JPH05291397A - Manufacture of collet and semiconductor device - Google Patents

Abstract

PURPOSE:To facilitate the handling of a very thin chip and increase its reliability by applying a sheet to the active surface side of a semiconductor integrated circuit substrate and polishing the rear surface thereof. CONSTITUTION:A cut groove 2 of a predetermined depth from the active surface side of a semiconductor substrate 1 is formed along the divided line of a semiconductor device on the surface of a semiconductor integrated circuit substrate (semiconductor substrate) 1. In addition, after a fixing sheet 3 is applied to the active surface side, the semiconductor substrate 1 is polished from the rear surface side up to the cut groove 2 in such manner that individually divided semiconductor integrated circuit chips are obtained. Furthermore, the application of the sheet 3 is performed through a ultraviolet hardening type adhesive. Even after divided, the sheet 3 remains in one body to protect the chips on the whole until they are separated from the sheet 3 to facilitate its handling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a collet and a semiconductor device, and more particularly to dicing a thin chip,
The present invention relates to a collet and chip transport using the collet.

[0002]

2. Description of the Related Art In recent years, in the field of semiconductor integrated circuits, densification and integration of elements have been promoted, and the miniaturization of elements has been progressing.

Such a semiconductor integrated circuit device is usually
A large number of integrated circuits are made on a semiconductor substrate such as a silicon substrate, after completion, it is divided into semiconductor integrated circuit chips, and these semiconductor integrated circuit chips are mounted on a mounting member such as a lead frame or film carrier, It is formed by sealing with resin or the like.

The process of dividing this integrated circuit board into semiconductor integrated circuit chips is usually performed as follows.

As shown in FIG. 18 (a), a fixing sheet 3 is attached to the back surface of the semiconductor integrated circuit board 1 via an adhesive layer 4, the semiconductor integrated circuit board 1 is mounted on a suction stage, and the suction hole is inserted. By vacuum suction, the semiconductor integrated circuit board 1 is fixed to the suction stage.

Then, the thin-blade cutter is scanned while aligning with the TV camera to sequentially cut the semiconductor integrated circuit board 1 to a half depth as shown in FIG. 18 (b), or as shown in FIG. 18 (c). As described above, the semiconductor integrated circuit chip 6 is completely cut.

After being divided in this way, it is conveyed to the mounting line.

Such a method for dividing a semiconductor integrated circuit board can be used when the semiconductor integrated circuit chip is easy to handle and there is no risk of damage, but the ultrathin semiconductor integrated circuit board remains the same. The shape may be too thin and may be damaged during transportation. Therefore, the conventional method has a problem that the manufacturing yield of an extremely thin semiconductor integrated circuit chip is low.

Incidentally, when mounting such a semiconductor integrated circuit element on a lead frame, tweezers or collet is usually used.

When tweezers are used, as shown in FIGS. 19 (a) and 19 (b), several mount agents (adhesives) are applied to the semiconductor element mounting portion of the lead frame, and the chip 5 is tweezers 13. Then, lift it up so that the back side will adhere to the applied mount agent. The applied mount agent is crushed on the back surface of the chip, and the chip is moved up and down or left and right so that the entire back surface can be painted.

Most of the heat generated in the chip flows from the back surface of the chip to the package through the mount material. Therefore, in order to make this heat dissipation as high as possible, it is necessary to make the mount agent as thin as possible, and it is necessary to have good wettability so that air bubbles are not contained in the mount agent.

However, in a mount using tweezers, if the thickness is reduced, excessive force may be applied and the tweezers may hit the edge portion of the chip.

Therefore, as a method of mounting without contacting the edge portion, there is a method of using a flat collet 14 as shown in FIGS. 20 (a) and 20 (b).

According to this method, the surface of the chip is directly adsorbed by vacuum and placed on the mount agent coated with the chip, and the surface is lightly pressed with a flat collet. With this method, the wettability and the thickness of the mounting agent are much more reliable than those with tweezers.

However, a problem in the mounting method using the flat collet is to directly touch the surface of the chip 5. In this way, the flat collet directly inserts the tip 5
Since the surface of the chip is touched, if dust is attached to the contact surface of the flat collet, or if the chips of the silicon substrate are clogged, they may directly hit the chip surface, causing dust to be attached or scratched. This may cause the performance of the semiconductor chip to be significantly reduced. Therefore, there is a problem that this method cannot be used particularly in the case of a semiconductor chip having no protective film on the surface.

Therefore, as shown in FIG. 21, there has been proposed a method using a corner cone collet 15 which can be mounted without contacting the chip surface. in this way,
The taper of the collet 15 is formed in accordance with the chip 5, and the collet 15 is surrounded in four directions so that the edge of the chip is touched. It is used so that it projects about 1/2. Since such a corner cone collet hits the edge of the chip, it has no effect on the surface,
Since it corresponds to one size chip and one collet, there is a problem that a collet is required for each size.

Therefore, as shown in FIG. 22, a collet 1 constructed so as to contact two opposite sides of the chip.
There is 7. In this case, since only one side facing each other is managed, it has applicability unlike the corner cone collet. The function of the collet is the same as that of the square-corner collet.

However, when the chip 5 is cut by dicing, scraps of the silicon substrate remain at the cut portions, and the scraps of the silicon substrate are displaced toward the pattern side of the chip 5 due to the taper of the collets 15 and 17. The surface of the chip 1 is soiled. Chips such as solid-state image sensors may malfunction if dust or dirt adheres to the surface,
May be adversely affected.

Although there has been a problem with the silicon scrap generated during the dicing, the tweezers 13
When mounting using the flat collet 14 or the flat collet 14, there was no relation to the edge portion of the chip, so the problem was small.

However, with the use of the square-corner collet 15 and collet 17, scraps of the silicon substrate which are broken by the taper of the collet poses a problem.

Further, in the bonding method using such a pyramidal collet, since it is adsorbed by vacuum to lift the element, it is used for a large and extremely thin semiconductor chip as shown in FIG. 22 (a). There is a problem that the tip 5 is broken by the suction force, or as shown in FIG. 22 (b), the tip 5 is detached from the pyramid collet with a slight angle shift.

[0022]

As the package, that is, the sealing resin layer is made thinner, the thickness of the chip greatly affects the thickness of the entire semiconductor device.
It is necessary to make the chip thinner.

Therefore, the chip is being made thinner,
As the chips are made thinner, the conventional dividing method has a problem that it is easily damaged during handling and the manufacturing yield is low.

Further, with the reduction in the thickness of such a chip, the collet used in the conventional mounting is in contact with the surface of the chip or the edge of the chip. In some cases, there is a problem that it cannot be used.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a highly reliable semiconductor device that facilitates the handling of ultrathin chips.

It is an object of the present invention to provide a method of dividing an ultra-thin chip with good yield from the substrate along the scribe line.

It is another object of the present invention to provide a collet which allows easy handling of ultrathin chips.

[0028]

Therefore, in the first aspect of the present invention, a kerf having a predetermined depth is formed on the surface of the semiconductor integrated circuit substrate along the dividing line of the semiconductor device from the active surface side of the semiconductor substrate. After further adhering a fixing sheet to the active surface side, the semiconductor integrated circuit substrate is polished from the back surface side until reaching the kerf, thereby obtaining individually divided semiconductor integrated circuit chips. ing.

Desirably, the sheet is adhered via an ultraviolet curable adhesive, and prior to peeling, the surface of the semiconductor integrated circuit substrate is irradiated with ultraviolet rays to cure the ultraviolet curable adhesive, and the sheet To make it easy to peel off.

In the second aspect of the present invention, an electromagnet for generating a magnetic force is provided at the tip to form a collet capable of generating and erasing a magnetic force.

In the third aspect of the present invention, a magnetic material region is formed on the active surface side or the back surface side of the semiconductor chip, and the magnetic material region is magnetically supported by a collet having an electromagnet for generating magnetic force at its tip. Then, it is transferred to a chip mounting area such as a lead frame or film carrier to erase the magnetic force.

[0032]

According to the first configuration, the sheet is attached to the active surface side of the semiconductor integrated circuit substrate and is polished from the back surface side. Therefore, as the semiconductor integrated circuit substrate becomes thinner, Since it is gradually divided into semiconductor integrated circuit chips, damage is greatly reduced.

Further, even after the sheet is cut, the sheet remains as a unit and is protected integrally until it is peeled from the sheet, which makes it easy to handle.

Then, the sheet is adhered through an ultraviolet curable adhesive, and before the peeling, the surface of the semiconductor integrated circuit substrate is irradiated with ultraviolet rays so that the ultraviolet curable adhesive is cured. As a result, the sheet is easily peeled off.

If the sheets are thus easily peeled off and the sheets are mounted on the lead structure one by one with the collet, the handling is extremely easy.

Further, in the second and third aspects of the present invention, since the collet is provided with an electromagnet to support the chip by magnetic force, even a large and thin chip can be firmly supported in a fine area. It does not require vacuum suction, so there is no risk of damage. Further, by making the magnitude of the magnetic force changeable as needed, the chip can be supported by a necessary suction force according to the size and thickness of the chip, and damage to the chip can be prevented. Furthermore, by forming the magnetic region by avoiding the back side of the chip or the element region, it is possible to maintain a very clean surface without contamination of the chip and improve the yield of semiconductor devices. ..

[0037]

Embodiments of the present invention will be described in detail below with reference to the drawings.

Example 1 FIG. 1 is a diagram showing a method for cutting a semiconductor integrated circuit board according to a first example of the present invention.

First, as shown in FIGS. 1 (a) and 1 (b), a thin blade cutter is used on the active surface side of the semiconductor integrated circuit substrate 1 such as a silicon IC having a thickness of about 600 μm, that is, on the side where the integrated circuit is formed. Depth 10 along the scribe line
A groove 2 of 0 μm is formed. That is, the integrated circuit board 1 is irradiated with light, the pattern of the scribe line formed on the circuit board 1 is displayed on the monitor TV using the infrared vidicon camera, and the height-adjusted thin-blade cutter is scanned while performing the alignment. , The groove 2 on the semiconductor integrated circuit substrate 1 in order
To form.

Thereafter, as shown in FIG. 2, a fixing sheet 3 made of a polyethylene or polyolefin film having a thickness of 80 μm is further attached to the active surface side of the substrate via an ultraviolet curing adhesive 4 having a thickness of 10 μm. Here, as the fixing sheet 3 and the UV-curable adhesive 4, an UV-curable dicing sheet of Lintec Co., which is called D-604MS and which is integrated with each other, was used.

Then, as shown in FIG. 3, polishing is carried out from the back surface of the substrate by mechanical polishing using silica powder until the groove 2 is reached. The fixing sheet 3R is attached to the back surface side of the semiconductor integrated circuit substrate 1 while being fixed. This fixing sheet 3R is also made of a polyethylene or polyolefin film having a thickness of 80 μm, like the fixing sheet 3 on the surface, and is adhered via an ultraviolet curable adhesive 4R. Then, as shown in FIG. 4, from the front surface side of the semiconductor integrated circuit substrate 1,
UV irradiation is performed.

Here, as shown in FIG. 5, the ultraviolet curable adhesive 4 is cured to change its state to 4P, the adhesive force is reduced, and the adhesive is easily peeled off. The sheet 3 is peeled off at once. Here, the adhesive strength of the ultraviolet curable adhesive of the fixing sheet 3R on the back surface is also reduced in the area exposed to light, but in this case, since it is UV irradiation from the front surface side of the substrate, that is, the side where the integrated circuit is formed. In a certain area of the chip wiring pattern, light is blocked, and the bonded state can be maintained. Then, as shown in FIG. 6, the back surface is fixed to the fixing sheet 3R and is conveyed to the mounting line.

Then, the fixing sheet 3R is extended, the interval between chips is increased, UV irradiation is performed again from the pasting surface, that is, the back surface side of the substrate, and the adhesive sheet is cured in the same manner. By the way, using collet 1
Transfer them one by one, position them on a lead frame or film carrier, and mount them.

Further, the sheet remains unintegrated without being divided, and the adhesive force of the fixing sheet can be reduced by UV irradiation, so that the fixing sheet can be easily peeled off.

Second Embodiment Next, a second embodiment of the present invention will be described.

FIGS. 7 (a) and 7 (b) are a rear view and a sectional view showing a collet used in the semiconductor mounted device of the second embodiment of the present invention.

This collet 21 has a magnetic field generator 22 at the tip.
It is composed of a cylindrical body with a coil 2 inside.
3 and is configured to be able to turn on and off the generation of the magnetic field via the switch 24.

FIG. 8 is a view showing an ultrathin semiconductor chip used here. The semiconductor chip 5 is provided with a nickel pattern 27 having the same size as the magnetic field generating portion 22 at the tip of the collet at the center of the active surface side 5a. The nickel pattern 27 is a magnetic field generating portion at the tip of the collet. It is characterized in that it is supported by the magnetic force from 22.

This nickel pattern can be easily obtained by leaving the nickel layer used in the step of forming the element region in a desired shape, but it may be formed separately.

Further, as shown in FIG. 9A, the magnetic material pattern 27s may be formed by coating method or selective plating.

As shown in FIG. 9 (b), a magnetic layer is formed on the back surface 5b of the semiconductor substrate by using a sputtering method or the like, and after applying a resist R, patterning is performed by photolithography to selectively remove the magnetic layer. Body pattern 2
7s may be formed.

Next, a method of mounting a semiconductor substrate on a lead frame using this collet will be described.

First, as shown in FIG. 10 (a), the fixing sheet 3 was diced in the same manner as in Example 1.
The collet 21 is positioned on the nickel pattern 27 of the divided semiconductor chip 5 fixed by (see Embodiment 1).

By the way, as shown in FIG. 10B, the switch 24 is turned on and the magnetic field is generated by the magnetic field generator 22.
The tip 5 is supported by the magnetic force of the collet.

Then, as shown in FIG. 10C, this chip is positioned on the lead frame 8, the switch 24 is turned off, the magnetic field is erased, and the chip is placed on the lead frame. Then, the pads on the chip and the leads are connected by wire bonding, and a semiconductor device is formed through a resin sealing step and the like.

According to this method, since the nickel pattern 27, which is the magnetic region of the chip, is supported by the magnetic flux from the magnetic field generating portion 22 at the tip of the collet,
There is no risk of damaging the element by applying no unnatural force to the element.

Further, since it is not necessary to replace the collet even if the size of the element changes, it is possible to cope with small-volume production of other products. Furthermore, since the tip is attracted to the collet by the magnetic flux at the tip of the collet, the degree of freedom in aligning the collet and the element is improved.

Although the magnetic field of the collet is only on and off in this example, the current flowing through the electromagnet may be made variable so that the magnitude of the magnetic flux can be changed according to the weight and strength of the chip.

Further, as shown in FIGS. 11A and 11B in another embodiment of the collet, two magnetic field generators 22a and 22a are provided.
b may be provided. At this time, the coils 23a and 23b need to be configured so that magnetic fluxes are generated in the same direction when a current is passed.

Next, another embodiment of the chip will be described.

In the above-mentioned embodiment, the nickel pattern is formed on the central portion of the active surface of the chip. However, if the nickel pattern is formed on the end portion of the chip as shown in FIG. 12, the circuit is shocked at the time of mounting. Can be prevented. 9 is a bonding pad.

Further, as shown in FIG. 13, the bonding pad 29 may be made of nickel. In this case, a semiconductor chip usable for the electromagnet collet can be formed without requiring an additional step.

Furthermore, as shown in FIG. 14, a nickel pattern 27 may be formed on the bonding pad 9. Although nickel patterns are formed on all the bonding pads 9 here, they may be formed on only a part of them.

Next, FIGS. 15A to 15C show a method of mounting using a chip in which the nickel pattern 27 is formed on the bonding pad 9.

In this example, a collet having the two magnetic field generators 22a and 22b shown in FIGS. 11A and 11B is used. The mounting method is the same as that shown in FIG.
The collet is well maintained without contacting the circuit forming surface of the chip.

Further, as shown in FIGS. 16 and 17, the nickel pattern 2 which is a magnetic material region is formed on the back surface side 5b of the chip.
7 may be formed. According to this method, the chip can be satisfactorily connected face down to the electrode wiring pattern on the mounting substrate 10 via the bump 28. This method has an effect that it can be mounted without contacting the active surface side of the chip.

As described above, when the collet according to the present invention is used in a semiconductor device mounting apparatus, the mounting work can be performed without contacting the collet in the operation area of the semiconductor chip, so that the chip surface cannot be touched. Alternatively, a highly reliable semiconductor device which can be used even in the case of a chip which dislikes dust can be provided.

[0068]

As described above, the first aspect of the present invention
According to, by forming a shallow groove along the scribe line on the active surface side of the semiconductor integrated circuit substrate, affixing the fixing sheet, and by polishing until reaching the groove from the back surface side,
Since the semiconductor integrated circuit chip is divided and the sheet is peeled off thereafter, the reliability of the ultrathin chip can be improved.

Further, according to the second and third aspects of the present invention, since the chip is supported by using the electromagnet, it can be used even in the case where the chip surface cannot be touched or the chip dislikes dust. Therefore, a highly reliable semiconductor device can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a cutting process of a semiconductor integrated circuit device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a method of cutting the semiconductor integrated circuit device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a step of cutting the semiconductor integrated circuit device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a step of cutting the semiconductor integrated circuit device according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a step of cutting the semiconductor integrated circuit device according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a step of cutting the semiconductor integrated circuit device according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a collet according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a semiconductor integrated circuit chip used in a second embodiment of the present invention.

FIG. 9 is a diagram showing a process of forming a semiconductor integrated circuit chip used in the second embodiment of the present invention.

FIG. 10 is a diagram showing a mounting process according to the second embodiment of the present invention.

FIG. 11 is a view showing a modified example of the collet according to the second embodiment of the present invention.

FIG. 12 is a diagram showing a modification of the semiconductor integrated circuit chip used in the second embodiment of the present invention.

FIG. 13 is a diagram showing a modification of the semiconductor integrated circuit chip used in the second embodiment of the present invention.

FIG. 14 is a diagram showing a modification of the semiconductor integrated circuit chip used in the second embodiment of the present invention.

FIG. 15 is a diagram showing a modification of the mounting process according to the second embodiment of the present invention.

FIG. 16 is a diagram showing a modification of the semiconductor integrated circuit chip used in the second embodiment of the present invention.

FIG. 17 is a diagram showing a modified example of the mounting process according to the second embodiment of the present invention.

FIG. 18 is a diagram showing a cutting process of a conventional semiconductor integrated circuit device.

FIG. 19 is a diagram showing a conventional tweezers.

FIG. 20 is a diagram showing a conventional collet.

FIG. 21 is a diagram showing a conventional collet.

FIG. 22 is a view showing a supporting state of a chip using a collet of a conventional example.

[Explanation of symbols]

 1 Semiconductor Integrated Circuit Board 2 Groove 3 Fixing Sheet 4 Adhesive Layer 3R Fixing Sheet 4R Adhesive Layer 5 Chip 6 Chip 8 Lead Frame 9 Bonding Pad 10 Substrate 27 Nickel Pattern

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location H01L 21/78 L 8617-4M Y 8617-4M (72) Inventor Masao Mochizuki Kawasaki, Kanagawa Prefecture Komukai-Toshiba-cho, Ltd. 1 Toshiba Research Institute, Ltd. (72) Inventor, Mamoru Sasaki, Kawasaki-shi, Kanagawa Kanako Komukai-Toshiba-cho 1, Ltd., Toshiba Research Institute, Ltd. (72) Inventor, Hiroshi Tazawa, Kouki-ku, Kawasaki, Kanagawa Muko Toshiba-cho 1 Co., Ltd. within Toshiba Research Institute (72) Inventor Hideo Ota Komu-Koshi, Kawasaki-shi, Kanagawa Komukai Toshiba-cho 1 Co. Ltd. within Toshiba Research Institute (72) Yasuhiro Yamaji Komukai-Toshiba, Kawasaki-shi, Kanagawa Machi 1 Toshiba Research Institute Co., Ltd. (72) Inventor Yoichi Hikita Komukai Toshiba-cho, Kouki-ku, Kawasaki City, Kanagawa 1 Toshiba Research Institute Co., Ltd.

Claims (3)

[Claims] 1. A step of forming an element region on a semiconductor substrate to form a large number of semiconductor devices, and a groove formation for forming a kerf having a predetermined depth from an active surface side of the semiconductor substrate along division lines of the semiconductor devices. Step and a sheet attaching step of attaching a fixing sheet to the active surface side of the semiconductor substrate, a polishing step of polishing the semiconductor substrate from the back surface side until reaching the kerf, and peeling from the sheet, And a mounting step of mounting the semiconductor device on a lead structure including a plurality of leads. 2. A collet comprising: a collet body; and a magnetic field generating section composed of an electromagnet arranged at the tip of the collet body, and a switching means for generating and erasing the magnetic force of the magnetic field generating section. 3. A step of generating a magnetic field by bringing a magnetic field generating section of a collet having a magnetic field generating section made of an electromagnet at its tip to approach a magnetic body region formed on the active surface side or the back surface side of a semiconductor chip, and the magnetic field. A step of supporting the magnetic body region of the semiconductor chip by a magnetic force by the generating unit and carrying the magnetic substance region to the semiconductor chip mounting region; and a step of erasing the magnetic field of the magnetic field generating unit and releasing the semiconductor chip from the collet. A method for manufacturing a semiconductor device, comprising: