JP3578011B2 - Semiconductor device mounting structure - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor device mounting structure in which a semiconductor device is mounted on a substrate using an anisotropic conductive film.
[0002]
[Prior art]
As a conventionally known technique, an anisotropic conductive film is used as a structure for electrically and mechanically connecting a bump which is a protruding electrode provided on an electrode of a semiconductor device and a pattern arranged on a substrate. The structures used are known. The prior art of this mounting structure will be described in the order of mounting steps with reference to FIG.
[0003]
FIG. 5 is a cross-sectional view showing a conventional technique. In FIG. 5A, a plurality of wiring patterns 4 are formed of a conductive material on a component mounting surface 3 of a substrate 2 on which a bare chip IC 1, which is a semiconductor device, is mounted. Is provided with a gold-plated electrode 5. Each wiring pattern 4 is covered with a solder resist 6 except for the electrode 5.
[0004]
The bare chip IC1 has a plurality of electrodes formed of a conductive material such as aluminum on a predetermined surface 7 corresponding to the electrodes of the substrate, and bumps 8 are formed on the surface of each electrode. The bump 8 is formed of a metal material such as Au or Sn-Pb alloy.
[0005]
FIG. 5B is a cross-sectional view of a step of temporarily pressing the anisotropic conductive film. The anisotropic conductive film 20 used for mounting the bare chip IC 1 is formed by dispersing conductive particles 22 in an insulating resin 21. The anisotropic conductive film 20 is formed in a tape shape having a width larger than the width of the predetermined surface 7 of the bare chip IC1, and is wound around a reel while being covered with a protective tape.
[0006]
When mounting the bare chip IC 1, first, the anisotropic conductive film 20 wound on a reel is cut into a required length together with the protective tape 23, and mounted on the component mounting surface 3 of the substrate 2. Next, the anisotropic conductive film 20 is heated from the side of the protective tape 23 and heated (80 ° C. for about 2 seconds) and pressed by the pressing tool 24 to temporarily press the anisotropic conductive film 20. In this case, the anisotropic conductive film 20 is bonded to the mounting position of the bare chip IC 1 so as to cover the wiring pattern 4 and the electrode 5 of the substrate 2. Preferably, the area of the anisotropic conductive film 20 is larger than the area of the predetermined surface 7 of the bare chip IC1. The thickness of the anisotropic conductive film 20 is preferably about 10 μm thicker than the height of the bump 8.
[0007]
Next, FIG. 5C shows a cross-sectional view in which the semiconductor device is mounted. The protective tape 23 of the anisotropic conductive film 20 adhered to the substrate 2 is peeled off, and a predetermined surface 7 of the bare chip IC 1 is set so as to face the anisotropic conductive film 20, and the bare chip IC 1 is placed on the anisotropic conductive film 20. The IC chip 1 is mounted, and the anisotropic conductive film 20 is pressed (at 180 ° C. for about 20 seconds) and heated via the bare chip IC 1 to mount the bare chip IC 1. By heating, the insulating resin 21 of the anisotropic conductive film 20 is softened and expanded by applying pressure, so that the space between the predetermined surface 7 of the bare chip IC 1 and the component mounting surface 3 of the substrate 2 is filled. The surplus insulating resin 21 is pushed out in the direction of arrow a to fill and protect the side surface of the bare chip IC1. This state is shown in FIG.
[0008]
Thus, the component mounting surface 3 of the substrate 2 and the predetermined surface 7 of the bare chip IC 1 are joined via the insulating resin 21 of the anisotropic conductive film 20. In addition, since the conductive particles 22 mixed in the anisotropic conductive film 20 are pressed by the bumps 8 against the electrodes 5 of the substrate 2, the substrate 2 and the bare chip IC 1 are also electrically connected.
[0009]
[Problems to be solved by the invention]
Along with the multi-functionality of electronic devices, multi-chip modules for mounting a plurality of semiconductor devices on a single substrate at high density have been widely used, but have the following disadvantages.
[0010]
In the case where a plurality of semiconductor devices are mounted on one substrate, anisotropic conductive films must be adhered to the portions where the respective semiconductor devices are mounted, as many as the number of the semiconductor devices, which significantly reduces productivity. Was. In addition, the production equipment required complicated and large-scale equipment.
[0011]
On the other hand, for the sake of simplicity, there is also a structure in which an anisotropic conductive film is collectively attached to a mounting portion of each semiconductor device, instead of being attached to each mounting portion of each semiconductor device. In this case, there is no problem if a plurality of semiconductor devices are sufficiently separated from each other, but when compactness and high density are required, the semiconductor devices have to be arranged adjacent to each other.
[0012]
In this case, first, one semiconductor device is mounted by heating and pressing. At this time, heat at the time of mounting conducts through the board and the wiring pattern arranged on the surface of the board, and heat of the insulating resin constituting the anisotropic conductive film which has been temporarily crimped to the portion where the other semiconductor device is to be mounted. The curing progresses, and when mounting the other semiconductor device, the insulating resin does not sufficiently soften even when heated and pressed, and the holding of the substrate and the semiconductor device becomes insufficient. There is a problem in that electrical conduction cannot be ensured, which is a fatal defect for electronic equipment.
[0013]
Therefore, each semiconductor device must be separated by a distance that does not allow thermal curing of the insulating resin to proceed by heating and pressing when mounting one of the semiconductor devices, which has been a great hindrance to high-density mounting. .
[0014]
Of course, there is also a method of individually attaching an anisotropic conductive film to each of a plurality of semiconductor devices. That is, an anisotropic conductive film for mounting one semiconductor device is first attached, and then the semiconductor device is mounted. After that, an anisotropic conductive film for mounting the other semiconductor device is attached and the other semiconductor device is mounted. In this case, there is no concern about heat curing, but the same process is repeated, and it is easily considered that productivity is significantly impaired.
[0015]
In other words, there is a demand for a mounting structure in which anisotropic conductive films can be attached together and a plurality of semiconductor devices can be arranged at short intervals.
[0016]
[Means for Solving the Problems]
In order to solve the above problems, the present invention relates to a semiconductor device mounting structure in which a plurality of semiconductor devices are mounted on a plurality of component mounting surfaces provided on a substrate with an integrated anisotropic conductive film interposed therebetween. A slit is provided on the substrate between adjacent mounting surfaces of the plurality of component mounting surfaces.
The present invention also provides a semiconductor device mounting structure in which a plurality of semiconductor devices are mounted on a plurality of component mounting surfaces provided on a substrate with an integrated anisotropic conductive film interposed therebetween, wherein A plurality of through holes are provided in the substrate between adjacent mounting surfaces.
Further, according to the present invention, the plurality of through holes are filled with a substance having a lower thermal conductivity than the substrate.
Further, the present invention is characterized in that the substance is carbon.
Further, the present invention provides a semiconductor device mounting structure in which a plurality of semiconductor devices are mounted on a plurality of component mounting surfaces provided on a substrate with an integrated anisotropic conductive film interposed therebetween, wherein: A slit is provided in the anisotropic conductive film located between adjacent mounting surfaces.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
(1) First Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a drawing of a multichip module in which a plurality of semiconductor devices of the present invention are mounted on a single substrate at a high density.
[0018]
FIG. 1A is a cross-sectional view showing a state in which an anisotropic conductive film is temporarily pressed on a substrate and immediately before one semiconductor device is mounted.
[0019]
1 (b) is a state except for the anisotropic cylinder conductive film is a plan view of FIG. 1 (a).
[0020]
FIG. 1C is a cross-sectional view showing a state where one semiconductor device is mounted.
[0021]
FIG. 1D is a cross-sectional view showing a state where the other semiconductor device is also mounted.
[0022]
FIG. 1A shows a state in which an anisotropic conductive film 20 is temporarily pressure-bonded on a component mounting surface 3 of a substrate 2 and a protective tape has already been removed. Reference numerals 25 and 27 indicate semiconductor devices. Here, h1 and h2 in the figure indicate the pump height of each semiconductor device. The thickness of the anisotropic conductive film 20 is about 10 μm thicker than the bump height h1 in consideration of the filling property between the predetermined surface 26 of the bare chip IC 25 and the component mounting surface 3 of the substrate 2. Reference numeral 29 denotes a slit portion of the substrate provided between the bare chip IC 25 and the bare chip IC 27.
[0023]
First, in FIG. 1A, the bare chip IC 25 is heated and pressurized and mounted via an anisotropic conductive film. FIG. 1B is a plan view showing a state immediately before the bare chip IC 25 is mounted. FIG. 3 is a plan view showing a state where the anisotropic conductive film 20 is removed so that the slit portion 29 provided on the substrate 2 can be easily understood. In FIG. 1C, the heating / pressing tool 24 mounts the bare chip IC 25, and the heat at the time of mounting is conducted in the directions of arrows a and b through the anisotropic conductive film 20, the wiring pattern 4, and the substrate 2. . However, since the slit 29 is provided on the substrate 2 having the largest heat capacity, most of the heat is transmitted in the direction of arrow a, and the heat is not conducted to the anisotropic conductive film where the bare chip IC 27 is mounted. Curing does not proceed.
[0024]
That is, by providing the slit 29 in the substrate 2 between the bare chip IC 25 and the bare chip IC 27, the interval between the bare chip ICs can be shortened, and a structure capable of higher-density mounting can be realized.
[0025]
In the present embodiment, an example in which two semiconductor devices are mounted on one substrate has been described, but it goes without saying that more effects can be obtained when more semiconductor devices are mounted.
[0026]
(2) Second Embodiment This embodiment is a modification of the first embodiment. The present modification is characterized in that a slit provided in a substrate between a plurality of semiconductor devices is replaced with a through hole for ensuring electrical continuity between wiring patterns arranged on the front and back surfaces of the substrate.
[0027]
FIG. 2 shows that a through hole 31 is formed in a substantially straight line between the portion of the substrate 2 where the bare chip IC 25 and the bare chip IC 27 are mounted, for electrically connecting the wiring pattern on the front surface and the wiring pattern on the back surface of the substrate 2. It is a top view showing a mode provided. In this embodiment, compared to the first embodiment, although the heat at the time of mounting the bare chip IC 25 is transmitted more, the wiring pattern 4 can be arranged between the through holes 31 and the degree of freedom in designing the board is increased.
[0028]
(3) Third Embodiment This embodiment is a modification of the second embodiment. The present embodiment is an example in which the inside of the through hole 31 provided between the portion where the bare chip IC 25 and the bare chip IC 27 of the substrate 2 are mounted is filled with a substance having low thermal conductivity.
[0029]
FIG. 3 is a sectional view showing the present embodiment.
[0030]
The inside of the through hole 31 is filled with carbon 32 whose thermal conductivity is lower than that of the material of the substrate 2 such as glass epoxy. As a result, as for the heat at the time of mounting the bare chip IC 25, the heat conduction to the anisotropic conductive film in the portion where the bare chip IC 27 is mounted is greatly reduced, and stable mounting quality can be obtained.
[0031]
(4) Fourth Embodiment This embodiment is a modification of the first embodiment. The present embodiment is characterized in that a slit between a portion where the bare chip IC 25 and the bare chip IC 27 of the substrate 2 are mounted is not provided on the substrate but is provided on the anisotropic conductive film 20.
[0032]
Drawing 4 (a) shows a sectional view of this embodiment, and drawing 4 (b) shows a top view.
[0033]
In FIG. 4B, reference numeral 30 denotes a slit provided in the anisotropic conductive film 20. In FIG. 4 (a), since no slits or holes are provided in the substrate 2 immediately below the slit portion 30, the wiring pattern 4 can be arranged freely, without impairing the degree of freedom of wiring in design at all. Heat conduction can be prevented.
[0034]
【The invention's effect】
According to the first aspect of the present invention, in the case of a so-called multi-chip module in which a plurality of bare chip ICs are mounted on one substrate, heat when mounting one bare chip IC is transmitted to the substrate and the other bare chip IC is mounted. Therefore, it is possible to prevent the problem that the heat is transmitted to the anisotropic conductive film that has been pasted in advance and heat curing is advanced, so that stable mounting quality cannot be obtained.
[0035]
By providing a slit in a portion of the substrate between one bare chip IC and the other bare chip IC, it is possible to prevent thermal curing and to arrange a plurality of bare chip ICs in close proximity to obtain a small and compact mounting structure. Can be.
[0036]
According to the second aspect of the present invention, by arranging a through hole in a portion of the substrate between one bare chip IC and the other bare chip IC, heat at the time of mounting one bare chip IC is transmitted to the substrate, and To the anisotropic conductive film that has been applied in advance to mount the bare chip IC, and prevent the problem of advancing the thermosetting, and at the same time, it is possible to arrange the wiring pattern between each through-hole, thus increasing the freedom of wiring design. Thus, a mounting structure that is improved can be realized.
[0037]
According to the third aspect of the present invention, it is possible to further reduce the heat conduction by filling the inside of the through hole arranged to prevent the heat conduction with a substance having a low heat conduction, thereby further reducing a plurality of bare chip ICs. Can be arranged close to each other.
[0038]
According to the fourth aspect of the present invention, the anisotropic conductive film bonded together is provided with a slit in the portion of the anisotropic conductive film between the mounting of a plurality of bare chip ICs, thereby providing thermosetting. Since no slits or through holes are arranged on the substrate, the degree of freedom in wiring can be maximized.
[Brief description of the drawings]
FIG. 1 is a sectional view of a mounting structure showing a first embodiment of the present invention.
FIG. 2 is a plan view of a mounting structure according to a second embodiment of the present invention.
FIG. 3 is a sectional view of a mounting structure showing a third embodiment of the present invention.
FIG. 4 is a drawing of a mounting structure showing a fourth embodiment of the present invention.
FIG. 5 shows a mounting structure showing a conventional example of the present invention.
[Explanation of symbols]
1, 25, 27 ... bare chip IC
2 ... board 3 ... component mounting surface 4 ... wiring pattern 5 ... electrode 6 ... solder resist 7, 26, 28 ... predetermined surface 8 ... bump 20 ... anisotropic conductive film 21 ... insulating resin 22 ... conductive particles 23 ... protection Tape 24: Heating and pressing tool 29: Slit portion 30 of substrate: Slit portion 31 of anisotropic conductive film: Through hole 32: Carbon

Claims (5)

In a semiconductor device mounting structure in which a plurality of semiconductor devices are mounted on a plurality of component mounting surfaces provided on a substrate with an integrated anisotropic conductive film interposed therebetween,
A mounting structure for a semiconductor device, wherein a slit is provided in the substrate between adjacent mounting surfaces among the plurality of component mounting surfaces. In a semiconductor device mounting structure in which a plurality of semiconductor devices are mounted on a plurality of component mounting surfaces provided on a substrate with an integrated anisotropic conductive film interposed therebetween,
A mounting structure for a semiconductor device, wherein a plurality of through holes are provided in the substrate between adjacent mounting surfaces of the plurality of component mounting surfaces. In claim 2,
The semiconductor device mounting structure, wherein the plurality of through holes are filled with a substance having a lower thermal conductivity than the substrate. In claim 3,
The mounting structure of a semiconductor device, wherein the substance is carbon. In a semiconductor device mounting structure in which a plurality of semiconductor devices are mounted on a plurality of component mounting surfaces provided on a substrate with an integrated anisotropic conductive film interposed therebetween,
A mounting structure for a semiconductor device, wherein a slit is provided in the anisotropic conductive film located between adjacent mounting surfaces of the plurality of component mounting surfaces.

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