the semiconductor wafer
A step of vacuum suction constant sheet, the said semiconductor wafer through the wafer fixing sheet
The method of manufacturing a semiconductor device, characterized in that it comprises a step of cleaving the semiconductor wafer push-up by member pushing up the backside corresponding to notch position.