JPH06334113A - Multichip module - Google Patents

Abstract

PURPOSE:To provide a multilayer three-dimensional MCM whose manufacturing cost is low, whose design can be changed easily and which can be mounted at high density. CONSTITUTION:Many electrodes 14 are formed at the peripheral part of a substrate 12, and a plurality of cavities 20 which are matched to the shape of semiconductor chips or the like to be mounted are formed in individual places at the inside. Metal layers 22 which are held at a ground potential are formed at the inside of the cavities 20, the bottom face of IC chips 16 or the like is coated with a conductive adhesive 24, and the IC chips or the like are fitted into the cavities 20. Parts between the IC chips 16 or parts between the IC chips 16 and the electrodes 14 on the substrate 12 are connected by fine metal wires 26 by a wire bonding operation. A polyimide layer is formed on the surface of the substrate 12, the fine metal wires 26 are insulated from each other, and the fine medal wires 20 are held by, and fixed to, the substrate 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-chip module in which a large number of semiconductor chips (hereinafter referred to as IC chips) and other chip parts etc. are mounted on a substrate.
The present invention relates to a multi-chip module that can be easily dimensioned, can easily respond to design changes, and can be manufactured economically.

[0002]

2. Description of the Related Art With the demand for large-scale and high-speed functions of electronic devices, the delay time per gate of a logic IC is
It has been accelerated or shortened to the level of several hundred ps. On the other hand, many DIPs (dual in-line p
ackage) and the conventional implementation of a pin grid array, the wiring between chips is longer than the signal propagation time, so the delay time cannot be shortened as required. Therefore, it has been difficult to sufficiently bring out the performance of the speeded up IC. Therefore, in order to reduce the wiring length between chips as much as possible, a multi-chip module (hereinafter, referred to as MCM) in which a large number of bare chips such as bare IC chips are mounted on one substrate and connected to achieve high performance. It has been developed and put into practical use.

[0003]

However, in the conventional MCM, the required wiring is formed in advance on a substrate made of silicon, ceramic, glass epoxy resin or the like, and then I
Place the C chip or other chips, connect them,
The MCM has a problem as described below because of the manufacturing steps and the structure of the MCM. That is, first, the process from the pattern design of the substrate to the manufacturing of the substrate is complicated, and moreover, the time required from the pattern design to the completion of the substrate for one MCM is long. When changing the pattern design,
Even if the change is insignificant, it is necessary to remake the MCM from the beginning, which causes a problem that the manufacturing cost increases. Secondly, since a large number of IC chips or other chip parts are mounted on the substrate, heat dissipation is inadequate, the temperature of the MCM rises, and the performance of the IC chips and chip parts cannot be exhibited. The problem arises.
Therefore, there is a problem in that the demand for high-density mounting cannot be satisfied because the IC chips and the like cannot be stacked and mounted in multiple layers.

According to the present invention, the manufacturing cost is low, the design can be easily changed, and a three-dimensional MCM can be formed.
The purpose is to provide a multi-chip module capable of high-density mounting.

[0005]

To achieve the above object, a multi-chip module according to the present invention comprises a semiconductor chip, a component element other than the semiconductor chip, a substrate electrode in the peripheral portion, and an opening upward. A multi-chip module having a cavity and a substrate having a metal layer formed on the bottom surface of the cavity so as to be connected to at least a part of a substrate electrode, wherein a semiconductor chip and a component element are provided in the cavity. The semiconductor chip, the component element, and the substrate electrode are arranged and bonded on the metal layer with a conductive adhesive or bonded with a conductive bonding agent. , Is electrically insulated from each other by a non-conductive adhesive layer and is held and fixed to the substrate. There.

The substrate used in the present invention is a substrate formed of a conventionally used material, for example, ceramics, silicon, synthetic resin, or a composite material thereof. A component element other than a semiconductor chip means an electrical or electronic component element, for example, a commonly used rectangular chip component or a resistor, capacitor or other component formed in a thin chip component.
It should be noted that the component element is provided with an electrode formed of a metal material so as to be bonded with a fine metal wire. The cavity is for thinning the MCM and flattening the wiring.
Formed by processing the upper surface of the substrate into a concave shape according to the size of the component, loading of semiconductor chips and component elements,
Opening upwards for easy bonding.

The metal layer is formed by metallizing a thin film or a thick film on the bottom surface of the cavity for ohmic contact and heat conduction of the semiconductor chip and the component device. A conductive adhesive or a conductive bonding agent is used for making ohmic contact and mechanical connection between the metal layer of the cavity and the semiconductor chip and component elements, and is usually called a die attach agent. It does not interfere with conduction. Examples of the adhesive include organic materials, and examples of the bonding agent include solder. As a bonding wire, I
Gold wires, aluminum wires having a thickness of, for example, 25 μm to 100 μm, which are usually used for bonding C chips,
Copper wire or the like can be used, but it is determined in detail taking into account the required characteristics and cost. For bonding, a conventional wire bonder is modified and used for the purposes of the present invention. Also,
To form a multi-layer three-dimensional multi-chip module, a coated wire coated with an electrically insulating material is preferably used as a bonding wire. The coating material used is one that is melted and removed by the heat during bonding.

A preferred embodiment of the multi-chip module according to the present invention is characterized in that the non-conductive adhesive layer is made of polyimide resin.

Furthermore, another preferred embodiment of the multi-chip module according to the present invention is characterized in that the metal layer attached to the inner surface of the cavity of the substrate fixes the semiconductor chip to the ground potential. .

In the multi-dimensional three-dimensional embodiment of the present invention, holes are formed in the non-conductive adhesive layer on the surface of the multi-chip module according to claim 1, and another semiconductor is formed on the non-conductive adhesive layer. A chip and a component element other than a semiconductor chip are mounted, and a bonding wire for connecting between the lower semiconductor chip, the component element and the electrode, and another semiconductor chip in the upper layer and the component element through another bonding wire through a hole. The feature is that they are connected to form a three-dimensional multilayer.

[0011]

The present multi-chip module (hereinafter, simply referred to as MCM for simplification) is constructed as described above, so that its manufacturing process is extremely simple and its implementation is simple. That is, first, a cavity is formed in conformity with the shape of a semiconductor chip (hereinafter referred to as an IC chip) to be mounted on a substrate, other chip components, or the like. Next, an electrode is provided on the peripheral portion of the substrate, and a metal layer is also provided on the inner surface of the cavity. Then, a conductive adhesive is coated on the bottom surface of the cavity, and an IC chip or the like is bonded to that portion. Next, using a wire bonder, bonding wires are connected between these IC chips and other chip components and between these and the substrate electrodes. Then, a non-conductive adhesive layer made of polyimide or the like is formed on the upper surface of the substrate to insulate the bonding wires from each other, and the bonding wires are held and fixed to the substrate.
Complete M.

Therefore, unlike the conventional case, it is not necessary to preliminarily provide necessary wiring on the substrate, so that the manufacturing process time is shortened, and even if the design is changed, the connection position of the bonding wire is simply changed. Is possible. Further, since another IC chip or the like can be mounted on the non-conductive adhesive, a high-density mounting three-dimensional MCM can be realized. Furthermore, the heat generated by the IC chip etc.
It is conducted to the outside through the metal layer on the inner surface of the cavity and the substrate electrode to radiate heat. Therefore, since the temperature of the MCM does not rise, the performance of each element of the MCM can be fully exhibited.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a perspective sectional view showing a configuration of a first embodiment of a multichip module according to the present invention. In FIG.
A multi-chip module (hereinafter abbreviated as MCM) 10 according to the present embodiment includes a substrate 12, an IC chip 16, and a chip component 18. Board 12
Is made of a material such as ceramic, silicon, resin, or a composite material thereof, which has characteristics such as mechanical strength, heat resistance, and electrical insulation required as a substrate. The substrate 12 is provided with a large number of substrate electrodes 14 in the peripheral portion and a plurality of cavities (recesses) 20 in the central portion. The cavity 20 is an IC mounted as an MCM
The chip 16 and the chip component 18 are formed in a shape that is open at the top so as to match the shapes of the chips 16 and the chip components 18 and to facilitate their insertion and bonding.

A bare IC chip is used as the IC chip 16. The performance of the IC chip 16 is MC
Since it is a factor that greatly affects the yield of M products, a good bare IC chip selected beforehand by pellet check or bare diver-in is used. The chip component 18 is
An ordinary rectangular chip part or a thin film chip part, on the upper surface of which an electrode made of a metal material is provided so as to be bonded by a fine metal wire (bonding wire). In this embodiment, the chip component 18 is, for example, a required capacitor element, resistance element, or the like.

A metal layer 22 is formed on the inner surfaces of these cavities 20, and the metal layer 22 is used as the substrate electrode 1.
It is connected to a part of 4 and kept at the ground potential. Inside these cavities 20, the IC chip 16
And the chip component 18 are arranged, and the bottom surfaces of the IC chip 16 and the chip component 18 are electrically conductive die attach agent 2
4 are joined to the metal layer 22 on the bottom surface of the cavity 20. The die attach agent 24 is for the purpose of ohmic contact and mechanical connection between the IC chip 16 / chip component 18 and the substrate 12, and for example, a conductive adhesive agent or solder can be used.

Between the IC chip 16 and the chip component 18, or between the IC chip 16 and the chip component 18 and the substrate electrode 14.
A bonding wire 26 is connected between these and. The bonding wire 26 is a gold wire or an aluminum wire used for normal IC wire bonding, and its diameter is in the range of 25 μm to 100 μm. Wiring is performed by a normal wire bonder (wiring machine) modified for this purpose.

On the surface of the substrate 12, a non-conductive adhesive (not shown) such as a polyimide resin is used except for a region of the substrate electrode 14 for connecting to an external mother substrate (not shown). It is covered with. The non-conductive adhesive has a function of electrically insulating the bonding wires 26 from each other and holding and fixing the bonding wires 26 to the substrate 12.

A coated wire may be used as the bonding wire 26. In this case, as the coating material for the coated wire, a coating material that can melt and remove the electric insulating layer by heat during bonding is used. When a covered wire is used as the bonding wire 26, it is not always necessary to electrically insulate the bonding wires 26 from each other by the above-mentioned non-conductive adhesive layer. In FIG. 1, A indicates a connection point where the bonding wires 26 are connected to each other. The structure of the connection point A when a covered wire is used as the bonding wire 26 is enlarged and shown in FIG. 2 (a) is a plan view and FIG. 2 (b) is a sectional view, and the connection points are formed in a metal ball shape.

In the present embodiment, it is not necessary to previously form the necessary wiring on the substrate, which has been conventionally done.
The time required from the pattern design of the substrate to the completion of manufacturing is shortened, and the time required for the manufacturing process is also shortened. The connection with the bonding wire is extremely simple as compared with other connection methods, so that the work efficiency is high. Further, even if the design is changed, it can be easily dealt with by changing the connection by the bonding wire 26 or by changing the connection position of the bonding wire 26.
The heat generated by the IC chip 16, the chip component 18, etc. is conducted to the outside through the metal layer 22 on the inner surface of the cavity 20 and the substrate electrode 14 connected thereto and is radiated, so that the temperature of the MCM does not rise. , The characteristics of each element in the MCM can be sufficiently exhibited.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a sectional view showing the configuration of the MCM of the second embodiment according to the present invention. In addition, the same or corresponding parts as those described in the previous embodiment are designated by the same reference numerals and the description thereof will be omitted. In the MCM 30 of the second embodiment shown in FIG. 3,
Similar to the MCM 10 of the first embodiment, the IC chip 16 and the chip component 18 are arranged in the cavity 20 having the metal layer 22 connected to at least a part of the substrate electrode 14 on the bottom surface. The bottom surface of the component 18 is joined to the metal layer 22 on the bottom surface of the cavity 20 by a conductive die attach agent 24. Between the IC chip 16 and the chip component 18, or between the IC chip 16 and the chip component 1
8 and the electrode 14 of the substrate 12 are connected by the first wiring layer 3
2 is connected by a bonding wire.

On the first wiring layer 32, the polyimide insulating layer 28 is provided as a non-conductive adhesive layer. Further, the wiring of the IC chip 16 and the like is drawn out through the hole 34 of the polyimide insulating layer 28 to form the second wiring layer 36. In addition, in FIG. 3, B shows the connection point of bonding wires, and FIG. 4 is the enlarged view. As shown in FIG. 4, the bonding wire 36 is formed of the polyimide insulating layer 28.
After vertically rising from the IC chip 18 through the hole 34, the substrate is bent horizontally along the upper surface of the polyimide insulating layer 28. One of the bonding wires 36a extends on the upper surface of the polyimide insulating layer 28, and then forms a curved portion 36b that is bent upward, and then is connected to the bent portion of the bonding wire 36.

Third Embodiment FIG. 5 is a sectional view showing the structure of a third embodiment in which the MCM shown in FIG. 3 is further processed to form a multilayer three-dimensional structure. In the MCM 40 of the third embodiment shown in FIG. 5, the substrate 12, the substrate electrode 14, the IC chip 16, the chip component 18, the cavity 20, the metal layer 22, the die attach agent 24, the polyimide insulating layer 28, the first wiring layer 32, Hole 34, second wiring layer 36
Has the same configuration as the MCM 30 of the second embodiment described above.
The MCM 40 further includes a second polyimide insulating layer 42, another IC chip 44 disposed on the second polyimide insulating layer 42, and another chip component 46, and the IC chip 44 and the chip component 46 include a third wiring layer 48. Via the holes 50 provided in the second polyimide insulating layer 42, and are further connected to the second wiring layer 36. The first polyimide insulating layer 28 and the second polyimide insulating layer 42 may be formed of a polyimide film, or may be a liquid polyimide that is applied and then cured.

In this embodiment, with such a structure, a multilayer circuit is formed by ordinary bonding wires, or another IC chip and chip component are mounted on the lower IC chip and chip component via a polyimide insulating layer. Realizes a three-dimensional MCM.

Next, the manufacturing process of the three-dimensional MCM shown in FIG. 5 will be described with reference to FIGS. 6 and 7. 6 and 7 are cross-sectional views of the MCM for explaining each manufacturing process of the MCM, and FIG. 6 shows steps (a) to (e), and FIG.
Indicates the subsequent steps (f) to (i). Step (a) The substrate 12 made of ceramic or organic material is machined to form a cavity 20 in which an element such as an IC chip is arranged. Step (b) A metal layer (metallized layer) 22 is formed on the inner surface of the cavity 20 and the substrate 12. The metal layer 22 in the cavity 20 fixes the IC chip 16 and the like to the ground potential, and the metal layer on the substrate 12 is the substrate electrode 14. Step (c) The IC chip 16 and other chip components 18 are mounted on the metal layer 22 in the cavity 20 and joined with a conductive adhesive or solder. Step (d) Using a fine metal wire bonder (improved wire bonder), the elements are wire-bonded to each other by a fine metal wire to form the first wiring layer 32. As the fine metal wire, a covered wire is used here. This coating is made of a resin that is decomposed by heat during bonding. Step (e) The photosensitive polyimide resin layer 28 is coated as an electrical insulating layer on the first wiring layer 32. Further, a hole 34 is formed by opening at a predetermined electrode portion by photolithography.

Step (f) The second wiring layer 36 is connected in the same manner as in (d). Here, since the covered wire is used for bonding in both steps (d) and (f), the polyimide resin layer 28 can be omitted, but this point is selected in consideration of circuit characteristics and reliability. . Step (g) After forming the second wiring layer 36,
An electrical insulation layer 42 is formed for mounting the upper part.
The insulating layer 42 is made of polyimide, epoxy, or the like, and the opening 50 is patterned by photolithography. Step (h) The IC chip 44 and the chip component 46 are arranged on the electrical insulating layer 42 as upper components. Here, when a metallized layer is required, the metallized layer is formed similarly to (b). Step (i) The elements 44 and 46 and the electrodes are connected in the same manner as in (d) to form the third wiring layer 48, and the manufacturing of the MCM 40 is completed. Further, when it is necessary to stack an element on it, steps (e) to (f) are similarly repeated. Step (j) The mounted MCM 40 is put in a package of ceramic, metal or the like, connected to external electrodes, and an electrical check is performed to complete the product.

According to this method, it is easy to flatten the mounting surface in order to mount another IC chip and chip component on the upper layer, and the wiring using fine metal wires has flexibility for design changes. , Production cost is low.

[0027]

As described above, according to the present invention as set forth in claim 1, the semiconductor chip and the element are arranged in the cavity of the substrate, and are adhered to the metal layer on the bottom surface of the cavity by a conductive adhesive, respectively. The following effects are obtained by connecting the semiconductor chip, the element and the substrate electrode with a bonding wire, and electrically insulating the bonding wire from each other with a non-conductive adhesive layer and holding and fixing it to the substrate. Can play. (1) Since it is not necessary to previously form the necessary wiring on the substrate as in the conventional case, a multi-chip module that can shorten the period required for pattern design and easily follow the design change is realized. (2) Since the metal layer formed on the bottom surface of the cavity is connected to at least a part of the electrode in the peripheral portion of the substrate, the heat generated from the element is radiated to the outside through the metal layer and the substrate electrode. Therefore, the multi-chip module according to the present invention has remarkably better heat dissipation characteristics than the conventional multi-chip module, and the temperature inside the module can be maintained at a predetermined value, so that the performance of each mounted element can be sufficiently exhibited. it can. (3) By connecting by wire bonding,
The connection process is simplified and the work efficiency can be improved. According to a fourth aspect of the invention, by covering the lower wiring surface with an electric insulating layer (for example, a polyimide layer), multilayer wiring is possible, and another semiconductor chip or the like is mounted on the electric insulating layer to form a three-dimensional structure. A multi-chip module can be formed and high-density mounting can be achieved.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

2 is an enlarged view of a point A in FIG. 1, where (a) is a plan view and (b) is a sectional view.

FIG. 3 is a sectional view of a second embodiment of the present invention.

FIG. 4 is an enlarged view of point B in FIG.

FIG. 5 is a sectional view of a third embodiment of the present invention.

FIG. 6 is a diagram showing a manufacturing process of a three-dimensional multi-chip module.

FIG. 7 is a diagram showing a manufacturing process of the three-dimensional multi-chip module subsequent to FIG. 6;

[Explanation of symbols]

10 Multi-chip module of the first embodiment 12 Substrate 14 Substrate electrode 16 IC chip 18 Chip component 20 Cavity 22 Metal layer 24 Conductive adhesive 26 Fine metal wire (bonding wire) 28 Non-conductive adhesive layer (Polyimide layer) 30 Multi-chip module 32 of the second embodiment 32 First wiring layer 34 Holes in the first non-conductive adhesive layer (polyimide layer) 36 Second wiring layer 40 Multi-chip module 42 of the third embodiment 42 Second non-conductive adhesive Layer (polyimide layer) 44 Another IC chip 46 Another chip component 48 Third wiring layer 50 Second non-conductive adhesive layer (polyimide layer) hole

Claims (4)

[Claims] 1. A semiconductor chip, a component element other than the semiconductor chip, a substrate electrode in a peripheral portion, and a cavity opened upward, the bottom surface of the cavity being connected to at least a part of the substrate electrode. And a substrate on which a metal layer is formed so that the semiconductor chip and the component element are arranged in the cavity, and are bonded to the metal layer by a conductive adhesive, respectively. Or bonded by a conductive bonding agent, the semiconductor chip, the component element and the substrate electrode are connected by a bonding wire, the bonding wire is a non-conductive adhesive layer,
A multi-chip module, which is electrically insulated from each other and is held and fixed to the substrate. 2. The multichip module according to claim 1, wherein the non-conductive adhesive layer is made of a polyimide resin. 3. The multi-chip module according to claim 1, wherein the metal layer deposited on the bottom surface of the cavity of the substrate fixes the semiconductor chip to the ground potential. 4. A hole is formed in the non-conductive adhesive layer on the surface of the multi-chip module according to claim 1, and another semiconductor chip and a component element other than the semiconductor chip are mounted on the non-conductive adhesive layer. Then, a bonding wire connecting between the lower semiconductor chip, the component element and the electrode, and the other upper semiconductor chip and the component element are connected through the hole by another bonding wire to form a multilayer three-dimensional structure. A multi-chip module characterized by the above.