JP3316998B2 - Thin film connector and semiconductor chip mounting method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mounting a semiconductor chip on a printed wiring board with solder bumps interposed therebetween, and more particularly, to a thin film connector and a method for mounting a semiconductor chip which enable high integration of the semiconductor chip. About.

At present, in mounting a highly integrated semiconductor chip having a very large number of connection pins per unit area, instead of the conventional wire bonding, a TAB method, a flip chip method, etc., which can be easily connected even if the number of connection pins is large. Is very commonly used.

[0003] In particular, the flip-chip method in which a semiconductor chip having a large number of connection pins is mounted on a printed wiring board via solder bumps requires all the connection pins simultaneously regardless of the number of connection pins. It is excellent in that it is shortened.

However, in order to increase the degree of integration of the semiconductor chip, the arrangement pitch of the connection pins is reduced to increase the number of connection pins per unit area. It is necessary to consider cooling means such as radiating heat.

However, in the conventional mounting method using the flip chip method, it is difficult to achieve both an increase in the number of connection pins and an improvement in heat radiation efficiency. Therefore, it is desired to establish a mounting method that reduces the arrangement pitch, enables an increase in the number of connection pins, and improves the heat radiation efficiency.

[0006]

2. Description of the Related Art FIG. 4 is a side sectional view showing a conventional mounting method. FIG. 4 shows a conventional method of mounting a semiconductor chip at a predetermined position on a printed wiring board by a flip chip method.
As shown in (a), an anisotropic conductive film 1 in which solder balls 12 are appropriately dispersed in an epoxy-based thermosetting adhesive material 11.
May be used.

That is, the semiconductor chip 3 is mounted on the printed wiring board 2 with the anisotropic conductive film 1 interposed therebetween, and is heated and pressed, so that the thermosetting adhesive 11 is softened and the solder balls 12 are 3 connection pin 31 and printed wiring board 2
It is sandwiched between the upper electrodes 21.

When the thermosetting adhesive 11 is further heated in this state, the thermosetting adhesive 11 is hardened to fix the semiconductor chip 3 on the printed wiring board 2, and the connection pins 31 of the semiconductor chip 3 and the electrodes 21 on the printed wiring board 2 are fixed. Are electrically connected by a solder ball 12 interposed therebetween.

FIG. 4 shows another method of mounting a semiconductor chip on a printed wiring board by a flip chip method.
As shown in (b), for example, the semiconductor chip 3 is pressed and fixed at a predetermined position via a thermosetting adhesive material 4 previously applied on the printed wiring board 2.

The solder balls 12 adhere to the connection pins 31 of the semiconductor chip 3 and, when pressed, contact the electrodes 21 on the printed wiring board 2. By heating in this state, the solder ball 12 is melted and the connection pin 31 and the electrode 21 are electrically connected via the solder.

Since the junction between the printed wiring board 2 and the semiconductor chip 3 is exposed, when moisture or the like enters, a connection failure or the like occurs. Therefore, protection is provided by filling the resin 5 so as to surround the joint between the printed wiring board 2 and the semiconductor chip 3 as shown.

[0012]

According to the above-mentioned method using an anisotropic conductive film, the entire surface of a semiconductor chip is in contact with a printed wiring board via the anisotropic conductive film, and a thermosetting adhesive having high thermal conductivity is provided. , Heat generated in the semiconductor chip can be efficiently released.

However, since the solder balls are appropriately dispersed in the thermosetting adhesive, it is extremely difficult to control the interval between the solder balls. There is a problem that a leak occurs between them.

In the method of bonding with a thermosetting adhesive, the arrangement pitch of connection pins can be reduced because no solder balls are interposed therebetween, but the area in contact with the thermosetting adhesive is small and the heat generated by the semiconductor chip is reduced. There was a problem that it was not possible to escape efficiently.

An object of the present invention is to provide a mounting method in which the arrangement pitch is reduced, the number of connection pins is increased, and the heat radiation efficiency is improved.

[0016]

FIG. 1 is a side sectional view showing a thin film connector according to the present invention. The same object is denoted by the same symbol throughout the drawings.

The above-mentioned problem is caused by a supporter 61 in which a plurality of conical holes 63 are formed on a heat-resistant adhesive film and surrounded by a slope and penetrate the film. With a plurality of conductive balls 62 larger than the opening 64, the conductive balls 62 are inserted into a space formed by facing the wide opening 65 side of the conical hole 63 of the two supporters 61,
Temporarily join the supporters 61 to each other to form conductive balls between the conical holes 63.
This is attained by the thin-film connector of the present invention comprising the pin 62.

[0018]

A supporter having a plurality of conical holes surrounded by a slope and penetrating the film, and a plurality of conductive materials formed of solder or conductive resin and having a particle size larger than the narrow opening of the conical holes. A conductive ball is inserted into a space formed with the wide-open sides of the conical holes of the two supporters facing each other, and the supporters are temporarily joined to sandwich the conductive balls between the conical holes. According to the thin film connector of the present invention, the interval between the solder balls is controlled with high precision, and the arrangement pitch of the connection pins can be reduced.

Moreover, the entire surface of the semiconductor chip mounted on the printed wiring board is in contact with the printed wiring board via the heat-resistant adhesive film, and is generated in the semiconductor chip by using a thermoplastic adhesive having a high thermal conductivity. Heat can be efficiently released. That is, it is possible to realize a mounting method in which the arrangement pitch is reduced, the number of connection pins is increased, and the heat radiation efficiency is improved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a side sectional view showing another embodiment of the thin film connector according to the present invention, and FIG. 3 is a side sectional view showing a mounting method according to the present invention.

As shown in FIG. 1, the thin film connector according to the present invention has a supporter 61 in which a plurality of conical holes 63 are formed in a heat-resistant adhesive film, and is surrounded by a 45-degree slope and penetrates the adhesive film. The hole 63 is formed using a KrF excimer laser or the like via a mask.

The two supporters 61 each having a plurality of conical holes 63 are overlapped so that the wide-opening 65 side of the conical holes 63 faces each other during assembly, and particles formed by solder between the conical holes 63 are formed. A conductive ball 62 having a diameter of 50 μm is inserted and partially heated and temporarily joined.

The conical hole 63 of the supporter 61, which is surrounded by a 45-degree slope, is formed to have a diameter of about 60 μm on the wide mouth 65 side, and a conductive ball 62 having a particle diameter of 50 μm inserted therein is formed. After temporarily joining the supporter 61, the narrow opening of the conical hole 63
Never drop out of 64.

In the case of another embodiment of the present invention, as shown in FIG. 2, a heat-resistant adhesive film has a supporter 61 having a plurality of conical holes 63 formed therein. The penetrating conical hole 63 is formed using a KrF excimer laser or the like via a mask.

In this embodiment, unlike the above embodiment, the thin film solder layer 66 is applied to the surface of the supporter 61 in which the narrow opening 64 side of the conical hole 63 is open, and the thin film on the supporter 61 is replaced with the conductive ball. A solder layer 67 is grown inside the conical hole 63 from the solder layer 66 through the narrow opening 64.

The two supporters 61 each having a plurality of conical holes 63 are stacked so that the wide-opening 65 side of the conical holes 63 face each other during assembly, and a solder layer grown inside the conical holes 63 facing each other. When 67 is melted, it is partially joined by applying heat so that it is easily integrated.

When the two supporters 61 are assembled and temporarily joined, the thin solder layer 66 adhered to the supporters 61 is exposed on the surface. However, since the thin solder layer 66 is extremely thin, heat is applied when mounting the semiconductor chip. There is no short circuit or leakage between the connection pins due to shredding.

In the mounting method according to the present invention, as shown in FIG. 3A, the above-mentioned thin film connector 6 is sandwiched between the semiconductor chip 3 and the printed wiring board 2, and as shown in FIG.
By applying pressure and heat to the thin film connector 6 through the supporters 61, the supporters 61 are permanently joined.

The semiconductor chip 3 and the thin film connector 6 and the thin film connector 6 and the printed wiring board 2 are joined by the heat applied at that time, and the conductive material melted and extruded out of the narrow opening 64 of the conical hole 63. Connection pin 31 and electrode 21 by conductive ball 62
Are electrically connected.

For example, the supporter 61 made of a heat-resistant polyimide film is temporarily joined by applying 200 ° C. heat for 10 minutes. When a pressure of 2.0 MPa is applied and the 270 ° C. heat is applied for 1 minute, the supporter 61 is completely bonded. The bonding of the semiconductor chip to the printed wiring board is performed.

In the conventional method of dispersing solder balls in a thermosetting adhesive, the distance between conductive balls is 100 μm.
m, but the formation of the conical hole 63 using a KrF excimer laser or the like can be performed with high precision and the spacing between the conductive balls should be 30
It can be reduced to about μm.

A supporter having a plurality of conical holes penetrating the film surrounded by a slope in the adhesive film and a plurality of conductive members formed of solder or conductive resin and having a particle size larger than the narrow opening of the conical holes. The conductive balls are inserted into the space formed with the wide-open sides of the conical holes of the two supporters facing each other, and the supporters are temporarily joined to form a conductive ball between the conical holes. With the thin film connector of the present invention sandwiched between the solder balls, the interval between the solder balls is controlled with high precision, and the arrangement pitch of the connection pins can be reduced.

Moreover, the entire surface of the semiconductor chip mounted on the printed wiring board is in contact with the printed wiring board via the anisotropic conductive film, and is generated in the semiconductor chip by using a thermoplastic adhesive having a high thermal conductivity. The heat generated can be efficiently dissipated. That is, it is possible to realize a mounting method in which the arrangement pitch is reduced, the number of connection pins is increased, and the heat radiation efficiency is improved.

[0034]

As described above, according to the present invention, it is possible to provide a mounting method in which the arrangement pitch is reduced, the number of connection pins is increased, and the heat radiation efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a thin film connector according to the present invention.

FIG. 2 is a side sectional view showing another embodiment of the thin film connector according to the present invention.

FIG. 3 is a side sectional view showing a mounting method according to the present invention.

FIG. 4 is a side sectional view showing a conventional mounting method.

[Explanation of symbols]

 2 Printed wiring board 3 Semiconductor chip 6 Thin film connector 21 Electrode 31 Connection pin 61 Supporter 62 Conductive ball 63 Conical hole 64 Narrow opening 65 Wide opening 66 Thin solder layer 67 Solder layer

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takashi Yokouchi 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (56) References JP-A-5-251505 (JP, A) JP-A-4- 312774 (JP, A) JP-A-5-6920 (JP, A) JP-A-4-19971 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/60 311 H01L 23/12 H05K 1/18 H05K 3/32

Claims (3)

(57) [Claims] 1. A supporter (61) which is surrounded by a slope on a heat-resistant adhesive film and has a plurality of conical holes (63) penetrating the film, a supporter (61) formed of solder or conductive resin and having a particle diameter of A plurality of conductive balls (6
2), and the conductive ball (62) is inserted into a space formed with the wide-opening (65) sides of the conical holes (63) of the two supporters (61) facing each other. (61) A thin-film connector characterized by comprising temporarily bonding the conductive balls (62) between the conical holes (63). 2. A supporter (61) in which a plurality of conical holes (63) penetrating the heat-resistant adhesive film and surrounded by a slope are formed, and a thin-film solder layer ( 66)
Layer grown in a conical hole (63) through a narrow opening (64)
(67) A thin film connector comprising two supporters (61) overlapped and temporarily joined so that the wide ports (65) of the conical holes (63) face each other. 3. The thin-film connector (6) according to claim 1 or 2 is sandwiched between a semiconductor chip (3) and a printed wiring board (2), and the thin-film connector (6) is inserted through the semiconductor chip (3). ), The supporter (61) is fully joined by applying pressure and heating.
Further, the semiconductor chip (3) is joined to the printed wiring board (2) via the supporter (61), and the conductive ball (62) or the solder layer (67) is melted to form the conical hole (63). ) Is pushed out of the thin-film connector (6) from the narrow opening (64), and the connection pins (31) of the semiconductor chip (3) are connected to the electrodes (21) of the printed wiring board (2). A semiconductor chip mounting method using a thin film connector.