JP2001053200A - Semiconductor device and manufacturing method of the semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable thinning the overall device, while ensuring mechanical strength of the overall device. SOLUTION: Thinning made possible, while strength is ensured by installing a semiconductor substrate 2, wherein a circuit element and an electrode pad 3 are formed on the surface side and thinning work is performed from the rear side, a surface protecting film 4 covering the surface of the substrate 2, in such a manner that the pad 3 is made to face the outside, a metal multilayer film 6 formed in the upper part of the pad 3, a solder bump 7 formed in the upper part of the multilayer film 6, a first sealing resin film 8 covering the surface side of the substrate 2, in such a manner that the bump 7 is surrounded by the height of the bump, and a second sealing resin film 9 covering the rear side of the substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip-chip type semiconductor device directly mounted on a wiring board and a method for manufacturing the semiconductor device.

[0002]

2. Description of the Related Art Conventionally, portable electronic devices such as digital video cameras, portable telephones, notebook personal computers, and portable information terminals have been required to be further reduced in size and weight. For this reason, a flip-chip type semiconductor device is directly mounted on a printed wiring board disposed in the housing of a portable electronic device, instead of a conventional flat type package having a semiconductor chip built therein. There are things. In this flip-chip type semiconductor device, an electrode pad is formed on a surface side of a semiconductor substrate on which circuit elements are formed, and a surface protective film is formed on the surface of the semiconductor substrate so that the electrode pad faces outward. A barrier metal is formed on the electrode pad. In such a flip-chip type semiconductor device, a solder bump is formed on a barrier metal, and the solder bump is soldered to a land portion of the printed wiring board to be mounted on the printed wiring board.

[0003]

However, in order to further increase the mounting density on a printed wiring board, it is necessary to reduce the mounting area and the thickness of the flip-chip type semiconductor device.

[0004] Thinning of this type of semiconductor device is performed, for example, by thinning the back surface side of the semiconductor substrate. However, when the semiconductor substrate is thinned, the semiconductor substrate itself is easily broken, and subsequent handling becomes very troublesome. In addition, when increasing the diameter of a semiconductor substrate in order to improve production efficiency, it is necessary to ensure sufficient mechanical strength of the semiconductor substrate.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel semiconductor device capable of reducing the overall thickness while maintaining the overall mechanical strength, and a method of manufacturing the semiconductor device.

[0006]

In order to solve the above-mentioned problems, a semiconductor device according to the present invention includes a semiconductor substrate having a circuit element and an electrode portion formed on a front surface side and a thinned back surface, and an electrode portion. A protective film that covers the surface of the semiconductor substrate so that the semiconductor substrate faces outward, a barrier metal film that is formed above the electrode portion, a solder bump that is formed above the barrier metal film, and a surface side of the semiconductor substrate. The semiconductor device includes a first sealing resin film that covers at least the solder bumps at the height of the solder bumps, and a second sealing resin film that covers the back surface of the semiconductor substrate.

In order to solve the above-mentioned problems, a method of manufacturing a semiconductor device according to the present invention includes the steps of: forming a solder bump on an electrode portion formed on a semiconductor substrate on which a circuit element is formed; A step of thinning the back surface of the semiconductor substrate after forming the solder bumps, and a first sealing resin film covering the front surface of the semiconductor substrate so as to surround the solder bumps after thinning the semiconductor substrate. Forming, forming a second sealing resin film covering the back surface of the semiconductor substrate, and simultaneously curing the first sealing resin film and the second sealing resin film. .

Further, the semiconductor device can be manufactured as follows. That is, a method of manufacturing a semiconductor device according to the present invention includes, in order to solve the above-described problems, a step of forming a solder bump on an electrode portion formed on a semiconductor substrate on which a circuit element is formed; After that, a first step of covering the front side of the semiconductor substrate so as to surround the solder bumps is performed.
Forming a first sealing resin film, forming a first sealing resin film, and then thinning the back surface of the semiconductor substrate, The method includes a step of forming a second sealing resin film to be coated, and a step of simultaneously curing the first sealing resin film and the second sealing resin film.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A flip-chip type semiconductor device to which the present invention is applied and a method for manufacturing the semiconductor device will be described below with reference to the drawings.

As shown in FIG. 1, a flip-chip type semiconductor device 1 includes a semiconductor substrate 2 made of silicon or the like having a plurality of circuit elements formed on a front surface side, and an Al-Cu alloy or the like serving as an external connection terminal. Are formed by sputtering, etching, or the like.
The semiconductor substrate 2 is thinned by mechanical grinding, etching, or the like on the back surface opposite to the front surface on which the circuit elements are formed, thereby reducing the overall thickness of the semiconductor device 1. Specifically, the semiconductor substrate 2 is thinned to a thickness that does not damage circuit elements formed on the surface of the semiconductor substrate 2, that is, 50 μm to 200 μm. Then, the semiconductor substrate 2 on which the circuit elements are formed
A surface protection film 4 for protecting the surface of the semiconductor substrate 2 on which the circuit elements are formed is formed on the surface of the substrate. The surface protection film 4 is formed of a polyimide film, a silicon nitride film, or the like. This surface protective film 4 is provided with solder bumps for connecting the electrode pads 3 to the lands of the printed wiring board on which the semiconductor device 1 is mounted, above the electrode pads 3 formed on the semiconductor substrate 2. Opening 5 is formed,
The electrode pad 3 faces outward from the opening 5.

In the opening 5, a metal multilayer film 6 is formed in contact with the electrode pad 3 constituting the bottom of the opening 5. The metal multilayer film 6 functions as a barrier metal for improving the adhesion between the solder and the electrode pads 3 and preventing the diffusion of the solder from the solder bumps 7 described later. The metal multilayer film 6 also functions as a BLM (Ball Limiting Metal) that regulates the size, shape, and the like of the solder bump. Specifically, the metal multilayer film 6 includes a Cr film, a Cu film,
It is formed by sequentially laminating Au films by sputtering or the like. The Cr film in contact with the electrode pad 3 mainly secures the adhesion to the electrode pad 3, and the Cu film as the intermediate film mainly prevents the diffusion of solder from the solder bump formed later on the metal multilayer film 6. Then, the Au film prevents oxidation of the Cu film.

On the metal multilayer film 6, a solder bump 7 made of a high melting point solder for connecting to a land portion of a printed wiring board on which the semiconductor device 1 is mounted by soldering is formed in a substantially spherical shape. Specifically, the solder bump 7
Are formed such that the height is about 50 μm to 100 μm.

A first sealing resin film 8 made of a resin material such as an epoxy resin is formed around the solder bumps 7. This first sealing resin film 8 is
Is formed to have a film thickness substantially equal to the height of
The substantially spherical solder bumps 7 formed on the multilayer metal film 6 are reinforced. In addition, the first sealing resin film 8 is formed over the entire surface of the surface protection film 4 formed on the semiconductor substrate 2 to reinforce the strength of the thinned semiconductor substrate 2. The surface of the first sealing resin film 8 is polished so that the solder bumps 7 face outward. And the first
Eutectic solder is attached to the solder bumps 7 facing outward from the surface of the sealing resin film 8 to establish connection with the lands of the printed wiring board. Note that the first sealing resin film 8 may be formed to have a thickness smaller than the height of the solder bump 7, and the top of the solder bump 7 may be exposed to the outside in advance.

On the back side of the thinned semiconductor substrate 2, a second sealing resin having substantially the same thickness as that of the first sealing resin film 8 and formed of the same resin material is provided. Membrane 9
Are formed. The second sealing resin film 9 works together with the first sealing resin film 8 formed on the front surface side of the semiconductor substrate 2 to improve the mechanical strength of the thinned semiconductor substrate 2. Further, the second sealing resin film 9 is cured at the same time as the first sealing resin film 8. Specifically, the first and second sealing resin films 8 and 9 are cured by performing a heat treatment at about 150 ° C. for about 3 hours. The semiconductor substrate 2 and the first and second sealing resin films 8 and 9 have different coefficients of thermal expansion, and a stress is applied to the semiconductor substrate 2. At this time, the first and second sealing resin films 8 and 9 are formed on both surfaces of the semiconductor substrate 2. Therefore, the first and second sealing resin films 8 and 9 can cancel the stress generated on each surface side of the semiconductor substrate 2 and prevent the semiconductor substrate 2 from being deformed by the heat treatment.

On the front side of the semiconductor substrate 2, a solder bump 7 formed of a high-melting-point solder exposed to the outside of the first sealing resin film 8 is placed on a land portion of the printed wiring board. A eutectic solder ball 10 for attachment is attached. The eutectic solder ball 10 is made of a solder having a lower melting point than the solder constituting the solder bump 7, and prevents the solder bump 7 from being melted when performing a heat treatment for connecting to the land portion of the printed wiring board.

In the flip-chip type semiconductor device 1 as described above, since the back surface of the semiconductor substrate 2 is thinned, the overall thickness is reduced. In addition, the semiconductor device 1 has a first surface on each main surface side of the semiconductor substrate 2.
Since the first and second sealing resin films 8 and 9 are formed, the strength of the thinned semiconductor substrate 2 is enhanced by the first and second sealing resin films 8 and 9 and the semiconductor substrate is strengthened. It is possible to prevent the mechanical strength of the entire device from dropping due to the reduction in thickness of 2. Further, in the semiconductor device 1, since the first and second sealing resin films 8 and 9 are formed on both sides of the semiconductor substrate 2, the stress generated on each surface of the semiconductor substrate 2 is canceled. Thus, the semiconductor substrate 2 can be prevented from being deformed by the heat treatment for curing the first and second sealing resin films 8 and 9.

Next, a method of manufacturing the flip-chip type semiconductor device 1 configured as described above will be described with reference to the drawings.

First, as shown in FIG. 2, an electrode pad 3 as an external connection terminal is formed on a semiconductor substrate 2 made of Si or the like on which a plurality of circuit elements are already formed by sputtering, etching, or the like. Here, the semiconductor substrate 2
Usually, it has a substrate thickness of 400 μm to 625 μm. Next, a surface protection film 4 made of a polyimide film, a silicon nitride film or the like for protecting the surface on which the circuit elements are formed is formed on the entire surface of the semiconductor substrate 2. An opening 5 is formed in the surface protection film 4 so that the electrode pad 3 faces outward. The opening 5 functions as a connection hole for connecting the electrode pad 3 forming the bottom surface of the opening 5 to the land of the printed wiring board on which the semiconductor device 1 is mounted. The opening 5 has an opening 5.
The metal multilayer film 6 is formed in contact with the electrode pad 3 constituting the bottom surface of the substrate. Specifically, this metal multilayer film 6 is made of a Cr film,
It is formed by sequentially laminating a Cu film and an Au film by sputtering or the like.

Next, as shown in FIG.
A sufficiently thick photoresist film 11 is formed on the entire surface, and solder bumps 7 for electrically connecting the land portions of the printed wiring board and the electrode pads 3 are formed on the photoresist film 11. Opening 12 is formed by photolithography. The opening 12 is used to form a three-dimensional, for example, spherical, solder bump 7 of a predetermined size on the multilayer metal film 6 on the bottom surface of the opening 12 and on the surface protection film 4 around the multilayer metal film 6. It is formed in such a size that a required solder vapor deposition film can be applied.

Next, as shown in FIG. 4, a solder for forming a solder bump 7 is formed on the photoresist film 11 and on the surface protection film 4 and the metal multilayer film 6 which are exposed outside the opening 12. The deposition films 7a and 7b are formed. These solder deposited films 7a and 7b are high melting point solders composed of Pb and Sn. Such solder deposition films 7a and 7b are
The photoresist film 11 and the surface protection film 4 in the opening 12 and the metal multilayer film 6 are formed separately.

Next, as shown in FIG. 5, the photoresist film 11 and the solder deposited film 7b formed on the photoresist film 11, which are unnecessary portions, are removed by lift-off, and only the solder deposited film 7a is opened. 12 on the surface protective film 4 and the metal multilayer film 6. Subsequently, as shown in FIG. 6, the solder vapor deposition film 7a is melted by being heated, and a substantially spherical solder having a height of about 100 μm is formed on the metal multilayer film 6 by the surface tension of the melted solder. The bump 7 is formed.

Next, as shown in FIG.
Is formed on the back side to a thickness that does not damage circuit elements formed on the surface of the semiconductor substrate 2 by etching or the like. For example, before the thinning process, the thickness is 40
A semiconductor substrate having a thickness of 0 μm to 625 μm is reduced to about 50 μm to 200 μm by the thinning process. In addition, the slimming process removes unavoidable scratches formed on the back surface of the semiconductor substrate 2.

FIG. 8 shows a spin etching apparatus 21 for etching the back side of the semiconductor substrate 2. As shown in FIG. 8, the spin etching apparatus 21 includes a wafer carrier 23 that is rotationally driven in a process chamber 22;
Chemical supply pipe 24 for supplying a chemical into wafer carrier 23
And an air supply pipe 25 for supplying air (nitrogen) into the process chamber 22, a chemical discharge pipe 26 for discharging the chemical from the process chamber 22, and an air discharge pipe 27 for discharging air from the process chamber 22. Prepare. This spin etching device 2
1 is a state in which the semiconductor substrate 2 is placed upside down on the wafer carrier 23 and the wafer carrier 23 is rotationally driven.
A mixed solution of hydrofluoric acid, nitric acid and water is supplied as a chemical into the process chamber 22 via a chemical supply pipe 24, and air is supplied from an air supply pipe 25. As a result, the chemical supplied to the process chamber 22 adheres to the back surface of the semiconductor substrate 2, and the chemical adhered to the back surface of the semiconductor substrate 2 is scattered by centrifugal force due to the rotation of the wafer carrier 23. The back surface of the semiconductor substrate 2 is uniformly etched.

In this case, the operating conditions of the spin etching apparatus 21 are set, for example, as follows.

Rotation speed of wafer carrier 2000 rpm
m Chemical composition HF: HNO ₃ = 1: 9 Chemical supply rate 40 l / min Substrate thickness of the semiconductor substrate after etching 125 μm (shaving allowance about 500 μ)
m) The spin etching apparatus 21 performs an etching process on the semiconductor substrate 2 under the above operating conditions.
The scratches formed on the back surface side of the semiconductor substrate 2 unavoidably formed in the various steps up to now are removed, and the semiconductor substrate 2 can be thinned to a predetermined thickness.

Next, as shown in FIG.
A liquid sealing resin formed of a resin material such as an epoxy resin is spin-coated on the surface protective film 4 formed on the front surface side of the substrate so as to surround the solder bumps 7.
Thereafter, the liquid sealing resin is pre-heated at about 100 ° C. for about 1 hour to form the first sealing resin film 8 having the same height as the solder bumps 7, that is, 100 μm. This first
The sealing resin film 8 protects the surface side of the semiconductor substrate 2 and reinforces the strength of the thinned semiconductor substrate 2 in the previous step.

When the semiconductor substrate 2 is thinned, the semiconductor substrate 2 is etched by the above-described spin etching apparatus 21, and is mechanically polished (grinded), chemically mechanically polished (chemical mechanical polished), and dried using a plasma processing apparatus. It may be performed by etching or the like.

Next, the same material as the first sealing resin film 8 on the front surface side of the semiconductor substrate 2, that is, a liquid sealing resin made of a resin material such as an epoxy resin is spin-coated on the back surface side of the semiconductor substrate 2. You. Thereafter, the liquid sealing resin is completely cured together with the first sealing resin film 8 formed on the surface side of the semiconductor substrate 2 by performing a heat treatment at about 150 ° C. for about 3 hours. A second sealing resin film 9 having the same thickness as that of the sealing resin film 8 is formed. The second sealing resin film 9 is formed together with the first sealing resin film 8 formed on the surface side of the semiconductor substrate 2 together with the thinned semiconductor substrate 2.
In addition to improving the mechanical strength of the semiconductor substrate 2, the back surface of the semiconductor substrate 2 is protected in the previous step so that the back surface of the semiconductor substrate 2 whose back surface has been etched is not damaged. Further, the second sealing resin film 9 is
And at the same time as the sealing resin film 8. The semiconductor substrate 2 and the first and second sealing resin films 8 and 9 have different coefficients of thermal expansion, and a stress is applied to the semiconductor substrate 2. At this time, on the back side of the semiconductor substrate 2, the first sealing resin film 8 formed on the front side is formed of the same material,
Since the second sealing resin film 9 having the same thickness is formed, the first and second sealing resin films 9 and 9 are subjected to heat treatment for forming the first and second sealing resin films 8 and 9. The resin films 8 and 9 can cancel the stress generated on each surface side of the semiconductor substrate 2 and can prevent the semiconductor substrate 2 from being deformed by the heat treatment.

Then, as shown by the dotted line in FIG. 9, the first sealing resin film 8 formed on the front surface side of the semiconductor substrate 2 has a surface facing a part of the solder bump 7 to the outside. Polished. Here, FIG. 10 shows a polishing apparatus 31 for polishing the surface of the first sealing resin film 8. As shown in FIG. 10, the polishing apparatus 31 includes a surface plate 33 driven to rotate by a rotation shaft 32 and a polishing cloth 3 attached to the upper surface of the surface plate 33.
4, a wafer carrier 35 that rotates while supporting the semiconductor substrate 2, and a nozzle 36 that drops a polishing solvent on the surface plate 33. Then, the polishing apparatus 31 attaches the semiconductor substrate 2 to the wafer carrier 35 so that the first sealing resin film 8 faces the polishing cloth 34 attached to the platen 33, and the first sealing resin film 8 The first sealing resin film 8 is polished by a predetermined amount by rotating the semiconductor substrate 2 while pressing the semiconductor substrate 2 against the polishing cloth 34. As a result, a part of the surface side of the first sealing resin film 8 and the top side of the solder bump 7 are polished by a predetermined amount, and a part of the solder bump 7 is outside the surface of the first sealing resin film 8. To face you.

Thereafter, as shown in FIG. 1, the solder bumps 7 formed of the high melting point solder exposed to the outside of the first sealing resin film 8 are soldered to the lands of the printed wiring board. A eutectic solder ball 10 for attachment is formed. The eutectic solder ball 10 is made of a solder having a lower melting point than the solder constituting the solder bump 7, and prevents the solder bump 7 from being melted when performing a heat treatment for connecting to a land portion of a printed wiring board. . The eutectic solder balls 10 are formed by forming a eutectic solder film on the solder bumps 7 by screen printing or the like, and heating and melting the eutectic solder film at a temperature lower than the melting point of the high melting point solder forming the solder bumps 7. As a result, while being formed into a substantially spherical shape by surface tension,
Connected to solder bump 7.

Thereafter, the semiconductor substrate 2 on which the solder bumps 7 and the first and second sealing resin films 8 and 9 are formed is cut out by dicing or the like into chips for each IC, as shown in FIG. Semiconductor device 1 is formed.

According to the method of manufacturing the semiconductor device 1 as described above, after the back surface side of the semiconductor substrate 2 is thinned, first, the front surface side of the semiconductor substrate 2 is preheated, so that the first sealing is performed. A stopper resin film 8 is formed, and subsequently, a liquid sealing resin for forming a second sealing resin film 9 is spin-coated on the back surface side of the semiconductor substrate 2, and thereafter, the first and second liquid sealing resins are heated with high heat. Are simultaneously cured by heating. Therefore, the semiconductor substrate 2 and the first and second sealing resin films 8 and 9 have different coefficients of thermal expansion, and a stress is applied to the semiconductor substrate 2.
Since the first sealing resin film 8 and the second sealing resin film 9 are formed on both surfaces of the substrate, a heat treatment for curing the first and second sealing resin films 8 and 9 is performed. The first and second
The sealing resin films 8 and 9 can cancel the stress generated on each surface side of the semiconductor substrate 2 and can prevent the semiconductor substrate 2 from being deformed by the heat treatment.

The semiconductor device 1 can be formed as follows. The steps up to the formation of the solder bumps 7 shown in FIGS. 2 to 6 on the semiconductor substrate 2 are the same as those of the above-described manufacturing method, and thus the details are omitted. In the method of manufacturing the semiconductor device 1 described above, the first sealing resin film 8 is formed on the front surface side and the second sealing resin film 9 is formed on the rear surface side after the semiconductor substrate 2 is reduced in thickness. However, in the method of manufacturing the semiconductor device 1 described below, the liquid sealing resin 8a is applied to the front surface side of the semiconductor substrate 2 and cured so as to suppress the fluidity. After that, a liquid sealing resin is applied to the back surface side of the semiconductor substrate 2,
Subsequently, the first and second sealing resin films 8 and 9 are simultaneously formed by performing a heat treatment.

That is, the electrode pads 3 are formed on the semiconductor substrate 2 on which the circuit elements are formed, then the surface protection film 4 is formed on the semiconductor substrate 2, and then the electrode pads 3 are formed.
When the multilayer metal film 6 is formed in the opening 5 formed in the surface protection film 4 that exposes the outside, and the solder bumps 7 are formed on the multilayer metal film 6, as shown in FIG. A liquid sealing resin 8a formed of a resin material such as an epoxy resin is spin-coated on the surface protection film 4 formed on the front surface side of the substrate 2 so as to surround the solder bumps 7. Thereafter, the liquid sealing resin 8a is pre-heated and hardened to the extent that fluidity is suppressed.

Next, as shown in FIG. 12, the semiconductor substrate 2 having the liquid sealing resin 8a applied on the front surface side is separated from the semiconductor substrate 2 by, for example, a spin etching apparatus 21 shown in FIG.
The thickness is reduced to a thickness that does not damage circuit elements formed on the surface of the substrate. In addition, the unavoidably formed scratch is removed from the back surface of the semiconductor substrate 2 by this etching.

Next, as shown in FIGS. 12 and 13,
The same material as the first sealing resin film 8 on the front surface side of the semiconductor substrate 2, that is, a liquid sealing resin made of a resin material such as an epoxy resin is spin-coated on the back surface side of the semiconductor substrate 2. Thereafter, the liquid sealing resin is subjected to a heat treatment at about 150 ° C. for about 3 hours, thereby being cured together with the first sealing resin film 8 formed on the surface side of the semiconductor substrate 2, and the first sealing resin is formed. A second sealing resin film 9 having the same thickness as the stopper resin film 8 is formed.

Then, as shown in FIG. 9 described above, the first sealing resin film 8 formed on the front side of the semiconductor substrate 2
The surface is polished to expose a part of the solder bump 7 to the outside. Thereafter, on the solder bumps 7 formed of the high melting point solder exposed to the outside of the first sealing resin film 8,
As shown in FIG. 1, a eutectic solder ball 10 for soldering to a land portion of a printed wiring board is formed.
Subsequently, the solder bumps 7, the first and second sealing resin films 8,
The semiconductor substrate 2 on which the components 9 and the like are formed is cut out into chips for each IC by dicing or the like, thereby forming the semiconductor device 1 as shown in FIG.

According to the method of manufacturing the semiconductor device 1 as described above, after the solder bumps 7 are formed, first, the solder bumps 7 are formed.
A liquid sealing resin 8a is applied to the periphery of the semiconductor substrate 2 and cured to such an extent that the fluidity is suppressed, and then the semiconductor substrate 2 is thinned. Therefore, when the semiconductor substrate 2 is thinned, the solder bumps 7 are protected by the liquid sealing resin 8a and are prevented from being stained.

The semiconductor device 1 manufactured by the above manufacturing method is mounted on a printed wiring board as follows. That is, as shown in FIG. 14, in the flip-chip type semiconductor device 1, the eutectic solder balls 10 formed on the solder bumps 7 are opposed to the lands 17 serving as the contact portions of the printed wiring board 16. Here, the surface of the printed wiring board 16 except for the land portion 17 formed of Cu or the like is covered with the solder resist 18, and the printed wiring board 16 has the same shape as the eutectic solder ball 10 of the semiconductor device 1 on the land portion 17. Crystal solder 19 is pre-coated. Then, as shown in FIGS. 14 and 15, the semiconductor device 1 is moved in a direction approaching the printed wiring board 16, and the eutectic solder balls 10 on the semiconductor device 1 side and the shared The crystal solder 19 is melted and joined together.

Thus, the semiconductor device 1 is mounted at a predetermined position on the printed wiring board 16. Eutectic solder ball 10 of semiconductor device 1 and land portion 17 of printed wiring board 16
Since the eutectic solder 19 deposited on the upper surface is formed of the same solder material, the eutectic solder 19 is well adapted to each other and can be securely soldered. Further, since the semiconductor device 1 in which the semiconductor substrate 2 is thinned is mounted on the printed wiring board 16, the printed wiring board 16 on which the semiconductor device 1 is mounted is reduced in size and weight. Therefore, the size and weight of the electronic device can be reduced.

The printed wiring board 1 of the semiconductor device 1
As a method of mounting on 6, a bonding means such as an Au stud bump, an anisotropic conductive film, or a conductive paste may be used.

[0042]

According to the semiconductor device of the present invention, since the back side of the semiconductor substrate is thinned, the overall thickness of the device can be reduced. Further, in this semiconductor device, since the first and second sealing resin films are formed on the respective main surface sides of the semiconductor substrate, the thickness is reduced by the first and second sealing resin films. Thus, the strength of the semiconductor substrate is reinforced, and it is possible to prevent the mechanical strength of the entire device from decreasing due to the thinning of the semiconductor substrate. Further, the semiconductor device has first and second surfaces on both sides of the semiconductor substrate.
Is formed, the stress generated on each surface side of the semiconductor substrate can be canceled, and the heat treatment and the soldering when the first and second sealing resin films are cured. It is possible to prevent the semiconductor substrate from being deformed due to heat at the time.

According to the method of manufacturing a semiconductor device of the present invention, the semiconductor substrate and the first and second sealing resin films are
Although the thermal expansion coefficient is different, stress stress is applied to the semiconductor substrate by heat treatment for curing the first and second sealing resin films, heat at the time of soldering, etc. Is formed of the same material as the first sealing resin film 8 formed on the front surface side, and the second sealing resin film 9 having the same thickness is formed. The sealing resin film can cancel the stress generated on each surface side of the semiconductor substrate, and can prevent the semiconductor substrate from being deformed and damaged by heat treatment.

In addition, according to the method of manufacturing a semiconductor device according to the present invention, after the solder bumps are formed, first, the first sealing resin film is formed around the solder bumps 7, and thereafter, the semiconductor substrate is formed. Since the thinning process 2 is performed, the solder bumps are protected by the first sealing resin film and are prevented from being stained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a flip-chip type semiconductor device to which the present invention is applied.

FIG. 2 is a cross-sectional view of a principal part showing a state where an electrode pad and a barrier metal film are formed on a semiconductor substrate.

FIG. 3 is a sectional view of a principal part showing a state in which an opening for forming a solder deposition film on a barrier metal is formed in the photoresist film;

FIG. 4 is a cross-sectional view of a principal part showing a state where a photoresist film and a solder vapor deposition film are applied in openings.

FIG. 5 is a cross-sectional view of a principal part showing a state where a photoresist film formed on a surface protective film formed on the surface of the semiconductor substrate is removed and a solder vapor-deposited film remains on a barrier metal film.

FIG. 6 is a fragmentary cross-sectional view showing a state where a solder bump is formed on a barrier metal.

FIG. 7 is a cross-sectional view of a main part showing a state where the back surface side of the semiconductor substrate has been thinned.

FIG. 8 is a partially cutaway perspective view of a spin etching apparatus for thinning the back surface side of the semiconductor substrate.

FIG. 9 is a cross-sectional view of a principal part showing a state where a sealing resin film is formed on the front side and the back side of the semiconductor substrate.

FIG. 10 is a side view of a polishing apparatus for removing a surface of a sealing resin film formed on a front surface side of a semiconductor substrate.

FIG. 11 is a fragmentary cross-sectional view showing another example of the method of manufacturing a semiconductor device, showing a state in which a sealing resin film is formed on the front surface side of a semiconductor substrate that has not been thinned;

FIG. 12 is a cross-sectional view of a principal part showing another example of a method of manufacturing a semiconductor device, showing a state where the back surface side of a semiconductor substrate having a sealing resin film formed on the front surface side is thinned.

FIG. 13 is a fragmentary cross-sectional view showing another example of a method for manufacturing a semiconductor device, showing a state in which a sealing resin film is formed on both the front surface side and the back surface side of the semiconductor substrate.

FIG. 14 is a fragmentary cross-sectional view showing a state immediately before mounting the semiconductor device on the printed wiring board;

FIG. 15 is a fragmentary cross-sectional view showing a state where the semiconductor device is mounted on a printed wiring board.

[Explanation of symbols]

1 semiconductor device, 2 semiconductor substrate, 3 electrode pads, 4
Surface protective film, 5 opening, 6 metal multilayer film, 7 solder bump, 8 first sealing resin film, 9 second sealing resin film, 10 eutectic solder ball, 11 photoresist film,
12 opening, 16 printed wiring board, 17 land, 18 solder resist, 19 eutectic solder, 21 spin etching device, 31, polishing device

Claims (5)

[Claims] 1. A circuit element and an electrode part are formed on a surface side,
A semiconductor substrate having a thinned back surface, a protective film covering the surface of the semiconductor substrate so that the electrode portion faces outward, a barrier metal film formed on the electrode portion, and the barrier metal A solder bump formed on an upper portion of the film; a first sealing resin film covering the front surface of the semiconductor substrate so as to surround the solder bump at least at the height of the solder bump; and a back surface of the semiconductor substrate. A second sealing resin film for covering the semiconductor device. 2. The semiconductor device according to claim 1, wherein the semiconductor device is directly mounted on a predetermined position on a printed wiring board. 3. A step of forming a solder bump on an electrode portion formed on a semiconductor substrate on which a circuit element is formed, and a step of thinning the back surface of the semiconductor substrate after forming the solder bump. Forming a first sealing resin film covering the front surface side of the semiconductor substrate so as to surround the solder bumps after thinning the semiconductor substrate; and forming a first sealing resin film covering the back surface of the semiconductor substrate. 2. A method of manufacturing a semiconductor device, comprising: a step of forming a second sealing resin film; and a step of simultaneously curing the first sealing resin film and the second sealing resin film. 4. The semiconductor substrate according to claim 1, wherein said semiconductor substrate has a thickness of
4. The method according to claim 3, wherein the semiconductor device is thinned to a thickness of m. 5. A step of forming a solder bump on an electrode portion formed on a semiconductor substrate on which a circuit element is formed, and after forming the solder bump, surround a surface of the semiconductor substrate around the solder bump. Forming a first encapsulating resin film to cover the semiconductor substrate, forming a first encapsulating resin film, and then thinning the back surface of the semiconductor substrate, and reducing the thickness of the semiconductor substrate. After processing, a step of forming a second sealing resin film covering the back surface of the semiconductor substrate; and a step of simultaneously curing the first sealing resin film and the second sealing resin film. The manufacturing method of the semiconductor device provided.