JP2002353370A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

(57) [Problem] When the pitch of element electrodes or electrodes is small, the width and thickness of the partial lead at the connection portion between the element electrode and the partial lead extending from the wiring circuit sheet become small,
The electrical connection between the partial lead and the device electrode becomes unstable. SOLUTION: A low elasticity insulating layer 14 is formed on a portion except for an element electrode 12 formed on an upper surface of a semiconductor substrate 11, and a ball electrode 13 made of solder is formed on the thin film metal layer 15 formed on the element electrode 12 by a thickness. The ball electrode 13 is mounted on the upper surface of the film metal layer 16 and supported by the ends of the openings of the thick film metal layer 16 and the low elasticity insulating layer 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device having a ball electrode formed on an electrode on a semiconductor substrate, and more particularly to a semiconductor device having a ball electrode mounted on a thick metal layer and a method of manufacturing the same. It is about.

[0002]

2. Description of the Related Art Conventionally, there has been a demand for a semiconductor device corresponding to miniaturization, higher density, and higher functionality of electronic equipment.

A conventional μBGA (Micro Ba
A semiconductor device called “II Grid Array” and a method for manufacturing the same will be described with reference to the drawings.

FIG. 6 is a sectional view showing a conventional semiconductor device.

As shown in FIG. 6, reference numeral 101 denotes a semiconductor substrate on which semiconductor elements are formed; 102, a flexible wiring circuit sheet formed above the semiconductor substrate 101; 103, a semiconductor substrate 101 and a wiring circuit sheet 102; A low-modulus layer interposed therebetween, 104 is a partial lead that becomes a part of the wiring layer,
105 is an element electrode formed on the surface of the semiconductor substrate 101 and electrically connected to the semiconductor element, and 106 is an electrode formed on the surface of the printed circuit sheet 102 for making an electrical connection with an external device. Reference numeral 107 denotes a solder ball as an external connection terminal.

As described above, the printed circuit board 102 has a structure in which the wiring circuit sheet 102 is formed on the semiconductor substrate 101 with the low elastic modulus layer 103 interposed therebetween.
5 and the electrodes 106 on the printed circuit sheet 102 are electrically connected by the partial leads 104, and the solder balls 107 are mounted on the electrodes 106.

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

First, a flexible sheet-shaped wiring circuit sheet 102 is formed on a semiconductor substrate 101 via a low elastic modulus layer 103.
To form The wiring circuit sheet 102 has a wiring pattern inside, and has an electrode 106 connected to the wiring pattern on the wiring circuit sheet 102, and has a structure in which a partial lead 104 extends from the electrode 106. . In this case, the low elastic modulus layer 103 is an insulating material and has an adhesive function.

In such a conventional semiconductor device typified by μBGA, the wiring circuit sheet 1 is formed while relaxing the stress.
02 enables electrical connection to external devices via a large number of electrodes 106 and solder balls 107 formed two-dimensionally on the device 02, thereby reducing the size of information communication devices, office electronic devices, etc. It is.

[0010]

However, the conventional semiconductor device has the following problems.

As shown in FIG. 6, first, an element electrode 105 is formed.
Alternatively, when the pitch of the electrode 106 is small, the partial lead 1 extending from the element electrode 105 and the wiring circuit sheet 102
The width and thickness of the partial lead 104 at the connection portion with the element 04 become small, and the electrical connection between the partial lead 104 and the element electrode 105 becomes unstable.

When the width of the partial lead 104 is reduced, the resistance value of the partial lead 104 is increased.
There was a problem that the electrical characteristics deteriorated.

Further, when electrically connecting to an external substrate via the solder ball 107, the stress received from the solder ball 107 is applied to the electrode 10 formed on the upper surface of the low elastic modulus layer 103.
6, the electrode 106 is mechanically damaged,
There was a defect such as damage.

A semiconductor device and a method of manufacturing the same according to the present invention solve the above-mentioned conventional problems, eliminate the instability of electrical connection at the end of a partial lead in a conventional semiconductor device, and receive an electrode. It is an object of the present invention to provide a semiconductor device that reduces mechanical damage and a method for manufacturing the same.

[0015]

In order to solve the above-mentioned conventional problems, a semiconductor device according to the present invention comprises a semiconductor substrate, an element electrode formed on a main surface of the semiconductor substrate, and an upper surface of the semiconductor substrate. At least two insulating layers formed in a portion excluding the device electrode, a metal layer formed on the device electrode, and an external electrode formed on an upper surface of the metal layer. The area of the opening of each layer of the insulating layer near the upper side increases as the distance from the semiconductor substrate increases.

The external electrode is a ball electrode.

The external electrodes are held by openings in the metal layer and the insulating layer.

Further, a method of manufacturing a semiconductor device according to the present invention
Preparing a semiconductor substrate having an element electrode formed on an upper surface thereof, forming at least two insulating layers on the semiconductor substrate excluding the element electrode, and forming each of the insulating layers in the vicinity of above the element electrode. The method includes a step of increasing the area of the opening as the distance from the semiconductor substrate increases, a step of forming a metal layer on the device electrode, and a step of forming an external electrode on the metal layer.

The semiconductor substrate is a semiconductor device.

The semiconductor substrate is a wafer on which a plurality of the semiconductor elements are formed.

As described above, since the external electrode and the device electrode can be electrically connected via the metal layer, there is no need to use a partial lead as in the prior art, and an electrically stable connection can be ensured. it can. In addition, since the external electrode is in contact with not only the element electrode but also the end face of the opening of the insulating layer, the stress applied to the external electrode after mounting the semiconductor device is distributed to the end face of the opening of the element electrode and the insulating layer. It is possible to do.

[0022]

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

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

FIG. 1 is a plan view showing the semiconductor device of the present embodiment, and FIG. 2 is a sectional view showing the semiconductor device of the present embodiment.

As shown in FIGS. 1 and 2, 11 is a semiconductor substrate, 12 is a device electrode of the semiconductor substrate, 13 is a ball electrode, 14 is a low elasticity insulating layer, 15 is a thin metal layer, and 16 is a thick metal layer. , 17 are passivation films.

The positional relationship and operation of such components will be described.

A plurality of device electrodes 12 are formed on the upper surface of a semiconductor substrate 11 made of Si, and the device electrodes 12 are covered with a thin metal layer 15 on the semiconductor substrate 11. Thick metal layer 1 thicker than
6 are formed. Then, a low-elasticity insulating layer 14 is formed on the semiconductor substrate 11 except for the element electrode 12, the thin-film metal layer 15, and the thick-film metal layer 16. Here, the upper surface of the thick metal layer 16 is formed lower than the upper surface of the low elasticity insulating layer 14. The ball electrode 13 is mounted on the upper surface of the thick metal layer 16, and the ball electrode 13 is in contact with the upper surface of the thick metal layer 16 and the end of the opening above the element electrode 12 of the low elasticity insulating layer 14. . In the present embodiment, a solder ball made of solder is used as the ball electrode 13.

The low-elasticity insulating layer 14 has at least two layers.
The area of the opening formed at the end of each low-elasticity insulating layer 14 near the upper side of the device electrode 12 increases as the distance from the semiconductor substrate 11 increases.
The outer shape formed by the end face of the opening 4 is inclined with respect to the semiconductor substrate 11 or the element electrode 12. Therefore, the outer surface below the ball electrode 13 is
And it is held in contact with the opening of the low elasticity insulating layer 14.

As described above, since the semiconductor device of the present embodiment does not have a structure in which the device electrode is electrically connected to another electrode using the lead, instability of the electrical connection at the end of the lead is caused. In addition, it is possible to prevent electrical characteristics from deteriorating due to a decrease in the resistivity of the leads.

The ball electrode and the device electrode formed on the semiconductor substrate are electrically connected via various metal layers, and a part of the outer surface of the ball electrode is formed on the upper surface of the semiconductor substrate excluding the device electrode. When the semiconductor device is mounted on the external substrate, the stress received via the ball electrode is not only at the element electrode but also at the low elastic insulating layer, since the semiconductor device is in contact with the end face of the opening of the formed low elastic insulating layer. However, since it holds, damage to the device electrode can be reduced.

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

The same contents as those in the above-described embodiment are omitted, and the same components are denoted by the same reference numerals.

FIGS. 3 to 5 are cross-sectional views showing each step of the method for manufacturing a semiconductor device according to the present embodiment.

First, as shown in FIG. 3A, an element electrode 12 made of Al is formed on an upper surface of a semiconductor substrate 11 made of Si.
Is formed, and a passivation film 17 made of a polyimide resin is formed on the upper surface of the semiconductor substrate 11 except for the element electrodes 12. In addition, the surface of the semiconductor substrate 11 has therein a semiconductor integrated circuit including a semiconductor element such as a transistor. In the present embodiment, the semiconductor substrate 11 is a wafer on which a plurality of semiconductor elements are formed, but may be a chip-based semiconductor element. The device electrodes 12 on the semiconductor substrate 11 are arranged in a lattice.

Next, as shown in FIG. 3B, the photosensitive low-elastic insulating layer 14 is formed on the upper surface of the device electrode 12 and the passivation film 17 formed on the upper surface of the semiconductor substrate 11 by spin coating. Is applied and dried.

Further, as shown in FIG. 3C, exposure and development are sequentially performed on the dried low-elasticity insulating layer 14, and a low-elasticity resin made of at least two layers of a thermosetting resin is formed on the passivation film. An insulating layer 14 is formed. At this time, the device electrode 12 formed on the end face of the multilayer low-elasticity insulating layer 14 is formed.
The low-elasticity insulating layer 14 of each layer is formed such that the area of the upper opening increases as the distance from the semiconductor substrate 11 increases. The shape of the opening is adjusted by adjusting the heating conditions such as the heating temperature, thereby adjusting the position of the end face of the low-elasticity insulating layer 14 of each layer to form a slope on the side surface of the opening.

As the low elastic insulating layer 14 having photosensitivity, for example, a polymer such as an ester bond type polyimide and an acrylate-based epoxy is used, and any material may be used as long as it is insulating. In addition, the low elastic insulating layer 14 having photosensitivity may use a material formed in a film shape in advance. In that case, the low-elastic insulating layer 14 is bonded to the semiconductor substrate 11 and exposed and developed to form the low-elastic insulating layer 1.
4, an opening is formed in the device electrode 12 on the semiconductor substrate 11.
To expose.

Next, as shown in FIG. 4A, the upper surface and the side surfaces of the low-elasticity insulating layer 14 and the upper surface of the device electrode 12 are formed by sputtering to a thickness of about 0.2 [μm].
C having a thickness of about 0.5 μm formed on the film and the upper surface thereof
A thin metal layer 15 made of a u film is formed. The method for forming the thin film metal layer 15 may be a thin film forming technique other than the sputtering method, such as a vacuum deposition method, a CVD method, or an electroless plating method.

Next, as shown in FIG. 4B, a positive photosensitive resist film or a negative photosensitive resist film 18 is formed on the thin metal layer 15 by spin coating,
An opening is formed above the element electrode 12 by development, and the resist film 1
8 is formed.

Next, as shown in FIG. 4C, the thin film metal layer 15 is formed on the thin film metal layer 15 in a portion other than the resist film 18 except the portion above the device electrode 12 by patterning. The thick metal layer 16 is selectively formed by a forming technique. For example, the thick metal layer 16 made of a Cu film is selectively formed.

Next, as shown in FIG. 5A, after forming the thick film metal layer 16, the resist film is melted and removed, and an etching solution capable of melting and removing the thin film metal layer 15 is applied. For example, Cu
Cupric iron chloride solution for the film, E for the Ti film
When the entire surface is etched with a DTA solution, the thin metal layer 15 having a smaller thickness than the thick metal layer 16 is removed first.
By this step, the thick metal layer 16 is formed on the element electrode 12 and on a part of the low elastic insulating layer 14 on the main surface of the semiconductor substrate 11.
Is formed.

Next, as shown in FIG. 5B, the ball electrode 13 is mounted on the upper surface of the thick film metal layer 16 and the end surface of the low-elasticity insulating layer 14, and then fused and joined.

Thereafter, the semiconductor substrate is divided into semiconductor elements by a dicing saw.

Although Cu was used as a material for forming the thin film metal layer and the thick film metal layer, Cr, W, Ti /
Cu, Ni or the like may be used. Further, the thin film metal layer 15
The thick metal layer 16 and the thick metal layer 16 are made of different metal materials.
Only 5 may be selectively etched.

As described above, the method of manufacturing a semiconductor device according to the present embodiment does not require the use of a lead for electrically connecting an element electrode on a semiconductor substrate to another electrode. Problems such as a decrease in resistance can be prevented.

Further, two or more low-elasticity insulating layers are formed on the upper surface of the semiconductor substrate except for the element electrodes, and the ball electrodes are formed on the element electrodes and the low-elasticity insulating layer by opening the upper part of the element electrodes. It is held at the end face of the opening and the external force transmitted from the ball electrode is held not only at the element electrode but also at the end face of low elastic modulus, so damage to the element electrode is reduced and stable electrical connection Can be secured.

[0047]

According to the semiconductor device of the present invention and the method of manufacturing the same, it is possible to prevent problems such as poor connection or reduced resistance. Further, damage to the device electrode can be reduced, and stable electrical connection can be ensured.

[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 sectional view showing each step of a method for manufacturing a semiconductor device according to one embodiment of the present invention;

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

FIG. 6 is a sectional view showing a conventional semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Semiconductor substrate 12 Element electrode 13 Ball electrode 14 Low elastic insulating layer 15 Thin metal layer 16 Thick metal layer 17 Passivation film 18 Resist film 101 Semiconductor substrate 102 Wiring circuit sheet 103 Low elastic modulus layer 104 Partial lead 105 Element electrode 106 Electrode 107 Solder ball

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Nozomu Shimoishizaka 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshifumi Nakamura 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Takahiro Kumakawa 1006 Odaka, Kadoma, Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] A semiconductor substrate; an element electrode formed on a main surface of the semiconductor substrate; at least two insulating layers formed on a portion of the upper surface of the semiconductor substrate other than the element electrode; A metal layer formed on the electrode, and an external electrode formed on the upper surface of the metal layer, wherein the area of the opening of each layer of the insulating layer near the upper side of the element electrode increases as the distance from the semiconductor substrate increases. A semiconductor device which is large. 2. The semiconductor device according to claim 1, wherein the external electrode is a ball electrode. 3. The semiconductor device according to claim 1, wherein the external electrode is held by openings of the metal layer and the insulating layer. 4. A step of preparing a semiconductor substrate on which an element electrode is formed on an upper surface, forming at least two insulating layers on the semiconductor substrate except for the element electrode, A step of increasing the area of the opening of each layer of the insulating layer as the distance from the semiconductor substrate increases, a step of forming a metal layer on the element electrode, and a step of forming an external electrode on the metal layer A method for manufacturing a semiconductor device, comprising: 5. The method according to claim 4, wherein the external electrode is a ball electrode. 6. The method according to claim 4, wherein the external electrodes are held by openings of the metal layer and the insulating layer. 7. The method according to claim 4, wherein the semiconductor substrate is a semiconductor element. 8. The method according to claim 4, wherein the semiconductor substrate is a wafer on which a plurality of semiconductor elements are formed.