JPH06268017A - Method for mounting bare chip type semiconductor device - Google Patents

Abstract

PURPOSE:To allow inspection, modification and electric inspection of a mounting position. CONSTITUTION:After forming a three-layer bump provided with high-melting point solder 4, a core layer 5 and low-melting point solder 6 on the electrode pad 2 of a bare chip type semiconductor device 1, the bare chip type semiconductor device 1 is mounted on a wiring board 10. Then, the device 1 is tentatively connected on the mounting pad 9 of the wiring board 10 by heating and melting the bump at the melting temperature of the solder 6 and the device 1 is inspected under such conditions. The bump is heated and melted at the melting temperature of the high-melting point solder 4 and pressure is applied so as to connect the high-melting point solder 4 with the mounting pad 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bare chip type semiconductor device mounting method, and more particularly to a bare chip type semiconductor device mounting method for connecting a semiconductor device to a substrate using solder bumps.

[0002]

2. Description of the Related Art FIGS. 4 (a) to 4 (f) are process sectional views for explaining an example of the prior art. In the bare chip type semiconductor device mounting method shown in FIGS. 4A to 4F, the solder bumps 6a are formed on the electrode pads 2 of the bare chip type semiconductor device 1 by using a plating method, and then the solder bumps 6a are formed by a flow process.
Is formed into a hemispherical shape and is aligned and mounted on the mounting pad 9 on the wiring board 10 as shown in FIG. Figure 4 after mounting
As shown in (f), the mounting pad 9 and the solder bump 6a are joined by heating to the melting temperature of the solder. Further, as disclosed in Japanese Unexamined Patent Publication No. 62-250647, there is a technique of performing an operation inspection of the bare chip type semiconductor device 1 while heating the solder bumps 6a to a semi-molten state.

[0003]

This conventional bare-chip type semiconductor device mounting method is used when the mounting pad 5 and the solder bump 7 are misaligned or when an electrical inspection determines that the product is defective. It is necessary to heat and melt the solder bumps 7 and remove the bare chip type semiconductor device 1 from the substrate and mount it again. In the conventional bare chip type semiconductor device mounting method, when the bare chip type semiconductor device 1 is removed from the wiring substrate 6, solder remains on the mounting pads 5 and the shape of the bumps 7 is destroyed. Therefore, when the misalignment is corrected, an open defect occurs due to a defective shape of the solder bump. Further, when the non-defective bare chip is remounted, a short circuit between adjacent pads may occur due to a solder residue on the mounting pad 5, or an open defect may occur in a pad having less solder residue than other pads. there were. Further, in the method of performing the operation inspection of the bare chip type semiconductor device while heating the solder bumps to the semi-melting temperature, it is necessary to control the temperature with high accuracy, and it is difficult to stably maintain the manufacturing process.

[0004]

According to a method of mounting a bare chip type semiconductor device of the present invention, a three-layer bump having a high melting point solder, a core layer and a low melting point solder is formed on an electrode pad of the bare chip type semiconductor device, Alternatively, a two-layer bump having a high melting point solder and a core layer is formed on the electrode pad of the bare chip type semiconductor device, and the low melting point solder is formed on the mounting pad of the wiring board or the electrical selection jig. Next, an electrical inspection and a mounting position inspection are carried out in a state where the bare chip type semiconductor device is temporarily mounted by heating to the melting temperature of the low melting point solder. At this time, if the electrical inspection fails or the mounting position is defective, the bare chip type semiconductor device having the defective product or the mounting defect is removed by heating again to the melting temperature of the low melting point solder, and the non-defective bare chip semiconductor device is mounted. Or correct the mounting position. When the electrical inspection and the mounting position are normal, the melting point of the high melting point solder is heated and pressed, the core layer is wrapped with the high melting point solder, and the high melting point solder and the mounting pad of the wiring board are connected.

[0005]

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

FIGS. 1A to 1G are process sectional views showing a first embodiment of the present invention. 1A to 1D show steps of forming bumps. In manufacturing the bump, first, the electrode pad 2 of the bare chip semiconductor device 1 is manufactured.
A resist 3 is formed elsewhere as shown in FIG. 1B, and then the electrode pad 2 is electroplated to form the resist 3 shown in FIG.
High melting point solder 4 (Pb-Sn 5 wt% S as shown in (c))
n), core layer 5 (Cu), low melting point solder 6 (Sn-Pb)
37 wt% Pb) is sequentially plated. After that, Fig. 1 (d)
Then, the resist 3 is peeled off.

FIGS. 1E to 1G show a process of mounting a bare chip type semiconductor device on a wiring board. As shown in FIG. 1E, a three-layer bump made of a high melting point solder 4, a core layer 5 and a low melting point solder 6 formed on the bare chip type semiconductor device 1 is mounted on a mounting pad 9 on a wiring substrate 10 by aligning the positions. To do. FIG. 1F is a cross-sectional view showing a state in which the low melting point solder 6 and the mounting pad 9 are joined by heating to the melting temperature of the low melting point solder (220 ° C. which is lower than the melting temperature of the high melting point solder in this embodiment). Is. In this state, the mounting position inspection and electrical inspection are performed. When the mounting position is displaced or when the electrical inspection fails, the bare chip type semiconductor device 1 is removed by reheating to the melting temperature of the low melting point solder 6. When the bare chip type semiconductor device 1 is detached, the core layer 5 functions as a barrier, so that the high melting point solder 4 does not partially melt into the low melting point solder 6 and the low melting point solder 6 is maintained at a stable temperature.
Can be melted. Further, since the high melting point solder 4 is not destroyed when the bare chip type semiconductor device 1 is removed and the amount of the residual solder on the mounting pad 9 is small, an open defect due to a bump shape defect when correcting the mounting position deviation. Further, when a non-defective bare chip type semiconductor device is re-mounted, it is possible to eliminate short-circuit defects between adjacent pads due to residual solder on the mounting pads. Figure 1
After the mounting position inspection and the electrical inspection are completed, (g) shows that the core chip 5 is heated to the melting temperature of the high melting point solder (which is 324 ° C. in this embodiment) and the bare chip type semiconductor device 1 is pressed to make the core layer 5 high melting point solder 4 is a cross-sectional view showing a state in which the high melting point solder 4 and the mounting pad 9 are wrapped in each other and joined to each other. By wrapping and bonding the core layer 5 in this way, the mechanical strength of the bumps is improved, and bump crushing due to the load when the cooling module or the like is mounted can be reduced.

2 (a) and 2 (b) are process sectional views showing a second embodiment of the present invention. Using the punch 7 and the die 8, the high melting point solder 4 (Pb-Sn 5 wt% Sn), the core layer 5 (Cu), and the low melting point solder 6 (Sn-Pb 37 wt%).
Pb) is punched out from the three-layer foil material 11, and the punched piece is heated by the stroke of the punch 7 at this time (120 ° C. in this embodiment) to be thermocompression bonded onto the electrode pad 2 of the bare chip type semiconductor device 1. To do.

3A to 3C are process sectional views showing a third embodiment of the present invention. In this embodiment, the bumps are formed by forming the high melting point solder 4 and the core layer 5 on the electrode pad 2 of the bare chip type semiconductor device 1 by using the plating method as described with reference to FIGS. Or Fig. 2
Using the punching method as described in (a) and (b),
On the electrode pad 2 of the bare chip type semiconductor device 1, a punched piece of a two-layer material composed of the high melting point solder 4 and the core layer 5 is thermocompression bonded. In these cases, the low melting point solder 6 is formed on the mounting pad 9 of the wiring board 10 by the plating method. The mounting position inspection and the electrical inspection can be performed in the same manner as in the first embodiment. Also, when the bare chip type semiconductor device is permanently connected to the wiring substrate, it can be performed in the same manner as in the first embodiment.

When the bare chip type semiconductor device is inspected by the electrical sorting jig, the bare chip type semiconductor device is mounted on the electrical sorting jig, heated to the melting temperature of the low melting point solder and temporarily connected, and in that state. Conduct an electrical inspection, then reheat to the melting temperature of the low melting point solder, remove the bare chip type semiconductor device from the electrical sorting jig, transfer it to the wiring board, heat to the melting temperature of the high melting point solder, and bare chip type semiconductor The device is permanently connected to the wiring board.

[0011]

As described above, according to the present invention, a bump formed on a bare chip type semiconductor device has a three-layer structure having a high melting point solder, a core layer and a low melting point solder, or a bare chip type semiconductor device. The bump to be formed has a two-layer structure having a high melting point solder and a core layer, and a low melting point solder is provided on the mounting pad of the wiring board or the mounting pad of the electric jig to form an equivalent three layer structure. Since the mounting can be carried out by heating and melting in two steps, the mounting position inspection and the electrical inspection can be performed in the low melting point solder melting and joining step. That is, when the inspection is defective, the melting point of the low melting point solder is set to the melting point and the shape of the high melting point solder bump is not destroyed when the bare chip type semiconductor device is removed. Open defects due to bump shape defects when repairing, short defects between adjacent pads due to residual solder on the mounting pads when remounting a good bare chip type semiconductor device, and pads with less residual solder than other pads Open defects can be eliminated. Further, when the defective bare chip type semiconductor device is removed, the core layer serves as a barrier so that a part of the high melting point solder does not melt into the low melting point solder and the low melting point solder can be melted at a stable temperature. . When mounting a good bare chip type semiconductor device on the wiring board, it is heated and pressed, and the core layer is wrapped with high-melting point solder to improve the mechanical strength of the bumps and improve the cooling module. There is an effect that bump crushing due to the load when mounted can be reduced.

[Brief description of drawings]

1A to 1G are process cross-sectional views showing a first embodiment of the present invention.

2A to 2B are process sectional views showing a second embodiment of the present invention.

3A to 3C are process sectional views showing a third embodiment of the present invention.

4A to 4F are process cross-sectional views showing a conventional example.

[Explanation of symbols]

 1 Bare Chip Type Semiconductor Device 2 Electrode Pad 3 Resist 4 High Melting Point Solder 5 Core Layer 6 Low Melting Point Solder 6a Solder Bump 7 Punch 8 Die 9 Mounting Pad 10 Wiring Board 11 Three Layer Foil Material

Claims (8)

[Claims] 1. A three-layer bump having a high melting point solder layer, a core layer and a low melting point solder layer is formed on an electrode portion of a bare chip type semiconductor device, and then the bare chip type semiconductor device is mounted on a wiring board. Next, the low melting point solder is heated and melted at the melting temperature of the low melting point solder to be temporarily connected to the mounting pad on the wiring board, and in this state, the bare chip type semiconductor device is inspected and if there is a defective product, Replacing with a non-defective product, and then heating and melting the high melting point solder at the melting temperature of the high melting point solder and pressurizing the bare chip type semiconductor device to permanently connect the bare chip type semiconductor device to a mounting pad on the wiring board. A method for mounting a bare chip type semiconductor device, comprising: 2. After forming a three-layer bump having a high melting point solder layer, a core layer and a low melting point solder layer on an electrode portion of a bare chip type semiconductor device, the bare chip type semiconductor device is placed on an electrical sorting jig. After mounting, the low melting point solder is heated and melted at the melting temperature of the low melting point solder to be temporarily connected to the mounting pad of the electrical sorting jig, and in this state, the bare chip type semiconductor device is inspected, and then the Re-melt the low melting point solder at the melting temperature of the low melting point solder and remove the bare chip type semiconductor device from the electrical sorting jig, and only the bare chip type semiconductor device selected as a good product is mounted on the wiring board mounting pad. The bare chip type semiconductor device is mounted by pressing the bare chip type semiconductor device while heating and melting the high melting point solder at the melting temperature of the high melting point solder. A method of mounting a bare chip type semiconductor device, comprising: making a main connection to a mounting pad of the wiring board. 3. A bare chip type semiconductor device, wherein a two-layer bump having a high melting point solder layer and a core layer is formed on an electrode portion of the bare chip type semiconductor device, and a low melting point solder layer is formed on a mounting pad of a wiring board, and then the bare chip type semiconductor device is formed. The device is mounted on a wiring board, then the low melting point solder is heated and melted at the melting temperature of the low melting point solder, and temporarily connected to the low melting point solder layer on the mounting pad on the wiring board, and in this state, inspection is performed. If there is a defective product, replace it with a non-defective product, then heat and melt at the melting temperature of the high melting point solder and pressurize the bare chip type semiconductor device, and mount the bare chip type semiconductor device on a mounting pad on the wiring board. A method for mounting a bare chip type semiconductor device, characterized in that the main connection is performed. 4. A two-layer bump having a high melting point solder layer and a core layer is formed on an electrode portion of a bare chip type semiconductor device, and a low melting point solder layer is formed on a mounting pad of an electrical selection jig and a mounting pad of a wiring board. After forming the above, the bare chip type semiconductor device is mounted on the electrical sorting jig, and then the low melting point solder is heated and melted at the melting temperature of the low melting point solder to temporarily mount it on the mounting pad of the electrical sorting jig. Connect, inspect in this state, then remove the bare chip type semiconductor device by heating and melting at the melting temperature of the low melting point solder from the electrical sorting jig, and only the bare chip type semiconductor device sorted as a good product The bare chip type semiconductor device is mounted on the wiring board to heat and melt the high melting point solder at the melting temperature of the high melting point solder, and pressurize the bare chip type semiconductor device. A method of mounting a bare chip type semiconductor device, characterized in that a conductor device is permanently connected to a mounting pad of the wiring board. 5. The method of mounting a bare chip type semiconductor device according to claim 1, wherein said three-layer bump is formed by a plating method in the order of a high melting point solder layer, a core layer and a low melting point solder layer. 6. The method of mounting a bare chip type semiconductor device according to claim 1, wherein the three-layer bump is formed by punching out a three-layer foil material having a high melting point solder layer, a core layer and a low melting point solder layer. 7. The double-layer bump is formed by plating a high melting point solder layer and a core layer in this order, and the low melting point solder layer is formed on a mounting pad of the wiring board by a plating method. A method for mounting a bare chip type semiconductor device as described. 8. The two-layer bump is formed by stamping a two-layer foil material having a high melting point solder layer and a core layer, and the low melting point solder layer is formed on a mounting pad of the wiring board by a plating method. Item 4. A method of mounting a bare chip type semiconductor device according to items 3 and 4.