WO2004012247A1

WO2004012247A1 - Method for manufacturing semiconductor device

Info

Publication number: WO2004012247A1
Application number: PCT/JP2003/008906
Authority: WO
Inventors: Satoshi Bannai
Original assignee: Sony Corporation
Priority date: 2002-07-29
Filing date: 2003-07-14
Publication date: 2004-02-05
Also published as: JP2004063799A; TW200415718A

Abstract

A method for manufacturing a semiconductor device wherein an ultra-thin semiconductor chip having a thickness of 50 μm or less is properly picked up and mounted. A protective tape (42) for use in back grinding is adhered to a surface of a wafer (40), and back grinding, wafer mounting and dicing are conducted as it is. Accordingly, the protective tape (42) adhered to the surface of the chip improves the fracture-resistant property of the chip, thereby preventing the chip from cracking or breaking during the pick-up and chip-mounting steps. After the mounting, the protective tape (42) is removed from the surface of the chip.

Description

Method for manufacturing semiconductor device

Technical field

Light

The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of manufacturing a semiconductor device capable of picking up and mounting a semiconductor chip thinned by back grinding of a semiconductor wafer without damaging or damaging the semiconductor chip.

Background art

The demand for smaller and thinner electronic devices in recent years, thinning of a required has become conditions _{(semiconductor} chip product development of thinning the future that a component semiconductor chip. Conventionally, the element This is realized by the back grinding process of the semiconductor wafer where the pits are formed.

FIGS. 4A to 4G show a first conventional example for explaining various steps from the production of a thin semiconductor chip to the mounting thereof. This conventional example is the most general process, and is suitable mainly when the target value for thinning is a wafer thickness of 150 μm or more.

An adhesive protective tape 8 is attached to the surface (element formation surface) of the semiconductor wafer 10 on which the element is formed (FIG. 4A), and then the back surface of the semiconductor wafer 10 is ground using the grinding device 1. (Figure 4B). Then, after the protective tape 8 is peeled off from the surface of the semiconductor wafer 10 using the peeling tape 2 or the like (FIG. 4C), the semiconductor wafer 10 is mounted on the ring frame 3 via the adhesive dicing tape 9. (FIG. 4D), dicing saw 4 singulates semiconductor ゥ a wafer 10 (FIG. 4E). After dicing process, semiconductor The chip 11 is pushed up to the needle 5 and is sucked by the collet 6 at the same time (FIG. 4F), and is mounted on the lead frame 7 using the mounter 12 (FIG. 4G).

This method is applied to wafers with a wafer thickness of 150 μm or less, since the semiconductor wafer 10 may crack or chip during handling during the back grinding process to the dicing process. I can't do it.

—On the other hand, when the wafer thickness is reduced to 150 μm or less, the processes shown in the following second and third conventional examples are effective.

In the second conventional example, as shown in FIGS. 5A to 5G, a half-power dicing process for the surface of the semiconductor wafer 20 (FIG. 5A), and the application of the protective tape 8 to the surface of the semiconductor wafer 20 Process (Fig. 5B), grinding process of semiconductor wafer 20 back surface (Fig. 5C), wafer mounting process (Fig. 5D), peeling process of protective tape 8 (Fig. 5E), pick-up process of semiconductor chip 21 (Fig. 5F) and the chip mounting process (Fig. 5G).

Note that, in the figure, the same reference numerals are given to portions common to the first conventional example.

In this method, a semiconductor wafer 20 is individually formed by forming a groove at a depth corresponding to a target wafer thickness in an initial half-die dicing process, and thereafter performing back surface grinding to the groove. The semiconductor chip 21 is divided into two. Therefore, as compared with the first conventional example, cracking of the semiconductor wafer 20 at the time of the above-mentioned handling can be avoided, and the thickness can be reduced to 150 μm or less.

The semiconductor chip thinning process according to the second conventional example is disclosed, for example, in Japanese Patent Application Laid-Open No. 2002-16021.

Next, as shown in FIG. 6A and FIG. Affixing process of protective tape 8 to wafer 30 surface (阔 6A), grinding process of backside of semiconductor wafer 30 (Fig. 6B), wafer mounting process (Fig. 6C), peeling process of protective tape 8 (Fig. 6C) It consists of a dicing process (Fig. 6D), a semiconductor chip 31 pick-up process (Fig. 6F), and a chip mounting process (Fig. 6G).

In this method, by providing a step of peeling the protective tape 8 adhered to the surface of the semiconductor wafer 30 before the dicing step after the wafer mounting step, the semiconductor wafer 30 during the transportation from the back surface grinding step to the dicing step is provided. The protection tape 8 is used to prevent cracks and chips in the chip. As a result, a chip thickness of 150 m or less is realized.

The semiconductor chip thinning process according to the third conventional example is disclosed in Japanese Patent No. 2879797.

In the second and third conventional examples, the so-called needleless method is used in the pick-up process of the semiconductor chips 21 and 31. This is a method in which an ultraviolet-curing dicing tape 9 is used to pick up the semiconductor chips 21 and 31 while irradiating the dicing tape 9 with ultraviolet light to reduce the adhesive force. The semiconductor chips 21 and 31 can be prevented from being cracked or chipped as compared with the needle type pickup method used in the conventional example.

As described above, by employing the second and third conventional examples, the pickup step and the mounting step of a semiconductor chip thinned to 150 μm or less can be properly performed.

However, when the chip thickness becomes extremely thin, 50 μm or less, the die-resistant pick-up of the needleless method is required because the bending resistance of the semiconductor chip is extremely reduced. There is also a problem that the semiconductor chip may be broken at the time of pickup, depending on the method of picking up.

Also, even if the pickup is successful, there is a problem that the possibility that the semiconductor chip is broken during mounting is extremely high.

-In recent years, there has been a high demand for thinner or thinner semiconductor chips, and although semiconductor chips of the desired thickness can be manufactured, there is still no technology that can properly handle the manufactured semiconductor chips. It has not been established yet.

The present invention has been made in view of the above problems, and has as its object to provide a method of manufacturing a semiconductor device capable of appropriately picking up and mounting an ultra-thin semiconductor chip of 50 μm or less. Disclosure of the invention

In order to solve the above problems, the method for manufacturing a semiconductor device according to the present invention includes a protective tape attaching step of attaching a protective tape for grinding a back surface to the surface of the semiconductor wafer, and a grinding process for grinding the back surface of the semiconductor wafer to reduce the thickness. Back surface grinding process, dicing adhesive tape is applied to the back surface of the thinned semiconductor wafer, the dicing process is used to divide the semiconductor wafer into individual chips together with the protective tape, and the chips are picked up and transferred to the chip mounting section. And a protective tape separating step of separating the protective tape from the chip surface.

In the present invention, the dicing, pick-up, and chip mounting processes after grinding the back surface of the wafer are performed not with the chip alone, but with the protective tape attached, thereby reducing the bending resistance of the chip. Because of this, an ultra-thin semiconductor chip of 50 μηι or less can be picked up and mounted without damaging it. Preferably, a UV-curable tape material is used for the protective tape, and the protective tape is separated by irradiating UV rays to reduce the adhesive strength.

If a protective tape that has both UV curability and heat shrinkability is used, not only can the protective tape be separated and removed easily, but the protective tape can be separated and removed simultaneously with the chip mounting process. It becomes. BRIEF DESCRIPTION OF THE FIGURES

1A to 1H are perspective views illustrating a process for manufacturing a semiconductor device according to an embodiment of the present invention. 1A shows a protective tape attaching process, FIG. 1B shows a back surface grinding process, FIG. 1C shows a post process of the wafer back surface, FIG. 1D shows a wafer mounting process, and FIG. 1E shows a dicing process. 1F shows an ultraviolet irradiation step, FIG. 1G shows a pickup step, and FIG. 1H shows a chip mounting step.

FIG. 2 is a perspective view for explaining a manufacturing process of the semiconductor device according to the embodiment of the present invention, and shows a protective tape separating process.

FIG. 3 is a flowchart illustrating a manufacturing process of the semiconductor device according to the embodiment of the present invention.

4A to 4G are perspective views illustrating the steps of manufacturing the semiconductor device according to the first conventional example. 4A shows the protective tape attaching process, FIG. 4B shows the back surface grinding process, FIG. 4C shows the protective tape separating process, FIG. 4D shows the wafer mounting process, and FIG. 4E shows the dicing process. 4F shows a pick-up process, and FIG. 4G shows a chip mounting process.

5A to 5G are perspective views illustrating the steps of manufacturing a semiconductor device according to the second conventional example. FIG. 5A shows a half-cut dicing process, FIG. 5B shows a protective tape attaching process, FIG. 5C shows a back surface grinding process, FIG. 5D shows a wafer mounting process, and FIG. 5E shows a protective tape separating process. Show, FIG. 5F shows a pickup process, and FIG. 5G shows a chip mounting process.

6A to 6G are perspective views illustrating the steps of manufacturing a semiconductor device according to a third conventional example. FIG. 6A shows a protective tape attaching process, FIG. 6B shows a back surface grinding process, FIG. 6C shows a wafer mounting process, FIG. 6D shows a protective tape separating process, and FIG. 6E shows a dicing process. FIG. 6F shows a pick-up process, and FIG. 6G shows a chip mounting process. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1A to 3 show an embodiment of the present invention.

Here, FIGS. 1A to 1H are perspective views schematically illustrating each step of the present embodiment, FIG. 2 is an explanatory view of a chip mounting step, and FIG. 3 is a process flow diagram of the present embodiment. .

FIG. 1A shows a protective tape attaching process in which a protective tape 42 for backside grinding is attached to the front surface 40 a of the semiconductor wafer 40 (step S 1), and the protection for the wafer surface 40 a is performed. Conventionally, a common laminating device 43 is applied for attaching the tape 42.

The thickness of the protective tape 42 can be appropriately selected, and is selected according to the planar state of the wafer surface 40a. That is, when a metal projection such as a bump is formed on each element of the wafer surface 40a, a thickness that can absorb the metal projection is required.

In the present embodiment, the thickness of the protective tape 42 is about 200 μm.

The protective tape 42 is made of a UV-curable and heat-shrinkable adhesive tape. In particular, in the present embodiment, a dicing tape (N series) manufactured by Lintec Corporation is used as the protective tape 42. Next, as shown in FIG. IB, a grinding process of the back surface 40b of the semiconductor wafer 40 using the back surface grinding device 44 is performed (Step S2).

The amount of grinding is determined according to the target wafer thickness. In the present embodiment, the wafer thickness is reduced to about 20 μm by the back surface grinding step.

FIG. 1C shows a post-processing step after backside grinding. This post-processing step is performed for the purpose of removing residual stress on the wafer back surface 40b after the back surface grinding step, and mechanical polishing by a polishing device 45 or wet etching is performed as necessary. In the latter case, the protective tape 42 can function as a mask covering the wafer surface 40a.

Next, as shown in FIG. 1D, a step of mounting the thinned semiconductor wafer 40 on a ring frame 48 via a dicing adhesive tape (dicing tape) 47 is performed (step S 3). .

As the dicing tape 47, an ultraviolet-curing tape that facilitates chip pickup later is used.

According to the present embodiment, since the semiconductor wafer 40 has a protective tape 42 attached to the surface 40a of the semiconductor wafer 40 to enhance the bending resistance, the semiconductor wafer 40 may be broken during handling. Is prevented.

FIG. 1E shows the dicing process (step S 4).

In this dicing step, the semiconductor wafer 40 is divided into individual chips together with the protective tape 42 attached to the surface 40a. In the dicing of the semiconductor wafer 40 with the protective tape 42, the blade 49 may be clogged in a general single cut, and the dicing quality may be degraded. In this case, a step-cut method of dicing the semiconductor wafer 40 by exchanging the blades 49 after dicing only the protection tape 42 first can be applied. Next, as shown in FIG. IF, the protective tape 42 attached to the front surface 40a of the diced semiconductor wafer 40 and the dicing tape attached to the back surface 40b of the semiconductor wafer 40 A step of irradiating the tape 47 with ultraviolet light using the ultraviolet light irradiation devices 50A and 50B, respectively, is performed (step S5).

Since each of the protective tape 42 and the dicing tape 47 is made of a UV-curable tape material, the protective tape 42 and the dicing tape 47 are cured by irradiation with ultraviolet light, and the adhesive strength to the semiconductor wafer 40 is reduced.

In the present embodiment, the process of irradiating the protective tape 42 with ultraviolet light and the process of irradiating the dicing tape 47 with ultraviolet light are performed at the same time to reduce the process cost.

Note that the ultraviolet irradiation step for each of the protective tape 42 and the dicing tape 47 is not limited to the case where the steps are performed simultaneously.

Subsequently, as shown in FIG. 1G, a chip 41 pickup process is performed (step S6).

In the present embodiment, a conventional needleless method is used for separation between the chip 41 and the dicing tape 47 during pickup. In the dicing tape 47 cured in the previous ultraviolet irradiation step, although the adhesive strength between the back surface of the chip 41 and the back surface is reduced, the integrated relationship between the two surfaces is still maintained due to the adhesive action between the surfaces. I have. Therefore, the separating device 52 is disposed directly below the dicing tape 47, and the slider 52a, which can move horizontally along the lower surface of the chip to be picked up, is driven to connect the chip 41 and the dicing tape 47. Between them.

However, in the case of an ultra-thin chip alone having a chip thickness of 50 μm or less, the chip often cracked or chipped when the slider 52a was driven. Therefore, in the present embodiment, the surface 40 a of the semiconductor wafer 40 is Since dicing is performed with the protective tape 42 adhered to the surface, the protective tape 42 remains on the surface of each divided chip 41 as it is.

Therefore, the protective tape 42 serves to reinforce the chip 41, and acts to enhance the bending resistance of the chip 41. Thus, it is possible to prevent the chip 41 from breaking when the slider 52a is driven.

Also, according to the present embodiment, since the protective tape 42 is attached to the surface of the chip 41, not only can the chip 41 be prevented from cracking due to the suction action of the collet 51, The contamination and scratches on the surface of the chip 41 due to the direct contact with the collet 51 can be avoided. Subsequently, as shown in FIG. 1H, a chip mounting step of transferring the picked-up semiconductor chip 41 to, for example, a chip mounting portion of a lead frame 54 is performed (step S7).

The “chip mounting section” is not limited to the one related to the illustrated lead frame, but also includes a chip mounting section on a printed wiring board and a chip mounting section in a package container.

For mounting the chip 41 on the lead frame 54, a conventionally known center 53 is used. The mounter 53 sucks the surface of the chip 41 and transports it to the chip mounting portion on the lead frame 54, and mounts it via an adhesive or an adhesive sheet prepared in advance. At this time, since the chip 41 is reinforced by the protective tape 42, the chip 41 is prevented from cracking due to pressure during mounting.

Next, a step of separating and removing the protective tape 42 from the surface of the mounted chip 41 is performed (step S8).

Fig. 2 is a side sectional view of the chip mounting part for explaining the chip mounting process. It is. The chip 41 is joined to the lead frame 54 with an adhesive material 55. The adhesive material 55 is made of an adhesive that is cured by a heating action from a heater 56 applied to the lower surface of the lead frame 54.

As described above, the protective tape 42 is made of a tape material having ultraviolet curability and heat shrinkability. Although the adhesive force has been reduced in the previous ultraviolet irradiation step, the protective tape 42 is in close contact with the surface of the chip 41. The effect remains.

Therefore, in the present embodiment, at the time of chip mounting, the protective tape 42 is thermally contracted by using the heat of the heater 56 for curing the adhesive 55.

Thus, the protective tape 42 can be easily separated and removed from the surface of the chip 41.

Therefore, according to the present embodiment, chip breakage during pickup and chip breakage during mounting can be effectively prevented, and semiconductor chips manufactured as thin as 50 μm or less are properly handled. Thus, a semiconductor device that can contribute to miniaturization and thinning of a device can be manufactured.

In particular, according to the present embodiment, the chip mounting step and the protective tape separating step can be performed in the same step, thereby reducing the process cost and removing the protective tape 42. The present invention can be implemented without using additional tools for Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the protective tape 42 is made of an ultraviolet-curable Depending on the strength S of the heat-shrinkable tape material and the properties of the chip surface, the protective tape can be made of a heat-foamable sheet material. In this case, the protective tape can be easily separated and removed from the chip surface only by the heating action on the protective tape.

Further, in the above embodiment, the chip mounting step and the protective tape separation / removal step are performed in the same step. However, of course, these steps may be performed independently. Industrial applicability

As described above, according to the method for manufacturing a semiconductor device of the present invention, chip cracking and chipping can be effectively prevented, and the chip pick-up step and the mounting step can be appropriately performed.・ Semiconductor devices that can contribute to thinning can be manufactured.

Claims

The scope of the claims

1. A protective tape attaching process for attaching a protective tape for backside grinding to the surface of the semiconductor wafer,

A backside grinding step of grinding the backside of the semiconductor wafer to make it thinner; a dicing step of attaching a dicing adhesive tape to the backside of the thinned semiconductor wafer and dividing the semiconductor wafer into individual chips together with the protective tape. When,

A chip mounting step of picking up the chip and transferring it to a chip mounting portion;

A protective tape separating step of separating the protective tape from the chip surface.

A method for manufacturing a semiconductor device, comprising:

2. Perform the chip mounting step and the protective tape separating step in the same step

2. The method for manufacturing a semiconductor device according to claim 1, wherein:

3. UV-curable tape material is used for the protective tape and the adhesive tape,

Irradiating ultraviolet rays to the protective tape and the adhesive tape after the dicing step and before the chip mounting step;

4. Separation of the chip from the adhesive tape in the chip pickup step is performed by a needleless method.

4. The method for manufacturing a semiconductor device according to claim 3, wherein:

5. Using a heat-shrinkable tape material as the protective tape,

The protection tape from the chip surface in the protection tape separating step; 2. The method for manufacturing a semiconductor device according to claim 1, wherein the separation of the tape is performed by utilizing heat shrinkage of the protective tape.