JP2003298007A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

[57] A manufacturing method of a semiconductor device in which two semiconductor chips face each other, because the method of forming a metal layer on the internal electrode and the external electrode of one semiconductor chip is a different process, and thus the manufacturing cost. There was a problem that became high. A first bump 24 and a metal film 29 are simultaneously applied to an internal electrode and an external electrode of a first semiconductor chip.
Respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention A semiconductor device and a method of manufacturing the same according to the present invention include a COC in which two semiconductor chips face each other.
The present invention relates to a (Chip On Chip) type semiconductor device and a method for manufacturing the same, and in particular, a semiconductor that realizes highly efficient manufacturing and assembly by improving a method for forming bumps (projection electrodes) formed on electrodes of a semiconductor chip. The present invention relates to a device and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, in order to reduce the cost and size of a semiconductor device, a COC (Chi) is used in which semiconductor chips having different functions are joined to each other.
A p-on-chip type semiconductor device has been proposed.

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

First, a conventional semiconductor device will be described.

FIG. 5 is a sectional view showing a conventional semiconductor device.

As shown in FIG. 5, the first semiconductor chip 1
The first bumps 3 made of Ni formed by electroless plating are formed on the surfaces of the internal electrodes 2. Further, a barrier metal 6 is formed on the surface of the internal electrode 5 of the second semiconductor chip 4 whose surfaces are opposed to the first semiconductor chip 1, and a second bump 7 made of solder is further formed. ing. Then, the first bump 3 and the second bump 7 are connected to each other, and the first semiconductor chip 1 and the second semiconductor chip 4 are electrically connected to each other.

An external electrode 8 is formed on the first semiconductor chip 1, a wire bonding auxiliary electrode 9 is formed on the surface of the external electrode 8, and a lead frame on which the first semiconductor chip 1 is mounted is mounted. The lead 11 formed around the die pad 10 and the external electrode 8 of the first semiconductor chip 1 are electrically connected by the thin metal wire 12. Also,
An insulating resin 13 is filled between the first semiconductor chip 1 and the second semiconductor chip 4, and the first semiconductor chip 1, the second semiconductor chip 4, the fine metal wire 12 and the die pad 10 are sealed. It is sealed with resin 13.

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

6 to 9 are sectional views showing the steps of a conventional method for manufacturing a semiconductor device.

First, a bump forming method for the first semiconductor chip will be described.

As shown in FIG. 6A, the external electrode 8 of the wafer 14 before being separated as the first semiconductor chip.
Then, the auxiliary electrode 9 for wire bonding having a film thickness of about 0.6 [μm] is formed by vapor deposition. The wire bonding auxiliary electrode 9 is made of a metal film and is formed to secure the bondability with the metal thin wire 12.

Next, as shown in FIG. 6B, when the first bump is formed on the internal electrode 2 of the first semiconductor chip 1 by the electroless plating method, the auxiliary electrode 9 for wire bonding is used. Protective film 1 to prevent plating from depositing on top
5 is formed by a resist.

Next, as shown in FIG. 7 (a), the first semiconductor chip 1 is immersed in the electroless plating bath 16 to form the first semiconductor chip 1 on the internal electrodes 2 of the first semiconductor chip 1 by electroless plating. The bump 3 of 1 is formed.

Next, as shown in FIG. 7B, the protective film is removed and the bump formation of the first semiconductor chip 1 is completed.

A manufacturing process for mounting the second semiconductor chip on the first semiconductor chip thus completed and assembling will be described.

First, as shown in FIG. 8A, solder bumps 7 are formed on the internal electrodes 5 of the second semiconductor chip 4 by electrolytic plating. Regarding the formation of the solder bumps 7, after forming the barrier metal 6 on the internal electrodes 5 of the second semiconductor chip 4 by the vapor deposition method, a bump pattern is formed by a resist and the solder bumps 7 are formed by electrolytic solder plating. Then, after the barrier metal 6 is dissolved and removed by wet etching using the solder bumps 7 as a mask, the solder bumps 7 are reflowed into a hemispherical shape.

Next, as shown in FIG. 8B, the first semiconductor chip 1 is prepared.

Next, as shown in FIG. 8C, the surface of the first semiconductor chip 1 is coated with the insulating resin 13 and is soldered to the second semiconductor chip 4 which is vacuum-sucked by the connecting tool 17. The second bumps 7 are aligned with the first bumps 3 formed on the internal electrodes 2 of the first semiconductor chip 1.

Next, as shown in FIG. 9A, the second semiconductor chip 4 is placed on the first semiconductor chip 1, and the second bumps 7 made of solder are heated and melted to form the second bumps 7. The internal electrodes 5 of the semiconductor chip 4 and the internal electrodes 2 of the first semiconductor chip 1 are electrically connected.

Finally, as shown in FIG. 9B, the first semiconductor chip 1 is adhered to the die pad 10 of the lead frame, and the wire bonding auxiliary formed on the external electrode 8 of the first semiconductor chip 1 is bonded. The electrodes 9 for use and the leads 11 of the lead frame are connected by the thin metal wires 12 and sealed by the sealing resin 13.

[0021]

However, in the conventional method for manufacturing a semiconductor device, the bumps are formed on the internal electrodes of the first semiconductor chip, and the metal film is formed on the external electrodes of the same first semiconductor chip. Since the forming process is separate from the plating process, a vapor deposition process for forming the metal film is added, and the manufacturing cost is increased.

A semiconductor device and a manufacturing method thereof according to the present invention solve the above-mentioned conventional problems, and an object thereof is to realize a low-cost manufacturing and assembling by improving a bump forming method. .

[0023]

In order to solve the above-mentioned conventional problems, a method of manufacturing a semiconductor device according to the present invention provides a first bump and a metal film on an internal electrode and an external electrode of a first semiconductor chip. Forming them simultaneously, forming second bumps on the internal electrodes of the second semiconductor chip, electrically connecting the first bumps and the second bumps, and the first bumps. The step of adhering the back surface of the semiconductor chip to the die pad, and the step of electrically connecting the external electrode of the first semiconductor chip and the lead formed around the die pad with a thin metal wire.

After the step of electrically connecting the external electrodes of the first semiconductor chip and the leads formed around the die pad with a thin metal wire, the first semiconductor chip,
A step of electrically connecting the second semiconductor chip, the die pad and the thin metal wire with a sealing resin is provided.

As a result, the step of forming the bump on the internal electrode of the first semiconductor chip and the step of forming the metal film on the external electrode of the same first semiconductor chip are performed at the same time, so that separate facilities are provided. This eliminates the need for additional steps and enables low cost and highly efficient formation of bumps and metal films.

Further, in the semiconductor device of the present invention, the internal electrode of the first semiconductor chip and the internal electrode of the second semiconductor chip are electrically connected via the bump by the manufacturing method, and the first electrode is formed. The back surface of the semiconductor chip is adhered to a die pad, the external electrodes of the first semiconductor chip having a metal film formed on the surface thereof and the leads formed around the die pad are electrically connected by a thin metal wire, The material of the metal film formed on the surface of the external electrode and the material of the bump are the same.

[0027]

DETAILED DESCRIPTION OF THE INVENTION A semiconductor device and a method of manufacturing the same according to an embodiment of the present invention will be described below with reference to the drawings.

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

FIG. 1 is a sectional view showing the semiconductor device of this embodiment.

As shown in FIG. 1, the first semiconductor chip 1
Internal electrodes 19 and external electrodes 20 are formed on the surface of No. 8, and internal electrodes 22 are formed on the surface of the second semiconductor chip 21. Internal electrode 2 of second semiconductor chip 21
A barrier metal 23 is formed on the second semiconductor chip 2, and a first bump 24 having a height of 5 μm and made of Ni formed by electrolytic plating is formed on the internal electrode 19 of the first semiconductor chip 18. A second bump 25 made of Sn-3.5Ag solder is formed on the barrier metal 23 on the surface of the internal electrode 22 of the semiconductor chip 21, and the first bump 24 and the second bump 25 are formed.
Bumps 25 are electrically connected. Also, the first
An insulating resin 26 of epoxy or polyimide is filled between the semiconductor chip 18 and the second semiconductor chip 21.

The back surface of the first semiconductor chip 18 is bonded to the die pad 27 of the lead frame with a die bond resin 28, and a metal film 29 made of Ni is formed on the external electrode 20 of the first semiconductor chip 18. It is electrically connected to the lead 30 of the lead frame through a thin metal wire 31. Part of the first semiconductor chip 18, the second semiconductor chip 21, the thin metal wires 31, the die pad 27 and the leads 30 are sealed with a sealing resin 32.

Here, the characteristic configuration of the semiconductor device of this embodiment is that the material of the first bumps formed on the internal electrodes of the first semiconductor chip and the external electrodes of the first semiconductor chip are formed. The material of the metal film is composed of the same material, and the material is composed of two kinds of metals of Ni and Au, or Ti, Cu,
It is made of a metal selected from W, Pd, Pt, Ag, Ni and Au.

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

2 to 4 are sectional views showing the steps of the method for manufacturing a semiconductor device of this embodiment.

First, as shown in FIG. 2A, a first semiconductor chip 18 having an internal electrode 19 and an external electrode 20 formed on its surface is prepared.

Next, as shown in FIGS. 2 (b) and 2 (c), the first semiconductor chip 18 is subjected to pretreatment for electroless Ni plating, and the first semiconductor chip 18 is stored in the plating bath 33 at 90 ° C. After being immersed in the electrolytic Ni plating solution for about 15 minutes and then immersed in the substitution Au plating solution at 80 [° C.], the internal electrode 19 of the first semiconductor chip 18 and the external electrode 20 of the first semiconductor chip 18 are When the Ni film thickness is about 5 μm, Au
The first bump 24 and the metal film 29 made of two kinds of metal having a film thickness of about 0.05 [μm] are formed.

In another step (not shown), the second
A barrier metal having a Ti film thickness of 0.2 [μm] and a Cu film thickness of 0.5 [μm] is formed on the internal electrodes of the semiconductor chip (not shown) by vapor deposition. Then, a resist having a thickness of about 30 [μm] is formed on a portion of the second semiconductor chip excluding the internal electrodes and has a diameter of 50 [μm].
m] metal film (not shown) is formed on the surface of the barrier metal, and Ni is plated on the upper surface of the metal film of 3 [μm] by electrolytic Ni plating, and further 25 [μm] by electrolytic Sn-3.5Ag plating. The second bump 2 by plating with the thickness of
5 is formed. Then, using the second bumps 25 made of Ni and Sn-3.5Ag as a mask, the second barrier metal 23 made of Ti / Cu is dissolved by wet etching with hydrogen peroxide water for Ti and sulfuric acid for Cu by wet etching. After removal, the Sn-3.5Ag plated layer is reflowed into a hemispherical shape.

Next, as shown in FIG. 3A, the second semiconductor chip 21 on which the second bumps 25 are formed as described above is prepared.

At the same time, as shown in FIG. 3B, the first semiconductor chip 18 on which the first bumps 24 and the metal film 29 are formed is prepared.

Next, as shown in FIG. 3C, the external electrode 20 of the first semiconductor chip 18 is not blocked at the position where the second semiconductor chip 21 is mounted on the first semiconductor chip 18. Insulating resin 26 such as epoxy, polyimide, or acrylic is applied as described above, and the second semiconductor chip 21 that has been vacuum-adsorbed by the bonding tool 34 is lowered to make the first bump 24
And the second bump 25 are electrically connected.

Next, as shown in FIG. 4A, the first bumps 24 are heated by heating through the bonding tool 34.
And the second bump 25 are joined. Then 200
By heating to [° C.] to 270 [° C.], the second bump 25 formed of Sn-3.5Ag solder is melted, and Ni /
It is bonded to the first bump 24 formed of Au, and the insulating resin 26 is cured. Ni / A when solder is melted
The Au in the u film is entirely diffused inside the solder, and the joint is only Ni and the solder. At this time, the gap between the surfaces of the first semiconductor chip 18 and the second semiconductor chip 21 is several [μm] to 30 [μm].

Next, as shown in FIG. 4B, the back surface of the first semiconductor chip 18 to which the second semiconductor chip 21 is connected is adhered to the die pad 27 of the lead frame by the die bond resin 28 to form the first semiconductor chip 18. The metal film 29 made of Ni on the external electrode 20 of the semiconductor chip 18 and the lead 30 of the lead frame are connected by a metal thin wire 31, and the first semiconductor chip 18, the second semiconductor chip 21, the metal thin wire 31 and the die pad 27. Is sealed with the sealing resin 32.

As described above, in the semiconductor device and the manufacturing method thereof according to the present embodiment, the equipment is provided separately by simultaneously forming the bump and the metal film on the internal electrode and the external electrode of the first semiconductor chip, respectively. The process becomes unnecessary, and it becomes possible to form bumps and metal films at low cost and with high efficiency.

[0044]

According to the semiconductor device and the method of manufacturing the same of the present invention, a bump and a metal film are simultaneously formed on the internal electrode and the external electrode of the first semiconductor chip, respectively, to obtain a low-cost semiconductor device. it can.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing each step of the method for manufacturing the semiconductor device according to the embodiment of the present invention.

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

FIG. 4 is a sectional view showing each step of the method for manufacturing the semiconductor device according to the embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional semiconductor device.

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

FIG. 7 is a cross-sectional view showing each step of a conventional method for manufacturing a semiconductor device.

FIG. 8 is a sectional view showing each step of a conventional method for manufacturing a semiconductor device.

FIG. 9 is a sectional view showing each step of a conventional semiconductor device manufacturing method.

[Explanation of symbols]

1 First semiconductor chip 2 internal electrodes 3 first bump 4 Second semiconductor chip 5 internal electrodes 6 barrier metal 7 Second bump 8 external electrodes 9 Auxiliary electrode for wire bonding 10 die pad 11 leads 12 thin metal wires 13 Insulating resin 14 wafers 15 Protective film 16 Electroless plating bath 17 Connection tools 18 First semiconductor chip 19 internal electrodes 20 external electrodes 21 Second semiconductor chip 22 Internal electrode 23 Barrier Metal 24 First bump 25 Second bump 26 Insulating resin 27 die pad 28 Die bond resin 29 Metal film 30 leads 31 thin metal wire 32 sealing resin 33 plating tank 34 Joining tool

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI theme code (reference) H01L 25/18 H01L 21/92 603B 604B (72) Inventor Hideyuki Kaneko 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Industry Co., Ltd. (72) Inventor Yukiko Nakaoka 1006, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor, Hiroaki Fujimoto 1006, Kadoma, Kadoma City, Osaka F Term (Reference) ) 5F044 AA01 EE04 FF04 LL04 LL13 QQ03 QQ04 QQ05 RR02

Claims (4)

[Claims] 1. A step of simultaneously forming a first bump and a metal film on an internal electrode and an external electrode of a first semiconductor chip, respectively, and a step of forming a second bump on an internal electrode of a second semiconductor chip.
Forming the bumps, electrically connecting the first bumps to the second bumps, adhering the back surface of the first semiconductor chip to a die pad, and the first semiconductor A method of manufacturing a semiconductor device, comprising the step of electrically connecting an external electrode of a chip and a lead formed around the die pad with a thin metal wire. 2. After the step of electrically connecting the external electrodes of the first semiconductor chip and the leads formed around the die pad with a thin metal wire, the first semiconductor chip, the second semiconductor chip
2. The method of manufacturing a semiconductor device according to claim 1, further comprising the step of electrically connecting the semiconductor chip, the die pad, and the thin metal wire with a sealing resin. 3. The internal electrodes of the first semiconductor chip and the internal electrodes of the second semiconductor chip are electrically connected via bumps, and the back surface of the first semiconductor chip is adhered to the die pad and The external electrode of the first semiconductor chip on which the metal film is formed and the leads formed around the die pad are electrically connected by a thin metal wire, and the material of the metal film formed on the surface of the external electrode. And a material of the bump is the same, a semiconductor device. 4. The semiconductor device according to claim 3, wherein the material of the metal film formed on the surface of the external electrode is Ni and Au.