JP2003023034A - Flip-chip mounting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flip-chip mounting method for stably electrically connecting a circuit board and a chip. SOLUTION: The flip-chip mounting method has a process for electrically connecting projected electrodes 3 arranged on the mounting face of the chip 1 with conduction parts 5 disposed on the surface of the circuit board 4. The method includes a process for arranging a resin layer 7 on the mounting face of the chip 1 so that it becomes almost equal to the height of the projected electrodes 3, a process for installing a resin film 6 on the conduction parts 5 and a process for pressing the chip 1 to the resin film 6 so that the projected electrodes 3 reach the conduction parts 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip chip mounting method for fixing a chip on a circuit board provided with a predetermined conductive portion and electrically connecting the chip and the circuit board.

[0002]

2. Description of the Related Art As a conventional flip chip mounting method, for example, as shown in FIG. 4, a bump electrode 3 such as a solder bump is formed on an electrode pad 2 made of Al or the like provided on a mounting surface of a chip 1, and a chip is formed. 1 is turned over to mount the protruding electrode 3 at a predetermined position on the circuit board 4 so that the protruding electrode 3 provided on the chip 1 and the conductive portion 5 such as a substrate electrode provided on the surface of the circuit board 4 are connected. There is a method.

In this flip-chip mounting method, a plurality of (two in FIG. 4) resin films 6 obtained by processing a thermosetting resin such as an epoxy resin into a film shape are provided on the conductive portion 5 of the circuit board 4. The protruding electrode 3 provided on the surface so as to cover the conductive portion 5 is provided on the chip 1 with resin so that the protruding electrode 3 reaches the conductive portion 5 from the plurality of resin films 6 to the circuit board 4. The film 6 is pressed and electrically connected. Then, the resin film 6 is cured by performing heat treatment.

As described above, the flip-chip mounting method using the resin film 6 is efficient because electrical connection between the protruding electrode 3 on the chip 1 side and the conductive portion 5 on the circuit board 4 side and resin filling are performed only once. Target.

[0005]

However, in the flip-chip mounting method using a resin film as described above, it is necessary to stack a plurality of resin films (usually 2 to 3) with a thickness of about 30 μm. is there.

This is because, for example, when a board electrode is used as a conductive portion on the circuit board side, the height of the board electrode is usually 3
Since it is 0 μm or more, and the protruding electrode of the chip is usually 30 μm or more, the gap between the chip and the circuit board at the time of flip chip mounting is 60 μm or more. This is because it is insufficient to fill the gap.

When a plurality of resin films are stacked and used, it is necessary for the protruding electrodes on the chip side to break through the plurality of resin films and be connected to the conductive portions on the circuit board side. As a result, the protruding electrode is less likely to break through the resin film, and as a result, there is a possibility that a defective connection may occur between the protruding electrode and the conductive portion, and there is a problem that the yield is reduced.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a flip chip mounting method for realizing stable electrical connection between a circuit board and a chip.

[0009]

A chip mounting method according to a first aspect of the present invention comprises a protruding electrode 3 provided on a mounting surface of the chip 1.
In a flip-chip mounting method including a step of electrically connecting to a conductive portion 5 provided on the surface of a circuit board 4, a resin layer is formed on the mounting surface of the chip 1 so as to have a height substantially equal to the height of the protruding electrode 3. 7, a step of providing a resin film 6 on at least the conductive portion 5, and a step of pressing and connecting the chip 1 to the resin film 6 so that the protruding electrode 3 reaches the conductive portion 5. It is characterized by including and.

The flip-chip mounting method according to the second aspect of the present invention comprises a step of electrically connecting the protruding electrode 3 provided on the mounting surface of the chip 1 and the conductive portion 5 provided on the surface of the circuit board 4. In the provided flip-chip mounting method,
A resin layer 7 is provided on the mounting surface of the semiconductor substrate 8 having the protruding electrodes 3 so as to have a thickness approximately equal to the height of the protruding electrodes 3, and the semiconductor substrate 8 is cut and separated together with the resin layer 7. To form the chip 1 which is an element piece by the above, a step of providing a resin film 6 on at least the conductive portion 5, and the chip 1 to the resin film so that the protruding electrode 3 reaches the conductive portion 5. And a step of connecting by pressing.

The flip-chip mounting method according to a third aspect of the present invention is the method of the first or second aspect, wherein the mounting surface of the chip 1 or the semiconductor substrate 8 is resin-coated with respect to the resin film 70. The resin layer 7 is formed by pressing the film 70 until the heights of the bump electrodes 3 become substantially equal to each other and providing the resin film 70 on the mounting surface of the chip 1 or the semiconductor substrate 8. To do.

The flip-chip mounting method according to claim 4 is the method according to any one of claims 1 to 3, wherein the resin layer 71 is thicker than the height of the protruding electrode 3.
And a part of the resin layer 71 is removed to expose at least the tip of the bump electrode 3 to form the resin layer 7.

A flip chip mounting method according to a fifth aspect is characterized in that, in the invention according to any one of the first to fourth aspects, the resin layer 7 is a thermosetting resin. To do.

Here, the bump electrode 3 includes a solder bump having an arbitrary shape, a solder ball having a substantially spherical shape, a stud bump having an arbitrary shape, and the like.

Further, the conductive portion 5 includes any electrically conductive portion such as a conductive pattern and a substrate electrode. Further, the resin films 6 and 70 have desired thicknesses such as those obtained by processing a thermosetting resin that is cured by heating into a film shape, or those obtained by processing a UV curing resin that is cured by UV irradiation into a film shape. Included. The semiconductor substrate 8 includes a wafer made of Si, a wafer made of GaAs, and the like.

The method for removing a part of the resin layer 71 includes any method such as a method using polishing and a method using a squeegee or the like.

[0017]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic sectional view showing a flip chip mounting method according to the first embodiment of the present invention.

The flip chip mounting method will be described below. As shown in FIG. 1A, a wafer made of, for example, Si as a semiconductor substrate 8 is provided with electrode pads 2 made of Al, and solder bumps are formed as protruding electrodes 3 on the electrode pads 2, for example. There is. Here, the surface of the semiconductor substrate 8 on which the electrode pads 2 and the protruding electrodes 3 are formed is hereinafter referred to as a mounting surface of the semiconductor substrate 8.

As shown in FIG. 1D, a circuit board 4 made of, for example, glass epoxy resin is provided with a board electrode as a conductive portion 5, and a resin film 6 made of a film-processed epoxy resin is made conductive. It is provided so as to cover both the part 5 and the surface of the circuit board 4. The resin film 6
Need only be provided so as to cover at least the conductive portion 5. In addition, the film-shaped epoxy resin which is the resin film 6 is a thermosetting resin and has a thickness of 30.
It is about μm.

Here, as shown in FIGS. 1 (a) and 1 (b), in the first embodiment, the semiconductor substrate 8 has a height substantially equal to that of the protruding electrode 3, preferably the tip portion of the protruding electrode 3. The epoxy resin is applied as the resin layer 7 using, for example, the dispenser 9 so that it is slightly exposed, for example, about 1 to 5 μm thin from the tip of the protruding electrode 3. Next, heat treatment is performed so that the resin layer 7 is cured.

Then, as shown in FIG. 1C, the semiconductor substrate 8 is cut together with the cured resin layer 7 by, for example, dicing, and separated into desired chips 1 which are individual pieces of the element. Here, the surface of the chip 1 on which the electrode pads 2 and the protruding electrodes 3 are formed is hereinafter referred to as a mounting surface of the chip 1.

Next, as shown in FIG. 1D, the chip 1
The mounting surface of is opposed to the circuit board 4, and the chip electrode 1 provided on the chip 1 side is pressed against the resin film 6 from above one resin film 6 so that the plate electrode 3 reaches the conductive portion 5. , The resin film 6 from between the chip 1 and the conductive portion 5.
The chip 1 is electrically connected to the circuit board 4 by extruding and then heat-bonding. The resin film 6 is cured by this heating.

In such a flip-chip mounting method, the resin film 6 is provided on the circuit board 4 side, and
Since the resin layer 7 is provided on the chip 1 side, it is not necessary to use a plurality of resin films 6 on at least the conductive portion 5 of the circuit board 4, so that stable electrical connection between the circuit board 4 and the chip 1 is realized. It is possible to provide a flip-chip mounting method.

Further, it is possible to achieve improvement in yield due to poor electrical connection between the circuit board 4 and the chip 1. Further, by providing the resin layer 7 on the mounting surface of the semiconductor substrate 8 and cutting the semiconductor substrate 8 together with the resin layer 7 to separate the chip 1 which is an element piece, the chip 1 provided with the resin layer 7 is obtained. Easy to make.

In the first embodiment, the thermosetting epoxy resin is used as the resin layer 7 provided on the mounting surface of the semiconductor substrate 8 and the mounting surface of the chip 1. However, thermosetting polyimide resin is used. Alternatively, a silicone resin, a phenol resin, or the like may be used. Also, a thermosetting resin containing an anisotropic conductive material, for example, an epoxy resin containing Ag particles or an epoxy resin containing particles obtained by coating plastic spheres with Cu, Ni or the like may be used. Good.

Further, as the resin layer 7, a UV curable resin obtained by processing an epoxy resin, a silicone resin, an acrylic resin or the like into a film shape which is cured by UV irradiation is used, and is cured by UV irradiation. Good.

Next, an embodiment showing another step of forming the resin layer 7 provided on the mounting surface of the semiconductor substrate 8 or the mounting surface of the chip 1 will be described as a second embodiment of the present invention with reference to FIG. FIG. 2 is a schematic sectional view showing a part of the flip chip mounting method according to the second embodiment of the present invention. The first
The description of the common parts with the embodiment will be omitted by giving the same reference numerals to the same parts.

FIG. 2A is a schematic diagram of FIG. 1 in the first embodiment.
2A, but as shown in FIG. 2B, on the mounting surface of the wafer made of Si as the semiconductor substrate 8, at least solder bumps as the protruding electrodes 3 are included, and the resin layer 71 is thicker than the protruding electrodes 3. As an epoxy resin containing Ag particles, which is a resin containing an anisotropic conductive material, is applied, and then the epoxy resin is cured by heating.

Then, as shown in FIG. 2C, the cured resin layer 71 is mechanically polished using, for example, a polishing machine (not shown) until the height of the resin layer 71 becomes substantially equal to the height of the protrusion electrode 3. After forming the resin layer 7 by exposing the tip end portion of the electrode 3, the semiconductor substrate 8 and the cured resin layer 7 are cut together, for example, by dicing to form a desired chip 1 as shown in FIG. 2D. And separate.

The mounting of the chip 1 on the circuit board 4 is as follows.
This is performed in the same manner as the method shown in FIG. 1D in the first embodiment.

In such a flip-chip mounting method, the resin layer 71 obtained by once providing a thickness thicker than the height of the bump electrode 3 and then heating and curing the resin layer 71 exposes at least the tip of the bump electrode 3. Since the layer 7 is used, it is not necessary to precisely control the thickness of the resin layer 71 provided first (before being heat-cured), so that the mounting process can be rationalized.

Here, in the first and second embodiments, the semiconductor substrate 8 is collectively processed to form the resin layer 7 on the mounting surface, and then the separately formed chips 1 are flipped onto the circuit board 4. Although mounted on a chip, the chip 1 which has already been separated into the element pieces is shown in FIGS.
The resin layer 7 may be formed as shown in FIGS. 2 (a) and 2 (b).

Next, the resin layer 7 is formed on the mounting surface of the chip 1.
An embodiment showing another step of providing the above will be described as a third embodiment of the present invention with reference to FIG. FIG. 3 is a schematic sectional view showing a part of a flip chip mounting method according to the third embodiment of the present invention. Note that the description of the same parts as those of the first embodiment will be omitted by giving the same reference numerals to the same parts.

In the third embodiment, first, the flat surface portion 1
A stage 10 having 0a and having releasability is prepared. Next, on the flat surface portion 10a of the stage 10, for example, an epoxy resin which is a thermosetting resin processed into a film shape having a thickness of about 30 μm as the resin film 70 is previously arranged. Then, as shown in FIG. 3A, the mounting surface of the chip 1 is directed toward the resin film 70 provided on the stage 10, and the tip portion of the protruding electrode 3 comes into contact with the flat surface portion 10 a of the stage 10 and the tip portion thereof is contacted. Is pressed so as to be at least exposed from the resin film 70. Next, heat treatment is performed so that the resin film 70 is cured.

The mounting of the chip 1 on the circuit board 4 is as follows.
This is performed in the same manner as the method shown in FIG. 1D in the first embodiment.

In such a flip chip mounting method, since the resin film 70 is used as the resin layer 7 on the mounting surface side of the chip 1, the resin layer 7 can be easily formed on the mounting surface of the chip 1.

Here, in the third embodiment, the resin layer 7 is formed on the mounting surface of the chip 1, which is previously separated into the element pieces.
As described above, the resin film 70 is provided, but as in the first and second embodiments, the semiconductor substrate 8 is collectively processed to form the resin film 70 on the mounting surface, and then the chip 1 is formed separately. May be flip-chip mounted on the circuit board 4.

In the first to third embodiments, each of the resin films 6 and 70 provided on the mounting surface of the chip 1 or the circuit board 4 side is a thermosetting resin processed into a film shape. Although a certain epoxy resin was used, a thermosetting polyimide resin processed into a film shape, a silicone resin, a phenol resin, or a thermosetting resin containing an anisotropic conductive material processed into a film shape, for example, It may be an epoxy resin processed into a film containing Ag particles or an epoxy resin processed into a film containing particles in which plastic spheres are coated with Cu, Ni or the like, or cured by UV irradiation. Even if a UV curable resin obtained by processing a film of epoxy resin, silicone resin, acrylic resin or the like is used and cured by UV irradiation. There.

[0039]

As described above, in the flip chip mounting method according to claim 1, since the resin film is provided on the circuit board side and the resin layer is provided on the chip side, the resin film is provided on the circuit side. Since it is not necessary to use a plurality of sheets on at least the conductive portion of the board, it is possible to provide a flip-chip mounting method that realizes stable electrical connection between the circuit board and the chip. Further, it is possible to achieve an improvement in yield due to a poor electrical connection between the circuit board and the chip.

In the flip-chip mounting method according to the second aspect, a resin layer is provided on the mounting surface of the semiconductor substrate, and the semiconductor substrate and the resin layer are cut together to form a chip that is an element piece. The effect of separating the resin layer on the mounting surface of the chip can be easily obtained. Further, it is possible to provide a flip-chip mounting method that realizes stable electrical connection between the circuit board and the chip. Further, it is possible to achieve an improvement in yield due to a poor electrical connection between the circuit board and the chip.

Further, in the flip chip mounting method described in claim 3, in the invention described in claim 1 or 2, a resin film is used as a resin layer on the mounting surface side of the chip or the semiconductor substrate. Therefore, it is possible to easily form the resin layer on the mounting surface of the chip or the semiconductor substrate.

Further, in the flip-chip mounting method described in claim 4, in the invention described in any one of claims 1 to 3, a resin layer thicker than the height of the protruding electrode is provided, and the resin layer is provided. Since the resin layer is formed on the mounting surface side of the chip or semiconductor substrate by exposing at least the tip of the protruding electrode by removing a part of the thickness of the resin layer provided on the mounting surface of the chip or semiconductor substrate first. This eliminates the need for precise management of the mounting process, and has the effect of enabling rationalization of the mounting process.

Further, in the flip-chip mounting method according to the fifth aspect, in the invention according to any one of the first to fourth aspects, the resin layer provided on the mounting surface of the chip or the semiconductor substrate is made of heat. Since it is made of a curable resin, it is possible to easily form the resin layer on the mounting surface of the chip or the semiconductor substrate.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a flip-chip mounting method according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a part of a flip chip mounting method according to a second embodiment of the present invention.

FIG. 3 is a schematic sectional view showing a part of a flip chip mounting method according to a third embodiment of the present invention.

FIG. 4 is a schematic sectional view showing a flip-chip mounting method according to a conventional example.

[Explanation of symbols]

1 chip 2 electrode pad 3 protruding electrodes 4 circuit board 5 Conductive part 6,70 Resin film 7,71 Resin layer 8 Semiconductor substrate 9 dispensers 10 stages

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinobu Kida             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F-term (reference) 5F044 LL09 LL11 QQ00

Claims (5)

[Claims] 1. A flip-chip mounting method comprising a step of electrically connecting a protruding electrode provided on a mounting surface of a chip and a conductive portion provided on a surface of a circuit board, wherein the mounting surface of the chip is provided with: A step of providing a resin layer so as to be approximately equal to the height of the protruding electrode; a step of providing a resin film on at least the conductive portion; and pressing the chip against the resin film so that the protruding electrode reaches the conductive portion. And the step of connecting the flip chip mounting method. 2. A flip-chip mounting method comprising a step of electrically connecting a protruding electrode provided on a mounting surface of a chip and a conductive portion provided on a surface of a circuit board, wherein a semiconductor provided with a protruding electrode. A step of forming a chip, which is an element piece, by providing a resin layer on the mounting surface of the substrate so as to have a thickness substantially equal to the height of the protruding electrode, and cutting and separating the semiconductor substrate together with the resin layer; A flip chip, comprising: a step of providing a resin film on at least the conductive portion; and a step of pressing and connecting the chip to the resin film so that the protruding electrode reaches the conductive portion. How to implement. 3. The mounting surface of the chip or the semiconductor substrate is pressed against the resin film until the height of the resin film and the height of the protruding electrode become substantially equal to each other, and the resin film of the chip or the semiconductor substrate. The flip chip mounting method according to claim 1, wherein the resin layer is formed by providing the resin layer on a mounting surface. 4. The resin layer is formed by providing a resin layer thicker than the height of the protruding electrode, and removing at least a tip portion of the protruding electrode by removing a part of the resin layer. Item 5. The flip chip mounting method according to any one of Items 3. 5. The flip chip mounting method according to claim 1, wherein the resin layer is a thermosetting resin.