JPS6347942A - Semiconductor device - Google Patents

Abstract

PURPOSE:To be able to connect a semiconductor element of an IC chip to a circuit substrate without disposing microcapsules only on a connecting pad and without damaging the chip by narrowing a gap between the pad and a corresponding electrode part on the substrate as compared with the other part. CONSTITUTION:A circuit substrate 4 having a wiring pattern on the upper surface and a semiconductor element 1 having a connecting pad 2 to an exterior are connected to be bonded by anisotropically conductive microcapsules 10. In such a semiconductor device, a gap between the pad 2 and an electrode part 5 on the substrate 4 is narrowed as compared with the other part. For example, the thickness of the electrode 5 is increased, and conductive particles 12 are not arrived at a passivation film 3 at the part except the electrode 5 and the pad 2 in a state that the pad 2 of the chip 1 and the electrode 5 are connected by the particles 12. That is, x >a+alpha is satisfied, where a is the thickness of the film 3, and x is the thickness of the electrode 5. However, alphais the quantity of the particles 12 in anticipation of the irregularity of the particles and a safety factor.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a connection structure for connecting a semiconductor element such as an IC chip or a transistor to a wiring board, and particularly relates to a connection structure for connecting a semiconductor element such as an IC chip or a transistor to a wiring board, and particularly relates to a connection structure for connecting a semiconductor element such as an IC chip or a transistor to a wiring board, and particularly relates to a connection structure for connecting a semiconductor element such as an IC chip or a transistor to a wiring board. Regarding structure.

[Prior Art] Various methods have been proposed for connecting semiconductor elements such as IC chips and transistors to wiring boards. For example, on a ceramic substrate on which lead wiring is formed,
After mounting and fixing the IC chip, the wire bonding method connects the lead wiring part and the pad part of the IC chip etc. using gold wire, etc. A tape-shaped polyimide film having inner leads with bumps formed on the tip 81. i of
The tape automated bonding method (TAB) connects the bump part of the i-marked part to the pad part of an IC chip, etc.
There is also a flip-chip method in which bumps are formed on the pads of an IC chip and these bumps are connected to a substrate on which lead wiring is formed. Each of these methods has its own advantages and has been widely used in the past, but each method requires relatively complicated equipment and processes for automation.

Therefore, a method using an adhesive having anisotropic conductivity has recently been proposed (Japanese Unexamined Patent Publication No. 180132/1983).

One of these methods has been proposed using anisotropically conductive microcapsules. This uses microcapsules as shown in FIG. In FIG. 6, a microcapsule 10 is a conductive spherical particle 12 such as a metal wrapped in a thermoplastic resin 11, and the diameter d of the conductive spherical particle 12 is about 1 to 10 μm, and the outside heat The thickness z of the plastic resin 11 is about 1 to 5 μm.

For example, Pd powder is used as the conductive spherical particles 12. Pd powder is spherical and has a uniform particle size, and by adjusting the particle size, an error of about ±2% can be obtained. There is. Various resins can be used as the thermoplastic resin 11, such as styrene/acrylonitrile thermoplastic polymer, polybutylene terephthalate, poly(
4-methylpentene-1) and the like are preferred. The conductive spherical particles 12 do not need to be metal particles (for example, fine polymer particles plated with Ni may also be used).

Such a microcapsule 10 is shown in FIG. 7 (a).
As shown in FIG. 2, it is placed on the electrode 5 portion of the wiring board 4 corresponding to the pad portion 2 of the IC chip 1, and then heated and pressurized. In this way, microcapsule 1
The thermoplastic resin 11 on the outside of the pad portion 2 is melted, and the pad portion 2 and the electrode 5 are connected by conductive spherical particles 12 made of metal or the like. When the heating is stopped in this state and the pad is cooled, the pad and the electrode are fixed by the thermoplastic resin 11 in a connected state. Note that in order to place the microcapsules 10 only on the electrode 5 portion of the wiring board 4, it is sufficient to provide the adhesive 6 only on the electrode 5 portion and sprinkle the microcapsules thereon. After spraying, the substrate 5 is turned over to remove the microcapsules that have been sprayed onto unnecessary areas. The microcapsules 10 are insulated from each other in the stacking direction in a fixed state after being melted, but have electrical conductivity in the longitudinal direction.

As an example of this method, Pd with an average particle size of 1.19 μm is used.
In an example using an anisotropically conductive microcapsule made of powder coated with a styrene/acrylonitrile thermoplastic polymer with a film thickness of 0.5 μm, the resolution is approximately 20 lines/mm (line space 25 μm) and the connection resistance is approximately 0.16 to 0.5 μm. An anisotropic conductivity of 36 Ω/but was obtained. (Pad area, 1.9
(approximately 138 x 138 μm2).

Note that 3 is a passivation film provided on a normal IC chip, and as shown in the figure, it slightly protrudes from the pad portion 2.

[Problem that the invention seeks to solve]

In the conventional example described above, sufficient performance is obtained in terms of resolution and connection resistance when mounting an IC chip, but in this conventional example, the microcapsule is only connected to the electrode 5. The problem is that a special processing step is required to arrange the structure.

In addition, there are some devices that take advantage of the anisotropic conductivity of microcapsules and place microcapsules on the entire surface and then heat and pressurize them for mounting. This has had the problem of destroying the IC chip and, in some cases, even destroying the wiring pattern on the surface of the IC chip. Also, in this case, the IC
There were times when short circuits occurred between the substrate and the dicing part of the chip.

This invention was made in order to solve these problems, and it is possible to attach semiconductor elements such as IC chips without damaging the IC chips and without arranging microcapsules only in the pad portions. An object of the present invention is to provide a semiconductor device that can connect a semiconductor device and a wiring board.

[Means for solving problems]

In order to solve the above problems, in the present invention, a substrate having a wiring pattern on the upper surface and a semiconductor element such as an IC chip having a pad portion for connection to the outside are connected using an anisotropically conductive microphone. A semiconductor device connected and fixed by a capsule is characterized in that the thickness of the electrode in the portion corresponding to the pad of the semiconductor element is thicker than in the other portion.

With this configuration, even if the microcapsules are not placed only on the pad area, but are placed over the entire surface, the passivation film and wiring pattern of the semiconductor element will not be destroyed, and short circuits with the substrate will not occur. It is possible to realize a mounting structure for semiconductor elements that does not cause problems.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, 1 is an IC chip, which includes an element region 20 formed on a semiconductor substrate and a wiring pattern region 2 formed in multiple layers.
1. 2 is a pad area of the IC chip, and this portion is connected to an electrode of an external wiring board. A passivation film 3 is provided on the surface of the wiring pattern region 21 and the like except the pad region 2.

4 is a wiring board, and has an electrode 5.

The electrode 5 faces the pad area 2 of the IC chip,
They will be interconnected by microcapsules 10 as will be explained later.

As explained in FIG. 6, the microcapsule 10 is
Conductive particles 12 in the center (in Figure 1, micro-conductors on both sides)
The capsules are made up of a thermoplastic layer (indicated by a broken line) and a thermoplastic resin layer (sealing layer 11) on the outside, and are arranged in a single layer as shown in the figure.In this way, when the microcapsules are arranged in a single layer, In this case, adhesive is applied to the entire surface of the wiring board 4, microcapsules are sprinkled on the adhesive-coated surface, and the excess microcapsules are then removed.After that, the IC chip 1 is Pressure is applied to the wiring board 4 while heating it.As explained in conjunction with FIG. The pad region 2 and the electrode 5 are electrically connected.When cooled thereafter, the resin 11 fixes the IC chip 1 and the wiring board 4 while keeping them bonded.

In this invention, the thickness of the electrode 5 is increased so that the pad area 2 of the IC chip 1 and the electrode 5 are connected by the conductive particles 12, and the area other than the electrode 5 and the pad area 2 is Make sure that it does not reach the passivation film 3. That is, the thickness of the passivation film 3 is a
(The passivation film 3 will protrude by an amount a from the path/nod part), and if the thickness of the electrode 5 is X, then x
>a+α ・・−・−・・−−−−1・−・−・・−
-----(1) The stock α is an amount that takes into account the dispersion of the conductive particles 12 and the safety factor. With this configuration, the microcapsules 10 whose particle size is controlled do not come into contact with any part of the IC chip 1 other than the pad area.

FIG. 2 also shows a state in which the electrode 5 is constructed thickly, but in this case, the electrode 5 has a region 5' for extending to the electrode 5''; The thickness of the pull-out area 5' is greater than the thickness of the drawing area 5'.

At this time, between the electrode 5 and the lead-out region 5' and the film adhesion If the variation in dimensions is C, then X'≧a+b+c. Generally, a=1μmf1 degree, b”=0.5~1
μm, c″=0.1 to 0.5 μm, so X′ is approximately 2
It is good if it is a little stronger than μm.

In this case, the dicing part 6 of the IC chip and the micro
The capsule 10 will not be melted, and the basic resistors of the IC chip will not be short-circuited.

In order to form the lead-out region 5', the electrode 5 which is made thicker as a whole may be etched, or only the electrode 5 may be made thicker than the electrode 5 which is made thicker as a whole.

FIG. 3 and FIG. 4 are examples of application of the wiring board.

In the case of FIG. 3, in addition to the electrode 5 and the lead-out region 5', a pattern 7 for increasing the current capacity of the wiring pattern is provided. Further, in the case of FIG. 4, there is no need to increase the current capacity, and the entire portion other than the electrode 5 is configured to be tingling.

FIG. 5 shows yet another embodiment of the invention.

In this case, in order to increase the thickness of the pad portion 2 of the IC chip 1 instead of increasing the thickness of a part of the electrode 5 of the wiring board t, a bump 7 is further provided, and the thickness of the bump 7 is increased. , which is larger than the thickness of the passivation film 3. The thickness X of the bump 7 may be as described in FIG. 1.

Moreover, instead of using microcapsules, commercially available anisotropic conductive adhesives (for example, Japanese Patent Laid-Open No. 60-193353
Publication No. 60-262489, Japanese Patent Application Laid-open No. 1982-262489
As described in Publication No. 207397, if this method is applied even when styrene-butadiene rubber and mixtures of solder balls or Ni fine particles are used, it is possible to Substrate short circuits can be prevented, and reliable IC connections can be made.

Further, although not particularly shown in the drawings, wiring electrodes may be formed only in portions corresponding to wire bonding pads via through holes on the insulating layer (front surface) of a multilayer substrate.

〔Effect of the invention〕

As described above, according to the present invention, even if an adhesive is provided on the entire surface of the wiring board including the electrode portions and microcapsules are provided on the entire surface of the wiring board, the passivation film will not be damaged and the IC Since the chip and the wiring board can be reliably bonded, the connection process is simple and efficient.

In particular, there is no need for a special process to form a patterned adhesive, which facilitates manufacturing.

[Brief explanation of drawings]

1 and 2 show one embodiment of the invention, and FIGS. 3, 4, and 5 show other embodiments of the invention, respectively. 6th
The figure shows microcapsules used in the present invention, and FIG. 7 shows a conventional example. 1--IC chip 2-pad region 3-passivation film 4-wiring board 5-electrode 6-dicing portion 7-bump 10-m-microcapsule 1]-thermoplastic resin 12-conductive particles FIG. Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 0 (a) 0 (b) Figure 7

Claims (4)

[Claims] (1) In a semiconductor device in which a wiring board having a wiring pattern on the upper surface and a semiconductor element having connection pads to the outside are connected and fixed by anisotropically conductive microcapsules, the connection pads and the corresponding wiring board A semiconductor device characterized in that a gap between the electrode portion and the electrode portion is narrower than other portions. (2) By increasing the thickness of the electrodes on the wiring board,
2. The semiconductor device according to claim 1, wherein the gap between the connection pad and the electrode portion is narrowed. (3) The semiconductor device according to claim 1, wherein the gap between the connection pad and the electrode portion is narrowed by increasing the thickness of the connection pad. (4) The semiconductor device according to claim 1 or 2, wherein the gap between the connection pad and the electrode is narrowed by at least the thickness of a passivation film of the semiconductor device.