JP3660817B2 - Electronic circuit module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic circuit module which is used for an important part of various electronic devices and electronic devices and which covers a semiconductor element mounted on a substrate with a lid such as a metal case. The present invention relates to an electronic circuit module used for the structure.
[0002]
[Prior art]
The demand for downsizing, thinning, high functionality, low cost, etc. is not constant for recent electronic devices and electronic devices, and electronic devices and electronic devices are configured in order to fulfill those requirements. Similarly, electronic circuit modules, which are semiconductor devices, are rapidly being studied for downsizing, thinning, high functionality, and cost reduction.
[0003]
Such an electronic circuit module generally includes an electronic component or semiconductor element mounted on a substrate constituting the circuit board to form an electronic circuit, and further, the electronic component or semiconductor element is used for protecting the electronic circuit or electromagnetic shielding. It is comprised by attaching a metal case so that it may cover.
[0004]
The substrate constituting the electronic circuit module includes, for example, a ceramic material mainly composed of an aluminum oxide sintered body, a highly thermally conductive ceramic material mainly composed of an aluminum nitride sintered body, or a glass material and an organic material. The glass epoxy which consists of materials, or the glass ceramics etc. which can be fired at a low temperature compared with a ceramic material are used. With respect to these substrate materials, in the electronic circuit module, each substrate material is properly used as follows depending on the application.
[0005]
For example, a ceramic material whose main component is an aluminum oxide sintered body is an insulating material with high stability and reliability, but it must be fired at a high temperature of about 1400 to 1650 ° C. It is necessary to use tungsten, molybdenum, or the like, which is a high melting point metal, and since these high melting point metals are high specific resistance metal materials, it is difficult to apply them to electronic circuit modules that perform high-speed signal processing.
[0006]
In addition, a high thermal conductivity ceramic material mainly composed of an aluminum nitride sintered body is effective in terms of good heat dissipation, but is expensive for general consumer electronic circuit modules. It is difficult to reduce the cost.
[0007]
Glass epoxy composed of a glass material and an organic material is inexpensive but has insufficient heat resistance, and is not suitable for an electronic circuit module that requires thermal stability.
[0008]
In contrast, glass ceramics that can be fired at a low temperature and in a short time compared to ceramic materials can be produced at a low cost, and Au, Ag, Cu, and the like, which are low melting point metal materials, can be used for the material of the wiring conductor Therefore, it is advantageous for an electronic circuit module that performs high-speed signal processing.
[0009]
In addition, these substrate materials are properly used depending on the application. In response to the recent enhancement of functionality of electronic circuit modules, semiconductor devices can be directly mounted to achieve miniaturization. An important issue is how to dissipate the heat generated by the semiconductor elements accompanying the process. As a heat dissipation countermeasure, for example, a method in which a semiconductor element is directly mounted on a substrate made of a high thermal conductivity material, or a heat dissipation member called a thermal via hole is formed through a substrate directly below the semiconductor element. The method etc. are mentioned.
[0010]
On the other hand, as for the electrical connection method in mounting a semiconductor element, a so-called flip chip mounting method using metal bumps or the like has been put into practical use instead of the conventional wire bonding in order to reduce the mounting area.
[0011]
In addition, from the viewpoint of miniaturization of the substrate, instead of mounting a semiconductor element on the front side of the substrate, a chip is mounted on the surface of the substrate by embedding and mounting the semiconductor element by providing a cavity on the back side of the substrate. By making effective use of an increased area, further downsizing is possible.
[0012]
[Problems to be solved by the invention]
However, there is an increasing demand for electronic circuit modules that achieve both smaller size and lower cost, and in order to ensure the reliability of semiconductor elements, there is a need for electronic circuit modules that are higher than conventional ones. Good heat dissipation is required.
[0013]
Such heat dissipation is ensured by, for example, installing a heat-dissipating through conductor called a thermal via hole from the bottom of a cavity provided on the back side of the substrate and penetrating the surface of the substrate, and forming the metal on the surface of the substrate. This can be achieved by connecting to the electrode part and attaching a heat radiating member made of metal or the like to the metal electrode part by soldering. Furthermore, further heat dissipation can be achieved by bringing the metal heat radiating member into close contact with a case (lid) of an electronic circuit module made of a metal having good heat dissipation.
[0014]
However, since the thermal via hole is formed through the substrate to transmit heat from the semiconductor element and dissipate it, the circuit wiring inside the multilayer wiring board can be arbitrarily set at the portion where the thermal via hole penetrates the substrate. Electronic circuit modules such as, for example, circuit wiring that is inner layer must be arranged avoiding thermal via holes, leading to longer circuit wiring and increased electrical loss. There was a problem that it was greatly restricted in terms of downsizing.
[0015]
Furthermore, it is necessary to prepare an additional heat radiating member, and at the same time, the height of the heat radiating member in connection with the case determines the height of the case, that is, the product height. Since it is difficult to control the amount of solder and the thickness of the solder in soldering for attachment, there is a problem that the variation in product height becomes large.
[0016]
The present invention has been devised in view of the above-described problems of the prior art, and an object of the present invention is to arbitrarily arrange internal circuit wiring using an inexpensive multilayer circuit board and to generate heat from a semiconductor element. It is an object of the present invention to provide a highly reliable electronic circuit module that can efficiently dissipate heat and can meet demands for higher density, smaller size, and lower cost.
[0017]
[Means for Solving the Problems]
In the electronic circuit module of the present invention, the heat conductive layer having the semiconductor element mounting portion and the lid contact portion is formed on the upper surface of the multilayer wiring board with a thickness of one layer or more of the uppermost layer of the insulating layer of the multilayer wiring board. The semiconductor element is mounted on the semiconductor element mounting portion, and a lid body made of a heat conductive material and having a protruding portion on the inside is attached by bringing the protruding portion into contact with the lid contacting portion. It is characterized by being.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electronic circuit module of the present invention will be described in detail with reference to the drawings.
[0019]
FIG. 1 is a top view of an electronic circuit module according to an embodiment of the present invention with a cover removed, and FIG. 2 is a cross-sectional view taken along line AA ′ in FIG. It is sectional drawing.
[0020]
In these drawings, reference numeral 1 denotes a multilayer wiring board that is a substrate body of an electronic circuit module, and the circuit board is constituted by a plurality of insulating layers, circuit wiring layers, through conductors, and the like. The multilayer wiring board 1 may be a substrate made of various materials such as a ceramic multilayer wiring board or a glass ceramic multilayer wiring board or a glass epoxy board.
[0021]
Reference numeral 2 denotes a heat conductive layer formed on the upper surface of the multilayer wiring substrate 1, and the heat conductive layer 2 has a semiconductor element mounting portion 2 a and a lid contact portion 2 b on the upper surface of the multilayer wiring substrate 1. For such a heat conductive layer 2, a heat transfer material having a good heat conductivity such as a metal material similar to a via conductor for ensuring electrical continuity between the insulating layers of the multilayer wiring board 1 is used. Can do. For example, in the case of forming using a conductor paste in the same manner as a via conductor, a paste prepared with a metal powder such as Ag, Au, Cu and an organic binder may be used, and the insulating layer of the multilayer wiring board 1 is configured. What is necessary is just to form the heat conductive layer 2 of a desired shape and a dimension by printing on the recessed part formed in the ceramic green sheet to fill, baking it, etc.
[0022]
As the dimension of the heat conductive layer 2, the thickness may be, for example, one uppermost layer of the insulating layer of the multilayer wiring board 1, but it is advantageous in terms of heat conductivity if the thickness is several layers. Become. Moreover, the area should just have the area which can ensure the semiconductor element mounting part 2a which mounts the semiconductor element 3, and the cover body contact part 2b which contact | abuts the protrusion part 5a of the cover body 5 mentioned later. Consider enough heat to escape.
[0023]
Reference numeral 3 denotes a semiconductor element, which is mounted on the semiconductor element mounting portion 2a by being bonded with an adhesive material having good thermal conductivity such as AuSn brazing, AuSi brazing, or thermosetting Ag paste. Are electrically connected by wire bonding or the like, and heat generated by the operation is transmitted to the heat conductive layer 2. Further, the semiconductor element 3 is sealed with a sealing resin such as an epoxy resin or a silicone resin for sealing the semiconductor element for the purpose of protecting the element and the bonding wire after mounting.
[0024]
Further, an insulating resin having a good thermal conductivity, so-called under, is connected between the lower surface of the semiconductor element 3 and the multilayer wiring board 1 (semiconductor element mounting portion 2a) by a metal bump by a so-called flip-chip mounting method. Fill may be injected to improve the heat conduction of the semiconductor element 3 to the heat conductive layer 2.
[0025]
Reference numeral 4 denotes various electronic components that are mounted on and mounted on the upper surface of the multilayer wiring board 1 together with the semiconductor element 3, such as a chip capacitor, a chip resistor, and a chip inductor.
[0026]
Reference numeral 5 denotes a lid made of a heat conductive material, which is attached to the multilayer wiring board 1 so as to cover the upper surface thereof, and protects the semiconductor element 3 and the electronic component 4 mounted on the board 1 by accommodating them inside the container. It is. Further, the lid 5 has a protruding portion 5 a on the inner side, and this protruding portion 5 a is brought into contact with the lid contacting portion 2 b of the heat conductive layer 2. The protrusion 5a and the lid contact part 2b may be connected using a belt-type reflow furnace or the like using solder or the like in order to increase thermal conductivity.
[0027]
Such a lid 5 is attached to the multilayer wiring board 1 for the purpose of electromagnetic shielding as well as protection of the semiconductor element 3 and the electronic component 4. For example, materials such as white, iron, and SUS are used. The surface can be plated with Ni, Sn, solder, etc. to improve solder wettability. The lid 5 is formed by processing to a desired dimension using a mold, for example.
[0028]
The lid 5 is provided with a flange portion 5b for alignment with the multilayer wiring board 1, and this is provided with a flange portion insertion hole or a groove portion insertion groove (not shown) provided on the side surface of the multilayer wiring substrate 1. ) Can be accurately aligned and attached.
[0029]
Further, the protruding portion 5a may be shaped and dimensioned so as to be brought into contact with the lid contact portion 2b of the heat conducting layer 2 so that the heat from the semiconductor element 3 can be sufficiently conducted and dissipated from the lid 5. Further, the contact portion with the lid contact portion 2b may be soldered so as to have a shape and size that can satisfy the adhesive strength with the multilayer wiring board 1.
[0030]
Such a protruding portion 5a is formed by forming a portion that becomes the protruding portion 5a on a mold for processing the lid 5, or by processing the lid 5 by punching or the like to form a concave portion. Formed in shape, position and dimensions.
[0031]
Thus, according to the electronic circuit module of the present invention, the protrusion 5a of the lid 5 is brought into contact with the lid abutment 2b of the heat conductive layer 2 on which the semiconductor element 3 is mounted on the upper surface of the multilayer wiring board 1. Therefore, the heat generated in the semiconductor element 3 is efficiently conducted from the protruding portion 5a to the lid body 5 through the heat conductive layer 2, and is attached to the lid 5 from the lid 5 in the atmosphere. It is dissipated to a heat radiating member (not shown).
[0032]
Further, the heat conductive layer 2 is formed on the upper surface of the multilayer wiring board 1 so as to be integrated with the uppermost layer of the multilayer insulating layer, and does not penetrate through the inside of the multilayer wiring board 1 unlike the conventional thermal via hole. The circuit wiring inside the multilayer wiring board 1 can be freely routed even below the heat conductive layer 2, and the inner circuit wiring layer can be arranged without any restriction to increase the density and miniaturization of the multilayer wiring board 1. Can be achieved.
[0033]
Furthermore, the heat generated from the semiconductor element 3 can be effectively conducted and dissipated by merely bringing the protrusion 5a of the lid 5 into contact with the lid contact part 2b of the heat conductive layer 2, and the protrusion 5a can be dissipated. Even when the lid abutting portion 2b is bonded with a good heat conductive adhesive such as solder, the protruding portion 5a has good wettability with respect to the adhesive, so that the extra adhesive is on the side surface of the protruding portion 5a. Since the projecting portion 5a can be brought into close contact with the lid contact portion 2b using the dead weight of the lid 5, the height variation of the lid 5, that is, the height of the product can be increased. Variations can also be reduced.
[0034]
Further, since the heat conductive layer 2 can be integrally formed in the manufacturing process of the multilayer wiring board 1, and it is not necessary to separately mount a heat dissipation member on the multilayer wiring board 1, the cost of the electronic circuit module can be reduced. You can also plan.
[0035]
It should be noted that the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.
[0036]
【The invention's effect】
According to the electronic circuit module of the present invention, the heat conductive layer having the semiconductor element mounting portion and the lid contact portion on the upper surface of the multilayer wiring board is formed with a thickness of one layer or more of the uppermost layer of the insulating layer of the multilayer wiring board. The semiconductor element is mounted on the semiconductor element mounting portion, and a protrusion is formed on the inner side of the cover made of a heat conductive material, and the protrusion is brought into contact with the cover contact portion to connect the cover to the multilayer wiring. Since it is attached to the substrate, it is possible to efficiently transmit and dissipate the heat generated by the semiconductor element to the lid through the heat conductive layer and the protruding portion.
[0037]
In addition, since the heat conduction layer which is a heat dissipation member in the multilayer wiring board is formed on the upper surface of the multilayer wiring board with a thickness of one layer or more of the uppermost layer of the insulating layer of the multilayer wiring board and does not penetrate the board, Even in the lower part of the heat conductive layer, it is possible to arrange the circuit wiring layer inside the multilayer wiring board without any particular restriction, and the electronic circuit module becomes denser and smaller than those using conventional thermal via holes.
[0038]
As described above, according to the present invention, the internal circuit wiring can be arbitrarily arranged using an inexpensive multilayer circuit board, and the heat generated from the semiconductor element can be efficiently radiated, and the density and size can be reduced.・ We were able to provide a highly reliable electronic circuit module that can meet the demand for lower costs.
[Brief description of the drawings]
FIG. 1 is a top view showing an example of an embodiment of an electronic circuit module of the present invention with a lid removed.
2 is a cross-sectional view taken along the line AA ′ of FIG. 1 in a state where a lid is attached, showing an example of an embodiment of the electronic circuit module of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Multi-layer wiring board 2 ... Thermal conductive layer 2a ... Semiconductor element mounting part 2b ... Cover body contact part 3 ... Semiconductor element 5 ... -Lid 5a ... Projection

Claims (1)

A heat conductive layer having a semiconductor element mounting portion and a lid contact portion is formed on the upper surface of the multilayer wiring board with a thickness of one layer or more of the uppermost layer of the insulating layer of the multilayer wiring board. An electronic circuit mounted on a mounting portion and made of a heat conductive material, and having a lid having a protruding portion on the inside thereof, the mounting portion being attached to the lid contacting portion module.

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