JP2002359262A - Semiconductor device and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the nonconformity of cracks occuring near a bump electrode, which electrically connects lead wiring and the electrode of a semiconductor element due to the difference of the thermal expansion coefficients of respective materials, when sealing resin whose one end is heated drops to room temperature, in a process where a part between a film base material in which lead wiring is formed on a surface and the semiconductor element is sealed by encapsulating resin. SOLUTION: Lead wiring 9 and the film base material 8 are separated by heating them. When the temperature of sealing resin 12 heated in the sealing process drops to the room temperature, stress caused near a bump electrode 16 is absorbed, in a part which is detached from the film base material 8 of lead wiring 9. Thus, the nonconformity of cracks in a protective film 15 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a semiconductor element mounted on a film-like substrate, and more particularly to a semiconductor device in which wiring formed on a substrate is movable and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, semiconductor products such as LSIs have been required to be mounted at a high density in order to realize a reduction in price, weight, thickness and thickness.

[0003] Generally, TCP (Tape Carrier) is used as a semiconductor device for realizing high-density mounting of semiconductor elements.
There is a semiconductor device called “r Package”. Among them, a device without a device hole or a bending slit and a lead wire connected to an electrode of a semiconductor chip is in close contact with a tape base material is a COF (Chip On Fil).
m). The COF has no device hole and the lead wiring is in close contact with the film substrate, so that the lead wiring can be made thinner. As a result, as compared with the conventional TCP having a device hole, the etching of the lead wiring becomes easier, and a finer conductor pattern can be formed. At present, COF tapes having a pitch of 45 [μm] are emerging in the industry, and further refinement is required.

Hereinafter, a conventional semiconductor device and a method of manufacturing the same will be described with reference to the drawings.

[0005] First, a conventional semiconductor device will be described.

FIG. 4A is a plan view showing a conventional semiconductor device, and FIG. 4B is a cross-sectional view taken along a line AA1 in FIG. 4A.

As shown in FIGS. 4A and 4B, a film substrate 1 has insulating and flexible properties, and a film substrate 2 made of a resin such as polyimide and a film substrate 2 made of copper or the like. And a lead wiring 3 formed of a metal foil. Regions of the lead wiring 3 that are connected to the protruding electrodes (not shown) of the semiconductor element 4 and that are not covered with the solder resist 5 are defined as inner leads 3a and inner leads 3
lead wiring 3 extended on film substrate 2 out of a
Of the outer leads 3
Called b. The lead wiring 3 is usually plated. On the electrode of the semiconductor element 4, a protruding electrode 6 necessary for connecting the electrode formed on the semiconductor element 4 and the inner lead 3a is formed. The height of the protruding electrode 6 varies, and there is a configuration in which the protruding electrode 6 is not formed. The area around the inner leads 3a is covered with a sealing resin 7 to protect the surface of the semiconductor element 4 and secure the strength of the semiconductor device itself.

Next, a conventional method for manufacturing a semiconductor device will be described.

The same components as those of the semiconductor device described above are denoted by the same reference numerals.

FIGS. 5 and 6 are cross-sectional views showing steps of a conventional method for manufacturing a semiconductor device.

[0011] As shown in FIG.
The inner lead 3a formed above and the protruding electrode 6 formed on the electrode of the semiconductor element 4 are aligned. Here, the surface of the inner lead 3a is plated with tin, gold, or the like. The thickness of the film substrate 2 is 3
It is 8 [μm] or 25 [μm]. The height of the protruding electrode 6 is 10 to 20 [μm].

Next, as shown in FIG. 5B, the back surface of the semiconductor element 4 is placed on the upper surface of the stage 8 and pressed by the bonding tool 9 from the upper surface of the film substrate 2.
Here, the projecting electrode 6 formed on the semiconductor element 4 and the inner lead 3a of the film substrate 1 are joined to each other by a thermocompression bonding method in a predetermined position, and the thermocompression bonding method refers to plating performed on the inner lead 3a. Temperature required for eutectic fusion or solid phase diffusion between the material and the protruding electrode (300 to
400 [° C.]) and joining while applying a load.

Next, as shown in FIG. 5C, the joint between the inner lead 3a and the protruding electrode 6 and the surface where the circuit of the semiconductor element 4 exists are protected, and the mechanical strength of the entire semiconductor device is secured. For this purpose, a sealing resin 7 is injected into a gap between the film substrate 1 and the semiconductor element 4 using a resin supply nozzle 10. After sealing, stamping and inspection are performed to complete the COF product.

[0014]

It is known that in the sealing step of the conventional method for manufacturing a semiconductor device, a large stress is generated in the peripheral portion of the bump electrode. This stress is generated when the inner lead 3a and the bump electrode 6 are joined as shown in FIG. The cause of the stress is that the shrinkage rate of the COF constituent material according to the temperature change in the sealing step differs depending on the material. That is, this is because the thermal expansion coefficient of the film substrate 2 has a value larger than that of silicon which is a main material of the semiconductor element 4. Due to this difference in shrinkage, a shear stress is generated in the protruding electrode 6, which is a joint between the lead wiring 3 and the electrode of the semiconductor element 4. If the stress exceeds a certain limit value, a problem occurs that a circuit of the semiconductor element 4 located around the bump electrode 6 is mechanically broken.

FIG. 6 is a cross-sectional view showing a state of occurrence of a defect in a conventional semiconductor device manufacturing process.

A description will be given of the mechanism from the occurrence of stress to the occurrence of failure in each step of the conventional method for manufacturing a semiconductor device as shown in FIG. Part A is an enlarged part shown in the following drawings.

As shown in FIG. 6B, A in FIG.
In the portion, the tape contraction stress acts in the direction toward the center line of the semiconductor element 4 (the direction indicated by the arrow 11) due to the contraction of the film substrate 1 due to the temperature drop.

Due to the tape shrinkage stress, first, the protective layer 1
2, a crack 13 originating from the end of the metal projection 6 on the side facing the tip end of the inner lead 3a. This portion is a mechanically weak portion because the thickness of the protective layer 12 is thinner than other portions, and the crack 13 is easily generated.

Next, as shown in FIG. 6C, the crack 13 grows along the side surface of the metal electrode 14.

Next, as shown in FIG. 6D, the process proceeds to the separation of the bonding surface between the metal electrode 14 and the silicon substrate 15.

The present invention is directed to a semiconductor device and a method of manufacturing the same which solve the above-mentioned conventional problems. The present invention relates to a semiconductor device in which a lead wiring is separated from a film base material and a stress generated in a sealing step is absorbed by the lead wiring. An object of the present invention is to provide a manufacturing method thereof.

[0022]

According to a semiconductor device of the present invention for solving the above-mentioned conventional problems, a lead wiring formed on a surface of a film substrate and an electrode of a semiconductor element are electrically connected to each other via a protruding electrode. The sealing material is filled between the film base and the semiconductor element, and the surface of the lead wiring to which the protruding electrode is connected is on the film base side.
It is separated from the surface of the film substrate.

Further, the portion of the lead wiring away from the surface of the film substrate is within a range where the semiconductor element faces.

The distance between the surface of the film substrate and the film-side surface of the lead wiring remote from the surface of the film substrate is 1 to 20 [μm].

As described above, in the step of separating the semiconductor element and the film substrate with the sealing resin by separating the lead wiring and the film substrate, the semiconductor element, the film substrate, the sealing resin and the lead wiring are formed. The movable lead wiring separates and separates the stress caused by the different thermal expansion coefficients from the film substrate and absorbs the stress at the boundary between the protruding electrode and the electrode of the semiconductor element. Defects such as cracks can be prevented.

Further, a method of manufacturing a semiconductor device according to the present invention
The lead wiring formed on the surface of the film substrate and the electrode of the semiconductor element are thermocompressed via the protruding electrode, and the front surface of the film substrate and the back side of the portion where the protruding electrode of the lead wiring is thermocompressed. And a step of separating the
Injecting and curing a sealing resin between the semiconductor element and the film substrate.

In addition, the lead wire formed on the surface of the film substrate and the electrode of the semiconductor element are thermocompression-bonded via the protruding electrode, and the surface of the film substrate and the protruding electrode of the lead wire are thermally bonded. The step of separating the back side of the portion to be press-bonded is a first step of thermo-compression bonding the lead wiring and the electrode of the semiconductor element via a protruding electrode, and releasing the pressure for the thermo-compression bonding, A second step of separating a back surface side of a portion of the lead wiring to which the protruding electrode is thermocompression-bonded from a surface of the film substrate.

In the step of thermocompression-bonding the lead wiring formed on the surface of the film substrate and the electrode of the semiconductor element via the protruding electrode, and separating the surface of the film substrate and the lead wiring, Temperature during crimping is 4
00 to 500 [° C.], and the thermocompression bonding time is 1 to 5
[s].

According to such a method of manufacturing a semiconductor device,
Since the sealing resin is injected and sealed between the semiconductor element and the film substrate in a state where the back surface of the portion where the protruding electrode of the lead wiring is connected is away from the film substrate, the semiconductor element, the film substrate, and the sealing are formed. Separation at the boundary between the protruding electrode and the electrode of the semiconductor element by absorbing the stress caused by the different thermal expansion coefficients of the resin and the lead wiring away from the film substrate and absorbing the stress by the movable lead wiring. In addition, problems such as cracks in the semiconductor element can be prevented.

The sealing resin injected between the semiconductor element and the film substrate is made of only a liquid resin.

As described above, by using a resin containing no solid filler as the sealing resin, the sealing resin flows between the lead wiring and the film substrate. A portion where the sealing resin does not penetrate between the film substrate and the film substrate does not occur, and it is possible to prevent defects such as cracks and peeling between the semiconductor element and the film substrate.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor device according to the present invention and a method for manufacturing the same will be described below with reference to the drawings.

First, the semiconductor device of this embodiment will be described.

FIG. 1 is a plan view showing a semiconductor device according to the present embodiment, and FIG. 2 is a cross-sectional view taken along a line AA1 in FIG.

As shown in FIG. 1, a film substrate 10 is formed by forming a plurality of lead wires 9 on a film base 8 made of polyimide, and the protruding electrodes formed on the electrodes of the semiconductor element 11 and the lead wires 9 are formed. And are electrically connected. A sealing resin 12 is injected and sealed between the semiconductor element 11 and the film substrate 10. Further, a solder resist 13 is formed on the surface of the lead wiring 9 near the semiconductor element 11 to prevent the lead wiring 9 from short-circuiting with another conductive member.

Next, a portion where the electrode of the semiconductor element is electrically connected to the lead wiring via the protruding electrode will be described in detail.

As shown in FIG. 2, a protective film 15 made of a polyimide film is formed around the electrode 14 of the semiconductor element 11. One end is separated from the surface of the film base 8, and the other end is electrically connected to one end of the lead wire 9 formed on the surface of the film base 8 and the protruding electrode 16 formed on the electrode of the semiconductor element 11. Have been. The portion where the lead wiring 9 is separated from the film substrate 8 is within a range where the semiconductor element 11 faces.

A sealing resin 1 made of a resin containing no filler is provided between the lead wiring 9 and the film substrate 10.
2 are filled and sealed. The contact surface between the film substrate 8 and the lead wiring 9 is provided with a metal layer made of nickel or chromium. In this embodiment, the reason why the resin containing no filler is used as the sealing resin 12 is that the lead wiring 9 separating from the film base material 8 is formed smoothly, and the lead wiring 9 and the film base material 8 Is a very small gap in the separation portion, so that the sealing resin 12 is desirably a resin containing no filler that enters the minute gap. Here, the distance between the surface of the film substrate 8 and the surface of the lead wiring 9 on the film substrate 8 side is 1 to 20 [μm].

According to the experiments by the inventors, when the distance between the film substrate and the surface of the lead wiring on the film substrate side is smaller than 1 [μm], the lead wiring is free with respect to the surface of the film substrate. It is difficult to move. In addition, the distance between the film substrate and the surface of the lead wiring on the film substrate side is 2 mm.
If it is larger than 0 [μm], in the sealing step, the flow resistance of the sealing resin to the lead wiring becomes large, which causes a problem that the lead wiring becomes unstable.

As described above, according to the semiconductor device of the present embodiment, the stress generated in the sealing step can be absorbed by the lead wiring by separating the portion of the lead wiring to which the projecting electrode is connected from the film substrate. Problems such as cracks in the protective film on the surface of the semiconductor element near the electrodes can be prevented.

Next, a method of manufacturing the semiconductor device of the present embodiment will be described.

The same components as those of the semiconductor device described above are denoted by the same reference numerals, and the same contents are omitted.

FIG. 3 is a cross-sectional view showing each step of the method for manufacturing a semiconductor device according to the present embodiment.

First, as shown in FIG. 3A, a film substrate 10 having lead wires 9 formed on the surface and a semiconductor element 11 having projecting electrodes 16 formed on the electrodes are prepared. The projection electrode 16 is positioned. In addition,
A solder resist 13 is formed on the surface of the lead wiring 9 in order to prevent a short circuit with another conductive member.

Next, as shown in FIG. 3B, the back surface of the semiconductor element 11 is placed on the first tool 18, and 400 to 5 mm from the back surface of the film substrate 10 by the second tool 19.
By applying pressure while heating to 00 [° C.], the protruding electrodes 16 formed on the electrodes of the semiconductor element 11 and the lead wires 9 formed on the surface of the film base 8 are thermocompression bonded. Here, due to the heating, the adhesion at the interface between the film substrate 8 and the lead wiring 9 is reduced.

Next, as shown in FIG. 3C, the pressure applied by the first tool 18 and the second tool 19 is released, and the temperature is lowered to room temperature, whereby the film substrate 8 shrinks to generate stress, and the lead wiring 9 and the film substrate 8 are separated. Here, the heating temperature of the junction between the protruding electrode 16 and the lead wiring 9 is 40 in the present embodiment.
Although set at 0 to 500 [° C.], the temperature at which the lead wiring 9 and the film base material 8 are separated is not limited to 400 to 500 [° C.]. Depends on the material.

Next, as shown in FIG. 3D, a sealing resin 12 is injected between the semiconductor element 11 and the film substrate 10, and the sealing resin 12 is cured by heating.
Cool to room temperature.

In this embodiment, the film substrate 8 has a coefficient of linear expansion of 10 to 15 ppm / ° C. and a thickness of 40 μm.
And the shape of the semiconductor element 11 is 10 to 20
[mm] and the short side is 0.5 to 3 [mm].

As described above, according to the method of manufacturing a semiconductor device of the present embodiment, the stress generated in the sealing step can be absorbed by the lead wiring by separating the portion of the lead wiring to which the projecting electrode is connected from the film base material. This can prevent defects such as cracks in the protective film on the surface of the semiconductor element near the protruding electrodes.

[0050]

According to the present invention, since the lead wiring electrically connected to the protruding electrode formed on the electrode of the semiconductor element is separated from the surface of the film base, the semiconductor element and the film base are separated. The stress generated in the sealing step of sealing the gap can be absorbed by the lead wiring separated from the film base material, and the occurrence of a defect such as a crack in the connection portion near the protruding electrode can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing a semiconductor device according to one embodiment of the present invention;

FIG. 3 is a sectional view showing each step of a method for manufacturing a semiconductor device according to one embodiment of the present invention

FIG. 4 is a diagram showing a conventional semiconductor device.

FIG. 5 is a sectional view showing each step of a conventional method for manufacturing a semiconductor device.

FIG. 6 is a sectional view showing each step of a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film board 2 Film base 3 Lead wiring 4 Semiconductor element 5 Solder resist 6 Protruding electrode 7 Sealing resin 8 Film base 9 Lead wiring 10 Film substrate 11 Semiconductor element 12 Sealing resin 13 Solder resist 14 Electrode 15 Protective film 16 Projection electrode

Claims (7)

[Claims] 1. A lead wire formed on the surface of a film substrate and an electrode of a semiconductor element are electrically connected via a protruding electrode, and a sealing resin is filled between the film substrate and the semiconductor element. A semiconductor device, wherein a surface of the lead wiring to which the protruding electrode is connected on the film substrate side is separated from a surface of the film substrate. 2. The semiconductor device according to claim 1, wherein a portion of the lead wiring away from the surface of the film substrate is within a range facing the semiconductor element. 3. The distance between the surface of the film substrate and the surface of the lead wiring remote from the surface of the film substrate on the film substrate side is 1 to 20 [μm]. The semiconductor device according to claim 1. 4. A lead wire formed on a surface of a film substrate and an electrode of a semiconductor element are thermocompression-bonded via a protruding electrode, and the surface of the film substrate and the protruding electrode of the lead wire are thermally bonded. A method of manufacturing a semiconductor device, comprising: a step of separating a back surface side of a portion to be press-bonded; and a step of injecting and curing a sealing resin between the semiconductor element and the film substrate. 5. A thermo-compression bonding between a lead wiring formed on a surface of a film base and an electrode of a semiconductor element via a protruding electrode, and the surface of the film base and the protruding electrode of the lead wiring are heat-bonded. The step of separating the back surface side of the portion to be crimped is a first step of thermocompression bonding the lead wiring and the electrode of the semiconductor element via a protruding electrode, and releasing the pressure for the thermocompression bonding, 5. The method according to claim 4, further comprising: a second step of separating a back surface of a portion of the lead wiring on which the protruding electrode is thermocompression-bonded from a surface of the film base. 6. . 6. The step of thermocompression bonding a lead wiring formed on a surface of a film substrate and an electrode of a semiconductor element via a protruding electrode, and separating the surface of the film substrate from the lead wiring. The temperature during the thermocompression bonding is 400
5. The method according to claim 4, wherein the temperature is approximately 500 ° C., and the time of the thermocompression bonding is approximately 1 to 5 seconds. 6. 7. The method for manufacturing a semiconductor device according to claim 4, wherein the sealing resin injected between the semiconductor element and the film substrate comprises only a liquid resin.