JPH09252025A - Semiconductor device and manufacturing method and mounting structure of it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a semiconductor element and, at the same time, to relax a stress applied to an electrical junction area caused by the difference of coefficient of linear expansion between a semiconductor element and an outer device. SOLUTION: A solder ball 12 is arranged on a barrier metal layer 11 on an electrode pad formed over the whole surface of a semiconductor element 10, and the surface of the semiconductor element 10 among every solder ball 12 is covered by a protective resin sheet 13. Arranging the protective resin sheet 13 over the surface of the semiconductor element 10 makes it possible to protect the surface of the semiconductor 10 without conventional sealing resin. Moreover, the protective resin sheet 13 acts as a buffer and, when the semiconductor device is connected to an outer circuit substrate and so on, makes it possible to relax the stress applied to an electrical junction area caused by the difference of coefficient of linear expansion between the semiconductor element and the circuit substrate, and to improve a heat fatigue life time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device which protects an integrated circuit portion of a semiconductor, ensures electrical connection between an external device and a semiconductor element, and enables high-density mounting, and a method of manufacturing the same. The present invention relates to a mounting structure of the semiconductor device. The semiconductor device of the present invention facilitates miniaturization of information communication equipment, office electronic equipment, and the like.

[0002]

2. Description of the Related Art In recent years, semiconductor devices have been required to be miniaturized and have a higher density as electronic devices have been miniaturized, and a quad flat package (QF) having a narrow lead pitch has been demanded.
P), a chip size package (CSP), or a flip chip bonding technique for directly mounting a semiconductor element on a circuit board has been developed.

A conventional semiconductor device called flip chip bonding will be described below.

First, a conventional semiconductor device is a semiconductor device having a semiconductor element 2 having a plurality of electrode pads 1 formed on the entire surface thereof, as shown in FIG. Next, the structure of the conventional semiconductor device will be described. 11 is a plan view showing a conventional semiconductor device, FIG. 12 is a bottom view thereof, and FIG.
FIG. 12 is a sectional view taken along the line BB in FIG. 11.

As shown in FIGS. 11 to 13, solder is formed on the barrier metal layer 3 provided on the electrode pads (not shown) formed on the entire surface of the semiconductor element 2 to form a semicircular solder. The bumps 4 are provided.

Next, a conventional method of manufacturing a semiconductor device will be described with reference to FIGS.

First, as shown in FIG. 14, chromium / copper (Cr / C) is formed on an electrode pad (not shown) on the surface of the semiconductor element 2.
A barrier metal layer 3 such as u) is deposited.

Next, as shown in FIG. 15, solder (lead (Pb) 95% / tin (Sn) 5%, etc.) is formed on the barrier metal layer 3.
Is vapor-deposited, and the solder bumps 4 are formed by heating and melting to form a semiconductor device.

As a mounting structure thereof, as shown in FIG. 16, a conductor portion 6 of an external device 5 such as a circuit board formed in advance with flux or solder paste is used as shown in FIG.
17, the solder bumps 4 formed on the semiconductor element 2 of the semiconductor device are aligned, and the surface of the semiconductor element 2 is mounted face down on the external device 5 with solder 7 as shown in FIG. Then, by heating and melting, the semiconductor element 2
The solder bumps 4 and the conductor portions 6 on the external device 5 are electrically joined.

Further, as shown in FIG. 18, the semiconductor device 2
Since a space is formed between the semiconductor device 2 and the external device 5, the purpose of protecting the surface of the semiconductor element 2 is to reduce the stress on the electrical junction due to the mismatch of the linear expansion coefficient of the semiconductor device 2 and the external device 5, and to reduce thermal fatigue. The sealing resin 8 is injected and sealed for the purpose of improving the life.

The semiconductor device is mounted on an external device by the above method.

[0012]

However, in the conventional semiconductor device, as shown in FIG. 18, after the semiconductor element 2 is electrically connected to the conductor portion 6 of the external device 5, the sealing resin 8 is injected into the gap. However, the process is complicated and the surface of the semiconductor element 2 is not protected before the injection of the sealing resin 8. Therefore, the cleanliness of the working environment needs to be carefully considered.

The present invention solves such a conventional problem, and protects a semiconductor element and alleviates stress on an electrical junction due to a mismatch in the linear expansion coefficient between the semiconductor element and an external device to reduce thermal fatigue life. It is an object of the present invention to provide a semiconductor device, a manufacturing method thereof, and a mounting structure for improving the semiconductor device.

[0014]

In order to achieve this object, a semiconductor device according to the present invention comprises a semiconductor element having electrode pads formed on the entire surface region, and a barrier metal provided on the electrode pad of the semiconductor element. Layer, the ball electrode provided on the barrier metal layer, and the stress on the ball electrode generated by the difference in the coefficient of linear expansion between the semiconductor element and the circuit board when the semiconductor device is configured and bonded to the circuit board. The protective sheet is provided on the surface of the semiconductor element other than the ball electrode to alleviate the above.

Further, the manufacturing method thereof includes a step of forming a barrier metal layer on the electrode pad of a semiconductor element having an electrode pad formed over the entire surface region, a step of forming a protective sheet on the surface of the semiconductor element, and a semiconductor It comprises a step of removing the protective sheet on the barrier metal layer on the electrode pad on the element surface, and a step of mounting a ball electrode on the barrier metal layer on the semiconductor element surface and heating and melting.

Further, in the mounting structure of the semiconductor device, a semiconductor element having an electrode pad formed over the entire surface region, a barrier metal layer provided on the electrode pad of the semiconductor element,
A mounting structure of a semiconductor device in which a ball electrode provided on the barrier metal layer and a semiconductor device including a protective sheet provided on the surface of a semiconductor element other than the ball electrode are flip-chip bonded to a circuit board, The ball electrode of the semiconductor device and the conductor portion of the circuit board are joined together, and the protective sheet on the surface of the semiconductor element relieves the stress on the ball electrode caused by the difference in linear expansion coefficient between the semiconductor element and the circuit board. .

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION With the above structure, in the semiconductor device of the present invention, by providing the protective sheet on the surface of the semiconductor element, the surface of the semiconductor element is protected without the use of the sealing resin as in the conventional case, and the protective sheet is Since it acts as a cushioning material, when the semiconductor device is bonded to an external circuit board,
It is possible to relieve the stress on the electrical junction due to the mismatch of the linear expansion coefficient between the semiconductor element and the circuit board and improve the thermal fatigue life.

An embodiment of the present invention will be described below with reference to the drawings. First, the semiconductor device of the present embodiment is a semiconductor device having a semiconductor element 10 having a plurality of electrode pads 9 formed on the entire surface thereof, as shown in FIG. Here, the semiconductor element 10 is a semiconductor element 10 that can secure wiring without increasing the chip area in response to the trend of semiconductor elements in which the number of wirings tends to increase in the future.
A large number of electrode pads 9 are formed using the surface area. Further, in such a semiconductor element 10, an active region having the original function of the semiconductor element is formed in the lower layer of each electrode pad 9, and if wire bonding is performed with respect to the electrode pad 9, The impact of the wire bond may destroy the lower active region. Therefore, for such a semiconductor element 10, it is convenient to form a protruding electrode such as a solder ball on the electrode pad 9 and perform flip-chip bonding to the substrate without using the wire bonding method.

Next, the structure of the semiconductor device of this embodiment will be described. 2 is a plan view of the semiconductor device according to the present embodiment, FIG. 3 is a bottom view thereof, and FIG. 4 is a cross-sectional view taken along the line AA1 of FIG.

As shown in FIGS. 2 to 4, solder balls 12 are provided on a barrier metal layer 11 on an electrode pad (not shown) formed on the entire surface of the semiconductor element 10, and each solder is provided. The surface of the semiconductor element 10 between the balls 12 is covered with a resin protective sheet 13. By providing the resin protection sheet 13 on the surface of the semiconductor element 10, the surface of the semiconductor element 10 is protected without the use of the sealing resin as in the conventional case, and the resin protection sheet 13 acts as a cushioning material. When the semiconductor device is bonded to an external circuit board or the like, it is possible to relieve the stress on the electrical bonding portion due to the mismatch of the linear expansion coefficient between the semiconductor element and the circuit board, and improve the thermal fatigue life.

Next, a method of manufacturing the semiconductor device of this embodiment will be described. 5 to 7 are cross-sectional views showing the method for manufacturing the semiconductor device of this embodiment.

First, as shown in FIG. 5, a nickel / gold alloy layer (Ni / Au) is formed as a barrier metal layer 11 on an electrode pad (not shown) on the semiconductor element 10, and the surface of the semiconductor element 10 is further formed. The resin protective sheet 13 is formed on the whole by thermocompression bonding. Other metals for the barrier metal layer 11 include copper (Cu), chromium (Cr), silver (A
g) and molybdenum (Mo) may be used. The barrier metal layer 11 may be formed by vapor deposition or plating. In addition, the formation of the barrier metal layer 11 may be omitted depending on the composition of the electrode pad, the composition of the solder ball formed in the subsequent step, and the joining method thereof. Resin protection sheet 13
The material for the above is a material capable of protecting the semiconductor element 10, and when the semiconductor device is bonded to an external device such as a circuit board, stress to the electrical bonding portion due to a mismatch of the coefficient of linear expansion with the external device is applied. Any sheet that can relax can be used, and for example, a sheet of polyimide resin, aramid resin, or epoxy resin is used. Further, a prepreg obtained by impregnating glass cloth with a resin may be used, and an inorganic protective sheet may be used instead of the resin protective sheet. Further, instead of attaching the resin protective sheet, a protective resin such as polyimide may be applied (printing, spin coating, etc.) and cured.

Next, as shown in FIG. 6, carbon dioxide gas (C
O ₂ ) laser, yttrium-argon (YAG) laser, excimer laser
By irradiating a laser beam from the resin protection sheet 13 side on the semiconductor element 10 toward the barrier metal layer 11 of the semiconductor element 10, a through hole is provided in the resin protection sheet 13 and an opening 14 is formed. The opening 14 may be formed by an etching process other than the laser processing described above. Further, if through holes are formed in advance on the resin protection sheet at positions corresponding to the electrode pads of the semiconductor element and the sheet is attached to the surface of the semiconductor element, the formation of openings by laser is not necessary. In this case, the barrier metal can be formed on the electrode pad using the sheet as a mask.

Next, as shown in FIG. 7, solder plating is performed on the barrier metal layer 11 of the semiconductor element 10, flux is applied, and solder balls 12 are mounted. And heating,
The semiconductor device is configured by melting and electrically bonding the solder ball 12 and the barrier metal layer 11 (electrode portion) of the semiconductor element 10. Instead of mounting the solder ball 12 on the semiconductor element, a solder paste may be formed in the opening and heated and melted to form the solder bump. Instead of the solder balls, a metal material such as gold or copper, or a metal-coated resin ball may be used.

The purpose of solder plating before mounting the solder balls 12 is to improve the wettability of the solder balls 12 and the barrier metal layer 11 during heating and fusion bonding. Further, the solder plating may not be performed depending on the opening 14 shown in FIG. 6 and the diameter of the solder ball 12 shown in FIG. 7, the composition of the electrode ball other than the solder ball 12, and the joining method thereof.

Next, the mounting structure of the semiconductor device of this embodiment will be described. 8 and 9 are cross-sectional views showing the mounting structure of the semiconductor device of this embodiment.

First, as shown in FIG. 8, the solder balls 12 of the semiconductor device are aligned with the conductor portion 16 of the external device 15 such as a circuit board to which flux or solder paste has been supplied in advance. In this case, the conductor portion 16 is provided with the joining solder 17 in advance.

Next, as shown in FIG. 9, the solder balls 12 and the conductor portion 16 of the semiconductor device are electrically joined by heating and melting.

By providing the resin protective sheet 13 on the surface of the semiconductor element 10 as in this embodiment, the semiconductor element 1
0 is protected and the resin protection sheet 13 acts as a cushioning material, so that the semiconductor element 10 and the external device 1
The stress on the electrical joint due to the mismatch of the coefficient of linear expansion with No. 5 can be relaxed, and the thermal fatigue life can be improved.

[0030]

As described above, according to the present invention, after the protective sheet is attached to the semiconductor element, the opening is formed in the electrode portion,
By connecting the solder balls, not only can the semiconductor element be protected by the conventionally required process of injecting the sealing resin, but also the protective sheet acts as a cushioning material, so that external devices such as circuit boards can be protected. Also, it is possible to realize an excellent semiconductor device, a manufacturing method thereof, and a mounting structure capable of relieving the stress on the electrical junction due to the mismatch of the linear expansion coefficient between the semiconductor device and the external device and improving the thermal fatigue life. It is a thing.

[Brief description of drawings]

FIG. 1 is a plan view of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a plan view of a semiconductor device according to an embodiment of the present invention.

FIG. 3 is a bottom view of the semiconductor device according to the embodiment of the present invention.

FIG. 4 is a sectional view of a semiconductor device according to an embodiment of the present invention.

FIG. 5 is a sectional view showing a method for manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 6 is a sectional view showing a method of manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 7 is a sectional view showing a method for manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 8 is a sectional view showing a mounting structure of a semiconductor device according to an embodiment of the present invention.

FIG. 9 is a sectional view showing a mounting structure of a semiconductor device according to an embodiment of the present invention.

FIG. 10 is a plan view of a conventional semiconductor device.

FIG. 11 is a plan view of a conventional semiconductor device.

FIG. 12 is a bottom view of a conventional semiconductor device.

FIG. 13 is a sectional view of a conventional semiconductor device.

FIG. 14 is a sectional view showing a conventional method for manufacturing a semiconductor device.

FIG. 15 is a sectional view showing a conventional method for manufacturing a semiconductor device.

FIG. 16 is a sectional view showing a mounting structure of a conventional semiconductor device.

FIG. 17 is a sectional view showing a mounting structure of a conventional semiconductor device.

FIG. 18 is a sectional view showing a mounting structure of a conventional semiconductor device.

[Explanation of symbols]

 1 Electrode Pad 2 Semiconductor Element 3 Barrier Metal Layer 4 Solder Bump 5 External Device 6 Conductor 7 Solder 8 Sealing Resin 9 Electrode Pad 10 Semiconductor Element 11 Barrier Metal Layer 12 Solder Ball 13 Resin Protective Sheet 14 Opening 15 External Device 16 Conductor Part 17 Bonding solder

Claims (12)

[Claims] 1. A semiconductor element, a ball electrode provided on an electrode pad formed on the surface of the semiconductor element, and a protective sheet provided on the surface of the semiconductor element other than the ball electrode. Semiconductor device. 2. A semiconductor element having an electrode pad formed over the entire surface region, a barrier metal layer provided on the electrode pad of the semiconductor element, a ball electrode provided on the barrier metal layer, and a semiconductor. Provided on the surface of the semiconductor element other than the ball electrode in order to relieve stress on the ball electrode caused by the difference in linear expansion coefficient between the semiconductor element and the circuit board when the device is configured and bonded to the circuit board. A semiconductor device comprising: 3. The semiconductor device according to claim 1, wherein the ball electrode is a solder ball electrode. 4. The ball electrode is a ball electrode in which a resin ball is covered with a metal film.
Alternatively, the semiconductor device according to claim 2. 5. A step of forming a protective sheet on the surface of the semiconductor element, a step of removing the protective sheet on the electrode pad on the surface of the semiconductor element, a ball electrode mounted on the electrode pad on the surface of the semiconductor element, and heating. A method of manufacturing a semiconductor device, comprising the step of melting. 6. A step of forming a barrier metal layer on the electrode pad of a semiconductor element having an electrode pad formed over the entire surface region, a step of forming a protective sheet on the surface of the semiconductor element, and a step of forming a protective sheet on the surface of the semiconductor element. A method of manufacturing a semiconductor device, comprising: a step of removing a protective sheet on a barrier metal layer on an electrode pad; and a step of mounting a ball electrode on the barrier metal layer on the surface of the semiconductor element and heating and melting the ball electrode. . 7. The method of manufacturing a semiconductor device according to claim 5, wherein the step of removing the protective sheet is a step of removing the protective sheet using a laser. 8. The method of manufacturing a semiconductor device according to claim 5, wherein the step of forming the protective sheet on the surface of the semiconductor element is a step of thermocompression bonding a resin protective sheet. 9. The method of manufacturing a semiconductor device according to claim 5, wherein the step of forming the protective sheet on the surface of the semiconductor element is a step of forming the resin protective sheet by applying a resin. 10. The step of mounting a ball electrode is a step of mounting a solder ball electrode.
7. A method for manufacturing a semiconductor device according to claim 6. 11. The method of manufacturing a semiconductor device according to claim 5, wherein the step of mounting the ball electrode is a step of mounting a ball electrode in which a resin film is coated with a metal film. . 12. A semiconductor element having electrode pads formed on the entire surface region, a barrier metal layer provided on the electrode pads of the semiconductor element, a ball electrode provided on the barrier metal layer, A mounting structure of a semiconductor device in which a semiconductor device including a protective sheet provided on the surface of a semiconductor element other than the ball electrode is flip-chip bonded to a circuit board, the ball electrode of the semiconductor device and a conductor portion of the circuit board. And a structure in which the stress applied to the ball electrode caused by the difference in linear expansion coefficient between the semiconductor element and the circuit board is relaxed by the protection sheet on the surface of the semiconductor element. Construction.