JPH06252207A - Method for mounting semiconductor chip - Google Patents

Abstract

PURPOSE:To provide a large tolerance of the height of a connecting bump forming the electrode of an IC chip while maintaining the connection strength between the IC chip and a liquid crystal display panel, and to prevent the occurrence of a crack in the connecting bump due to solder. CONSTITUTION:A solder foil 7 mounted on a conductor board 5 is heated and melt in a reducing gas atmosphere, a connecting bump 3 of an IC chip 1 is put in contact with a molten solder 7a to deposit the solder 7a on the connecting bump 3. With a solder part 7b on the tip of the connecting bump 3 on which the solder 7a is deposited being in contact with an electrode 19 on a liquid crystal display panel 17, the IC chip 1 is heated in a reducing gas atmosphere, thereby connecting the connecting bump 3 on the IC chip 3 with the electrode 19 on the liquid crystal display panel 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor chip mounting method for mounting a semiconductor chip on a circuit board.

[0002]

2. Description of the Related Art In recent years, a semiconductor chip has been directly attached to a metallized transparent electrode on a glass substrate of a liquid crystal display panel by face down, whereby an efficient use of a mounting area and a rationalization of wiring are attempted.

As a method of mounting such a semiconductor chip, for example, there is one described in Japanese Patent Application Laid-Open No. 2-199847. In this method, first, the tip of a protruding electrode formed on a semiconductor chip is brought into contact with a hot-melt conductive adhesive provided on a support film under heating conditions, and the adhesive is attached to the tip of the protruding electrode. Next, when the semiconductor chip is pressed and heated while the tip of the protruding electrode of this semiconductor chip is in contact with the transparent electrode on the glass substrate of the liquid crystal display panel, the adhesive at the tip of the protruding electrode melts The transparent electrode is electrically connected via an adhesive. By using a heat-melting type of conductive adhesive, the semiconductor chip can be replaced by heating, and the semiconductor chip has repairability.

On the other hand, face down bonding by the so-called flip chip method, in which connection bumps made of solder are formed on the electrodes of a semiconductor chip, and the bumps are brought into contact with transparent electrodes on a glass substrate to melt and fix the solder,
It was announced by IBM Corporation in 964, and since then, each company has developed the material and forming method of the bump electrode, that is, the solder bump. Among them, in JP-A-63-122155, after forming a multi-layered intermediate metal layer consisting of a barrier layer such as Cr and Ti and an adhesion strength enhancing layer such as Cu and Au on an Al electrode of a semiconductor chip. , Spherical connection bumps are formed.
This connection bump is made of In-Sn as a base material and is made of Zn, S.
By adding an element having a high oxygen affinity, such as b, Al, Ti, or Cu, it is possible to mount directly on the transparent electrode by electroless plating or vapor deposition without forming a metal film, and the manufacturing cost is reduced.

[0005]

However, in the conventional method of mounting a semiconductor chip as described above, since the adhesive strength of the former adhesive is not sufficient, it is mounted on, for example, a glass substrate. It is necessary to coat the encapsulant so as to wrap the entire semiconductor chip in the opened state, and to strengthen the connection strength by the adhesive force between the coating agent and the glass substrate. Therefore, in the conventional mounting method, the number of working steps is increased, and if the height of the protruding electrode is too high, the coating agent is cracked between the semiconductor chip and the glass substrate, and therefore the height of the protruding electrode is ± 2 μm.
The manufacturing cost must be high because it must be within a very strict tolerance of about m. Further, in the latter case where the spherical solder connection bumps are formed on the Al electrodes of the semiconductor chip, cracks are likely to occur in the spherical solder portion due to thermal shock or the like, which may cause poor conduction. is there.

Therefore, according to the present invention, while maintaining a high connection strength between the semiconductor chip and the glass substrate, the tolerance of the height of the protruding electrode on the semiconductor chip can be made large, and further, the occurrence of cracks at the connection portion due to solder can be prevented. Is intended.

[0007]

In order to achieve the above-mentioned object, the present invention is to form a protruding electrode on a semiconductor chip while placing a solder foil on a heating plate in a reducing gas atmosphere and heating and melting. Then, the projecting electrodes are brought into contact with the heated and melted solder to attach the solder to the projecting electrodes, and the projecting electrodes having the solder adhered and solidified are heated in a reducing gas atmosphere in a state of being brought into contact with the electrodes on the circuit board. The protruding electrodes on the semiconductor chip and the electrodes on the circuit board are connected by melting the solder and solidifying the melted solder.

[0008]

According to such a semiconductor chip mounting method,
Since solder is used to connect the protruding electrode on the semiconductor chip to the circuit board, the connection strength is higher than that using an adhesive. Moreover, since the solder only adheres to the protruding electrodes, there is no problem if the tolerance of the height of the protruding electrodes is increased to some extent, and cracks occur even when subjected to thermal shock, as compared to spherical solder parts. It becomes difficult to do.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1A to 1D are work process diagrams of a semiconductor chip mounting method showing an embodiment of the present invention.
In FIG. 1A, the connection bumps 3 made of Au which is a protruding electrode are formed on the IC chip 1 which is a semiconductor chip. In FIG. 1B, a Sn or In-based solder foil 7 having a thickness of about 10 to 50 μm is placed on a conductor plate 5 such as a Cu plate serving as a heating plate, and the solder foil 7 is connected to a power source 9 and a resistor. Bowl 11
And using an ammeter 13 to heat and melt in a reducing atmosphere of N ₂ + H ₂ . In FIG. 1C, the IC chip 1 on which the connection bumps 3 are formed is vacuum-chucked by the collet 15 in a reducing atmosphere of N ₂ + H ₂ , and the tips of the connection bumps 3 are melted with solder 7a on the conductor plate 5. In the figure, an operation of bringing them into close contact with each other as shown by an arrow A is shown. The solder attached to the tips of the connection bumps 3 by bringing the tips of the connection bumps 3 into contact with the solder 7a is 1/4 to 1 / the height of the connection bumps 3.
5 is enough.

Next, in FIG. 1D, the solder portion attached to the tip of the connection bump 3 of the IC chip 1 is attached to the metalized electrode 19 such as Au plating on the liquid crystal display panel 17 as a circuit board. With 7b in contact,
The IC chip 1 is heated in a reducing atmosphere of N ₂ + H ₂ to melt and connect the solder portion 7b at the tip of the connection bump 3. As a result, the solder diffuses into both the connection bumps 3 of the IC chip 1 and the electrodes 19 of the liquid crystal display panel 17, and the two can be electrically connected.

According to such a mounting method, since solder is used to connect the connection bumps 3 on the IC chip 1 to the electrodes 19 of the liquid crystal display panel 17, a sealing agent for strengthening the connection strength is used. The connection strength is high without the need for working steps such as coating. Moreover,
Since the solder portion 7b simply adheres to the tips of the connection bumps 3, there is no problem even if the tolerance of the height of the connection bumps 3 is increased to some extent, and even if a thermal shock is applied, it is more than that of a spherical solder portion. It is difficult for cracks to occur. Further, since Au is used for the connection bumps 3, the connection bumps 3 serve as a cushioning material when receiving a thermal shock, and cracks and the like in the solder portion 7b are further prevented.

[0013]

As described above, according to the present invention, since the solder is used to connect the protruding electrode on the semiconductor chip and the circuit board, a sealant for strengthening the connection strength is used. The connection strength can be increased without requiring a working process such as coating. Moreover, since the solder only adheres to the bump electrodes, the tolerance of the height of the bump electrodes can be increased to some extent, which can reduce the manufacturing cost, and even when the solder bumps are subjected to thermal shock, the spherical solder can be used. Cracks are less likely to occur compared to the parts.

[Brief description of drawings]

FIG. 1 is a work process diagram of a semiconductor chip mounting method according to an embodiment of the present invention.

[Explanation of symbols]

 1 IC Chip (Semiconductor Chip) 3 Connection Bump (Protruding Electrode) 5 Conductor Plate (Heating Plate) 7 Solder Foil 17 Liquid Crystal Display Panel (Circuit Board) 19 Electrode

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 4, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

According to such a mounting method, since solder is used to connect the connection bumps 3 on the IC chip 1 to the electrodes 19 of the liquid crystal display panel 17 , the connection strength is high. In addition, since the solder portion 7b simply adheres to the tip of the connection bump 3, there is no problem even if the tolerance of the height of the connection bump 3 is increased to some extent, and the solder portion 7b has a spherical shape even when it is subjected to thermal shock. Compared to this, cracks are less likely to occur. Further, since Au is used for the connection bumps 3, the connection bumps 3 serve as a cushioning material when receiving a thermal shock,
Generation of cracks or the like on the solder portion 7b is further prevented.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

As described above, according to the present invention, solder is used to connect the projecting electrodes on the semiconductor chip to the circuit board. Therefore, as compared with the heat-melting type conductive adhesive,
High connection strength can be obtained. Moreover, since the solder only adheres to the protruding electrodes, the height tolerance of the protruding electrodes is small.
Since it may be large, it is necessary to align the shape and height of the protruding electrodes.
Since it is not necessary, the manufacturing cost can be reduced, and cracks are less likely to occur even when subjected to thermal shock, as compared with the spherical solder portion.

Claims (1)

[Claims] 1. A bump electrode is formed on a semiconductor chip, and a solder foil is placed on a heating plate in a reducing gas atmosphere and heated and melted. On the semiconductor chip by heating in a reducing gas atmosphere with the protruding electrode with the solder adhered and solidified in contact with the electrode on the circuit board to melt the solder and solidifying the melted solder. A method of mounting a semiconductor chip, characterized in that the protruding electrode of (1) and the electrode on the circuit board are connected.