JPH05343448A - Soldering jig for semiconductor device - Google Patents

Abstract

PURPOSE:To provide a soldering jig for suitably soldering by ingeniously preventing flow-out of molten solder to a periphery of a semiconductor chip by a capillary action when the chip is solder-mounted on a board. CONSTITUTION:A chip holding soldering jig 4 to be used in the case of solder- mounting a semiconductor chip 1 on a board 2 comprises a chip insertion hole 4a corresponding to a profile size of the chip 1 and opened at the carbon jig 4 to be used to solder-mount the chip 1 by placing the jig 4 on the board, inserting a solder tape 3, the chip 1 in the hole and passing it through a soldering furnace, and a pocket 4b to become a relief of the molten solder and to be formed at a bottom side periphery of the hole 4a. Thus, in the case of soldering, the molten solder does not flow to a fine gap between the bottom of the jig 4 and the board 2 (capillary action), but a suitable solder fillet is formed in the pocket by a surface tension to solder the chip 1 to the board 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device such as a bipolar transistor module, and a soldering jig for holding a chip used in a process of solder-mounting a semiconductor chip on a substrate.

[0002]

2. Description of the Related Art As a method of solder-mounting a semiconductor chip on a board, the chip is mounted together with a solder preform (solder tape) on a soldering land formed at a predetermined position on the board, and the board is transported in a hydrogen atmosphere by a conveyor. The method of soldering by passing through the soldering furnace is widely adopted. Further, in this case, a soldering jig for holding the chip is used in order to prevent the chip mounted on the substrate from deviating from a predetermined soldering position during the transportation process of passing through the soldering furnace.

Next, a conventional soldering jig is shown in FIG. In the figure, 1 is a semiconductor chip, 2 is a substrate, 3 is a solder tape, and 4 is a soldering jig. The soldering jig 4 is made of a carbon plate or the like having high heat resistance and low wettability with solder, and the carbon plate is provided with a chip insertion hole 4a having a cross-sectional shape corresponding to the outer size of the chip 1. is doing.

When the semiconductor chip 1 is solder-mounted on the substrate 2, the soldering jig 4 is placed on the substrate 2 with the chip insertion hole 4a aligned with the chip mounting position as shown in the figure. Then, the solder tape 3 and the chip 1 are sequentially inserted and set in the chip insertion hole 4a, and then the substrate 1 is passed through a soldering furnace (not shown) by a conveyor belt to perform soldering.

[0005]

By the way, when the above-mentioned conventional soldering jig is used, the substrate 2 and the jig 4 do not come into complete contact with each other due to warpage and uneven surfaces as shown in FIG. A minute gap g remains between the substrate 2 and the bottom surface of the jig 4. Therefore, when the chip 1 and the solder tape 3 are set in the jig 4 as shown in FIG. 3 and carried into a soldering furnace for soldering, the melted solder in the chip insertion hole 4a is capillary phenomenon. As a result, it will flow out into the gap g.
Therefore, an appropriate solder fillet is not formed on the periphery of the chip, and as shown in FIG. 4, the solder layer 5 solidified after soldering often spreads from the chip 1 to the periphery of the substrate 2. .. Moreover, when such molten solder flows out, voids are generated in the solder layer 5,
This may cause defects such as solder bridging of the circuit pattern on the board.

Therefore, conventionally, measures have been taken to prevent the molten solder from flowing out by adjusting the temperature inside the soldering furnace or changing the heat capacity (volume) of the soldering jig 4. However, when performing soldering by passing through various semiconductor devices with different chip sizes in the same soldering furnace, if the temperature inside the furnace is changed, it may not be possible to solder under optimal temperature conditions depending on the model. .. Further, it is difficult to optimize the heat capacity of the jig due to variations in the amount of solder.

The present invention has been made in view of the above points, and an object of the present invention is to solve the above-mentioned problems and to skillfully prevent molten solder from flowing out to the periphery of a chip due to a capillary phenomenon during soldering. To provide a soldering jig.

[0008]

According to the present invention, the above object is achieved by forming a pocket serving as an escape portion for molten solder in a peripheral area of a bottom surface of a chip insertion hole formed in a soldering jig. Here, the volume of the pocket is determined in accordance with the amount of protrusion of the solder fillet formed on the periphery of the chip during soldering, and the jig material is preferably carbon.

[0009]

As described above, by forming a pocket serving as an escape portion for the molten solder in the peripheral area on the bottom surface side of the chip insertion hole formed in the jig, the molten solder protruding from the peripheral edge of the chip during the soldering process is prevented. , Agglomerates in the pocket formed in the peripheral region of the insertion hole before reaching the narrow gap between the substrate and the bottom surface of the jig due to surface tension. Therefore, the capillary phenomenon that draws the molten solder into the narrow gap does not work, and thus an appropriate solder fillet can be formed on the periphery of the chip and soldered to the substrate.

[0010]

Embodiments of the present invention will be described below with reference to FIGS. In the figure, the same members corresponding to those in FIGS. 3 and 4 are designated by the same reference numerals. In the illustrated embodiment, the soldering jig 4 is made of a carbon material having high heat resistance and low wettability with respect to solder, and a chip insertion hole 4a formed in the jig 4 in accordance with the outer size of the chip 1. A pocket 4b having a diameter larger than that of the insertion hole 4a is formed on the peripheral edge on the bottom surface side of the. The pocket 4b functions as an escape portion for the molten solder that protrudes from the peripheral edge of the chip 1, and has a sufficient groove depth that does not form a capillary gap with the substrate 1 and the surface tension of the molten solder. The volume is set to be large enough to accommodate the fillet that protrudes from the peripheral edge of the chip and aggregates.

By soldering the chip 1 to the substrate 2 (solder mount) by using the soldering jig 4 having such a structure, the solder melted in the process of passing through the soldering furnace is removed from the peripheral edge of the chip 1. When it protrudes into the pocket 4a, it aggregates to form a spherical fillet by the action of surface tension before reaching the narrow gap g between the bottom surface of the jig 4 and the upper surface of the substrate 1. Therefore, the molten solder does not flow into the narrow gap g due to the capillary phenomenon, and an appropriate solder fillet can be formed on the peripheral edge of the chip 1 and soldered to the substrate 2 as shown in FIG.

[0012]

As described above, in the soldering jig of the present invention, since the pocket serving as the escape portion of the molten solder is formed in the peripheral area of the bottom surface side of the chip insertion hole, the semiconductor chip is used. By mounting the solder on the substrate, the molten solder is prevented from unnecessarily flowing out to the periphery of the chip due to the capillary phenomenon that works in the gap between the bottom surface of the jig and the substrate, and it is suitable for the periphery of the chip. By forming a simple solder fillet, optimum soldering can be performed without defects such as a chip, a substrate and a void.

[Brief description of drawings]

FIG. 1 is a sectional view showing a usage state of a soldering jig according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part showing a soldering state in FIG.

FIG. 3 is a cross-sectional view showing a usage state of a conventional soldering jig.

FIG. 4 is an enlarged view of a main part showing a soldering state in FIG.

[Explanation of symbols]

 1 semiconductor chip 2 substrate 3 solder tape 4 soldering jig 4a chip insertion hole 4b pocket 5 solder layer

Claims (3)

[Claims] 1. A soldering jig for holding a chip, which is used when a semiconductor chip is solder-mounted on a substrate, wherein the plate-shaped jig has a chip insertion hole corresponding to the outer size of the chip, Place the jig on the board, insert the solder preform and the chip into the hole, and in this state, run the soldering furnace to carry out the solder mount. A soldering jig for a semiconductor device, characterized in that a pocket serving as an escape portion for the molten solder is formed in the. 2. The semiconductor device according to claim 1, wherein the volume of the pocket is determined in accordance with the protrusion amount of the solder fillet formed on the periphery of the chip during soldering. Jig for soldering. 3. The soldering jig according to claim 1, wherein the material of the jig is carbon.