JP2000277550A - Semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent cut-off semiconductor devices from coming apart, by breaking a transfer mold resin left without being cut off into pieces of substrates to be processed. SOLUTION: A plurality of chips 2 are arranged at pitch P intervals on a continuous substrate 3a and are connected to the substrate 3a with wires 1. Thereafter, the plurality of chips 2 arranged on the substrate 3a are sealed by one operation with a transfer mold resin 4a. Next, the substrate 3a is turned over and the surface of the transfer mold resin 4 which is a reverse side is pressed against and placed on the upper surface of an adhesive tape 6. A laser beam is applied to a region 7 from the direction of the substrate 3a side to cut off the substrate 3a into pieces of substrates 3, and then to cut off the major portion of thickness of the transfer mold resin 4 which is left without being cut off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a plurality of CSPs (Chip Scale Packages) formed on a single substrate.
The present invention relates to a method for manufacturing a small semiconductor device such as a semiconductor device, and a structure of the semiconductor device.

[0002]

2. Description of the Related Art Various types of CSPs have been developed by LSI manufacturers in order to reduce the size and thickness of LSI packages, and to reduce the size of packages to almost the same outer size as the bare chip of the LSI. In particular, a method of manufacturing a CSP in which a chip is connected to a substrate by wire bonding, flip chip bonding, or the like, the chip is sealed with a resin, and then the chips are separated and separated into individual pieces is well known.

When individual chips are separated by separating the chips after resin encapsulation, the most efficient use of the substrate is to make the chip pitch on the substrate equal to the product outer size. In addition, since resin sealing is performed for each substrate, a mold for transfer molding and a dam for potting, which are necessary for each product, are not required, which leads to a reduction in manufacturing cost.

For example, as disclosed in Japanese Patent Application Laid-Open No. 9-36151, a plurality of chips mounted on a substrate are connected to a wiring pattern by wires, and a potting resin is uniformly applied over the entire surface of the substrate and the plurality of chips. After sealing with resin, the product is cut out for each product by a dicing saw or a laser beam, and the cut out outer surface is ground to provide a CPS manufacturing method with low cost.

However, it is generally known that the potting resin is limited in the material contained therein in order to ensure high flow characteristics, and it is difficult to improve the reliability as compared with a transfer mold resin which does not require high flow characteristics. ing. However, since the transfer mold resin has a higher silica (SiO ₂ ) content than the potting resin, there is a problem in that when cutting with a dicing saw, blade wear occurs in a shorter time.

Further, when a substrate to be resin-sealed is cut with a laser beam that can be cut without coming into contact with an object to be cut, the parts are not worn out, but the parts are separated by cutting. Since the products are scattered apart, stable handling in processes such as pickup and palletizing has been difficult. Further, there is a problem that it is difficult to handle and grind the processing time to grind the outer surface of the semiconductor device cut by cutting for each product.

[0007]

SUMMARY OF THE INVENTION The present invention is intended to provide a semiconductor device of a type in which a chip is resin-encapsulated by using a transfer mold resin which can easily secure reliability.
Even if a semiconductor device is singulated using a laser,
It is an object of the present invention to obtain a low-cost and stable technique, in which a cut-out semiconductor device is not scattered separately, a substrate area for mounting a chip can be effectively used, and a low-cost and stable technique can be obtained.

[0008]

A method of manufacturing a semiconductor device according to the present invention includes a step of mounting a plurality of chips on a substrate at a pitch corresponding to a product outer dimension of a semiconductor substrate; A step of introducing a transfer mold resin onto the substrate and encapsulating the chip in a lump; a step of attaching an adhesive sheet to the surface of the substrate to be processed on the side of the transfer mold resin; A region corresponding to the outer periphery is irradiated with a laser beam which is easily absorbed by the transfer mold resin from the substrate side, and a step of cutting the thickness of the substrate and the transfer mold resin to a large extent, by the laser beam irradiation In cutting the substrate to be processed, the transfer mold resin left uncut is broken. It is intended to include the step of singulating the substrate to be processed.

Further, in the method of manufacturing a semiconductor device according to the present invention, in the above-described manufacturing method, the transfer mold resin in a region corresponding to the outer periphery of the outer shape of the product which remains uncut after cutting the substrate to be processed by the laser beam. Is a film thickness that can be cut by a break.

Further, in the method for manufacturing a semiconductor device according to the present invention, in the above-described manufacturing method, the transfer mold resin in a region corresponding to the outer periphery of a product outer shape which is not cut after cutting the substrate to be processed by the laser beam. Is cut using a dicing saw.

Further, in the method for manufacturing a semiconductor device according to the present invention, in the above-mentioned manufacturing method, after the substrate to be processed is cut by the laser beam, the surface to be processed by the laser beam is subjected to chemical polishing before cutting into individual pieces. It is something to give.

Further, in the semiconductor device according to the present invention, in a semiconductor device in which one chip is mounted on a substrate and resin-sealed with a transfer mold resin, the plane size of the transfer mold resin is smaller than the plane size of the substrate. The larger one is formed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIGS. FIG.
FIG. 1 is a cross-sectional view of a singulated semiconductor device according to the present invention, in which one chip 2 is mounted on a substrate 3, both are connected by a wire 1, and the chip is resin-sealed with a transfer mold resin 4. Is shown. Further, on the surface of the substrate 1 on which the chip 2 is not mounted,
Solder balls 5 are arranged and formed.

Further, as shown in FIG. 1, if the planar dimension of the external shape of the individualized semiconductor device is L1 on the side of the transfer mold resin 4 not bonded to the substrate 3, The outer dimensions of the substrate 3 are L2 smaller than L1, and the same relationship holds when the same semiconductor device is viewed from different cross sections. The difference in size between the resin surface and the substrate surface of one semiconductor device is related to the manufacturing method thereof.
After resin sealing, most of the thickness of the substrate to be processed in the manufacturing process is cut from the substrate 3 side using a laser beam.

Next, a method of manufacturing a semiconductor device encapsulated with a transfer molding resin 4 as shown in FIG. 1 will be described with reference to FIG. First, FIG.
As shown in the figure, a plurality of chips 2 are arranged on a continuous substrate 3a.
Are arranged at intervals of a pitch P corresponding to the outer dimension L1, and are connected to the substrate 3a by the wires 1.

Thereafter, as shown in FIG. 2B, a plurality of chips 2 arranged on the substrate 3a are collectively resin-sealed using the transfer mold resin 4. In the resin sealing step, by using a transfer mold resin whose material is suitable for resin sealing, reliability can be improved as compared with the case where a potting resin is used.

Next, as shown in FIG. 2C, the substrate to be processed in the manufacturing process is turned upside down so that the surface of the transfer mold resin 4 on the back side is placed on the upper surface of the adhesive tape 6. Press and paste. As the adhesive tape 6, a normal dicing tape is used. In addition,
Until the manufacturing process shown in FIG. 2B, the surface of the substrate 3a on which the chip 2 is mounted is illustrated as being on the upper side.
(C) In the subsequent steps, the surface of the substrate 3a on which the chips are not mounted is shown as the upper side in consideration of the adhesive stability such as the workability of attaching to the adhesive tape 6.

Thereafter, a laser beam is irradiated from the direction of the substrate 3a to the dotted line area shown in FIG. 2D, that is, the area corresponding to the outer periphery of the external dimensions of one semiconductor device. Is cut into individualized substrates 3,
Subsequently, the transfer mold resin 4 is further cut by a laser beam to cut most of the thickness. Reference numeral 7 indicating an arrow in the drawing indicates a laser beam irradiation direction, and reference numeral 7a indicates a laser cutting groove.

As the laser beam used for cutting, a laser beam having a large absorption to the transfer mold resin is suitable, and a laser beam having a large output is preferable in order to secure a processing speed. For example, a carbon dioxide laser is suitable. However, since the wavelength easily absorbed by the transfer mold resin can easily process the adhesive tape 6, the cutting by the laser beam only cuts most of the thickness of the transfer mold resin 4, and is not cut slightly. The remaining thickness is cut by a method such as a subsequent break. The thickness of the transfer mold resin that is left without being cut by the laser is a thickness that can be cut without damaging the product due to the break.

Needless to say, when high precision control is possible in the cutting by the laser beam, if the transfer mold resin 4 can be completely cut without damaging the adhesive tape 6, a subsequent break or the like will occur. Can be omitted.

Next, as shown in FIG. 2E, a force is applied by laser cutting the substrate to be processed so as to push up from below a groove formed in a region corresponding to the outer periphery of the external dimensions of the semiconductor device. That is, a force is applied to push up the laser cutting groove 7a along the breaking direction indicated by arrows 8a to 8c in the figure on the back side of the adhesive tape 6, and the transfer mold resin 4 remaining without being cut by the laser processing is applied.
Is broken to separate the semiconductor device. In addition,
The break can be performed a plurality of times in the order of, for example, 8a, 8b, and 8c, and the break can be performed by simultaneously applying a force to a plurality of locations.

Thereafter, as shown in FIG. 2 (f), the adhesive tape 6 is stretched and spread around, to increase the interval between the individualized semiconductor devices, and to perform processes such as pickup and palletizing. In the drawing, reference numeral 9 indicates the direction in which the adhesive tape is stretched. As described above, even after the semiconductor device is singulated by breaking, the semiconductor device is in a state of being adhered by the adhesive tape 6, and it is possible to prevent the semiconductor device from being scattered separately and to stably hold the semiconductor device. It becomes possible.

Further, when a semiconductor device is manufactured according to such a manufacturing method, a margin for discarding the continuous substrate 3a can be made as small as possible, and the substrate 3a can be used efficiently. Furthermore, the mold used for resin sealing may be shared, and the manufacturing cost may be reduced. Further, since the product after singulation can be held in a state of being attached to the adhesive tape 6, handling in the process after singulation can be stably performed.

Further, at the time of laser irradiation, a substrate such as air, for example, nitrogen, or a liquid such as water may be sprayed onto the laser processing surface to perform processing while removing processing soot generated by laser processing. Needless to say. Although the illustration of the solder balls 5 is omitted in FIG. 2, even if the solder balls 5 are arranged and formed at predetermined positions, it is possible to singulate by the same processing.

In the step of attaching the surface of the transfer mold resin 4 of the substrate to be processed and the adhesive tape 6 in the step shown in FIG. Although the example in which the adhesive is applied so as to be placed is shown, in consideration of the weight of the substrate to be processed and the adhesive strength of the adhesive tape 6, if the adhesive strength becomes sufficiently large with respect to the weight of the substrate to be processed, With the resin surface of the processing substrate facing upward, the adhesive surface of the adhesive tape 6 may be covered by pressing it from above, and the two may be adhered to each other, and the process may be shifted to a subsequent singulation process.

Embodiment 2 Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3A is an enlarged cross-sectional view centered on the laser cutting groove 7a when the substrate to be processed is cut by the laser beam in the first embodiment. As shown in this figure, a continuous substrate 3a is cut by a laser beam into a substrate 3a having a plane dimension corresponding to the external dimension L2, and further, the transfer mold resin 4a is also cut to form a laser cutting groove. 7
When a is formed, the carbide 10 adheres to the cut surface, and the laser processing surface is contaminated.

Then, after cutting by a laser beam, as shown in FIG. 3B, a chemical polishing liquid 11 such as an etching liquid is injected into a laser cutting groove 7a of a substrate to be processed and adheres to a processed surface. The carbide 10 and the processing surface are chemically polished. After that, by cleaning, the contaminants on the outer surface of the portion subjected to the laser processing are removed as shown in FIG.

Since the chemical polishing liquid 11 is injected so as to be in contact only with the laser cutting groove 7a, it does not affect the product and other places at all, and requires a small amount of polishing liquid. In FIG. 3, the description of the adhesive tape 6 is omitted. In this way, the laser-processed surface can be polished in a lump in a state where the products are not separated,
The outer surface can be easily cleaned at low cost.

It is also possible to adopt a method in which the substrate to be processed is attached to the adhesive sheet 6 after the chemical polishing, and the thickness of the transfer mold resin remaining without being cut by the laser processing is broken and then washed. .

Third Embodiment In the first and second embodiments, a slight thickness of the transfer mold resin 4a is reduced by irradiating a laser beam from a continuous substrate 3a constituting a substrate to be processed. A method was shown in which most of the remaining thickness was cut, and then the remaining thickness was cut by breaking. However, other than the break, it is also possible to use a dicing saw to cut a small thickness of the transfer mold resin 4a into individual pieces.

As described in the prior art, since the transfer mold resin contains more silica than the potting resin, there is a problem that the blade is greatly worn when all thicknesses are cut by a dicing saw. However, if the remaining transfer mold resin 4a is cut to a small thickness after cutting the substrate to be processed by the laser beam, the wear of the blade is small and the blade replacement cycle is set for a long time. And this problem can be solved.

Even when individual semiconductor devices are obtained by using a dicing saw, scattering of products can be suppressed because the semiconductor devices are adhered by the adhesive tape, and a stable handling operation can be performed. It goes without saying that, similarly to the above-described embodiment, the effect of reducing the amount of discarding of the substrate 3a can be obtained.

[0033]

According to the method of manufacturing a semiconductor device according to the present invention, a small-sized semiconductor device sealed with a resin using a transfer mold resin can be manufactured at low cost. Also,
Since the transfer molding resin is used for the resin encapsulation, reliability can be ensured due to the difference in the material, as compared with the case where the potting resin is used.

Further, after a plurality of chips arranged on a continuous substrate are collectively sealed with a resin, the resin surface is attached to an adhesive tape, and then cut by a laser beam, Since singulation is performed in combination with cutting with any of the dicing saws, the semiconductor device after singulation is adhered to the adhesive tape without being scattered separately. Therefore, a stable handling process can be performed even after the singulation, and the discarding amount of the substrate can be suppressed as small as possible.

Further, the method of manufacturing a semiconductor device according to the present invention includes a step of cutting a substrate to be processed by a laser beam and then removing a carbide generated by the processing by a chemical polishing process. Thus, the laser processing surface can be cleaned.

Further, in the semiconductor device according to the present invention, the substrate to be processed, which has been sealed with the transfer mold resin as described above, is cut from the substrate side by a laser beam, and is cut by a break or a dicing saw. In this case, the transfer molding resin is formed so as to have a larger planar dimension than the planar dimension of the substrate. Therefore, efficient use of the substrate is possible, and low-cost manufacturing is possible. Further, the reliability of the product can be improved as compared with the case where a potting resin is used.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of an individualized semiconductor device according to a first embodiment of the present invention;

FIG. 2 is a diagram showing a method of manufacturing the semiconductor device according to the first embodiment of the present invention in the order of steps.

FIG. 3 is a diagram showing a method of manufacturing a semiconductor device according to a second embodiment of the present invention in the order of steps.

[Explanation of symbols]

1. wire, 2. chip, 3, 3a. Substrate, 4, 4
a. Transfer molding resin, 5. Solder ball, 6. Adhesive tape, 7. Laser beam irradiation direction, 7
a. Laser cutting groove, 8a-8c. Break direction, 9. Adhesive tape stretching direction, 10. Carbide, 11. Chemical polishing liquid.

Claims (5)

[Claims] A step of mounting a plurality of chips on a substrate at a pitch corresponding to the external dimensions of a semiconductor device; introducing a transfer mold resin onto a substrate to be processed on which the chips are mounted; Encapsulating the resin, attaching an adhesive sheet to the surface of the substrate to be processed on the side of the transfer mold resin, absorbing the transfer mold resin into a region corresponding to the outer periphery of the product outer shape of the substrate to be processed. A step of irradiating a laser beam that is likely to be emitted from the substrate side and cutting the thickness of the substrate and the transfer mold resin, and cutting the substrate to be processed by the irradiation of the laser beam, is left uncut. Breaking the transfer mold resin to singulate the substrate to be processed. Semiconductor device manufacturing method. 2. The method according to claim 1, wherein the thickness of the transfer mold resin in a region corresponding to the outer periphery of the outer shape of the product which has not been cut after cutting the substrate to be processed by the laser beam is set to a thickness that can be cut by a break. The method for manufacturing a semiconductor device according to claim 1, wherein: 3. The method according to claim 1, wherein, after the substrate to be processed is cut by the laser beam, the transfer mold resin in an area corresponding to the outer periphery of the product outer shape that has not been cut is cut using a dicing saw. The manufacturing method of the semiconductor device described in the above. 4. The method for manufacturing a semiconductor device according to claim 1, wherein after the substrate to be processed is cut by the laser beam, the surface to be processed by the laser beam is subjected to a chemical polishing treatment before the substrate is separated. . 5. A semiconductor device having one chip mounted on a substrate and resin-sealed with a transfer mold resin, wherein the transfer mold resin has a larger planar dimension than the substrate. A semiconductor device characterized by the above-mentioned.