JP2002141433A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device capable of satisfactorily dissipating heat from semiconductor elements with miniaturizing the structure and reducing the device height. SOLUTION: A semiconductor device 1 is manufactured by mounting a semiconductor element 4 in the bottom of a recess 2a formed into the downside of a first wiring board 2 with surface electrodes mutually opposed and bonded with conductor bumps 3, filling an insulative resin 5 between the bottom of the recess 2a and the semiconductor element 4, filling a metal powder 6 in the recess 2a to cover the semiconductor element 4, and bonding an exposed part of the powder 2a through the opening of the recess 2a to a radiating conductor on a second wiring board 7 through solder 8. This very efficiently conducts and disperses heat from the element 4 to the second board 7, resulting in a high-reliability and high-performance lower-height and compact semiconductor device 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device which is used as an electronic circuit module of various kinds of electronic equipment and electronic devices, and is constituted by mounting and mounting a semiconductor element on a wiring board. The present invention relates to a semiconductor device which has improved heat radiation performance with respect to a semiconductor device and also has improved mechanical connection reliability with a wiring board on which the semiconductor device is mounted.

[0002]

2. Description of the Related Art In recent years, there has been a growing demand for various electronic devices and electronic devices to be smaller, thinner, more functional, and lower in cost. Similarly, for semiconductor devices used for electronic circuit modules and the like in electronic devices and the like, studies on miniaturization, thinning, high functionality, and low cost have been rapidly promoted. Examples of a material for forming a wiring substrate serving as a substrate for mounting such a semiconductor device include the following.

A ceramic material containing alumina ceramic or the like as a main component must be fired at a high temperature of about 1400 to 1650 ° C., and a conductor material for forming circuit wiring is tungsten (W) which is a high melting point metal. And molybdenum (M
It is necessary to use a high resistivity metal material such as o). Therefore, there is a problem that it is difficult to apply to an electronic circuit that performs high-speed signal processing.

On the other hand, a wiring board using a high heat conductive material such as aluminum nitride among ceramic materials is useful as a substrate for mounting a semiconductor element requiring good heat dissipation, but is generally used in the consumer field. However, there is a problem in that it is expensive to use in the field and it is difficult to reduce the cost.

A glass epoxy substrate containing an organic insulating material as a main component is inexpensive, but has a problem in that it is inferior in heat dissipation from heat generated by a semiconductor element mounted and mounted.

On the other hand, a glass-ceramic substrate that can be fired at a low temperature has the advantage that it can be fired at a lower temperature and in a shorter time than a ceramic material, and a low-cost wiring substrate can be realized. In addition, a low-melting-point metal material such as gold (Au), silver (Ag), or copper (Cu) can be used as the conductor material, which is advantageous for high-speed signal processing in an electronic circuit. There are also features.

[0007] The wiring boards made of these materials are used properly depending on the application. However, miniaturization is achieved by directly mounting a semiconductor element, which has become an indispensable technology due to the recent enhancement of functions. In any case, how to efficiently dissipate the heat generated by the semiconductor element due to the miniaturization, higher density, and higher power of the semiconductor element to prevent thermal destruction and deterioration of the characteristics of the semiconductor element However, this is an important issue for ensuring the reliability of the semiconductor device.

As a measure for heat dissipation, for example, a method of directly mounting a semiconductor element on a substrate made of a material having a high thermal conductivity, a method of forming a large number of heat dissipating members called thermal via holes on a substrate immediately below the semiconductor element, and the like are given. Can be

Further, while it is necessary to have better heat radiation to ensure the reliability of the semiconductor element against heat generation, in order to achieve further miniaturization and lower cost, the semiconductor element mounting technology must be improved. In place of conventional wire bonding, a face-down mounting technology for mounting and mounting a semiconductor element on a wiring board using conductor bumps has been adopted. In this case, there is a tendency that it is difficult to effectively dissipate the heat generated by the semiconductor element. Therefore, there is an increasing demand for a semiconductor device in which the heat dissipation of the semiconductor element is further improved.

As an example of a semiconductor device using such a face-down mounting technique, for example, Japanese Patent Application Laid-Open No. 4-346250 discloses a semiconductor device in a cavity provided in a wiring board, face-down through a conductive bump via a conductive bump. It has been proposed to dissipate heat to the entire wiring substrate by mounting the semiconductor device on the back and sealing the back surface of the semiconductor element and the inner wall of the cavity with a resin having high thermal conductivity. Furthermore, the heat dissipation of the semiconductor element is enhanced by attaching the heat dissipation fin to the upper part.

[0011]

However, in the above-described structure proposed in Japanese Patent Application Laid-Open No. 4-346250, heat generated by the semiconductor element is transmitted to the entire wiring board through a resin having a high thermal conductivity. Further, although the heat radiating fin is mounted on the upper part, there is a problem that it is difficult to obtain a sufficient heat radiating effect with a resin having a high thermal conductivity as compared with a metal heat radiating member.

Further, since the heat dissipation to the entire wiring board becomes smaller as the size of the heat dissipation capacity of the wiring board becomes smaller, the heat is confined to the wiring board. Is difficult to obtain.

Furthermore, when the wiring board itself is exposed to a high temperature and other electronic components are mounted thereon, the electric characteristics of those electronic components are deteriorated or the connection reliability is adversely affected. There was a problem that becomes.

Further, when the heat radiating fins are attached, the semiconductor device itself becomes large, and it is no longer possible to satisfy the important characteristics required of the semiconductor device, such as reduction in height and size. There were also points.

The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to dissipate the heat generated by the semiconductor element satisfactorily and reduce the reliability and electrical characteristics of the semiconductor element itself by the heat generated by the semiconductor element. It is an object of the present invention to provide a small and small semiconductor device which has high reliability and high performance without deterioration.

[0016]

According to the present invention, there is provided a semiconductor device comprising:
A semiconductor element is mounted and mounted on the bottom surface of the concave portion formed on the lower surface of the first wiring board with the electrodes on the respective surfaces facing each other by bonding with a conductor bump, and between the bottom surface of the concave portion and the semiconductor element. A metal powder is filled so as to cover the semiconductor element in the recess while filling the insulating resin, and a portion of the metal powder exposed to the opening of the recess is used as a heat dissipation conductor on the second wiring board. It is characterized by being joined via a brazing material.

Further, in the semiconductor device according to the present invention, in the above structure, a high heat is applied between a portion of the first wiring substrate around the opening of the concave portion and an upper surface of the second wiring substrate opposed thereto. It is characterized by being filled with a conductive resin.

[0018]

According to the semiconductor device of the present invention, a semiconductor element is joined to a bottom surface of a concave portion formed on a lower surface of a first wiring board by a conductor bump with electrodes on each surface facing each other. Mounting and mounting, filling the insulating resin between the bottom surface of the concave portion and the semiconductor element, filling the concave portion with metal powder so as to cover the semiconductor element, and forming a portion of the metal powder exposed at the opening of the concave portion into the second portion. Since the semiconductor element housed in the recess of the first wiring board is partially connected to the heat dissipation conductor portion on the wiring board of the second wiring board via the brazing material, a part of the heat generated by the semiconductor element is recessed through the insulating resin. From the bottom surface to the first wiring board, and most of the metal powder is efficiently transmitted to the second wiring board, which can be used as an external electric circuit board such as a motherboard, via a metal powder covering the semiconductor element, and is radiated. Can, As compared with the case to be dissipated to the circuit board or the entire radiating fins through the high thermal conductivity covering the semiconductor element in the recess resins can be well heat radiation as in the semiconductor device.

As a result, the temperature rise of the semiconductor element due to heat generation can be suppressed to a junction breakdown temperature or less,
The semiconductor device has high reliability and high performance without deteriorating the reliability and electrical characteristics of the semiconductor device itself due to heat generated by the semiconductor device.

Further, a high thermal conductive resin is filled between a portion around the opening of the concave portion of the first wiring substrate in which the semiconductor element is accommodated in the concave portion and an upper surface of the second wiring substrate opposed thereto. Accordingly, the heat remaining on the first wiring board can also be radiated to the second wiring board via the high thermal conductive resin, and the reliability against the heat generation can be further improved.
Further, the reliability of mechanical connection between the first wiring board and the second wiring board constituting the semiconductor device can be improved at the same time.

As a result, it is possible to effectively avoid adverse thermal effects on other electronic components mounted on the same wiring substrate by dissipating heat to the entire wiring substrate as in a conventional semiconductor device, and to generate heat from the semiconductor element. Can be satisfactorily radiated from the second wiring board.

Hereinafter, the semiconductor device of the present invention will be described in detail with reference to the drawings, focusing on specific examples. FIG. 1 is a sectional view showing an example of an embodiment of a semiconductor device of the present invention.

In FIG. 1, a first wiring board 2 constituting a semiconductor device 1 has a predetermined wiring conductor (not shown) formed on the surface and inside of an insulating substrate, and a semiconductor element 4 is mounted on the lower surface thereof. It has a concave portion 2a to be formed. In the semiconductor element 4, an electrode (not shown) on the surface of the semiconductor element 4 is joined and electrically connected to an electrode (not shown) formed at a portion facing the bottom surface of the recess 2 a via the conductive bump 3. As a result, the semiconductor device is mounted and mounted in the concave portion 2a of the first wiring board 2.

Here, gold, solder, thermosetting silver paste or the like can be used for the conductor bumps 3. For example, when gold is used, the electrode on the bottom surface of the concave portion 2a of the first wiring board 2 and the electrode of the semiconductor element 4 can be electrically connected by an ultrasonic thermocompression bonding method.

As described above, since the semiconductor element 4 is mounted and mounted on the bottom surface of the concave portion 2a of the first wiring board 2 via the conductive bump 3, the gap between the bottom surface of the concave portion 2a and the surface facing the semiconductor element 4 is formed. Has a predetermined space. After the semiconductor element 4 is mounted in this space, the electric wiring and the electrode section of the first wiring board 2, the connection section with the semiconductor element 4, the element surface of the semiconductor element 4 and the like are completely insulated and protected, In order to dissipate part of the heat generated by the element 4, an insulating resin 5 is injected and filled between the bottom surface of the concave portion 2 a and the semiconductor element 4 and cured.

Here, the insulating resin 5 comprises a thermosetting resin component and an insulating filler for providing a desired coefficient of thermal expansion and thermal conductivity. As the resin component, for example, an epoxy-based thermosetting resin, a polyimide-based thermoplastic resin, a bismaleide-based thermosetting resin, or the like can be used. Aluminum oxide (Al ₂ O ₃ ) as a filler component
・ Aluminum nitride (AlN) ・ Silicon carbide (SiC) ・
Powders such as metal oxides and metal nitrides having high thermal conductivity such as beryllium oxide (BeO) and diamond can be used.

Next, in the recess 2a of the first wiring board 2,
A metal powder 6 as a heat transfer member for dissipating heat generated by the semiconductor element 4, for example, a conductive paste mainly containing a metal filler is filled so as to cover the mounted semiconductor element 4. As the metal powder 6, a metal having high thermal conductivity, specifically, a simple substance such as gold, silver, copper, or aluminum, or an alloy, metal carbide, or metal nitride thereof is used. The shape is preferably a shape such as a flaky powder or a polyhedral powder capable of providing a large contact area between the powders. In addition, a conductive paste containing these metal powders can be used as the metal powder 6. If such a paste is used, a dispenser or the like is used to fill the space in the recess 2 a of the first wiring board 2. The work of filling so as to cover the semiconductor element 4 becomes easy.

The conductive paste used as the metal powder 6 usually comprises a thermosetting resin component and a metal filler. As the resin component, for example, an epoxy-based thermosetting resin, a polyimide-based thermoplastic resin, a bismaleide-based thermosetting resin, or the like can be used. Further, as the metal filler, it is preferable to use a metal filler having a large contact area between powders, such as a flaky powder or a polyhedral powder made of silver or an alloy containing silver as a main component. The compounding ratio of the metal filler is preferably about 80% or more. If the mixing ratio is much less than 80%, the contact area between the metal fillers is hindered by the resin component and decreases. There is a tendency that a sufficient function as a heat transfer member cannot be obtained.

Next, the metal powder 6 at the portion exposed to the opening of the concave portion 2a of the first wiring board 2 is provided.
Is mounted, and can be used as an external electric circuit board such as a motherboard. A wiring electrode or the like on the second wiring board 7 having a predetermined wiring conductor (not shown) formed on the surface and inside of the insulating substrate is used. The heat dissipation conductor (not shown) is joined via the brazing material 8. Thereby, the semiconductor device 1 of the present invention is configured.

Here, as the brazing material 8, a general metal compound can be used, and for example, solder such as tin / lead or tin / silver / copper can be used.

Reference numeral 9 denotes a predetermined wiring conductor located around the opening of the concave portion 2a of the first wiring board 2 and a corresponding wiring conductor on the upper surface of the second wiring board 7, which is electrically connected to the predetermined wiring conductor. This is a conductor bump for mounting and mounting the first wiring board 2 on the second wiring board 7, and is the same as the conductor bump 3 joining the first wiring board 2 and the semiconductor element 4. The electrical connection between the first wiring board 2 and the second wiring board 7 may be made via bonding wires together with or instead of the conductor bumps 9.

As described above, in the semiconductor device 1 of the present invention, the semiconductor element 4 is mounted and mounted on the bottom surface of the recess 2a of the first wiring board 2 by bonding the semiconductor element 4 to the bottom surface of the recess 2a.
The space between the bottom surface of the semiconductor element 4 and the insulating resin 5 is filled, the metal powder 6 is filled in the recess 2a so as to cover the semiconductor element 4, and the portion of the metal powder 6 exposed at the opening of the recess 2a is removed. Since the heat dissipation conductors on the second wiring board 7 are joined via the brazing material 8, part of the heat generated by the semiconductor element 4 is transmitted to the first wiring board 2 via the insulating resin 5, and Most of the heat generated by the semiconductor element 4 can be transmitted to the second wiring board 7 very efficiently through the metal powder 6 and radiated to the second wiring board 7, and can be transmitted through a resin having a high thermal conductivity like a conventional semiconductor device. The heat from the semiconductor element 4 can be better radiated as compared with the case of radiating the heat.

As a result, according to the semiconductor device 1 of the present invention, the temperature rise of the semiconductor element 4 due to the heat generation can be suppressed to the junction breakdown temperature or less, and the reliability of the semiconductor element 4 itself due to the heat generation of the semiconductor element 4 can be suppressed. The semiconductor device 1 has high reliability and high performance without deteriorating the reliability and electric characteristics.

Further, in the semiconductor device 1 of the present invention, a portion around the opening of the concave portion 2 a of the first wiring board 2
It is preferable that the high thermal conductive resin 10 is injected into the space between the opposing upper surface of the second wiring board 7 and cured.

By filling the high thermal conductive resin 10 between the first wiring board 2 and the second wiring board 7 as described above, heat generated by the semiconductor element 4 remains on the first wiring board 2. The heat can be efficiently dissipated to the second wiring board 7 through the high thermal conductive resin 10, and furthermore,
The reliability of mechanical connection between the first wiring board 2 and the second wiring board 7 constituting the semiconductor device 1 can be improved at the same time. As a result, it is possible to avoid a thermal adverse effect on other electronic components on the same wiring board by dissipating heat to the entire wiring board as in a conventional semiconductor device, and to transfer heat from the semiconductor element 4 to the second wiring board 7. Can be further radiated more efficiently.

The high thermal conductive resin 10 is composed of a thermosetting resin component and an insulating filler for providing a desired coefficient of thermal expansion and thermal conductivity. A curable resin, a polyimide-based thermoplastic resin, a bismaleide-based thermosetting resin, or the like can be used. Examples of the filler component include metal oxides and metal nitrides having high thermal conductivity such as aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), silicon carbide (SiC), beryllium oxide (BeO), and diamond. Powder can be used. Further, the thermal conductivity is desirably equal to or higher than the thermal conductivity of the wiring board.

For example, when a glass ceramic is used for a wiring board, the thermal conductivity of the glass ceramic is generally 3 to 5 W / m · K, and the high thermal conductive resin usable for this has a thermal conductivity of 3 to 5 W / m · K. It is preferably 8 W / m · K or more, and aluminum oxide (Al ₂ O ₃ ) can be used as a filler component used for the same. Aluminum oxide is inexpensive, so that the cost of the high thermal conductive resin 10 and the cost of the semiconductor device 1 can be reduced. When this aluminum oxide is used, the filler component blending amount is preferably 65 wt% or more.
By adding at least wt%, the filler component can form a heat transfer path, and the heat accumulated in the first wiring board 2 can be transmitted to the second wiring board 7 very efficiently and dissipated. it can. On the other hand, if the content of the filler component is significantly lower than 65 wt%, it becomes difficult for the filler component to form a heat transfer path, and it tends to be difficult to obtain good heat dissipation.

For example, when aluminum nitride (AlN) is used as the wiring board material, the high thermal conductive resin 10 may be made of aluminum nitride (A) as a filler component.
1N) can be used.

It should be noted that the above is only an example of the embodiment of the present invention, and the present invention is not limited to these. Various modifications and improvements may be made without departing from the gist of the present invention. No problem.

[0040]

As described above, according to the semiconductor device of the present invention, the semiconductor element is formed on the bottom surface of the concave portion formed on the lower surface of the first wiring board by opposing the electrodes on the respective surfaces by the conductive bumps. Bonded and mounted, filled with insulating resin between the bottom surface of the concave portion and the semiconductor element, filled with metal powder so as to cover the semiconductor element in the concave portion, and exposed to the opening of the concave portion of the metal powder. Since the part is joined to the heat dissipation conductor on the second wiring board via the brazing filler metal, the heat generated by the semiconductor element housed in the recess of the first wiring board is partially removed by the insulating resin. Through the bottom surface of the recess to the first wiring board, and most of the metal powder is efficiently transferred to the second wiring board, which can be used as an external electric circuit board such as a motherboard, through a metal powder covering the semiconductor element, and is radiated. Can be It can, in comparison with the case where via the high thermal conductivity resin covering the semiconductor element in the recess is released to the wiring board or the entire radiating fins as in the conventional semiconductor device is excellently radiated.

As a result, the temperature rise of the semiconductor element due to heat generation can be suppressed to a junction breakdown temperature or less.
The semiconductor device has high reliability and high performance without deteriorating the reliability and electrical characteristics of the semiconductor device itself due to heat generated by the semiconductor device.

Further, since the high thermal conductive resin is filled between the portion around the opening of the concave portion of the first wiring board and the upper surface of the second wiring board facing the portion, the resin remains on the first wiring board. The heat generated can be radiated to the second wiring board via the high thermal conductive resin, so that the reliability against the heat generation can be further improved. Further, the first wiring board and the second wiring constituting the semiconductor device can be improved. The reliability of mechanical connection with the substrate can be improved at the same time.

As a result, it is possible to effectively avoid adverse thermal effects on other electronic components mounted on the same wiring substrate by dissipating heat to the entire wiring substrate as in a conventional semiconductor device, and to generate heat from the semiconductor element. Can be satisfactorily radiated from the second wiring board.

Further, since the heat dissipating fins as in the conventional semiconductor device can be dispensed with, the height and the size can be reduced.

As described above, according to the present invention, the heat generated by the semiconductor element is satisfactorily dissipated, and the heat generated by the semiconductor element does not deteriorate the reliability and electric characteristics of the semiconductor element itself. In addition, a low-profile and small-sized semiconductor device can be provided.

[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.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Semiconductor device 2 ... 1st wiring board 2a ... Depression 3 ... Conductor bump 4 ... Semiconductor element 5 ... Insulating resin 6 ... Metal powder 7 ... 2 wiring board 8 ... brazing material 10 ... high thermal conductive resin

Claims (2)

[Claims] 1. A semiconductor element is mounted and mounted on a bottom surface of a concave portion formed on a lower surface of a first wiring board by opposing electrodes on respective surfaces to each other and bonding them by conductor bumps. An insulating resin is filled between the second wiring board and an insulating resin, and a metal powder is filled in the recess to cover the semiconductor element, and a portion of the metal powder exposed to the opening of the recess is formed on the second wiring board. A semiconductor device which is joined to a heat dissipation conductor via a brazing material. 2. A high thermal conductive resin is filled between a portion around the opening of the concave portion of the first wiring substrate and an upper surface of the second wiring substrate facing the opening. The semiconductor device according to claim 1.