JP2002217355A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a semiconductor device achieving further integration and having high reliability since a single semiconductor element cannot further increase density and integration in an electronic circuit. SOLUTION: A semiconductor device 8 is covered with a resin covering material 7 after a first semiconductor element 2, an electrically insulating substrate 4, and a second semiconductor element 3 are arranged for sticking on a substrate 1 successively from the lower layer, and the first semiconductor element 2, the electrically insulating substrate 4, the second semiconductor element 3, and an external terminal 5 are electrically connected. In the semiconductor device 8, the thermal conductivity of the electrically insulating substrate 4 is set to 80 W/mK or lower, thus further integrating the electronic circuit. Further, the first semiconductor element 2 and the second semiconductor element 3 are not affected by heat that is generated in another semiconductor element, thus preventing malfunction and functional breakdown and hence obtaining the highly reliable semiconductor device 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a semiconductor device mounted on an electronic device such as an information processing device and a portable telephone.

[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 cellular phone generally includes a semiconductor element and an iron-nickel-cobalt alloy / iron-nickel alloy. A semiconductor element is composed of a base made of a metal material such as copper and a plurality of external terminals, and a resin coating material made of a thermosetting resin such as an epoxy resin. The semiconductor device is fixed via a material or a conductive or electrically insulating paste, and each electrode pad of the semiconductor element is electrically connected to an external terminal via a bonding metal wire. It is manufactured by coating a part of the terminal with a resin coating material.

[0003] This semiconductor device is mounted on an external electric circuit board by joining an external lead-out end of an 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 a semiconductor element. 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 elements forming the semiconductor devices mounted on these electronic devices have been required to have higher density and higher density. There is a strong demand for integration.

However, since the size of the semiconductor element itself has already been reduced, it is becoming difficult to form an electronic circuit further, and the miniaturization technology for forming the electronic circuit has become more sophisticated and complicated. Therefore, much cost is required to achieve ultra-high integration with one semiconductor element, and it is difficult to achieve higher density and higher integration of electronic circuits with one semiconductor element.

Therefore, in order to solve the above-mentioned problems, as shown in the sectional view of FIG. The electrode pad 23 is electrically connected to a connection pad (not shown) of the base 21 through a wire 24, and thereafter, the semiconductor element 21, the base 22, and external terminals as necessary.
There has been proposed a semiconductor device 27 in which a part of 25 is coated with a resin coating material 26.

According to the semiconductor device 27, the semiconductor element 22
Are mounted on the upper and lower surfaces of the base 21, respectively, so that high density and high integration of electronic circuits in the semiconductor device 27 can be easily achieved without increasing the planar area of the semiconductor device 27.

However, in this semiconductor device 27, first, one semiconductor element 22 is bonded and fixed to the upper surface of the base 21 with a brazing material or the like, and the electrode pads of the semiconductor element 22 are connected to the connection pads of the base 21 or the like. The connection is made via a wire 24, and then the substrate 21 is turned upside down and another semiconductor element 22 is bonded and fixed to the lower surface of the substrate 21, and the electrode pads of the semiconductor element 22 fixed to the lower surface of the substrate 21 are formed on the lower surface of the substrate 21. Must be connected via wires to the connection pads, etc.
There is a problem that the manufacturing process is complicated and long, and the productivity is poor.

Further, the substrate 21 is turned over and another semiconductor element 22 is bonded and fixed to the lower surface of the substrate 21, and the electrode pads of the semiconductor element 22 fixed to the lower surface of the substrate 21 are connected to connection pads formed on the lower surface of the substrate 21. When connecting via a wire, the wire connected to the semiconductor element 22 fixed on the upper surface side of the base 21 is disconnected or cut off, and the reliability and yield of the semiconductor device 27 as a product are greatly reduced. Has problems.

Further, another semiconductor element 22 is provided on the lower surface of the base 21.
The semiconductor element 22 is bonded to the upper surface when bonding the electrode pad of the semiconductor element 22 bonded and fixed to the lower surface of the base 21 and the connection pad formed on the lower surface of the base 21 via a wire. A special jig considering the shape of the semiconductor element 22 on the upper surface side is individually required to hold the fixed base 21, and the use of this special jig having no versatility makes the semiconductor device as a product. There is a problem that 27 is expensive.

Therefore, as shown in a sectional view of FIG. 3, two semiconductor elements 32 are formed on the upper surface of a base 31 made of metal or the like.
32 are stacked one above the other, adhesively fixed, and the electrode pads 33 of each semiconductor element 32, 32 are electrically connected to connection pads (not shown) of the base 31 and external terminals 34 via wires 35,
Thereafter, a semiconductor device 37 in which the semiconductor elements 32 and a part of the base 31 are covered with a resin coating material 36 has been proposed.

According to the semiconductor device 37, since the two semiconductor elements 32 and 32 are both laminated and fixed on the upper surface of the base 31, the semiconductor device 37 can be easily formed without increasing the planar area of the semiconductor device 37. The density of the device 37 can be increased. At the same time, the semiconductor device 37 has two semiconductor elements 32 and 32 adhered and fixed to the same surface of the base 31, so that the base
When the semiconductor element 32 is bonded and fixed to the base 31, or when the electrode pads 33 of the respective semiconductor elements 32 and 32 are electrically connected to the connection pads and the external terminals 34 of the base 31 via the wires 35, etc. There is no need to turn over each time, and as a result, there is no need to use special jigs that are not versatile to hold the base 31, and connection pads and external terminals of the base 31 are not required.
There is almost no disconnection or disconnection of the wire 35 connecting the 34 and the electrode pad 33 of each semiconductor element 32, 32,
The reliability, yield, and productivity of the semiconductor device 37 as a product can be greatly improved.

[0013]

However, the above-mentioned 2)
In the semiconductor device 37 in which the semiconductor elements 32 are stacked, the electronic circuit of each semiconductor element 32 is formed with extremely high density and high integration, so that the degree of freedom regarding the formation position of the electrode pad 33 is low. Predetermined electrode pad 33 at any desired location
Cannot be formed. Therefore, when connecting the electrode pads 33 of the semiconductor elements 32 and 32 stacked vertically with the wires 35, or connecting the electrode pads 33 of the semiconductor elements 32 and 32 with the connection pads of the base 31 and the external terminals 34 with the wires 35. At the time of connection, a plurality of wires 35 cross each other, and the wires 35 become unnecessary and prolonged and easily deformed.For example, when the semiconductor elements 32 Acts on the wire 35, the wire 35 easily falls down, and the adjacent wires 35 come into contact with each other, causing an electrical short circuit between the adjacent electrode pads 33, losing the function as the semiconductor device 37, or unstable characteristics. This causes a problem that the semiconductor elements 32 cannot always operate normally.

Since the thermal conductivity of the metal silicon forming the semiconductor elements 32 is as high as about 150 W / mK, the heat generated when the lower semiconductor element 32 operates is transferred to the upper semiconductor element 32. As a result, the upper semiconductor element 32 adds to the heat generated during its operation,
Since the temperature of the upper semiconductor element 32 exceeds the temperature at which normal operation is possible because of the influence of the heat generated by the upper semiconductor element 32, there is a serious problem that the upper semiconductor element 32 may malfunction or break down.

Conversely, the heat generated when the upper semiconductor element 32 operates is transferred to the lower semiconductor element 32, thereby causing the lower semiconductor element 32 to malfunction or break down for the same reason. There were also serious problems.

SUMMARY OF THE INVENTION The present invention has been completed to solve the above-mentioned problems in the prior art, and an object of the present invention is to enable a large number of electronic circuits to be formed with high density and high integration in a small area, and Effectively prevents contact of the wires connecting the device's electrode pads to external terminals, etc., and at the same time, when semiconductor devices are stacked, malfunctions due to the effect of heat generated by the lower semiconductor device on the upper semiconductor device Another object of the present invention is to provide a small and highly reliable semiconductor device capable of operating a semiconductor element normally and stably for a long period of time without causing functional destruction.

[0017]

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 electrode pads on an upper surface, and an electrical insulation disposed on the first semiconductor element and having a plurality of connection pads on the surface A conductive substrate, a second semiconductor element disposed on the electrically insulating substrate and having a plurality of electrode pads on an upper surface, and electrode pads of the first and second semiconductor elements, external terminals, and connection pads. A semiconductor device comprising a wire for electrical connection and a resin coating material for covering the first semiconductor element and the second semiconductor element, wherein the thermal conductivity of the electrically insulating substrate is 80 W / mK or less. It is characterized by the following.

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 with an electrically insulating substrate interposed therebetween. Since the electrode pads on the upper surface of the semiconductor element and the upper surface of the second semiconductor element are electrically connected to the connection pads provided on the upper surface of the electrically insulating substrate, the semiconductor device can be manufactured without increasing the planar area of the semiconductor device. In this case, it is possible to achieve higher density and higher integration of electronic circuits.

Further, according to the semiconductor device of the present invention, since two semiconductor elements are bonded and fixed to the same surface of the base, when the semiconductor elements are bonded and fixed to the base, or when the electrode pads of each semiconductor element are connected to each other. When electrically connecting to an external terminal or the like via a wire, there is no need to turn the substrate over each time. As a result, there is no need to use a special jig that is not versatile to hold the substrate. In addition, the wires connecting the external terminals and the like to the electrode pads of the respective semiconductor elements are hardly disconnected or cut, 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, since the electrically insulating substrate capable of arbitrarily setting the formation position of the connection pad is arranged between the upper and lower semiconductor elements, the connection pad of the electrically insulating substrate is provided. By forming the formation position of the semiconductor device in correspondence with the formation position of the electrode pad of the semiconductor element and the position of the external terminal, the electrode pad and the external terminal of the semiconductor element and the connection pad of the electrically insulating substrate are brought into a short distance. As a result, when the electrode pads of the semiconductor element and the connection pads of the electrically insulating substrate and the connection pads of the electrically insulating substrate and the external terminals are connected via wires, a plurality of wires are formed. Do not intersect, and the length of the wire is short, making it difficult to deform. Even if an external force acts on the wire, the wire can easily fall down. An electrical short circuit between the electrode pads of the semiconductor element due to the contact is effectively prevented, thereby enabling the semiconductor element to operate normally and stably for a long period of time. I can do it.

Further, according to the semiconductor device of the present invention, since the thermal conductivity of the electrically insulating substrate is set to 80 W / mK or less, the electrically insulating substrate is a lower first semiconductor element or an upper second semiconductor element. The first semiconductor element and the second semiconductor element are affected by the heat generated in the other semiconductor element in order to effectively block or suppress the transfer of heat generated during operation of the element to the other semiconductor element. As a result, the first semiconductor element and the second semiconductor element do not exceed the temperature at which normal operation is possible, so that a small and highly reliable semiconductor device that operates normally and stably for a long period of time can be obtained.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an example of an embodiment of the semiconductor device of the present invention. 1 is a base, 2 is a first semiconductor element, 3 is a second semiconductor element, 4 is an electrically insulating substrate interposed between the first semiconductor element 2 and the second semiconductor element 3, 5 is an external terminal, and 6 is bonding Reference numeral 7 denotes a resin coating material, and the base 1, the first semiconductor element 2, the second semiconductor element 3, the electrically insulating substrate 4, the external terminals 5, the wires 6
The semiconductor device 8 is constituted by the resin coating material 7.

The base 1 has a function of mounting and supporting the first semiconductor element 2, the second semiconductor element 3, and the electrically insulating substrate 4, and is composed of copper, copper alloy, iron-nickel alloy, iron-nickel-cobalt. It is formed of a metal material such as an alloy, aluminum, or an aluminum alloy.

The base 1 is formed, for example, by subjecting an ingot (a lump) made of a metal material such as copper to metal processing such as appropriate rolling or punching.

The first semiconductor element 2 is provided on the upper surface of the base 1.
The first semiconductor element 2 is bonded and fixed to the upper surface of the base 1 via an adhesive such as a brazing material, glass, or an organic resin.

In addition, external terminals 5 such as lead terminals are arranged outside the base 1, and the external terminals 5 connect the electronic circuits of the first semiconductor element 2 and the second semiconductor element 3 to external electric circuits. It is for connecting.

The external terminal 5 is made of a metal material such as copper / copper alloy / iron-nickel alloy / iron-nickel-cobalt alloy / aluminum / aluminum alloy, and is formed in a predetermined shape by the same method as the base 1. .

The external terminals 5 are usually formed of the same material as the base 1, and are integrated with the base 1 via suspension leads or the like.

The first semiconductor element 2 has a plurality of electrode pads 2a formed on the upper surface thereof.
“a” functions as a terminal for connecting an electronic circuit of the first semiconductor element 2 to an external terminal 5 or a connection pad 4 a provided on an electrically insulating substrate 4 described later, and a bonding wire 6 is bonded thereto.

Further, on the upper surface of the first semiconductor element 2, an electrically insulating substrate 4 having a plurality of connection pads 4a on its surface is arranged.

The electrically insulative substrate 4 supports the second semiconductor element 3 on the first semiconductor element 2 while maintaining electrical insulation, and also supports the electrode pads 2 a of the first semiconductor element 2 and the second semiconductor element 3. The electrode pad 3a functions as a support member for the connection pad 4a connected via the bonding wire 6.

The electrically insulating substrate 4 is made of aluminum oxide sintered body, aluminum nitride sintered body, mullite sintered body, silicon carbide sintered body, silicon nitride sintered body, glass ceramic sintered body. Body, epoxy resin, polyimide resin,
It is a plate made of an electrically insulating material such as a fluororesin / glass-epoxy resin composite and has a wiring conductor 4b inside and on its surface.

When the electrically insulating substrate 4 is made of, for example, an aluminum oxide sintered body,
An appropriate organic binder, a solvent, a plasticizer, a dispersing agent, etc. are added to raw material powders such as silicon oxide, magnesium oxide, calcium oxide, etc. to form a slurry, which is then formed into a sheet using a conventionally known doctor blade method. By obtaining a plurality of ceramic green sheets, a suitable punching process is performed on the ceramic green sheets, and metal materials such as tungsten, molybdenum, manganese, copper, silver, nickel, palladium, and gold are formed. After forming a connection pad 4a and a wiring conductor 4b by applying a conductive paste formed by mixing an appropriate organic binder and a solvent to the green sheet in a predetermined pattern by a screen printing method or the like in advance, the green sheet is required. By sintering it at a temperature of about 1600 ° C Be produced.

In the present invention, the thermal conductivity of the electrically insulating substrate 4 needs to be 80 W / mK or less. If the thermal conductivity of the electrically insulating substrate 4 is higher than 80 W / mK, the heat generated when the first semiconductor element 2 in the lower layer of the electrically insulating substrate 4 operates or the second semiconductor element 3 in the upper layer The heat generated during the operation cannot be effectively blocked or suppressed from being transferred to the other semiconductor elements, and the first semiconductor element 2 and the second semiconductor element 3 add to the heat generated during their own operation. It will be affected by the heat generated by other semiconductor elements, exceeding the temperature at which normal operation is possible, and as a result,
The first semiconductor element 2 and the second semiconductor element 3 may cause malfunction or functional destruction. Therefore, the thermal conductivity of the electrically insulating substrate 4 needs to be 80 W / mK or less.

When the electrically insulating substrate 4 is made of a sintered body such as a ceramic, for example, by controlling the ratio, particle diameter, firing temperature, firing time, etc. of the main raw material powder particles, The thermal conductivity of the insulating substrate 4 can be set to a thermal conductivity of 80 W / mK or less.

When the electrically insulating substrate 4 is made of an organic resin, the thermal conductivity of the ordinary organic resin is 1 W / mK or less, and the organic resin is made of inorganic particles such as silicon oxide or inorganic material using the organic resin as a matrix. Mixed fibrous material
Even when filled, the thermal conductivity of the resin is 80W
Since it is difficult to exceed / mK, it can be used without any problem.

The thickness of the electrically insulating substrate 4 depends on the thickness of the semiconductor device 8.
When considering the total thickness of
If the thickness is made thinner than necessary, a problem occurs in terms of internal thermal resistance.

In general, between the internal thermal resistance of a material and the thermal conductivity and thickness of the material, the internal thermal resistance = thickness / thickness
There is a relationship of (thermal conductivity × area), and by reducing the thickness of the material, the internal thermal resistance of the material is reduced, and the same effect as when the thermal conductivity is improved is produced. Therefore, when the thickness of the electrically insulating substrate 4 is made thinner than necessary, the internal thermal resistance value of the electrically insulating substrate 4 is reduced, and the same situation as when the thermal conductivity is improved is obtained. The electrically insulating substrate 4 can effectively transfer heat generated when the lower first semiconductor element 2 operates or heat generated when the upper second semiconductor element 3 operates to another semiconductor element. And the first semiconductor element 2 and the second semiconductor element 3 are affected by the heat generated by other semiconductor elements in addition to the heat generated when they operate themselves, and can operate normally. Temperature, and as a result, the first semiconductor element 2
And the second semiconductor element 3 may cause malfunction or functional destruction.

In addition, in order not to increase the area of the electrically insulating substrate 4, it is necessary to provide the wiring conductor 4 b not only on the surface of the electrically insulating substrate 4 but also inside it. Since the inside needs to be multilayered, the thickness of the electrically insulating substrate 4 needs to be a certain value or more. In this case, the thickness of the electrically insulating substrate 4 is preferably 60 μm or more.

When the outer dimensions of the first semiconductor element 2, the electrically insulating substrate 4 and the second semiconductor element 3 are T1, T2 and T3, respectively,
> T2, T2> T3, and 40 ≧ T1-T2 ≧ 1.3 (m
m) and 40 ≧ T2−T3 ≧ 2 (mm).

As described above, when the outer dimensions of the first semiconductor element 2, the electrically insulating substrate 4 and the second semiconductor element 3 are T1, T2 and T3, respectively, T1> T2, T2>
T3, and 40 ≧ T1-T2 ≧ 1.3 (mm), 40 ≧ T2-
When T3 ≧ 2 (mm), when the first semiconductor element 2, the electrically insulating substrate 4, and the second semiconductor element 3 are sequentially bonded and fixed on the base 1, the outer peripheral edge of the upper surface of the first semiconductor element 2 and the The electrode pads 2a and the connection pads 4a can be formed on the outer peripheral edge of the upper surface of the insulating substrate 4 without special design and without complicated arrangement of positions. A sufficient space can be secured for a capillary or the like of a bonding device for joining the first semiconductor element 2 and the second semiconductor element 3 to be provided with an electrode pad 2a. The connection pads 4a can be reliably formed on the substrate 4, and the first
Electrode pad 2a of semiconductor element 2 and second semiconductor element 3
3a and the connection pad 4a of the electrically insulating substrate 4 can be reliably connected via the wire 6.

Note that T1, T2 and T3 are T1-
When T2 <1.3 (mm) or T2−T3 <2 (mm), the space that can be secured on the outer peripheral edge of the upper surface of the first semiconductor element 2 and the upper peripheral edge of the electrically insulating substrate 4 becomes narrower.
It becomes difficult to form the electrode pads 2a on the first semiconductor element 2 and the connection pads 4a on the electrically insulating substrate 4, and the electrode pads 2a on the first semiconductor element 2 and the connection pads 4a on the electrically insulating substrate 4 There is a tendency that it is difficult to connect the wires 6 using a bonding device.

Further, when T1, T2 and T3 are 40 <
When T1−T2 (mm) or 40 <T2−T3 (mm), a space formed on the outer peripheral edge of the upper surface of the first semiconductor element 2 and a space formed on the outer peripheral edge of the upper surface of the electrically insulating substrate 4 are more than necessary. The electrode pad 2a of the first semiconductor element 2 and the connection pad 4 of the electrically insulating substrate 4
a, and the length of the wire 6 connecting the connection pad 4a of the electrically insulating substrate 4 and the electrode pad 3a of the second semiconductor element 3 becomes unnecessarily long. This tends to occur and the reliability of the semiconductor device 8 tends to decrease.

Further, a plurality of connection pads 4a formed on the electrically insulating substrate 4 are partially connected electrically to wiring conductors 4b formed on the surface and inside of the electrically insulating substrate 4. , The wiring conductor 4b is connected to the connection pad 4a
The electronic circuit of the first semiconductor element 2 and the electronic circuit of the second semiconductor element 3 or the electronic circuit of the second semiconductor element 3 or the second semiconductor element 3 and the base 1 are electrically connected to each other via a bonding wire 6.

The second semiconductor element 3 is mounted on the upper surface of the electrically insulating substrate 4, and the second semiconductor element 3 is connected to the first semiconductor element 2 via an adhesive such as a brazing material, glass or organic resin. It is adhesively fixed on the upper surface.

The second semiconductor element 3 has a plurality of electrode pads 3a formed on the upper surface thereof.
“a” functions 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 5, and the bonding wire 6 is joined.

In the present invention, it is important that the first semiconductor element 2, the electrically insulating substrate 4, and the second semiconductor element 3 are vertically stacked on the base 1. The first on the upper surface of the base 1
When the semiconductor element 2, the electrically insulating substrate 4, and the second semiconductor element 3 are sequentially stacked, it is possible to increase the density and integration of electronic circuits in the semiconductor device 8 without increasing the planar area of the semiconductor device 8. .

At the same time, since the two semiconductor elements 2 and 3 are bonded and fixed to the same surface of the base 1, the semiconductor elements 2 and 3 are bonded and fixed to the base 1, When electrically connecting the electrode pads 2a, 3a to the external terminals 5 and the like via the wires 6, the base 1
There is no need to turn over each time, and as a result, it is not necessary to use a special jig which is not versatile to hold the base 1, and the external terminals 5 and the like and the electrode pads 2a. The wire 6 connecting to the wire 3a is hardly detached or cut, and the reliability, yield, and productivity of the semiconductor device 8 as a product can be greatly improved.

Further, in the present invention, it is important to arrange an electrically insulating substrate 4 between the first semiconductor element 2 and the second semiconductor element 3. When the electrically insulating substrate 4 is provided between the first semiconductor element 2 and the second semiconductor element 3,
The electrically insulating substrate 4 has a plurality of connection pads 4 on its surface.
In addition, since only the wiring conductors 4b for connecting the connection pads 4a are formed inside and on the surface, there is a degree of freedom in the formation position of the connection pads 4a.
a can be formed at any position close to the electrode pads 2a and 3a of the first semiconductor element 2 and the second semiconductor element 3, and as a result, the electrode pad 2a of the first semiconductor element 2 and the second semiconductor element 3 When the electrode pad 3a is connected to the connection pad 4a of the electrically insulating substrate 4 and the connection pad 4a of the electrically insulating substrate 4 is connected to the external terminal 5 via the wire 6, the wire 6 is short. It is difficult to deform,
Even if an external force acts on the wire 6, the wire 6 does not easily fall down, and the first wire 6 caused by the contact between the adjacent wires 6
Each electrode pad 2 of the semiconductor element 2 and the second semiconductor element 3
Electrical short-circuit between a and 3a is effectively prevented, whereby the first semiconductor element 2 and the second semiconductor element 3 can be operated normally and stably for a long period of time, and the semiconductor device 8 has high reliability. Can be made.

A part of the external terminals 5, the base 1, and the first semiconductor element 2, the electrically insulating substrate 4 and the second semiconductor element 3 fixed on the base 1 are covered with the resin coating 7. The first semiconductor element 2 and the second semiconductor element 3 are sealed by the resin coating material 7.

As the resin coating material 7, a resin such as an epoxy resin, a silicone resin, a polyamide resin, and a polyimide resin, or a mixture of these resins and a suitable filler is used. For example, in the case of a thermosetting epoxy resin, the external terminals 5 are provided in a predetermined mold, and the first semiconductor element 2, the electrically insulating substrate 4 and the second semiconductor element 3 are provided on the upper surface.
Are set in order and a liquid resin such as an epoxy resin is injected into a mold, and thereafter,
The injected resin is heated and cured by applying a temperature of about 180 ° C., so that a part of the external terminal 5, the base 1, and the first semiconductor element 2 and the electrically insulating substrate 4 fixed on the base 1. And the second semiconductor element 3.

In addition, inorganic particles are added to the resin coating material 7 in order to reduce the coefficient of thermal expansion. As such inorganic particles, for example, silicon oxide, aluminum oxide, silicon nitride, aluminum nitride, and the like can be used.
It is desirable that the amount of addition be 1 wt% to 90 wt%.

In particular, when inorganic particles having a high thermal conductivity are used, the thermal conductivity of the resin coating material 7 increases, and heat is easily conducted, so that the first semiconductor element 2 and the second semiconductor element 2 operate. The heat sometimes generated can be satisfactorily dissipated into the atmosphere via the resin coating material 7, and the reliability of the semiconductor device 8 can be further improved.

Thus, the above-described semiconductor device 8 is mounted on the external electric circuit board by joining the external lead-out end of the external terminal 5 to the wiring conductor of the external electric circuit board via a joining material such as solder, and at the same time, the Each of the electrode pads 2 a and 3 a of the first semiconductor element 2 and the second semiconductor element 3 is electrically connected to an external electric circuit via an external terminal 5.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. In the above example, the first semiconductor element 2 and the second semiconductor element 3 may be semiconductor elements having the same kind of function such as a memory element, or may be semiconductor elements having different functions such as a control element and a memory element. It may be.

The electrically insulating substrate 4 is made of an optimal material that allows each of the semiconductor elements 2 and 3 to operate satisfactorily according to the function and performance of the first and second semiconductor elements 2 and 3 or the use of the semiconductor device 8. For example, if it is desired to suppress the dielectric constant of the electrically insulating substrate 4 to transmit signals at a high speed, a glass ceramic sintered body or a low dielectric constant resin may be used. When importance is placed on the mechanical strength, an aluminum oxide sintered body may be used.

[0058]

As described above, according to the semiconductor device of the present invention, two semiconductor elements, the first semiconductor element and the second semiconductor element, are disposed on the base with the electrically insulating substrate interposed therebetween. And the electrode pads on the upper surface of the first semiconductor element and the upper surface of the second semiconductor element are electrically connected to the connection pads provided on the upper surface of the electrically insulating substrate. It is possible to increase the density and integration of electronic circuits in a semiconductor device without increasing the number of semiconductor devices.

Further, according to the semiconductor device of the present invention, since two semiconductor elements are bonded and fixed to the same surface of the base, when the semiconductor elements are bonded and fixed to the base, or when the electrode pads of each semiconductor element are fixed. When electrically connecting to external terminals via wires, etc., there is no need to turn the substrate over each time. As a result, there is no need to use a special jig that is not versatile to hold the substrate. The wires connecting the external terminals and the like to the electrode pads of the respective semiconductor elements are hardly disconnected or cut, 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, the connection pads are formed between the upper and lower semiconductor elements by arranging an arbitrary electrically insulating substrate. Can be formed in correspondence with the formation position of the electrode pad of the semiconductor element and the position of the external terminal, thereby making it possible to make the distance between the electrode pad and the external terminal of the semiconductor element and the connection pad of the electrically insulating substrate short,
As a result, when the electrode pads of the semiconductor element and the connection pads of the electrically insulating substrate and the connection pads of the electrically insulating substrate and the external terminals are connected via wires, a plurality of wires do not intersect. In addition, the wires are short and difficult to deform, and even if an external force acts on the wires, the wires do not easily fall down, and an electrical short circuit between the electrode pads of the semiconductor element due to contact between adjacent wires. Is effectively prevented, which allows the semiconductor element to operate normally and stably for a long period of time, so that the semiconductor device can have high reliability.

Further, according to the semiconductor device of the present invention, the thermal conductivity of the electrically insulating substrate is set to 80 W / mK or less, so that the electrically insulating substrate is a lower first semiconductor element or an upper second semiconductor element. The first semiconductor element and the second semiconductor element are affected by the heat generated by the other semiconductor element in order to effectively block or suppress the transfer of heat generated during operation of the element to the other semiconductor element. As a result, the temperature does not exceed the temperature at which normal operation is possible, so that the first semiconductor element and the second semiconductor element do not cause malfunction or functional destruction, and operate normally and stably for a long period of time. A semiconductor device can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of a semiconductor device of the present invention.

FIG. 2 is a cross-sectional view illustrating an example of a conventional semiconductor device.

FIG. 3 is a cross-sectional view illustrating another example of a conventional semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base 2 ... 1st semiconductor element 3 ... 2nd semiconductor element 2a, 3a ... Electrode pad 4 ... Electric insulating substrate 4a ... Connection pad 4b Wiring conductor 5 External terminal 6 Wire 7 Resin coating 8 Semiconductor device

Claims (1)

[Claims] An external terminal, a base, a first semiconductor element disposed on the base, and having a plurality of electrode pads on an upper surface, and a plurality of connection elements disposed on the first semiconductor element and having a plurality of connections on the surface. An electrically insulating substrate having pads, a second semiconductor element disposed on the electrically insulating substrate and having a plurality of electrode pads on an upper surface, electrode pads of the first and second semiconductor elements, and the external A semiconductor device comprising: a wire for electrically connecting a terminal to the connection pad; and a resin coating material for covering the first semiconductor element and the second semiconductor element, wherein a thermal conductivity of the electrically insulating substrate is A semiconductor device having a power of 80 W / mK or less.