JPH07202078A - Semiconductor device - Google Patents

Abstract

PURPOSE:To surely prevent the short circuit and the disconnection of a bonding wire by heat change or mechanical shock, in a PGA-type semiconductor device. CONSTITUTION:Photo and thermo combination setting resin 9 is potted at the center of a PGA-type semiconductor device 1 until a semiconductor chip 3 and a bonding wire 8 are soaked, and surplus resin, is removed by tilting the PGA-type semiconductor device 1, and then it is hardened, being irradiated with light or the like so as not to flow out. When it is hardened to a specified hardness, the PGA-type semiconductor device 1 is heated to accelerate the hardening reaction, thus a tough coating layer is made. The thickness of the coating layer of the resin 9 is in the range of 15mum-30mum, and the adjustment of the coating layer of the resin 9 is performed by changing the quantity of solvent, the time of irradiation, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to a technique effectively applied to prevent breakage of a bonding wire of a PGA (Pin Grid Array) type semiconductor device.

[0002]

2. Description of the Related Art In recent years, semiconductor devices have tended to have higher pin counts and higher power consumption with higher integration and higher functionality.

A PGA type semiconductor device equipped with a thermal diffusion plate is used, for example, as the packaging for such high pin count and high power consumption.

According to a study made by the present inventor, in this PGA type semiconductor device, as shown in FIG. 3, the lead pin 30 for external connection is provided on, for example, a multi-layer plastic substrate 31 made of glass epoxy resin. After the insertion, the liquid adhesive 32 such as silicon is used to adhere to the heat diffusion plate 33.

Further, wiring (not shown) is provided on the plastic substrate 31 by copper or the like, and the lead pins 30 and the electrodes (not shown) provided on the plastic substrate 31 are electrically connected. Has been done.

Further, the semiconductor chip 35 is adhered on the heat diffusion plate 33 by using an adhesive 34 for pelletizing,
An electrode (not shown) on the semiconductor chip 35 and an electrode on the plastic substrate 31 are electrically connected by the bonding wire 36, and the periphery of the semiconductor chip 35 is fixed with, for example, a silicon gel 37 and made of aluminum or the like. It is sealed by the cap 38.

[0007]

However, in the PGA type semiconductor device as described above, the silicon gel encapsulating the semiconductor chip is changed by various temperature changes such as self-heating of the semiconductor device and solder reflow. The bonding wire may move due to repeated expansion and contraction, and a wire short circuit may occur due to contact.

Further, the mechanical shock such as centrifugal acceleration or dropping causes the silicon gel to move, resulting in a wire short circuit or a wire disconnection.

An object of the present invention is to provide a semiconductor device which can prevent short-circuiting and disconnection of the bonding wire due to thermal change such as temperature cycle and mechanical shock.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0011]

Of the inventions disclosed in the present application, a representative one will be briefly described below.
It is as follows.

That is, according to the invention of claim 1, the surfaces of the bonding wire and the semiconductor chip are coated with a resin.

According to a second aspect of the present invention, the resin is a light and heat combined curing type resin or a thermosetting type resin.

Further, in the invention according to claim 3, the resin coating has a thickness of 15 to 30 μm.

[0015]

According to the semiconductor device having the above structure, since the silicon gel is not used, the displacement of the silicon gel due to the thermal change such as the temperature cycle and the movement of the silicon gel due to the mechanical shock are eliminated.

As a result, it is possible to eliminate short-circuiting or defective disconnection of the bonding wire.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a PGA type semiconductor device coated with a resin according to an embodiment of the present invention.

In this embodiment, a PGA type semiconductor device 1
The semiconductor chip 3 is fixed to the central portion of the heat diffusion plate 2 for heat dissipation by the adhesive 4.

Further, the heat diffusion plate 2 on the outer periphery of the semiconductor chip 3
For example, a laminated plastic substrate 5 made of copper-clad glass / epoxy resin having the same structure as the printed circuit board is fixed by an adhesive 6 such as silicon rubber. Lead pins 7 for external connection are embedded in the laminated plastic substrate 5.

Then, a predetermined electrode portion (not shown) formed on the semiconductor chip 3 and the laminated plastic substrate 5 are formed.
A predetermined electrode portion (not shown) formed above is connected by a bonding wire 8. The lead pin 7 and the electrode portion on the laminated plastic substrate 5 are connected by a predetermined wiring.

Further, the semiconductor chip 3 and the bonding wires 8 are coated with a light and heat curing type resin 9.

As the photoreactive functional group of this resin 9, a vinyl group is crosslinked with a mercaptoalkyl group, an acryl group or an azide group, or a reaction initiator which decomposes by light such as ultraviolet rays to generate a radical is added. Can be promoted.

A solvent is added to these resins 9 in order to make them liquid, and a coupling agent is added to improve the adhesiveness between the bonding wires 8 and the surface of the semiconductor chip 3.

As the solvent, toluene, lexin, n-
Butyl alcohol, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol, cyclohexanol, methylcyclohexene, N-
Any material that can dissolve the resin used, such as methylpiperazine and ethyl glycol dimethyl ether, may be used.

As the coupling agent, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, triethoxysilane, trimethoxysilane,
Any material having a functional group that reacts with the bonding wire 8 such as aluminum chelate and titanate may be used.

Next, the operation of this embodiment will be described.

First, the resin 9 is potted in the central portion of the PGA type semiconductor device 1 until the semiconductor chip 3 and the bonding wire 8 are immersed.

Then, after the excess resin is removed by tilting the PGA type semiconductor device 1, light or the like is irradiated to cure the resin 9 so that the resin 9 does not flow from the bonding wire 8.

Next, when it is cured to a predetermined hardness, PGA
By heating the shaped semiconductor device 1, the curing reaction is further advanced to form a tough coating layer.

If the thickness of the coating layer of the bonding wire 8 made of the resin 9 is less than 15 μm, sufficient strength cannot be obtained, and there is a risk that the coating layer will be cracked due to temperature changes.

When the thickness of the coating layer is more than 30 μm, the adjacent bonding wires 8 are filled with the resin 9, and the coating layer is impacted or moved due to temperature change. There is a risk that the bonding wire 8 buried in will be cut.

Therefore, the thickness of the coating layer of the resin 9 is formed in the range of 15 μm to 30 μm. The thickness of the coating layer of the resin 9 is adjusted by changing the amount of the solvent of the resin 9 and the time of light irradiation.

Then, when the coating layer is formed of the resin 9, it is sealed with a cap (not shown) such as aluminum.

The resin may use a thermosetting functional group such as epoxy, phenol and amine, and a thermoplastic resin is added to these resins as a rubber component in order to impart flexibility.

As these coating resins, those having a carbon skeleton such as novolac, naphthalene and biferni and those having a silicon skeleton are used as the coating resin.

Further, as the solvent and coupling agent to be added to these resins, those used in the above-mentioned light and heat curable resin can be used.

In order to form a coating layer with this thermosetting resin, the thermosetting resin is potted until the semiconductor chip 3 and the bonding wire 8 are immersed in the central portion of the PGA type semiconductor device 1 to form the PGA type. Excess resin is removed by tilting the semiconductor device 1, and then heat is applied to cure the thermosetting resin so that it does not flow.

Then, when cured to a predetermined hardness, PG
The A-type semiconductor device 1 is further heated to a higher temperature to proceed with the curing reaction and form a tough coating layer.

The thickness of the coating layer of the bonding wire 8 made of thermosetting resin is 1 as in the case of the resin 9.
The thickness of the coating layer is 5 μm to 30 μm, and the thickness of the coating layer is also adjusted by changing the amount of the solvent of the thermosetting resin, the heating time, the heating temperature, and the like.

Further, the thickness of the coating of the resin 9 on the surface of the semiconductor chip may be 30 μm or more.

Therefore, according to the present embodiment, by coating the bonding wire 8 with resin,
It is possible to reliably prevent disconnection or short circuit of the wire.

Although the invention made by the present inventor has been described based on the embodiments, the present invention is not limited to the embodiments, and various modifications can be made without departing from the scope of the invention. There is no end.

For example, as shown in FIG. 2, the effect is the same even if the resin 9 is not coated in the gap between the semiconductor chip 3 on the heat diffusion plate and the laminated plastic substrate 5.

The semiconductor device coated with the resin 9 may be other than the PGA type semiconductor device of the above embodiment,
Multilayer Ceramic DIP (Dual In-line P)
package) semiconductor device and QFN (Quad Fl)
It can be used for a hermetically sealed semiconductor device such as an at non-leaded package type semiconductor device.

[0046]

The effects obtained by the typical ones of the inventions disclosed by the present application will be briefly described as follows.
It is as follows.

(1) According to the present invention, since the semiconductor chip and the bonding wire are coated with resin, it is possible to surely prevent the bonding wire from breaking and short-circuiting due to thermal change or mechanical shock.

(2) Further, in the present invention, by setting the resin coating thickness to 15 to 30 μm, cracks in the coating layer due to mechanical shock, temperature change, and the like, and adjacent bonding wires are filled with the resin. It is possible to prevent the bonding wire from being cut or short-circuited due to, for example, being caught.

(3) Further, in the present invention, the reliability of the semiconductor device is improved by the above (1) and (2).

(4) In the present invention, the light and thermosetting resin or the thermosetting resin is used as the resin, so that the coating can be easily and surely performed.

[Brief description of drawings]

FIG. 1 is a sectional view of a PGA type semiconductor device coated with a resin according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a PGA type semiconductor device coated with a resin according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a PGA type semiconductor device examined by the present inventor.

[Explanation of symbols]

 1 PGA type semiconductor device 2 Thermal diffusion plate 3 Semiconductor chip 4 Adhesive 5 Laminated plastic substrate 6 Adhesive 7 Lead pin 8 Bonding wire 9 Resin 30 Lead pin 31 Plastic substrate 32 Adhesive 33 Thermal diffusion plate 34 Adhesive 35 Semiconductor chip 36 Bonding wire 37 Silicon gel 38 Cap

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Honda 2326 Imai, Ome City, Tokyo, Hitachi Device Development Center (72) Inventor Yasumi Tsutsumi 2326 Imai, Ome City, Tokyo Hitachi, Ltd. Device In Development Center (72) Inventor Kenji Sato, 145 Nakajima, Nanae-cho, Kameda-gun, Hokkaido Inside Hitachi Hokkai Semiconductor Co., Ltd.

Claims (3)

[Claims] 1. A semiconductor device, wherein the surfaces of the bonding wire and the semiconductor chip are coated with a resin. 2. The resin according to claim 1, wherein the resin is a light- and heat-curable resin or a thermosetting resin.
The semiconductor device described. 3. The resin coating has a thickness of 15
3. The semiconductor device according to claim 1, wherein the semiconductor device has a thickness of about 30 μm.