JPH0817767A - Braking method and device of semiconductor wafer - Google Patents

Abstract

PURPOSE:To provide the braking technology of a semiconductor wafer which can accurately achieve braking without damaging' a pellet. CONSTITUTION:A wafer fixing sheet 32 which is applied to the reverse side of a semiconductor wafer 30 is subjected to vacuum suction to retain the semiconductor wafer and a thrust-up roller 18 is thrusted up to the part of a cutout 33 from the direction of the reverse side of the semiconductor wafer for cleaving the semiconductor wafer while both sides of the cutout 33 being formed on a split line between pellets 31 on the surface of the semiconductor wafer are pressed by a press member 11. Therefore, since the cutout part can be thrust up while both sides of the cutout of the semiconductor wafer are pressed by the press member, a cleavage force can be efficiently applied to only the cutout part without influencing the pellet other than the cleavage position and hence suppressing the damage of the pellet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer having a wafer fixing sheet adhered thereto and a plurality of semiconductor pellets (hereinafter,
It is called pellet. The present invention relates to a breaking technique for dividing a semiconductor wafer into individual pellets in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art A semiconductor device manufacturing process includes a pre-process in which a semiconductor integrated circuit and an optical semiconductor circuit are formed on the surface of a semiconductor wafer, and a semiconductor wafer is divided into pellets and then assembled into a lead frame or the like. Further, after the pellets are electrically connected, a subsequent step of resin sealing or the like is performed.

Generally, in the subsequent step of the manufacturing process of the semiconductor device, the step of dividing the semiconductor wafer into pellets is carried out by the following work.

First, in order to prevent the divided pellets from being dispersed, a wafer fixing sheet made of synthetic resin is attached to the back surface of the semiconductor wafer. Next, this semiconductor wafer is divided into individual pellets.

That is, using a diamond blade,
The following or alternatives are implemented. A cut is made up to about half the thickness of the semiconductor wafer (half dicing method). Some cutting is left in the thickness direction of the semiconductor wafer (semi-full dicing method). Completely cut and separate (full dicing method).

Alternatively, using a diamond tool, the following is performed. A relatively shallow notch is linearly added to the surface of a semiconductor wafer (scribing method).

In the above methods (1) to (3), the full dicing method does not require a braking process. However, this method is disadvantageous in that the cutting time is longer than other methods, and therefore, the method of or is often used.

Therefore, by the above or method,
A notch is formed on the surface of the semiconductor wafer, and then, using the added notch as a starting point, cleavage between the pellets of the semiconductor wafer in the crystal axis direction is performed, and braking for separating into individual pellets is performed. The task called is then carried out.

Conventionally, in this braking work, a semiconductor wafer is placed on a stage having an appropriate hardness such as a rubber plate with the cutout surface facing down, and rubber, metal, plastic, etc. are applied from the rear surface direction of the semiconductor wafer. The roller made of the material is pressed and rubbed while applying an appropriate pressure.

Note that Japanese Patent Publication No. 2-59636 and Japanese Patent Publication No. 2-60076 are examples of this type of braking method.

[0011]

However, the present inventor has clarified that the following problems occur in the conventional braking method.

In the method using a stage such as a roller and a rubber plate, the force is not efficiently transmitted to the notch portion to which a true force is to be applied, and an excessive force is applied to the pellet of the semiconductor wafer to May cause damage.

The above tendency becomes more remarkable as the size of the pellet becomes smaller, and in some cases, a crack residue is generated.

[0014] In order to completely divide this, if the roller rolling is further continued, the already broken pellets come into contact with each other, and damage such as cracking or chipping tends to occur frequently.

As a conventional measure, by changing the roller diameter according to the size of the pellet, the curvature of the local deformation applied to the semiconductor wafer is made smaller as the size of the pellet becomes smaller. There was a limit due to the difficulty of the holding method. In particular, when dividing into pellets of 1 mm square or less, the pellets are often damaged, which has been a problem.

It is an object of the present invention to provide a braking technique for a semiconductor wafer, which enables accurate braking without damaging the pellet.

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

[0018]

The typical ones of the inventions disclosed in the present application will be outlined below.

That is, a semiconductor wafer in which a wafer fixing sheet having a size larger than that of the semiconductor wafer is attached to the back surface of the semiconductor wafer, and notches are formed on the surface of the semiconductor wafer along the dividing lines between the pellets. In a method for breaking a semiconductor wafer in which a wafer is divided into individual pellets, a wafer fixing sheet portion around the semiconductor wafer is vacuum-sucked to hold the semiconductor wafer, and both sides of a cutout on the surface of the semiconductor wafer are held. The semiconductor wafer is cleaved by relatively pushing up the push-up member from the back surface direction of the semiconductor wafer to the position of the notch in the state where the pressing member is in contact.

[0020]

According to the above-mentioned means, the push-up member is pushed up relatively to the position of the notch while the pressing member is in contact with both sides of the notch formed on the surface of the semiconductor wafer. Since the semiconductor wafer is cleaved, the cleaving force can be efficiently applied only to a desired cutout portion without affecting other cutout portions or pellets. As a result, damage such as cracking or chipping of the pellet can be suppressed.

[0021]

1 is a plan view of a semiconductor wafer braking apparatus according to an embodiment of the present invention, and FIG. 1B is a sectional view taken along line bb of FIG. FIG. 2 is an enlarged partial view during braking.

A semiconductor wafer, which is a workpiece of the braking device according to this embodiment, is manufactured by the following work in the previous process. First, a part of the semiconductor wafer 30 is cut away to form a flat surface (orientation flat).
It is formed in a substantially disc shape having 30a, and a transistor, a diode, a semiconductor integrated circuit, an optical semiconductor circuit, or the like is formed in each pellet 31. Note that FIG. 1 (a)
In the figure, only the upper half of the semiconductor wafer 30 is displayed.

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 an elastic material such as synthetic resin,
It is formed in a circular thin film shape having a diameter larger than that of the semiconductor wafer 30, and an appropriate adhesive is applied to one surface thereof. As the sheet base material, for example, a vinyl chloride sheet or a polyester sheet is generally used.

Then, a method such as dicing or scribing is used to form a notch 33 on the dividing line between the pellets 31 on the surface of the semiconductor wafer 30. In this embodiment, a plurality of rows of cutouts 33 are formed on the surface of the semiconductor wafer 30 in a grid pattern, and the depth of the cutouts 33 is set to approximately half the thickness of the semiconductor wafer 30.

The semiconductor wafer breaking apparatus according to this embodiment includes a wafer holding unit 1, and the unit main body 2 is composed of an annular disc 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. . An on-off valve 4a is provided in a connection circuit to the vacuum source 4, and the vacuum connection and disconnection are performed by the valve 4a. A suction pad 5 is embedded and fixed in a ring shape on the lower surface of the unit body 2.
The wafer fixing sheet 32 around the semiconductor wafer 30 is vacuum-adsorbed via the
0 is held by the unit main body 2.

At the upper position in the wafer holding unit 1,
A light reflection type sensor 6 is installed. The two sensors 6 are provided at regular intervals, and are configured to detect the flat surface 30a serving as the reference position of the semiconductor wafer 30 or the notch 33 on the same straight line.

A sheet stretching unit 7 is provided at a lower position in the wafer holding unit 1, and its unit main body 8 is composed of an annular disc member. The lower surface of the unit main body 8 is supported by an appropriate vertical movement means 9 such as an air cylinder or a spring so as to be vertically movable. The lower end portion of the vertical movement means 9 is supported on a rotary table 10. ing. The sheet stretching unit body 8 is arranged concentrically with the wafer holding unit body 2, and its outer diameter is smaller than the inner diameter of the wafer holding unit body 2 by the thickness of the wafer fixing sheet 32. Therefore, when the sheet stretching unit body 8 rises into the wafer holding unit body 2, the portion of the wafer fixing sheet 32 where the semiconductor wafer 30 is not fixed rises from the lower surface of the wafer holding unit body 2 of the sheet stretching unit body 8. Be stretched. The semiconductor wafer 3
The tension is also applied to the wafer fixing sheet 32 portion to which 0 is fixed, but the wafer fixing sheet 32 portion to which the semiconductor wafer 30 is fixed is stretched due to the adhesive force between the semiconductor wafer 30 and the wafer fixing sheet 32. There is no such thing.

A pressing member 11 is provided in the wafer holding unit body 2. The pressing member 11 includes a horizontally elongated rectangular plate-shaped body 11a having a rectangular cross section, and a pair of support plates 11b vertically provided on the upper surfaces of both ends thereof. It has a slightly longer length. This pressing member 11 is
Bearings 12 are attached to the portions of the respective support plates 11b, and these portions of the support plates 11b are denoted by X- which will be described later.
The pair of support arms (not shown) extending from the Y-moving table 19 are rotatably held by the tips thereof. Since the pressing member 11 is rotatably supported, it is considered that the deformation of the semiconductor wafer 30 at the time of cleavage of the semiconductor wafer 30 described later can be absorbed. In addition, the support arm of the pressing member 11 is configured to be vertically movable by an appropriate means.

A slit 13 is formed in the elongated plate-like body 11a of the pressing member 11 over substantially the entire length in the longitudinal direction, and a lower portion of the slit 13 has a tapered portion 13a whose width gradually increases toward the lower surface side. Has been formed. This slit 13 is a push-up unit 1 described later.
7 forms a relief for lifting the wafer cleaved portion when the semiconductor wafer 30 is cleaved. The widths of the slit 13 and the taper portion 13a are preferably changed according to the size of the pellet 31.

Above the wafer holding unit 1, a supply roll 15 around which a non-adhesive protective tape 14 is wound,
A winding roll 16 for winding the tape is provided separately from each other, and the supply roll 15 and the winding roll 16 are provided.
The protective tape 14 that hangs down in between is configured to cover and protect the surface of the semiconductor wafer 30 fixed to the wafer fixing sheet 32 when the semiconductor wafer 30 is cleaved.

Therefore, when the semiconductor wafer 30 is cleaved, the pressing member 11 descends and abuts on the surface of the semiconductor wafer 30 via the protective tape 14 to hold the pressing member 11.
One row of notches 33 among the plurality of rows of notches 33 formed on the surface of the semiconductor wafer 30 in the slit 13 of
Are arranged so as to face.

The protective tape 14 is constructed so that after the semiconductor wafer 30 is cleaved, the used tape is wound up by the winding roll 16 in order.

A push-up unit 17 is provided in the main body 8 of the sheet stretching unit.
7 has a push-up roller 18 on the upper part. The push-up roller 18 is horizontal and is arranged in the same direction as the pressing member 11. The push-up unit 17 is configured to be vertically movable by an appropriate means, and the push-up roller 18 is set to have a length slightly longer than the diameter of the semiconductor wafer 30.

The push-up unit 17 is mounted on the XY moving table 19, and the pressing member 11 is connected to the XY moving table 19 by the supporting arm so as to be vertically movable as described above. The push-up roller 18 of the push-up unit 17 is arranged immediately below the slit 13 provided in the pressing member 11, and the push-up member 11 and the push-up unit 17 have a moving table 19.
Move together and rotate together by the turntable 10.

Further, the position of the notch 33 from the flat surface 30a, which is the reference position of the semiconductor wafer 30, is calculated based on the notch position design data inputted in advance, and the push-up unit 17 is sequentially positioned immediately below the notch position. The semiconductor wafer 30 is moved by the moving table 19 and pushed up at the positions of the notches 33, and the semiconductor wafer 30 is cleaved and divided into individual pellets 31.

Next, a description will be given of a semiconductor wafer braking method in which the semiconductor wafer braking device having the above-described structure is used to divide the semiconductor wafer 30 as a workpiece manufactured as described above into individual pellets 31. To do.

First, the semiconductor wafer 30 is arranged 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.
A part of the wafer holding unit main body 2 via the suction pad 5
Is vacuum-adsorbed on the lower surface of the.

Next, by the pair of light reflection type sensors 6,
The flat surface 30a serving as the reference position of the semiconductor wafer 30 is detected. Then, based on the outputs of both sensors 6, the slit 13 of the pressing member 11 and the push-up roller 18 of the push-up unit 17 cause the flat surface 30 a of the semiconductor wafer 30 to move.
The rotary table 10 is rotated so as to be arranged in parallel with respect to, and the θ alignment is performed.

Next, the position of the notch 33 from the flat surface 30a which is the reference position of the semiconductor wafer 30 is calculated based on the notch position design data inputted in advance, and the push-up unit 17 is moved to the first position of the notch 33. Table 1
The push-up roller 18 is moved to the position directly below the row of the notches 33. At this time, the pressing member 11 is also moved together with the push-up unit 17, so that the row of the notches 3 is arranged directly below the slit 13 of the pressing member 11 and directly above the push-up roller 18.
3 is arranged.

Next, the sheet stretching unit body 8 is lifted in the wafer holding unit body 2 by a predetermined height. As a result, the portion of the wafer fixing sheet 32 to which the semiconductor wafer 30 is not fixed is stretched by the amount of rise of the sheet stretching unit body 8 from the lower surface of the wafer holding unit body 2, and the wafer fixing sheet 32 is given tension. Held in a state.

Next, the pressing member 11 descends and comes into contact with the surface of the semiconductor wafer 30. In this state, the slits 13 of the pressing member 11 are arranged so that one row of the notches 33 formed on the surface of the semiconductor wafer 30 face each other, and are pressed against the surface portions of the semiconductor wafer 30 on both sides of the notches 33. The lower surface of the member 11 contacts.

Next, the push-up unit 17 is raised,
The push-up roller 18 pushes up the notch 33 of the semiconductor wafer 30 from the back surface of the semiconductor wafer 30. At this time, the push-up roller 18 is raised to about half the thickness of the semiconductor wafer 30. By pushing up the push-up roller 18, the semiconductor wafer 30 is cleaved starting from the position of the notch 33.

At this time, the push-up unit 17 pushes up the portion of the notch 33 while the pressing member 11 is in contact with both sides of the notch 33 formed on the surface of the semiconductor wafer 30, so that the semiconductor wafer 30 is lifted. Since the cleavage is performed, the cleavage force can be efficiently applied only to the portion of the notch 33 other than the cleavage position or the portion of the notch 33 at the cleavage position without affecting the pellet 31 and cracks or chips of the pellet 31. The damage of can be suppressed.

Further, since the pressing member 11 is rotatably supported, the deformation of the semiconductor wafer 30 due to the push-up of the push-up unit 17 can be absorbed.

Further, in the equilibrium state between the tension applied to the wafer fixing sheet 32 by the sheet stretching unit 7 and the force due to the adhesive force between the semiconductor wafer 30 and the wafer fixing sheet 32, the notch 33 is cleaved. Since the wafer fixing sheet 32 portion at the position of the cleaved notch 33 extends because it is partially broken at a time point, the pellet 31 row and the pellet 31 row arranged on both sides of the cleaved notch 33 position There is a gap between them. Therefore, during the cleaving operation of the notch 33 in the next row, it is possible to prevent the adjacent pellet 31 rows at the cleaved position from coming into contact with each other.

In the above, if the amount of push-up of the push-up roller 18 is too large, the cleaved pellet 31 abuts the adjacent pellet, causing chipping. Also, if the thrust amount is insufficient, it will not cleave.

Next, the pressing member 11 is raised, the push-up unit 17 is lowered, and the push-up unit 17 and the pressing member 11 are moved to the next position based on the notch position calculated based on the notch position design data input in advance. It is moved to the position of the row notch 33 by the moving table 19. Then, by repeating the above operation, the semiconductor wafer 30 is cleaved from the notch 33 as a starting point.

After all 33 rows of notches in the same direction are cleaved, the pressing member 11 and the push-up unit 17 are rotated 90 ° by the rotary table 10, and the 33 rows of notch in the other direction are sequentially cleaved in the same manner as described above. To be done.

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. Since the semiconductor wafer 30 is cleaved by the push-up unit 17 being pushed up to the cutout 33 while the pressing member 11 is in contact with both sides of the cutout 33 formed on the surface of the semiconductor wafer 30, the cleavage position is set. It is possible to efficiently apply the cleavage force only to the portion of the notch 33 at the cleavage position without affecting the other portions of the notch 33 or the pellet 31 and suppress damage such as cracking or chipping of the pellet 31.

Since the pressing member 11 is rotatably supported, the deformation of the semiconductor wafer 30 due to the push-up of the push-up unit 17 can be absorbed.

Since tension is applied to the wafer fixing sheet 32 by the sheet stretching unit 7,
At the time of cleavage, the portion of the wafer fixing sheet 32 at the position of the cleaved notch 33 extends to separate the pellet 31 row and the pellet 31 row arranged on both sides of the cleaved notch 33 from each other. Therefore, during the cleaving operation of the notch 33 in the next row, it is possible to prevent the pellet 31 row and the pellet row 31 arranged on both sides of the cleaved notch position from coming into contact with each other.

Since the stage for fixing the semiconductor wafer 30 can be omitted by vacuum-sucking the wafer fixing sheet 32 attached to the semiconductor wafer 30, the surface of the semiconductor wafer 30 can be in surface contact with the stage. Disappears. As a result, it is possible to prevent scratches on the surface of the semiconductor wafer 30 and adhesion of conductive foreign matter.

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

For example, the tip of the push-up unit for pushing up the semiconductor wafer may not be a roller but may have a pointed shape with an inverted V-shaped cross section in the width direction, or the tip may be formed in a smooth arc shape.

Instead of the slit formed in the pressing member,
By forming a long groove having an inverted V-shaped cross section on the lower surface of the pressing member, it is possible to form a relief for lifting the wafer cleaved portion when the semiconductor wafer is cleaved by the push-up unit. The long groove having an inverted V-shaped cross section has an advantage that it is easier to manufacture a groove having a width smaller than that of the slit.

Further, the pressing member is not limited to one having a slit or the like formed in an integral member, but may be a pair of separate members that abut on both sides of the notch.

Instead of the light reflection type sensor, a non-contact type position detecting means such as an image recognition device can be used.

Further, in the above embodiment, the push-up unit is configured to move with respect to the wafer holding unit body, but it may be configured to move the wafer holding unit body with respect to the push-up unit.

In the above description, the invention made by the present inventor was mainly described in the case of dividing a substantially circular semiconductor wafer into the vertical and horizontal directions, which is the field of application which is the background of the present invention. Semiconductor element,
It is effectively used for dividing a semiconductor wafer on which a pellet of 2 mm or less such as a diode is formed.

[0061]

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

The wafer fixing sheet around the semiconductor wafer is vacuum-sucked to hold the semiconductor wafer, and the pressing member is brought into contact with both sides of the notch on the front surface of the semiconductor wafer. By relatively pushing up the push-up member to the notch position from the direction to cleave the semiconductor wafer, an appropriate braking pressure can be applied to the notch position of the semiconductor wafer. It can be divided well.

[Brief description of drawings]

1A and 1B show a braking device for a semiconductor wafer according to an embodiment of the present invention, FIG. 1A is a plan view, and FIG. 1B is a sectional view taken along line bb of FIG.

FIG. 2 is an enlarged partial view during braking.

[Explanation of symbols]

1 ... Wafer holding unit, 2 ... Unit body, 3 ... Hole,
4 ... Vacuum source, 4a ... Open / close valve, 5 ... Adsorption pad, 6 ... Light reflection type sensor, 7 ... Sheet stretching unit, 8 ... Unit body, 9 ... Vertical moving means, 10 ... Rotating table, 11 ... Pressing member, 11a ... elongated plate-like body, 11b ... support plate, 1
2 ... Bearing, 13 ... Slit, 13a ... Tapered part,
14 ... Protective tape, 15 ... Supply roll, 16 ... Winding roll, 17 ... Push-up unit, 18 ... Push-up roller, 19 ... XY moving table, 30 ... Semiconductor wafer,
30a ... Flat surface, 31 ... Pellet, 32 ... Wafer fixing sheet, 33 ... Notch.

Claims (3)

[Claims] 1. A wafer fixing sheet having a size larger than that of the semiconductor wafer is attached to the back surface of the semiconductor wafer, and
In a method of breaking a semiconductor wafer in which a notch is formed on a surface of a semiconductor wafer along a dividing line between pellets, the semiconductor wafer is divided into individual pellets. While holding the semiconductor wafer by vacuum suction and holding the pressing member on both sides of the notch on the front surface of the semiconductor wafer, the push-up member is relatively moved to the notch position from the rear surface direction of the semiconductor wafer. A method of breaking a semiconductor wafer, comprising pushing up to cleave the semiconductor wafer. 2. A wafer fixing sheet having a size larger than that of the semiconductor wafer is attached to the back surface of the semiconductor wafer, and
A semiconductor wafer breaking device for dividing a semiconductor wafer in which notches are formed along a dividing line between pellets on the surface of a semiconductor wafer into individual pellets, wherein a wafer fixing sheet portion around the semiconductor wafer is Wafer holding means for holding the semiconductor wafer by vacuum suction, and pressing means for abutting the pressing member on both sides of the cutout on the surface of the semiconductor wafer, and pressing both sides of the cutout portion when the pushup member relatively pushes up, And a push-up means for cleaving the semiconductor wafer by relatively pushing the push-up member from the back surface direction of the semiconductor wafer to the cut-out position, and the pressing member and push-up member are sequentially arranged at a plurality of cut-out positions of the semiconductor wafer. The plurality of cutout portions of the semiconductor wafer can be sequentially cleaved. A semiconductor wafer breaking device characterized by the following. 3. The wafer fixing sheet is made of a stretchable material, and is provided with tension applying means for applying a tension to the wafer fixing sheet fixed to the semiconductor wafer. Semiconductor wafer breaking device.