JP2009032949A - Ic chip, and method of mounting ic chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique of connecting an IC chip using an anisotropic conductive adhesive, which can prevent a connection failure and improve conduction reliability. <P>SOLUTION: The IC chip has a plurality of mounting terminals 3, 4 as connection terminals on a chip body 2 and is mounted using an anisotropic conductive adhesive. Of the mounting terminals 3, 4, the mounting terminals 4 in previously specified regions are height-difference mounting terminals 4 each in which the height of a connection portion is different in a certain bump and a top portion 4a of the mounting terminal 4 is higher than the other mounting terminals 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an IC chip having bumps as connection terminals, and a mounting method using the IC chip.

  Conventionally, for example, an anisotropic conductive adhesive film has been used as means for mounting an IC chip on a wiring (glass) substrate such as a liquid crystal display device (see, for example, Patent Document 1).

  In order to mount an IC chip using this anisotropic conductive adhesive film, an anisotropic conductive adhesive film is interposed between the connection terminal (bump) of the IC chip and the electrode terminal of the wiring base, and the thermocompression bonding head. The IC chip is heated and pressed by thermocompression bonding.

  However, conventionally, a connection failure may occur with respect to a specific bump among the bumps provided on the IC chip.

  For example, as shown in FIG. 7 (a), poor connection between the bumps 103 and 104 provided on the edge of the chip body 102 of the IC chip 101 (within ellipses A and B) provided on the short side. May occur.

  Further, as shown in FIG. 7B, among the bumps 203 to 205 provided on the long side portion of the chip body 202 of the IC chip 201, the IC chip 201 in which the bumps are provided in a staggered manner on one long side. In such a case, connection failure may occur in the outer bump 204 (in the ellipse C).

Further, in recent years, there is a long and narrow shape of the connection surface of the bump of the IC chip. In such a bump, a connection failure may occur in the vicinity of the chip edge.
JP-A-8-7658

  The present invention has been made to solve the above-described problems of the prior art, and it is possible to connect an IC chip using an anisotropic conductive adhesive capable of improving conduction reliability without causing a connection failure. The purpose is to provide technology.

In order to achieve the above object, an invention according to claim 1 is an IC chip having a plurality of bumps on a chip body as connection electrodes and mounted by an anisotropic conductive adhesive, wherein the plurality of bumps Among the bumps in the region specified in advance, the height of the connection portion is different in one bump, and the top of the bump has a height difference bump higher than the height of the other bump.
The invention according to claim 2 is the invention according to claim 1, wherein the plurality of bumps are provided at an edge of a rectangular connection side surface, and the height difference bumps of the plurality of bumps are formed on the connection side surface. It is arranged at the long side edge.
The invention according to claim 3 is the invention according to claim 1, wherein the plurality of bumps are provided in a plurality of rows along the edge of the connection side surface, and the height difference bumps of the plurality of rows of bumps are , Is arranged outside the edge of the connection side surface.
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, a difference in height of a connection portion in one mounting terminal is used for the mounting terminal in the predetermined area. It is 5% to 95% of the particle size of the conductive particles of the anisotropic conductive adhesive.
According to a fifth aspect of the present invention, an anisotropic conductive adhesive is disposed between a wiring board on which a predetermined connection electrode is formed and the IC chip according to any one of the first to fourth aspects, and heating and An IC chip mounting method including a step of bonding the wiring substrate and the IC chip by applying pressure and electrically connecting the electrodes to each other.

In the case of the present invention, among a plurality of mounting terminals provided on the chip body as connection electrodes, a region specified in advance (for example, along the short-side edge region of the rectangular connection side surface or the edge of the connection side surface) For the mounting terminals in the outer edge area when the mounting terminals are arranged in a plurality of rows), the height of the connection portion is different within one mounting terminal, and the top of the mounting terminal is the other mounting terminal Because it has a height difference mounting terminal that is higher than the height, when conducting thermocompression bonding using an anisotropic conductive adhesive, it compresses sufficiently certain conductive particles that were insufficiently crushed by the prior art be able to.
As a result, according to the present invention, since the compression state of the conductive particles on each mounting terminal can be made uniform, the conduction reliability can be improved in various types of IC chips.
In particular, according to the present invention, it is possible to improve the conduction reliability without using conductive particles having a large diameter, and even when the connecting surface shape of the mounting terminal is elongated, so that fine pitch bump-shaped mounting is possible. This is useful for an IC chip having a terminal.

  ADVANTAGE OF THE INVENTION According to this invention, the connection technique of the IC chip using the anisotropic conductive adhesive which can improve conduction | electrical_connection reliability without generating a connection failure can be provided.

  Hereinafter, preferred embodiments of an IC chip and an IC chip mounting method according to the present invention will be described with reference to the drawings.

  As will be described later, the anisotropic conductive adhesive 7 used in the present invention is one in which conductive particles 9 are dispersed in an insulating adhesive resin 8. It can be applied to any of the shapes.

  1A and 1B are schematic views showing an embodiment of an IC chip according to the present invention. FIG. 1A is a plan view and FIG. 1B is a front view. FIGS. 2A and 2B and FIGS. 3A and 3B are explanatory views showing the principle of the present invention.

  As shown in FIGS. 1A and 1B, an IC chip 1 according to the present embodiment is used, for example, in a COG (Cip On Glass) system, and has a rectangular parallelepiped chip body 2. The connecting side surface 2a is formed in a rectangular shape.

  On the edge (long side and short side) of the connection side surface 2a of the IC chip 1, a plurality of mounting terminals 3 and 4 using bumps as below are provided as connection electrodes at a predetermined pitch. Yes. The mounting terminals 3 and 4 are arranged such that the planar shape thereof is a rectangular shape and the short side thereof faces the edge of the connection side surface 2 a of the IC chip 1.

  In the case of the present embodiment, the mounting terminals 3 and 4 are each formed by forming a bump made of Au (gold) on a patterned electrode part made of Al (aluminum).

Here, in order to form the Au bump on the Al electrode portion, for example, a known plating method described below (see, for example, Japanese Patent No. 2936680) can be used.
That is, in the plating method, an Si substrate on which an Al wiring (electrode part) and an insulating film are formed is prepared, an opening for connecting the Al wiring to the outside is formed in the insulating film, and Ti (titanium) is formed on the entire surface. ) Is sputtered to form a Ti film, and Pd (palladium) is sputtered to form a Pd film. Next, a resist is deposited thereon and patterned to form a resist mask having openings for forming Au bumps.
Further, Au plating is performed on the Pd film from the above-mentioned openings to form an Au plating layer, and then the above-described resist mask is removed, and the Pd film and Ti film are etched using the gold plating layer as a mask. . As a result, an Au bump formed on the Al electrode portion is obtained.

  In the present invention, among the plurality of mounting terminals 3 and 4, for the mounting terminals in the region specified in advance, the height of the connection portion is different in one mounting terminal, and the top of the mounting terminal is another mounting terminal. It is higher than the height.

  In the present embodiment, as shown in FIGS. 1A and 1B, the mounting terminals 4 provided on the short side edge portions (areas indicated by ellipses A and B) of the connection side surface 2a of the IC chip 1 are The height of the connecting portion is different in one mounting terminal, and the top portion 4a of the mounting terminal is configured to be higher than the height of the mounting terminal 3 on the long side edge (hereinafter referred to as “height difference mounting”). Terminal ").

  In the case of the present invention, the method of making the height of the top 4a of the height difference mounting terminal 4 on the short side edge of the IC chip 1 higher than the height of the mounting terminal 3 on the long side edge is particularly limited. However, from the viewpoint of the simplicity of the manufacturing process, the height difference mounting terminal 4 is initially formed thick, and the bump surface layer portion other than the region where the top portion 4a is formed is removed by etching or the like to increase the height of the region. It is preferable to reduce the thickness.

  In this case, for example, as shown in FIG. 3B, after forming the passivation film 21 on the connection side surface 2a of the IC chip 1, the bump part 40 is formed on the Al electrode part 20 by the above method, Further, the surface layer portion is partially lowered by etching (region indicated by reference numeral 4b).

  Thereby, the height of the connecting portion is different within one mounting terminal, and the height difference mounting terminal 4 is configured such that the top portion 4a of the mounting terminal is higher than the height of the mounting terminal 3 at the long side edge. An IC chip 1 having the following is obtained.

  In the case of the present invention, the position where the top portion 4a is provided in the height difference mounting terminal 4 is not particularly limited, but from the viewpoint of more reliably increasing the compression rate of the conductive particles 9, the IC chip of the height difference mounting terminal 4 is provided. It is preferable to provide the top part 4a in the part close | similar to the (short) edge part of the 1 connection side surface 2a.

The principle of the present invention will be described below with reference to FIGS. 2 (a) and 2 (b) and FIGS. 3 (a) and 3 (b).
Here, consider a case where the IC chip 1 is mounted on the wiring substrate 11 provided with the connection electrodes 13 and 14. The connection electrodes 13 and 14 of the wiring board 11 correspond to the mounting terminal 3 and the height difference mounting terminal 4 of the IC chip 1, respectively.

  When the IC chip 1 is mounted, as shown in FIG. 2A, the anisotropic conductive adhesive 7 is disposed between the wiring substrate 11 and the IC chip 1 and thermocompression bonding is performed. Heating and pressing are performed from the chip 1 side.

  In this case, the reached temperature of the IC chip 1 is about 200 to 250 ° C., but the reached temperature on the wiring board 11 side is about 100 to 150 ° C., which is lower than that of the IC chip 1. It is in an extended state. For this reason, the shrinkage of the chip body 2 of the IC chip 1 is large after cooling after mounting, for example, as shown in FIG. 2B, the warp of the IC chip 1 becomes larger than the wiring substrate 11, and as a result, Warpage occurs in the entire mounting part.

  In this state, stress is easily applied to the short side edge 2b of the edges of the connection side surface 2a of the IC chip 1, so that the conductive particles 9 of the anisotropic conductive adhesive 7 as shown in FIG. The conductive particles 9b in the region closest to the short side edge 2b are smaller than the conductive particles 9 in the region on the inner side of the connecting side surface 2a, and the deformation (compression) rate of the conductive particles 9b tends to be insufficient. It is in.

  Therefore, for example, as shown in FIG. 3B, the height difference mounting terminal 4 having the above-described top portion 4a is provided on the short side edge portion 2b of the connection side surface 2a of the IC chip 1, and the height of the top portion 4a is provided. Is higher than the height of the mounting terminal 3 provided at the long side edge of the connection side surface 2a, so that the height difference mounting terminal 4 at the short side edge of the IC chip 1 is uniform with respect to the conductive particles 9. The compression rate can be made uniform by pressing with force. As a result, the compressibility of the conductive particles 9 at each edge of the connection side surface 2a of the IC chip 1 can be made uniform.

  4 (a) (b), FIG. 5 (a) (b) and FIG. 6 (a) (b) show other embodiments of the present invention. These parts are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in FIGS. 4A and 4B, the IC chip 1A according to the present embodiment has mounting terminals 3, 4A, and 5 as connection electrodes on the long side edge of the connection side surface 2a of the chip body 2. It is provided.
That is, in this embodiment, two rows of mounting terminals 4A and 5 are arranged in a staggered pattern along one long side edge of the connection side surface 2a of the IC chip 1A. .

  Then, the above-described height difference mounting terminal 4A is provided on the outer side of one long side of the connection side surface 2a of the IC chip 1A (region indicated by an ellipse C). That is, the height difference mounting terminal 4A is configured such that the height of the connection portion is different in one mounting terminal, and the top portion 4a of the mounting terminal is higher than the height of the mounting terminal 3 on the long side edge. Has been.

  In this case, the top portion 4a of the height difference mounting terminal 4A is provided in a portion near the long edge portion of the connection side surface 2a of the IC chip 1A. Moreover, the method similar to the said embodiment can be employ | adopted for the method of providing the top part 4a in the elevation difference mounting terminal 4A.

  In the case of the present embodiment, no mounting terminal is provided on the short side edge of the connection side surface 2a of the IC chip 1A.

  In the present embodiment, when heating and pressurization are performed from the IC chip 1A side when the IC chip 1A is mounted, the center portion of the chip body 2 is compared with the long side edge as shown in FIG. Tend to sink.

  For this reason, after mounting the IC chip 1A, a difference occurs in the height between the central portion of the chip body 2 and the long side edge. This difference is particularly large (about several μm) at the long side edge on the side where the two rows of mounting terminals 4A and 5 are provided.

  As a result, the pressing force against the conductive particles 9 of the mounting terminals 4A outside the long side edge is smaller than that of the conductive particles 9 in other regions, and as shown in FIG. The deformation (compression) rate of the conductive particles 9c in the region closest to the edge 2c tends to be insufficient.

  Therefore, the height difference mounting terminal 4A having the top 4a is provided as a mounting terminal outside the long side edge 2c of the connection side 2a of the IC chip 1A, and the height of the top 4a is set to the long side of the connection side 2a. By making it higher than the height of the mounting terminal 3 inside the side edge portion 2c (see FIG. 6B), it is uniform with respect to the conductive particles 9 in each portion of the edge portion of the IC chip 1A as in the above embodiment. The compression rate can be made uniform by pressing with the force of.

The present invention is not limited to the above-described embodiment, and various changes can be made.
For example, the height difference mounting terminal having the top portion is not limited to all of the elements arranged on the edge (short side portion or long side portion) of the connection side surface as in the above-described embodiment, but part of the mounting It may be a terminal.

  In this case, various changes can be made according to the IC chip, such as providing height difference mounting terminals at the corners of the connection side surface of the chip body.

  Further, the shape and height of the top of the height difference mounting terminal can be appropriately changed according to the size and shape of the IC chip to be used.

  As for the method of providing the top portion on the height difference mounting terminal, as described above, the electrode portion is initially formed thick and the surface layer portion of the electrode portion in the region other than the region where the height of the mounting terminal is increased is etched. In addition to the method of removing the region by reducing the height of the region, the portion where the top portion of the height difference mounting terminal is provided can be multi-layered by providing a metal raised portion on the electrode portion.

  In this case, as a method for forming the raised portion, for example, a sputtering method using aluminum can be employed.

  Furthermore, the present invention can be applied not only to the IC chip of the above embodiment type but also to various types of IC chips.

(A): It is a schematic plan view which shows external appearance structure of embodiment of the IC chip concerning this invention. (B): It is a schematic front view which shows the external appearance structure of the IC chip. (A) (b): It is explanatory drawing which shows the principle of this invention. (A) (b): It is explanatory drawing which shows the principle of this invention. (A): It is a schematic plan view which shows external appearance structure of other embodiment of IC chip based on this invention. (B): It is a schematic side view which shows the external appearance structure of the IC chip. (A) (b): It is explanatory drawing which shows the principle of this invention. (A) (b): It is explanatory drawing which shows the principle of this invention. (A): It is a schematic plan view which shows the external appearance structure of the IC chip which concerns on a prior art example. (B): It is a schematic plan view which shows the external appearance structure of the IC chip based on another prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 IC chip 2 Chip body 2a Connection side surface 2b Short side edge part 3 Mounting terminal 4 Height difference mounting terminal 4a Top part 7 Anisotropic conductive adhesive 9 Conductive particle

Claims (5)

An IC chip having a plurality of mounting terminals on the chip body as connection electrodes and mounted by an anisotropic conductive adhesive,
Among the plurality of mounting terminals, for the mounting terminals in a predetermined area, the height of the connection portion is different in one mounting terminal, and the height difference between the tops of the mounting terminals is higher than the heights of the other mounting terminals. IC chip having mounting terminals.   The plurality of mounting terminals are provided at an edge of a rectangular connection side surface, and the height difference mounting terminal is disposed at an edge of a long side of the connection side among the plurality of mounting terminals. The IC chip described.   The plurality of mounting terminals are provided in a plurality of rows along the edge of the connection side surface, and the height difference mounting terminal is disposed outside the edge of the connection side surface among the plurality of rows of mounting terminals. The IC chip according to claim 1.   The mounting terminal in the region specified in advance has a difference in height of a connecting portion in one mounting terminal of 5% to 95% of a particle size of conductive particles of an anisotropic conductive adhesive to be used. The IC chip according to any one of 1 to 3. An anisotropic conductive adhesive is disposed between the wiring board on which the predetermined connection electrode is formed and the IC chip according to any one of claims 1 to 4,
An IC chip mounting method including a step of bonding the wiring board and the IC chip and electrically connecting the electrodes by heating and pressing.

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