JP2002134557A - Method for mounting semiconductor chip and structure for mounting semiconductor chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method a semiconductor chip and a structure of a semiconductor chip which can surely connect a bump of a semiconductor chip with a connecting terminal area of a board. SOLUTION: By this method, a semiconductor chip having a plurality of bumps protrudingly formed on the periphery of the main surface is mounted through an anisotropic conductive film on the board having a plurality of connecting terminal areas corresponding to the plurality of the bumps respectively. This method comprises a process for forming a plurality of protrusions having a predetermined thickness, corresponding to the regions between adjacent connecting terminal areas, respectively, outside the plurality of connecting terminal areas on the board, a process for arranging the anisotropic conductive film on the board, and a process for bonding the semiconductor chip facedown to the board by thermo-compression bonding so that each bump corresponds to each connecting terminal area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor chip mounting method for mounting a semiconductor chip on a substrate via an anisotropic conductive film, and a semiconductor chip mounting structure.

[0002]

2. Description of the Related Art In a semiconductor chip mounting structure, a semiconductor chip having a plurality of bumps protruding from a peripheral portion of a main surface is formed on a substrate having a plurality of connection terminal portions corresponding to each of the plurality of bumps. Is mounted via an anisotropic conductive film. FIG. 10 shows an example of this type of conventional semiconductor chip mounting structure. This semiconductor chip mounting structure is applied to a liquid crystal display module 100 incorporated in a liquid crystal television, a portable telephone, or the like, and the semiconductor chip 4 is directly mounted on one glass substrate 10 serving as a liquid crystal display surface. The mounted structure, so-called COG (Chip)
On Glass) method.

The liquid crystal display module 100 has a liquid crystal sealing portion between two overlapping glass substrates 10 and 20. One substrate 10 has a portion (extending portion 10A) extending from the side of the other substrate 20,
On its surface, a transparent electrode pattern P is formed so as to be drawn out of the liquid crystal sealing portion. In this conventional example, the plurality of connection terminal portions 2 corresponding to each of the plurality of bumps 41 of the semiconductor chip 4 are regions where the bumps 41 face the transparent electrode pattern P as shown in FIG. ing.

[0004] The semiconductor chip 4 is, in this conventional example,
It is a driver IC for driving a liquid crystal, and the number of bumps 41 serving as contacts is relatively large, and accordingly, the outer size of the bumps is relatively small in order to increase the definition of the liquid crystal display. Is used. Semiconductor chip 4
Are mounted via the anisotropic conductive film 3 so that each bump 41... And each connection terminal portion 2.

In order to mount the semiconductor chip 4, the anisotropic conductive film 3 is formed on the substrate 10, and then the semiconductor chip 4 is placed on the main surface with each bump 41 being connected to each connection terminal portion. 2. Thermocompression bonding is performed on the substrate 10 so as to correspond to 2.

The anisotropic conductive film 3 is made of, for example, conductive particles 3 formed by plating Ni and Au on the surface of a resin.
2 is a bonding base material 31 having an insulating property such as an epoxy resin.
It is dispersed and mixed in. When such an anisotropic conductive film 3 is used, the conductive particles 32 are interposed so as to sandwich the conductive particles 32 in a gap along the thickness direction between the bumps 41 and the connection terminal portions 2. The semiconductor chip 4 and the connection terminal portions 2.

However, the semiconductor chip 4 is mounted on the substrate 10
When thermocompression bonding is performed, the adhesive base material 31 is melted and becomes in a flowable state. When the semiconductor chip is pressed in such a state, the adhesive base material 31 and the conductive particles 32 tend to flow from the central portion of the semiconductor chip 4 toward the outside as a whole. At this time, in the gaps between the bumps 41 and the connection terminal portions 2, the distance is narrow, so that the flow velocity of the conductive particles 32 is large. Also, each bump 41 ...
Are small in size, it is extremely difficult to sandwich the conductive particles 32 in this gap. Therefore, as shown in FIG. 12, a sufficient number of conductive particles 32 cannot be interposed in the gap between each bump 41 and each connection terminal 2. …
Cannot be reliably conducted. as a result,
In some cases, connection failure of the semiconductor chip 4 may occur.

[0008]

SUMMARY OF THE INVENTION The present invention has been conceived in view of the above-mentioned circumstances, and provides a semiconductor chip capable of reliably connecting a bump of a semiconductor chip to a connection terminal of a substrate. It is an object of the present invention to provide a connection method and a semiconductor chip connection structure.

[0009]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

That is, the method of connecting a semiconductor chip provided by the first aspect of the present invention is a method of connecting a semiconductor chip having a plurality of bumps protrudingly formed on a peripheral portion of a main surface to each of the plurality of bumps. A method of mounting via a anisotropic conductive film on a substrate having a plurality of connection terminal portions to be performed, wherein, on the substrate, outside the plurality of connection terminal portions, each region between adjacent connection terminal portions and A step of forming a plurality of convex portions having a predetermined thickness corresponding to each other; a step of arranging an anisotropic conductive film on the substrate; Thermocompression bonding to the substrate so as to correspond to the terminal portion.

More specifically, the substrate is a glass substrate, and the connection terminal is a transparent electrode.

When the semiconductor chip is thermocompression-bonded, the adhesive base material of the anisotropic conductive film is melted and becomes flowable. When the semiconductor chip is pressed in such a state, the adhesive base material and the conductive particles as a whole tend to flow from the central portion of the semiconductor chip to the outside, but according to the first aspect of the present invention, the substrate Since the plurality of convex portions are formed in the semiconductor chip, the adhesive base material and the conductive particles tend to flow from the central portion of the semiconductor chip to between the convex portions. Since these convex portions are formed outside the plurality of connection terminal portions and in correspondence with each region between adjacent connection terminal portions, most of the conductive particles pass over each connection terminal portion. . Therefore, it is possible to increase the number of conductive particles sandwiched in the gap between each bump and each connection terminal portion.
As a result, each of the bumps and each of the connection terminal portions can be reliably connected to each other, and a connection failure of the semiconductor chip can be prevented.

In a preferred embodiment, the height of the projection from the surface of the substrate is larger than the particle diameter of conductive particles contained in the anisotropic conductive film, and the semiconductor chip is formed of the substrate. It is formed to be smaller than the distance between the semiconductor chip and the substrate when mounted on the substrate.

According to such a configuration, a gap is generated between the upper surface of the projection and the main surface of the semiconductor chip. As a result, the molten anisotropic conductive film can flow out of the gap. Therefore, it is possible to prevent the distance between the substrate and the semiconductor chip from becoming unnecessarily large when the semiconductor chip is mounted on the substrate. In addition, since the height of the protrusion from the surface of the substrate is larger than the particle diameter of the conductive particles, it is possible to suppress the conductive particles from flowing over the protrusion and flowing out. The effect of having a sufficient number of conductive particles interposed in the gaps between the connection terminals and the connection terminals is not significantly impaired.

In a preferred embodiment, the projection is formed by a photolithography method using a photosensitive resin. Therefore, it is easy to form a large number of relatively small convex portions.

According to a second aspect of the present invention, there is provided a connection structure for a semiconductor chip, wherein a semiconductor chip having a plurality of bumps protrudingly formed on a peripheral portion of a main surface is provided with a plurality of bumps corresponding to each of the plurality of bumps. A structure mounted on a substrate having a connection terminal portion through an anisotropic conductive film,
A plurality of projections having a predetermined thickness are formed outside the plurality of connection terminal portions on the substrate so as to correspond to respective regions between adjacent connection terminal portions.

The second aspect of the present invention is the first aspect of the present invention.
And a semiconductor chip mounting structure manufactured by the semiconductor chip mounting method provided by the aspect of the present invention. Therefore, the same operation and effect as those of the semiconductor chip mounting method according to the first aspect of the present invention can be obtained.

Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic perspective view showing an example of a semiconductor chip mounting structure according to the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG.
3 is a schematic perspective view showing the arrangement of the protrusions in FIG. 2. 4 to 7 are cross-sectional views illustrating a method for mounting a semiconductor chip according to the present invention. FIG. 8 is a plan view showing the distribution of the conductive particles in FIG. In these figures, the same reference numerals are given to members and parts equivalent to those shown in FIGS. 10 to 12 showing a conventional example.

As shown in FIGS. 1 and 2, the semiconductor chip mounting structure according to the present invention comprises a semiconductor chip 4 having a plurality of bumps 41 projecting from a peripheral portion of a main surface 4A. In this embodiment, the liquid crystal display module A is mounted on a substrate 10 having a plurality of connection terminals 2 corresponding to each of the plurality of bumps 41 via an anisotropic conductive film 3. Have been applied.

In the present embodiment, the semiconductor chip 4 is
This is a driver IC for driving a liquid crystal. The number of bumps 41 serving as contacts is relatively large in order to increase the definition of a liquid crystal display, and accordingly, the outer size of the bumps 41 is relatively small. What was done is used. The main surface 4A on which the bumps 41 are formed so as to protrude is flat. Each of the bumps 41 has a flat rectangular bottom surface.

In the present embodiment, the substrate 10 is a glass substrate, and constitutes a liquid crystal display surface of the liquid crystal display module A together with the glass substrate 20, as shown in FIG.
The extension 10 for mounting the semiconductor chip 4 is provided on the substrate 10 so as to protrude from the side portion 20 a of the other substrate 20.
A is formed. On the surface of the extension 10A, for example, ITO (Indium Tin Oxide) is deposited,
A transparent electrode pattern P is formed. In the present embodiment, the connection terminal portions 2 are regions in the transparent electrode pattern P where the bumps 41 face, as shown in FIG.

Further, on the substrate 10, adjacent connection terminal portions 2... Outside the plurality of connection terminal portions 2.
A plurality of convex portions 5 having a predetermined thickness corresponding to each region between
... are formed. In the present embodiment, each of the projections 5.
As shown in FIG. 3, when the semiconductor chip 4 is mounted, it is arranged so as to be outside each of the bumps 41... And is formed so as to straddle between the adjacent connection terminal portions 2. As shown in FIG. 2, each of the protrusions 5 has a height from the surface of the substrate 10 larger than the particle size of the conductive particles 32 included in the anisotropic conductive film 3 and the semiconductor chip 4 Substrate 10
Is formed so as to be smaller than the distance h between the semiconductor chip 4 and the substrate 10 when mounted on the substrate.

The anisotropic conductive film 3 is obtained by dispersing and mixing conductive particles 32 in an adhesive base material 31 having an insulating property. The adhesive base material 31 is formed of, for example, a thermosetting resin such as an epoxy resin, and may be in the form of a film (solid) or a viscous liquid before being thermally cured. Is used. In the present embodiment, each of the conductive particles 32 is in the form of a ball having a particle size of about 5 μm.
It is formed by plating Ni and Au on the surface of the resin. When the semiconductor chip 4 is mounted, such an anisotropic conductive film 3 is bonded to the adhesive base material 3 by pressing and heating.
1 is softened, and then cooled and solidified, thereby joining the main surface 4A of the semiconductor chip 4 and the surface of the substrate 10. At this time, in the portion where the thickness of the anisotropic conductive film 3 becomes relatively small, such as between the bumps 41 and the connection terminal portions 2, as shown in FIG.
1 and the connection terminal portions 2 are interposed so as to be sandwiched between the semiconductor chip 4 and the connection terminal portions 2.
On the other hand, in a portion where the thickness of the anisotropic conductive film 3 is relatively large, the conductive particles 32 are kept in a dispersed state, and the insulating property is maintained.

Hereinafter, a method for mounting a semiconductor chip will be described step by step.

In order to mount the semiconductor chip 4 on the substrate 10, first, as shown in FIG. 4, adjacent connection terminal portions 2 on the substrate 10 outside the plurality of connection terminal portions 2. A plurality of convex portions 5 having a predetermined thickness are formed in correspondence with the respective regions therebetween.

Each of the convex portions 5 is formed by a photolithography method using a photosensitive resin. More specifically, first, as shown in FIG.
... (and the transparent electrode pattern P) formed on the substrate 10
The photosensitive resin 5a is applied to the entire surface of the substrate. In this step, the photosensitive resin 5a has a predetermined thickness of the convex portion 5, that is, a height from the surface of the substrate 10 larger than a particle size of the conductive particles 32, and the semiconductor chip 4 is mounted on the substrate 10. The coating is performed so as to be smaller than the distance h between the semiconductor chip 4 and the substrate 10 at the time of the contact. In addition, photosensitive resin 5
In the present embodiment, a negative photosensitive polyimide in which the exposed portion is insoluble in the developer is used as a. Next, exposure is performed according to the shape of each convex portion 5. In this step, in the present embodiment, in this embodiment, the exposure mask 50 having an opening 50a of a predetermined shape at a portion corresponding to each of the protrusions 5.
Is used. As shown in FIG. 7B, the exposure mask 50 is brought into close contact with the photosensitive resin 5a, and ultraviolet light or the like is irradiated thereon. Thereafter, unnecessary portions of the photosensitive resin are removed by immersion in a developer or the like, so that the respective convex portions 5 are formed.

The semiconductor chip 4 is a drive I for driving a liquid crystal.
In the case of C, in order to increase the definition of the liquid crystal display,
The number of bumps becomes relatively large, and accordingly, the distance between adjacent connection terminal parts 2 must be made relatively small (about several tens of μm). Therefore, it is necessary to form a large amount of the protrusions 5 having a relatively small size. As described above, by forming each of the protrusions 5 by the photolithography method using the photosensitive resin, the protrusions 5 are formed. Formation can be facilitated.

Next, as shown in FIG.
An anisotropic conductive film 3 is disposed thereon. In the present embodiment, the anisotropic conductive film 3 is formed such that the adhesive base material 31 is formed in a film shape and is sized to cover a predetermined region including the connection terminal portions 2 on the substrate 10. The object is placed on the substrate 10. Note that the anisotropic conductive film 3 is
Substrate 10 so as not to be inadvertently displaced on
Preferably, it is temporarily fixed to the surface.

Next, the semiconductor chip 4 is attached to the main surface 4A.
Is thermocompression-bonded to the substrate 10 so that the bumps 41 correspond to the connection terminals 2. In the present embodiment, in this step, the semiconductor chip 4 is previously placed on the anisotropic conductive film 3 by using an adsorption collet or the like.
As shown in FIG. 6, the heating head 9 is pressed against the substrate 10 from above the semiconductor chip 4 with a predetermined pressure. At this time, the conductive particles 32 are connected to the bumps 41 and the connection terminals 2.
, So that the semiconductor chip 4 and the connection terminal portions 2 can be electrically connected. afterwards,
The anisotropic conductive film 3 is cooled and solidified, and the semiconductor chip 4 and the substrate 10 are joined.

Next, the operation of the above-described semiconductor chip mounting method will be briefly described.

When the semiconductor chip 4 is thermocompression-bonded, the adhesive base material 31 of the anisotropic conductive film 3 is melted by the heat of the heating head 9 and becomes in a flowable state. When the semiconductor chip 4 is pressed in such a state, the adhesive base material 31 and the conductive particles 3 are pressed.
2 tend to flow from the central portion of the semiconductor chip 4 toward the outside thereof. In the related art, it is extremely difficult to sandwich the conductive particles 32 in this gap, and a sufficient number of the conductive particles 32 cannot be interposed in this gap.

However, according to the above-described method for mounting a semiconductor chip, a plurality of protrusions 5 having a predetermined thickness are formed on the substrate 10, so that the conductive particles 32 It tends to flow from the central portion of the chip 4 to between the convex portions 5. These convex portions 5 are formed outside the plurality of connection terminal portions 2 so as to correspond to the respective regions between the adjacent connection terminal portions 2. Therefore, most of the conductive particles 32. Terminal part 2 ... passes over. Therefore, as shown in FIG.
Conductive particles 3 sandwiched in the gaps between
2 can be increased. As a result, the respective bumps 41 and the respective connection terminal portions 2 can be reliably connected to each other, and a connection failure of the semiconductor chip can be prevented.

As described above, each of the projections 5 is formed when the height from the surface of the substrate 10 is larger than the particle size of the conductive particles 32 and the semiconductor chip 4 is mounted on the substrate 10. Since it is formed to be smaller than the distance h between the semiconductor chip 4 and the substrate 10, a gap is generated between the upper surface of the protrusions 5 and the main surface 4A of the semiconductor chip. Thereby, the melted anisotropic conductive film 3 can flow out of the gap. Therefore, when the semiconductor chip 4 is mounted on the substrate 10, it is possible to prevent the distance between the substrate 10 and the semiconductor chip 4 from becoming unnecessarily large. As described above, since the height of each of the protrusions 5 from the surface of the substrate 10 is larger than the particle diameter of the conductive particles 32, the conductive particles 32 pass over the protrusions 5. Outflow can be suppressed, and the effect of increasing the number of conductive particles 32 interposed in the gap between each bump 41 and each connection terminal portion 2 is not significantly impaired.

FIG. 9 shows the area S of the connection terminals 2 and the conductive particles 32 interposed in the gaps between the bumps 41 and the connection terminals 2 in the semiconductor chip mounting structure described above. Is a graph showing the relationship with the number N of ... based on the results of experiments conducted by the inventor of the present application. In this experiment, the distance between the semiconductor chip 4 and the substrate 10 when the semiconductor chip 4 was mounted on the substrate 10 was 17 μm.
m, the height of the projection 5 is 10 μm, and the length of the connection terminal 2 is 1
00 μm, the distance between the connection terminal portions 2...: The length between the connection terminal portions 2.
The number N of the conductive particles was counted for each of 0, 3000, 4000, and 5000 μm ² . Further, in the graph of FIG. 9, the mounting structure (conventional example) of the semiconductor chip on which the above-mentioned protrusions 5 are not formed is indicated by a chain line.

According to this graph, in the semiconductor chip mounting method of the present embodiment, the conductive particles interposed in the gaps between each bump 41 and each connection terminal portion 2 per unit area of each connection terminal portion 2. It can be seen that the number of 32... Is about twice that of the conventional example. In this manner, by forming the above-mentioned protrusions 5.
And the conductive particles 32 interposed in the gaps between the connecting terminals 2.
… Can be greatly increased.

Of course, the scope of the present invention is not limited to the above embodiment. For example, the above embodiment is applied to a liquid crystal display module,
Needless to say, the present invention is applicable not only to the liquid crystal display module but also to other devices.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an example of a mounting structure of a semiconductor chip according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a schematic perspective view showing an arrangement of convex portions in FIG.

FIG. 4 is a cross-sectional view for explaining a semiconductor chip mounting method according to the present invention.

FIG. 5 is a cross-sectional view for explaining a semiconductor chip mounting method according to the present invention.

FIG. 6 is a cross-sectional view for explaining a semiconductor chip mounting method according to the present invention.

FIG. 7 is a cross-sectional view for explaining a semiconductor chip mounting method according to the present invention.

FIG. 8 is a plan view showing a distribution state of conductive particles in FIG.

FIG. 9 is a graph showing experimental results according to the embodiment of the semiconductor chip mounting method according to the present invention.

FIG. 10 is a schematic perspective view showing an example of a conventional mounting structure of a semiconductor chip.

FIG. 11 is a sectional view taken along the line XI-XI in FIG. 10;

FIG. 12 is a plan view showing a distribution state of conductive particles in FIG.

[Explanation of symbols]

 2 Connection terminal part 3 Anisotropic conductive film 4 Semiconductor chip 5 Convex part 4A Main surface 10 Substrate 32 Conductive particles 41 Bump

Claims (5)

[Claims] 1. A semiconductor chip having a plurality of bumps protrudingly formed at a peripheral portion of a main surface is provided on a substrate having a plurality of connection terminals corresponding to each of the plurality of bumps via an anisotropic conductive film. Forming a plurality of convex portions having a predetermined thickness corresponding to each region between adjacent connection terminal portions, outside the plurality of connection terminal portions in the substrate, A step of disposing an anisotropic conductive film on the substrate; and a step of thermocompression-bonding the semiconductor chip toward the substrate such that each bump corresponds to each connection terminal, with the main surface facing down. A method of mounting a semiconductor chip, comprising: 2. The method according to claim 1, wherein the height of the projection from the surface of the substrate is larger than the particle size of conductive particles contained in the anisotropic conductive film, and the semiconductor chip is mounted on the substrate. The method of mounting a semiconductor chip according to claim 1, wherein the semiconductor chip is formed to be smaller than a distance between the semiconductor chip and the substrate. 3. The semiconductor chip mounting method according to claim 1, wherein the substrate is a glass substrate, and the connection terminal portion is a transparent electrode. 4. The method according to claim 3, wherein the projection is formed by a photolithography method using a photosensitive resin. 5. A semiconductor chip having a plurality of bumps protrudingly formed on a peripheral portion of a main surface is provided on a substrate having a plurality of connection terminal portions corresponding to each of the plurality of bumps via an anisotropic conductive film. A plurality of protrusions having a predetermined thickness are formed outside the plurality of connection terminal portions on the substrate in correspondence with each region between adjacent connection terminal portions. A mounting structure of a semiconductor chip, characterized in that: