JPH06216284A - Semiconductor device and method of mounting the same - Google Patents

Abstract

PURPOSE:To enhance flexibility of bare chip mounting system by providing erected pins at the corners of a heat diffusing plate on which a semiconductor pellet is deposited by die bonding method. CONSTITUTION:A quadrilateral cubic heat sink 4 is provided on a semiconductor chip 1 having a bump electrode 2. The pins 3 are erected by the die bonding method at the corners so that these are directed in the same direction as the bump electrode 2 at the rear surface of the quadrilateral cubic heat sink 4. Thereby, when a semiconductor device composed of a semiconductor chip 1 is housed in a case, the pins 3 are dropped in the groove 6 provided in the case 5 for fixing purpose. Therefore, since the semiconductor device is protected during transportation and handling, the device can be freed from damage and also can be treated easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and its mounting method, and more particularly to a semiconductor bare chip mounting technique in the field of electronic equipment.

[0002]

2. Description of the Related Art The conventional technology is "bare chip mounting" Co., Ltd.
Published by Technical Information Association (1990) P. 360-P. 361
IBM's General Purpose Large Computer 308X Series, as described in. Multilayer ceramic substrate (MLC = Multi Layer Cerami)
c) Multiple LSI chips on C-4 connection method (Cont.
rolled Collapse Chip Conn
The heat conduction module (TCM = Thermal Condition Mo
(dule) adopted in the structure.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
(1) Supporting high-density mounting (improving the occupied area ratio of LSI on the board), (2) Productivity, (3) Establishing the mounting form with the minimum number of connection points and high reliability, (4) Many While excellent in handling pins, (1) bump electrodes and LSI chips are easily damaged during transportation and handling, and handling is difficult. (2) alignment and temporary fixing when mounting chips are difficult. There were problems such as the need for dedicated equipment. It is an object of the present invention to solve the above problems and improve the versatility of a bare chip mounting system.
The above and other objects and novel characteristics of the present invention are
It will be apparent from the description of the present specification and the accompanying drawings.

[0004]

The outline of the representative ones of the inventions disclosed in the present application will be briefly described as follows. In order to achieve the above object, an upright pin is provided at a corner portion of a heat diffusion plate to which a semiconductor pellet is die-bonded.

[0005]

According to the above means, the pins installed at the corners of the heat diffusion plate have a function of protecting the bumps and the LSI chips, so that they are not damaged during transportation or handling. Moreover, since the above-mentioned pins function as guide pins when the chip is mounted, alignment is facilitated and dedicated equipment is not required.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. An embodiment will be described with reference to FIG. 1. The semiconductor device shown in the embodiment has an I / 0 (input / output) on the element surface.
Bump electrode 2 made of Pb-Sn fine solder or the like on the terminal portion
A semiconductor chip 1 made of, for example, single crystal silicon
However, it has a structure in which it is die-bonded to a heat sink 4 made of, for example, aluminum nitride, silicon carbide or the like having a pin 3 at a corner portion. As shown in Figure 1,
A semiconductor chip 1 having bump electrodes 2 is provided on the back surface of a quadrilateral heat sink 4 having pins 3 at each corner.
It is die-bonded so that the bump electrode 2 has the same direction as the pin 3. As shown in Figure 1,
The pin 3 projects more than the bump electrode 2 on the semiconductor chip 1. The pins 3 provided at the corners of the heat sink 4 are made of metal, organic material, shape memory alloy, or the like. The chip 1 has a large number of circuit elements formed therein by a well-known technique and is given one circuit function. A specific example of the circuit element includes, for example, a MOS transistor, and these circuit elements form a circuit function of a logic circuit and a memory, for example.

FIG. 2 shows a state in which the semiconductor device of FIG. 1 is housed in a case 5 made of resin or the like.
The pin 3 of the semiconductor device is dropped and fixed in the groove 6 provided in the semiconductor device.

According to the above-described embodiment, the semiconductor chip 1 and the bump electrodes 2 are protected by the heat sink 4 and the pins 3 which are the supports thereof, so that they may be damaged during transportation or handling of the semiconductor device. I will not receive it. In addition, the heat sink 4
Since the parts can be vacuum-adsorbed or load-locked, the semiconductor chip 1 and the bump electrodes 2 do not come into direct contact with the outside, and there is an effect that they can be kept in a clean state.

FIG. 3 shows an example of a method of assembling the semiconductor device of FIG. A base metal layer 7 for improving the wetting of the solder is provided on one main surface of the heat sink 4 provided with the pins 3 and on the rear surface of the semiconductor chip 1, and the preform solder 8 is sandwiched between the base metal layer 7 and the base metal layer 7 to heat the solder above the melting temperature of the solder. By doing so, a close contact structure is obtained. At this time, the soldering apparatus for the semiconductor chip 1 can be self-aligned by the surface tension when the solder is melted by the pattern position of the underlying metal layer 7 having the same size as the semiconductor chip 1 provided on the surface of the heat sink 4.

FIG. 4 shows a method of mounting the semiconductor device of FIG. 1 on a circuit board 9 having at least one layer of wiring (not shown). As shown in FIG. 4A, by inserting the pin 3 into the alignment hole 10 provided on the main surface of the circuit board 9, the bump electrode 2 is positioned at the external electrode portion on the main surface of the circuit board 9 not shown. It is fitted and temporarily fixed. Next, as shown in FIG. 4B, the flip-chip connection 20 is formed by heating the bump electrode 2 at a temperature equal to or higher than the melting temperature in the state of FIG. 4A, and the face-down mounting is completed. At this time, an inert gas having an oxygen concentration of 10 ppm or less, or a gas obtained by adding 10 to 20% of hydrogen thereto is used as a heating atmosphere, and a flux is also used if necessary. In addition, the alignment hole 10 is processed so that the pin 3 can slide smoothly,
In the mounting process described above, the pin 3 is slightly lowered to leave a clearance at the bottom of the hole 3. According to the above-mentioned embodiment, there is an effect that the positioning and the temporary fixing at the time of mounting the semiconductor chip become easy and the dedicated device becomes unnecessary.

FIG. 5 shows a modification of FIG. 1, in which a corner portion of the heat sink 4 is provided with a protrusion 11 and the pin 3 is attached thereto. According to the present embodiment, a larger semiconductor chip 1 can be attached to the heat sink 4, which has the effect of facilitating the inspection of the connection portion after mounting on the circuit board 9.

FIG. 6 is a modified example of FIG. 1, in which the middle of the pin 3 is bent in an L shape so that the mounting position of the corner pin projects outward from the four sides of the heat sink 4. For example: The pin 12 in this case also has the same effect as that of the embodiment shown in FIG.
Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

[0013]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows. According to the present invention, the bump electrode and the LSI chip are protected during transportation and handling, so that the bump electrode and the LSI chip can be prevented from being damaged and can be easily handled. Further, according to the present invention, there is an effect that alignment and temporary fixing when mounting the LSI chip face down are facilitated and further, dedicated equipment is not required.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

2 is a schematic cross-sectional view of the semiconductor device of FIG. 1 when housed in a case.

FIG. 3 is a schematic cross-sectional view showing a method of assembling the semiconductor of FIG.

4A and 4B are schematic cross-sectional views showing a mounting method of the semiconductor device of FIG.

FIG. 5 is a perspective view of a modification of FIG.

FIG. 6 is a perspective view of a modification of FIG. 1.

[Explanation of sign]

 DESCRIPTION OF SYMBOLS 1 ... Semiconductor chip 2 ... Bump electrode 3 ... Pin 4 ... Heat sink 5 ... Case 6 ... Groove 7 ... Base metal layer 8 ... Preform solder 9 ... Circuit board 10 ・ ・ ・ Alignment hole 11 ・ ・ ・ Projection 12 ・ ・ ・ Pin 20 ・ ・ ・ Flip chip connection

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kanji Otsuka 2326 Imai, Ome-shi, Tokyo Hitachi, Ltd. Device Development Center

Claims (3)

[Claims] 1. A semiconductor device, wherein a semiconductor pellet is die-bonded to one main surface of a heat diffusion plate, and upright pins are provided at corners of the heat diffusion plate. 2. The semiconductor pellet has a protruding electrode, and when the semiconductor pellet is die-bonded to the heat diffusion plate, the pin upright at the corner portion of the heat diffusion plate according to claim 1, The semiconductor device according to claim 1, wherein the semiconductor device protrudes from the protruding electrode of the semiconductor pellet. 3. A method of mounting a semiconductor device according to claim 1, wherein the semiconductor device according to claim 1 is mounted on a circuit board by pins that are upright at the corners of a heat diffusion plate.