JP2002208672A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized, highly reliable semiconductor device in which many electronic circuits are formed in a highly integrated manner at a high density in a small area, and a wire is precisely jointed to the electrode pad of a semiconductor element. SOLUTION: This semiconductor device 7 is composed of an external terminal 4, base body 1, first semiconductor element 2 arranged on the base body 1 and provided with a plurality of first electrode pads 2a on an upper surface, second semiconductor element 3 arranged on the first semiconductor element 2 and provided with a plurality of second electrode pads 3a on the upper surface, wire 5 electrically connecting the first electrode pads 2a and second electrode pads 3a of the first semiconductor element 2 and the second semiconductor element 3 and the external terminal 4, and resin-coating material 6 coating the first semiconductor element 2 and the second semiconductor element 3. If the external dimensions of the first semiconductor element and the second semiconductor element are defined respectively as T1 and T2, then T1>T2 and 40>=T1-T2>=1.3 (mm) hold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing device and a semiconductor device mounted on an electronic device such as a mobile phone.

[0002]

2. Description of the Related Art Conventionally, a resin-coated semiconductor device mounted on an information processing device such as a computer or an electronic device such as a mobile phone generally includes a semiconductor element and an iron-nickel-type semiconductor device.
A base made of a metal material such as a cobalt alloy or an iron-nickel alloy, and a plurality of external terminals, and a resin coating material made of a thermosetting resin such as an epoxy resin. Fixing via a brazing material such as a eutectic alloy and electrically connecting each electrode pad of the semiconductor element to an external terminal via a bonding wire,
Thereafter, the semiconductor element, the base, and a part of the external terminal are manufactured by coating with a resin coating material.

[0003] The semiconductor device is mounted on the external electric circuit board by joining the external lead-out end of the external terminal to a wiring conductor of the external electric circuit board via a bonding material such as solder, and at the same time, each electrode of the semiconductor element is connected. The pad is electrically connected to an external electric circuit via an external terminal.

In recent years, electronic devices such as computers and mobile phones have been rapidly reduced in size, faster in information processing, and more sophisticated, and semiconductor devices mounted on these electronic devices have also become electronic circuits formed of semiconductor elements. There is a strong demand for high density and high integration.

However, there is a limit in forming a large number of electronic circuits with high density and high integration in one semiconductor device.
It has become difficult to achieve the requirements of electronic devices with one semiconductor element.

Therefore, in order to solve the above-mentioned drawbacks, the semiconductor elements are bonded and fixed to the upper and lower surfaces of the electrically insulating base with a brazing material or the like, and the electrode pads of each semiconductor element are electrically connected to the connection pads of the base via wires. Connected, and then
There has been proposed a semiconductor device in which a semiconductor element, a base, and, if necessary, a part of an external terminal are covered with a resin coating material.

According to this semiconductor device, since the semiconductor element is mounted on each of the upper and lower surfaces of the base, the electronic circuit in the semiconductor device can be easily formed with high density and high integration without increasing the planar area of the semiconductor device. Can be achieved.

However, in the above-described semiconductor device, first, one semiconductor element is bonded and fixed to the upper surface of the base via a brazing material or the like, and the electrode pads of the semiconductor element are connected to connection pads or the like of the base via wires. Then, the substrate is turned upside down and another semiconductor element is bonded and fixed to the lower surface of the substrate, and the electrode pads of the semiconductor element fixed to the lower surface of the substrate are connected to connection pads formed on the lower surface of the substrate via wires. The manufacturing process is complicated, long, and has the disadvantage of low productivity.

In addition, the substrate is turned upside down and another semiconductor element is adhered and fixed to the lower surface of the substrate, and an electrode pad of the semiconductor element fixed to the lower surface of the substrate is connected to a connection pad formed on the lower surface of the substrate via a wire. In addition, the wire connected to the semiconductor element fixed on the upper surface side of the base is detached or cut off, and the reliability and yield of the semiconductor device as a product are greatly reduced.

Further, when another semiconductor element is bonded and fixed to the lower surface of the base, and when the electrode pads of the semiconductor element bonded and fixed to the lower surface of the base are connected to connection pads formed on the lower surface of the base via wires, A special jig considering the shape of the semiconductor element on the top side is individually required to hold the base on which the semiconductor element is bonded and fixed on the top side,
There is a disadvantage that the use of the special jig having no versatility makes the semiconductor device as a product expensive.

Further, two semiconductor elements are vertically stacked, adhered and fixed on the upper surface of the base, and the electrode pads of each semiconductor element are electrically connected to connection pads and external terminals of the base via wires. Thereafter, a semiconductor device in which a semiconductor element and a part of a base are covered with a resin coating material has been proposed.

According to this semiconductor device, since the two semiconductor elements are both stacked and fixed on the upper surface of the base, the density of the semiconductor device can be easily increased without increasing the planar area of the semiconductor device. Can be planned. At the same time, in this semiconductor device, two semiconductor elements are bonded and fixed to the same surface of the base, so that when the semiconductor elements are bonded and fixed to the base, electrode pads of each semiconductor element are connected to connection pads and external terminals of the base. There is no need to turn the substrate over, such as when making electrical connections via wires, and as a result, there is no need to use special jigs that are not versatile to hold the substrate, and the connection pads and external The wire connecting the terminal and the electrode pad of each semiconductor element is hardly disconnected or cut, and the reliability, yield, and productivity of the semiconductor device as a product can be greatly improved.

[0013]

However, conventionally,
Various semiconductor elements often have similar external dimensions,
When two semiconductor elements having similar outer dimensions are vertically stacked, the distance between the outer peripheral edge of the upper surface of the lower semiconductor element bonded and fixed to the base and the outer wall of the upper semiconductor element, For example, it is very short, about 0.5 mm or less. As a result, it is difficult to form an electrode pad on the outer peripheral edge of the upper surface of the lower semiconductor element, and it is difficult to form an electrode pad on the upper surface of the lower semiconductor element. When a bonding wire is bonded to the formed electrode pad using a well-known ultrasonic bonding device or the like, the capillary of the bonding device contacts the semiconductor device located on the upper side and the electrode pad of the semiconductor device located on the lower side. In this case, the wire cannot be bonded accurately and firmly, and the reliability of the semiconductor device is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has as its object to reduce the area and to form a large number of electronic circuits with high density and high integration. Another object of the present invention is to provide a small and highly reliable semiconductor device in which wires are accurately joined.

[0015]

According to the present invention, there is provided a semiconductor device comprising:
An external terminal, a base, a first semiconductor element disposed on the base and having a plurality of first electrode pads on the upper surface, and a plurality of second electrode pads disposed on the first semiconductor element and on the upper surface A second semiconductor element having the first semiconductor element and the second semiconductor element.
A semiconductor device comprising: a wire for electrically connecting a first electrode pad, a second electrode pad, and an external terminal of a semiconductor element; and a resin coating material for covering the first semiconductor element and the second semiconductor element, When the outer dimensions of the first semiconductor element and the second semiconductor element are T ₁ and T ₂ , respectively, T ₁ >
T ₂ and 40 ≧ T ₁ −T ₂ ≧ 1.3 (mm).

According to the semiconductor device of the present invention, two semiconductor elements of a first semiconductor element and a second semiconductor element are vertically stacked on a base, and the first electrode pad of the first semiconductor element and the second semiconductor element are connected to each other. Since the second electrode pad of the element and the external terminal are electrically connected via the wire, the electronic circuit in the semiconductor device is increased in density and integration without increasing the planar area of the semiconductor device. be able to.

According to the semiconductor device of the present invention, two semiconductor elements are bonded and fixed to the same surface of the base, so that the semiconductor elements are bonded and fixed to the base or the electrode pads of each semiconductor element are connected to the external terminals. There is no need to turn over the base at all when electrically connecting to the base via wires, etc. As a result, the use of special jigs that are not versatile to hold the base is unnecessary, and external terminals etc. There is almost no disconnection or breakage in the wire connecting the semiconductor device and the electrode pad of each semiconductor element, and the reliability, yield, and productivity of the semiconductor device as a product can be greatly improved.

Further, according to the semiconductor device of the present invention, when the outer dimensions of the first semiconductor element and the second semiconductor element are T ₁ and T ₂ , respectively, T ₁ > T ₂ and 40 ≧ T ₁
−T ₂ ≧ 1.3 (mm), the first
When the semiconductor element and the second semiconductor element are sequentially bonded and fixed,
An electrode pad can be easily formed on the outer peripheral edge of the upper surface of the first semiconductor element, and a sufficient space for a capillary or the like of a bonding apparatus for joining a wire to the electrode pad can be secured. The electrode pads of one semiconductor element can be reliably formed, and the electrode pads of the first semiconductor element, the electrode pads of the second semiconductor element, and the external terminals can be reliably connected via wires.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a semiconductor device according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an embodiment of a semiconductor device according to the present invention. In FIG. 1, reference numeral 1 denotes a base, 2 denotes a first semiconductor element, 3 denotes a second semiconductor element, 4 denotes an external terminal, and 5 denotes a bonding terminal. A wire 6 is a resin coating material, and a semiconductor device 7 is formed by the base 1, the first semiconductor element 2, the second semiconductor element 3, the external terminal 4, the wire 5, and the resin coating material 6.

The base 1 has a function of mounting and supporting the first semiconductor element 2 and the second semiconductor element 3, and is made of copper, copper alloy,
It is formed of a metal material such as an iron-nickel alloy, an iron-nickel-cobalt alloy, aluminum, and an aluminum alloy.

The base 1 is formed by subjecting an ingot (a lump) made of a metal material such as copper to a suitable metal working such as rolling or punching.

An external terminal 4 such as a lead terminal is arranged outside the base 1, and the external terminal 4 connects an electronic circuit of the first semiconductor element 2 and the second semiconductor element 3 to an external electric circuit. To act.

The external terminals 4 are made of a metal material such as copper, copper alloy, iron-nickel alloy, iron-nickel-cobalt alloy, aluminum, and aluminum alloy, and are formed in a predetermined shape by the same method as that of the base 1. You.

The external terminals 4 are usually formed of the same material as the base 1, and are integrated with the base 1 via suspension leads or the like.

A first semiconductor element 2 is mounted on the upper surface of the base 1, and the first semiconductor element 2 is bonded and fixed to the upper surface of the base 1 via an adhesive such as brazing material, glass, or organic resin. Have been. In this case, it is desirable to use an organic resin or the like having a low elastic coefficient as the adhesive. If an organic resin with a low elastic coefficient is used as the adhesive, the difference is caused by a difference in thermal expansion coefficient between the first semiconductor element 2 and the base 1. The adhesive effectively absorbs and alleviates the thermal stress generated by the adhesive, and it is effective that the thermal stress generated between the first semiconductor element 2 and the base 1 causes the first semiconductor element 2 to be mechanically broken such as a crack. Can be prevented.

The first semiconductor element 2 has a plurality of first electrode pads 2a formed on the outer peripheral edge of the upper surface thereof. The electrode pads 2a are used to connect the electronic circuit of the first semiconductor element 2 to the external terminals 4 and to be described later. Electrode pad 3a of the second semiconductor element 3 to be
, And the bonding wire 5 is joined.

Further, on the upper surface of the first semiconductor element 2, a second
The semiconductor element 3 is mounted, and the second semiconductor element 3 is bonded and fixed to the upper surface of the first semiconductor element 2 via an adhesive such as brazing material, glass, or organic resin. In this case, it is desirable to use an organic resin or the like having a low elastic coefficient as the adhesive. If an organic resin with a low elastic coefficient is used as the adhesive, the difference in the thermal expansion coefficient between the first semiconductor element 2 and the second semiconductor element 3 is obtained. The adhesive material effectively absorbs and relaxes the thermal stress caused by the first semiconductor element 2 and the second semiconductor element 3 due to the thermal stress generated between the first semiconductor element 2 and the second semiconductor element 3. It is possible to effectively prevent mechanical destruction such as cracks from occurring.

The second semiconductor element 3 has a plurality of electrode pads 3a formed on the upper surface thereof.
“a” acts as a terminal when the electronic circuit of the second semiconductor element 3 is connected to the first semiconductor element 2 and the external terminal 4, and the bonding wire 5 is joined.

In the present invention, it is important that the first semiconductor element 2 and the second semiconductor element 3 are vertically stacked on the base 1. When the first semiconductor element 2 and the second semiconductor element 3 are sequentially stacked on the upper surface of the base 1, the electronic circuit in the semiconductor device 7 can have higher density and higher integration without increasing the planar area of the semiconductor device 7. .

At the same time, the two semiconductor elements 2 and 3 are bonded and fixed to the same surface of the base 1, so that the semiconductor elements 2 and 3 are bonded and fixed to the base 1,
When the electrode pads 2a and 3a are electrically connected to the external terminals 4 and the like via the wires 5, there is no need to turn over the base 1 at all, and as a result, there is no versatility to hold the base 1. The use of a special jig becomes unnecessary, and the external terminals 4 and the like and the electrode pads 2a,
The wire 5 connecting to the wire 3a is hardly detached or cut, and the reliability, yield, and productivity of the semiconductor device 7 as a product can be greatly improved.

Further, in the present invention, when the outer dimensions of the first semiconductor element and the second semiconductor element are T ₁ and T ₂ , respectively, T ₁ > T ₂ and 40 ≧ T ₁ −T ₂ ≧ 1 .3
(Mm) is important.

When the outer dimensions of the first semiconductor element and the second semiconductor element are T ₁ and T ₂ , respectively, T ₁ > T ₂ and 40 ≧ T ₁ −T ₂ ≧ 1.3 (mm). In other words, when the first semiconductor element 2 and the second semiconductor element 3 are sequentially bonded and fixed on the base 1, an electrode pad 2 a can be formed on the outer peripheral edge of the upper surface of the first semiconductor element 2, and the wire 5 is connected to the electrode pad 2 a. Can secure a sufficient space for a capillary or the like of a bonding device for joining the first semiconductor element 2 to be formed, whereby the electrode pads 2a can be reliably formed on the first semiconductor element 2 and the first semiconductor element 2 Electrode pad 2a of the second semiconductor element 3
And the external terminal 4 can be reliably connected via the wire 5.

When the outer dimensions of the first semiconductor element 2 and the second semiconductor element 3 are T ₁ and T ₂ , respectively,
_{When 1−} T ₂ <1.3 (mm), the space that can be formed on the outer peripheral edge of the upper surface of the first semiconductor element 2 becomes narrow, and it becomes difficult to form the electrode pad 2 a on the first semiconductor element 2. The wire 5 is connected to the electrode pad 2a of the first semiconductor element 2.
Cannot be accurately connected using a bonding apparatus. Therefore, assuming that the outer dimensions of the first semiconductor element 2 and the second semiconductor element are T ₁ and T ₂ , respectively, they are specified as T ₁ −T ₂ ≧ 1.3 (mm).

When the outer dimensions of the first semiconductor element 2 and the second semiconductor element 3 are T ₁ and T ₂ , respectively,
If <T ₁ −T ₂ (mm), the space formed on the outer peripheral edge of the upper surface of the first semiconductor element 2 becomes too large, and the electrode pads 2 a of the first semiconductor element 2 and the electrode pads of the second semiconductor element 3 are formed. The length of the wire 5 connecting the 3a and the external terminal 4 becomes unnecessarily long, so that the wire is likely to fall or be cut, and the reliability of the semiconductor device 7 is reduced. Therefore, when the outer dimensions of the first semiconductor element 2 and the second semiconductor element 3 are T ₁ and T ₂ , respectively, 40 ≧ T ₁ −T
₂ (mm).

Part of the external terminal 4, the base 1, and the base 1
The surfaces of the first semiconductor element 2 and the second semiconductor element 3 fixed thereon are covered with a resin coating material 6, and the first semiconductor element 2 and the second semiconductor element 3 are hermetically sealed by the resin coating material 6. Is sealed.

The resin coating material 6 is made of a resin such as an epoxy resin, a silicone resin, a polyamide resin, and a polyimide resin.
Alternatively, a mixture of these resins mixed with an appropriate filler is used. For example, in the case of a thermosetting epoxy resin, the external terminals 4 are provided in a predetermined mold and the first semiconductor element 2 is provided on the upper surface. Then, the base 1 on which the second semiconductor element 3 is sequentially laminated is set, and a liquid resin such as an epoxy resin is injected into a mold.
A part of the external terminal 4, the base 1, and the first
It is attached to the surface of the semiconductor element 2 and the second semiconductor element 3. In this case, if the base 1 is formed of a metal containing aluminum or copper as a main component, the aluminum or the like has good adhesion to the resin coating 6 made of an epoxy resin. It can be firmly joined. Therefore, when the resin coating material 6 is formed of an epoxy resin, the base 1 is preferably formed of a metal containing aluminum or copper as a main component.

The resin coating material 6 can be prepared by adding an inorganic or metal powder having a thermal conductivity of 50 W / m · K or more at a rate of 2 to 30% by weight.
Has high thermal conductivity and is easy to conduct heat.
The heat generated during operation of the semiconductor element 2 and the second semiconductor element 3 can be satisfactorily radiated into the atmosphere via the resin coating material 6, and the reliability of the semiconductor device 7 can be further improved. Therefore, it is preferable to add an inorganic or metal powder having a thermal conductivity of 50 W / m · K or more in the resin coating material 6 at a ratio of 2 to 30% by weight. The thermal conductivity added to the resin coating material 6 is 50
As the inorganic or metal powder of W / m · K or more, an inorganic powder such as an aluminum nitride powder, a silicon carbide powder, a boron nitride powder, or a metal powder such as aluminum, copper, or an alloy thereof is preferably used.

Thus, the above-described semiconductor device 7 has the external terminal 4
Of the first semiconductor element 2 and the second semiconductor element 3 are simultaneously mounted on the external electric circuit board by joining the external lead-out end to the wiring conductor of the external electric circuit board via a bonding material such as solder. 2a and 3a are electrically connected to an external electric circuit via the external terminal 4.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. Even if the second semiconductor element 3 is a semiconductor element having the same kind of function as a memory element,
Further, semiconductor elements having different functions, such as a control element and a memory element, may be used.

[0040]

According to the semiconductor device of the present invention, two semiconductor elements, a first semiconductor element and a second semiconductor element, are vertically stacked on a base, and the first electrode pad of the first semiconductor element and the first electrode pad are stacked. (2) Since the second electrode pads of the semiconductor elements and the external terminals are electrically connected via wires, the density and density of electronic circuits in the semiconductor device are increased without increasing the planar area of the semiconductor device. Can be achieved.

According to the semiconductor device of the present invention, since two semiconductor elements are bonded and fixed to the same surface of the base, the semiconductor elements are bonded and fixed to the base, or the electrode pads of each semiconductor element are connected to the external terminals. There is no need to turn over the base at all times when electrically connecting to the base via wires, etc. As a result, there is no need to use special jigs that are not versatile to hold the base and external terminals etc. There is almost no disconnection or breakage in the wire connecting the semiconductor device and the electrode pad of each semiconductor element, and the reliability, yield, and productivity of the semiconductor device as a product can be greatly improved.

Further, according to the semiconductor device of the present invention, when the outer dimensions of the first semiconductor element and the second semiconductor element are T ₁ and T ₂ , respectively, T ₁ > T ₂ and 40 ≧ T ₁
−T ₂ ≧ 1.3 (mm), the first
When the semiconductor element and the second semiconductor element are sequentially bonded and fixed,
An electrode pad may be formed on the outer peripheral edge of the upper surface of the first semiconductor element,
In addition, it is possible to secure a sufficient space for a capillary or the like of a bonding device for bonding a wire to the electrode pad, thereby making it possible to reliably form the electrode pad on the first semiconductor element. 1
The electrode pads of the semiconductor element, the electrode pads of the second semiconductor element, and the external terminals can be reliably connected via wires.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a semiconductor device of the present invention.

[Explanation of symbols]

 1 Base 2 First semiconductor element 2a First electrode pad 3 Second semiconductor element 3a · 2nd electrode pad 4 · · · · · · external terminals 5 · · · · · · wires 6 · · · · · resin coating 7 · · · · · · · · semiconductor device

Claims (1)

[Claims] 1. An external terminal, a base, and disposed on the base,
A first semiconductor device having a plurality of first electrode pads on an upper surface, and a plurality of second semiconductor devices disposed on the first semiconductor device and having an upper surface;
A second semiconductor element having an electrode pad; wires for electrically connecting the first electrode pad, the second electrode pad, and the external terminal of the first semiconductor element and the second semiconductor element; A resin coating material for covering the two semiconductor elements, wherein T ₁ > T ₂ when the outer dimensions of the first semiconductor element and the second semiconductor element are T ₁ and T ₂ , respectively. And 40 ≧ T ₁ −T ₂ ≧ 1.3
(Mm).