JPH0746708B2 - Semiconductor mounting substrate and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a semiconductor mounting board used for mounting various semiconductor elements and a method for manufacturing the same.

In particular, the present invention provides a semiconductor mounting substrate and a method for manufacturing the same, which is excellent in heat dissipation generated from a mounted semiconductor element, and thus moisture hardly enters the semiconductor element from the outside, a camera, It is advantageously used for internal substrates such as watches, chip carriers, pin grid arrays, and hybrid substrates.

[Conventional technology]

The material of a conventional semiconductor mounting substrate on which a semiconductor element is directly mounted is plastic or ceramics, and plastics are most widely used because they are easy to process and relatively low in cost. Generally, semiconductor mounting boards using plastics such as glass epoxy have excellent dimensional accuracy,
The mechanical strength is superior to ceramic substrates such as alumina, but the thermal conductivity is extremely low, about 1/60 that of alumina. Therefore, the conventional plastic substrate has a high degree of integration.
It has not been fully satisfied as a substrate on which ICs and semiconductor elements with large power consumption are mounted.

In order to eliminate and improve this defect, a semiconductor mounting substrate having a structure in which a metal plate having high thermal conductivity is attached to a plastic substrate and a semiconductor element is directly attached to the metal plate to improve heat dissipation has been conventionally used. Has been done.

5 and 6 are vertical sectional views of a semiconductor mounting substrate according to the prior art.

[Problems to be solved by the invention]

However, in the above-described semiconductor mounting substrate, in a substrate in which a metal plate is bonded around the opening on the back surface side of the substrate via an adhesive layer as shown in FIG. 5, the semiconductor mounting recess is formed. It is extremely difficult to completely prevent the protrusion of the adhesive used for joining the substrate and the metal plate around the bottom surface of the opening, compared to the outer dimensions of the semiconductor element to be mounted. The size of the device must be increased and the size of the device must be increased. Alternatively, if the amount of protrusion of the adhesive material is further increased, it may not be possible to mount the semiconductor element at a proper position. Further, in the board as shown in FIG. 6, after the metal plate is joined to the back surface of the board, the opening is cut to reach the metal plate from the front surface of the board and the protruding portion of the adhesive is removed. It is difficult to process the surface of a carved metal plate to be completely smooth,
It has a drawback that stable quality cannot be obtained, leading to cost increase, or that the semiconductor element cannot be mounted in a proper position and shape.

The present invention has improved the drawbacks of the above-mentioned technology, has excellent heat dissipation, is highly reliable, facilitates the formation of high-density wiring, and makes it easy to reduce the size of the device. It is an object of the present invention to provide an improved semiconductor mounting substrate and a method for manufacturing the same.

[Means for solving problems]

 Hereinafter, the present invention will be described in detail with reference to the drawings.

1 and 2 are longitudinal sectional views of a semiconductor mounting substrate according to the present invention. In FIG. 1, metal foils (2) are formed on the upper and lower surfaces made of a plastic material such as glass-epoxy resin, glass-modified triazine resin and glass-polyimide resin.
An opening (3) penetrating from the front surface to the back surface is formed on the substrate (1) to which is adhered, and a metal plate (4) is adhered to the substrate rear surface side of the opening (3) so as to close the opening. The semiconductor mounting recess (6) is formed by joining the semiconductor mounting recess via the layer (5), and is continuous with the side surface of the semiconductor mounting recess (6) over the entire circumference of the bottom surface. A groove (7) having an outer peripheral portion is formed. Further, the entire surface of the portion exposed on the back side of the substrate (1), that is, the metal plate (4) and the substrate (1) on the back side of the substrate.
A plating film (9) is integrally formed on each exposed surface.

In order to prevent the adhesive from protruding, there is a method of retracting the adhesive to the inside of the side wall surface of the opening (3). In that method, the substrate (1) and the metal plate (4) are used.
Since the bonding area with and is reduced, the adhesive strength becomes insufficient, or the sealing resin used to protect the mounted semiconductor element does not easily get around to the part where the adhesive material has receded, causing voids. It is not the best means to solve the above problems because it has a drawback of being easy.

Therefore, in the present invention, a groove (7) having an outer peripheral portion continuous with the side surface of the semiconductor mounting recess (6) is formed over the entire circumference of the bottom surface of the semiconductor mounting recess (6), and at the same time, the protruding portion of the adhesive material is formed. By cutting (11), the surface from the substrate (1) forming the side wall of the recess for mounting semiconductor to the metal plate (4) was smoothed, and it was possible to eliminate the protruding portion of the adhesive. Here, in the cutting process, it is easier to cut a part of the metal plate (4) at the same time in terms of processing accuracy.

FIG. 2 is a vertical cross-sectional view of the structure of another embodiment of the semiconductor mounting substrate of the present invention, which is different from FIG. 1 in the recess (10) formed on the back surface side of the substrate (1). The metal plate (4) is joined via the adhesive layer (5). Even in the semiconductor mounting substrate shown in FIG. 2, the semiconductor mounting recess side wall surface is a smooth surface from the substrate (1) to the metal plate (4) as in the substrate according to the present invention shown in FIG. And the surface of the metal plate (4) of the bottom portion for directly fixing the semiconductor element is made of a metal flat plate as a material. By exposing the surface shape as it is, a smooth surface can be easily formed. The semiconductor mounting substrate shown in FIG. 2 can be thinner than the substrate shown in FIG.

The groove (7) provided over the entire circumference of the bottom surface of the semiconductor mounting recess (6) formed in this manner is used for inflow of an excessive portion of an adhesive such as silver paste used when mounting a semiconductor element on the substrate. You can also use it. Further, the plating film (9) integrally formed on the entire surface of the exposed portion on the back surface side of the substrate (1) prevents moisture from invading from the back surface of the substrate, and eventually damages or corrodes the mounted semiconductor element due to moisture. It is very effective in preventing

The adhesive used for the substrate of the present invention is an epoxy resin,
It is a polyimide resin, an acrylic resin, a triazine resin or a modified resin thereof, and these resins are advantageously used because of their excellent adhesiveness, heat resistance, durability and electrical insulating properties. As the metal plate, copper, aluminum,
It is possible to effectively use a material having a relatively high thermal conductivity such as iron or an alloy of each. Copper, nickel, gold, tin or the like can be used as the material of the plating film.

Next, a method for manufacturing a semiconductor mounting substrate of the present invention will be described with reference to the drawings.

3 (a) to 3 (d) are views showing a longitudinal section of the semiconductor mounting substrate of the present invention in the order of steps. As shown in FIG. 3A, an adhesive layer (5) provided only around the semiconductor mounting area is provided on the back surface side of the substrate (1) having the metal foil (2) adhered to the upper and lower surfaces of the substrate. The metal plates (4) are joined to each other. Next, as shown in FIG. 2B, the plating films (8) and (9) are integrally applied to the outer surfaces of the metal plate (4) and the substrate (1). Next, a desired conductor circuit (8) is formed on the substrate (1) as shown in FIG. Next, as shown in FIG. 3D, the substrate (1) is formed around the semiconductor mounting area of the substrate (1).
For semiconductor mounting by performing grooving with an end mill so as to reach the inside of the metal plate (4) from the surface of the substrate and removing a part of the substrate (1) and the protruding part (11) of the adhesive layer (5). At the same time as forming the concave portion (6), the metal plate (4) is cut to form a groove (7) having an outer peripheral portion which is continuous with the side surface of the semiconductor mounting concave portion over the entire bottom surface of the semiconductor mounting concave portion (6). By forming the substrate, the substrate intended by the present invention can be obtained.

After being processed in this way, a semiconductor element is mounted in the semiconductor mounting recess (6) via a silver paste or the like.

FIGS. 4A to 4E are views showing another vertical cross section of the embodiment of the semiconductor mounting substrate of the present invention in the order of steps. As shown in FIG. 3A, a recess (10) is formed using an end mill on the back surface side of the substrate (1) having the metal foil (2) attached to the upper and lower surfaces of the substrate. Next, as shown in FIG. 2B, a metal plate (4) is bonded to the bottom surface of the recess (10) via an adhesive layer (5) provided only around the semiconductor mounting region. Next, as shown in FIG. 3C, the plating films (8) and (9) are integrally applied to the outer surfaces of the metal plate (4) and the substrate (1). Next, a desired conductor circuit (8) is formed on the substrate (1) as shown in FIG. Next, as shown in (e) of the figure, a groove is formed by an end mill so as to reach the periphery of the semiconductor mounting region of the substrate (1) from the surface of the substrate (1) to the inside of the metal plate (4). A part of the substrate (1) and a protruding part (11) of the adhesive layer (5) are removed to form a semiconductor mounting recess (6), and at the same time, the metal plate (4) is cut to cut the semiconductor mounting recess. By forming the groove (7) having the outer peripheral portion continuous with the side surface of the semiconductor mounting concave portion over the entire bottom surface of (6), the substrate intended by the present invention can be obtained.

Further description will be given below based on examples.

〔Example〕

Example 1 In FIG. 1, a copper foil (2) is attached to the upper and lower surfaces of a substrate (1) made of glass-epoxy resin, and a rectangular hollowing process is performed on the back side of the substrate (1). The corval plate (4) was joined via the adhesive sheet (5) made of the epoxy resin. Next, after copper plating (8) and (9) is applied to the entire outer surfaces of the substrate (1) and the coval board (4), a photosensitive resin film is attached and exposed and developed to form a circuit pattern, Etching was performed, and the conductor surface was plated with nickel and gold to form a conductor circuit (8) and a plating film (9) on the back surface side of the substrate. After that, a rectangular groove is formed from the surface of the substrate (1) to a depth reaching the Kovar plate (4) by an end mill, and a part of the substrate (1) and a protruding portion of the adhesive layer (5) are removed to form a semiconductor. Mounting recess (6)
Simultaneously with the formation of the groove, the metal plate (4) is cut to form a groove (7) having an outer peripheral portion which is continuous with the side surface of the semiconductor mounting recess (6) over the entire bottom surface of the semiconductor mounting recess (6).
Then, a semiconductor mounting substrate according to the present invention was manufactured.

Example 2 In FIG. 2, a copper foil (2) is attached to the upper and lower surfaces of a substrate (1) made of a glass-modified triazine resin,
A cutting process was performed on the back surface side of the substrate (1) using an end mill to form a recess (10). Next, an adhesive sheet made of a glass-modified triazine resin was punched out in a rectangular shape and placed in the recess, and the phosphor bronze plate (4) was placed on the adhesive sheet.
Bonding was performed by applying pressure heating for a minute. After that, the entire outer surfaces of the substrate (1) and the phosphor bronze plate (4) are plated with copper, a photosensitive resin film is attached to the substrate surface, and the photosensitive resin film is left on a portion other than a desired circuit pattern. As described above, the conductor circuit (8) and the board are formed by exposing and developing, copper plating and solder plating only on a desired circuit pattern, etching using the solder plating as an etching resist, and nickel plating and gold plating on the conductor surface. A plating film (9) on the back side was formed. After that, from the surface of the substrate (1), an end mill is used to perform grooving processing to a depth reaching the phosphor bronze plate (4),
The semiconductor mounting recess (6) is formed by removing a part of the substrate (1) and the protruding portion of the adhesive layer (5), and at the same time, the metal plate (4) is cut to form the semiconductor mounting recess (6). A groove (7) having an outer peripheral portion continuous with the side surface of the semiconductor mounting recess (6) was formed over the entire circumference of the bottom surface to manufacture a semiconductor mounting substrate according to the present invention.

FIG. 7 is a perspective view of an embodiment of a pin grid array manufactured using the semiconductor mounting substrate of the present invention as seen from the back side of the substrate, and FIG. 8 shows the substrate shown in FIG. −
It is a longitudinal cross-sectional view cut along A. This pin grid array is wire-bonded after the semiconductor element (18) is mounted in the semiconductor mounting recess (6) of the semiconductor mounting substrate (1) of the present invention, and the periphery is further coated with an epoxy resin (20).
It is sealed with. A frame plate (13) for sealing resin is joined to the surface of the substrate (1) opposite to the metal plate (4) via an adhesive layer (14), and a conductor pin (16) for external connection is also provided.
Is fixed to a through hole (15) electrically connected to the conductor circuit in a form penetrating the frame plate (13) for sealing resin.

[Advantages of the Invention] As described above, in the semiconductor mounting substrate according to the present invention, since the protruding portion of the adhesive material to the semiconductor mounting portion, which occurs when the substrate and the metal plate are bonded, is completely removed. The recess for use can be effectively used, and the semiconductor mounting substrate can be easily miniaturized. Further, it is easy to finish the bottom surface of the semiconductor mounting recess smoothly, and the excess portion of the paste used when fixing the semiconductor element to the substrate can be poured into the groove around the recess, so that the semiconductor mounted. It is possible to improve the positional accuracy of the element and reduce the cost by obtaining the substrate with stable quality.

Further, in this semiconductor mounting substrate, since the plating film is formed on the entire surface exposed on the back surface side, this protects the metal plate and improves the moisture resistance of the semiconductor mounting substrate. There is.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a semiconductor mounting substrate according to the present invention, and FIG. 2 is a vertical sectional view of a structure of another embodiment of the semiconductor mounting substrate of the present invention. FIG. 3 is a diagram showing a vertical cross section of a semiconductor mounting substrate according to the present invention in the order of steps, and FIG. 4 is a vertical cross section of another embodiment of the semiconductor mounting substrate of the present invention in the order of steps. 5 and 6 are vertical cross-sectional views of a conventional semiconductor mounting substrate. FIG. 7 is a perspective view of a substrate showing an example of a pin grid array manufactured by using the semiconductor mounting substrate of the present invention when viewed from the back side, and FIG. 8 is a diagram showing the substrate shown in FIG. It is a longitudinal cross-sectional view cut along. Explanation of symbols 1 ... Substrate, 2 ... Copper foil, 3 ... Opening, 4 ... Metal plate, 5 ... Adhesive layer, 6 ... Recess for semiconductor mounting, 7 ...
Groove, 8 ... Conductor circuit, 9 ... Plating film, 10 ... Recess,
11 …… Adhesive material protruding part, 12 …… Concavo-convex bottom surface of semiconductor mounting recess, 13 …… Sealing resin frame plate, 14 …… Adhesive layer, 15
...... Through hole, 16 ...... Conductor pin, 17 …… Collector pin collar, 18 …… Semiconductor element, 19 …… Bonding wire,
20 ... Sealing resin.

Claims (4)

[Claims] 1. A semiconductor mounting area of a semiconductor mounting substrate made of a plastic material is formed with an opening penetrating from the front surface to the back surface of the substrate, and the opening is closed on the back surface side of the substrate. In the semiconductor mounting substrate in which the semiconductor mounting recess is formed by bonding the metal plates through the adhesive layer as described above, the side surface of the semiconductor mounting recess is continuous over the entire bottom surface of the semiconductor mounting recess. A semiconductor mounting substrate, wherein a groove having an outer peripheral portion is formed, and a plating film is integrally formed on the entire surface of a portion exposed on the back surface side of the substrate. 2. A recess is formed in a peripheral region of the opening of the semiconductor mounting substrate on the back surface side of the substrate, and a metal plate is bonded to the recess through an adhesive layer. The semiconductor mounting substrate according to claim 1. 3. A method of manufacturing a semiconductor mounting substrate comprising the steps (a) to (d) below. (A) a step of joining a metal plate to the back side of a semiconductor mounting substrate made of a plastic material via an adhesive layer provided only around the semiconductor mounting region of the substrate; (b) each of the metal plate and the substrate A step of plating an outer surface; (c) a step of forming a conductor circuit on the substrate; (d) a continuous grooving around the semiconductor mounting area of the substrate to reach the inside of the metal plate from the surface of the substrate By processing, a part of the substrate and the protruding portion of the adhesive layer are removed to form a semiconductor mounting recess, and at the same time, the metal plate is cut to cover the entire bottom surface of the semiconductor mounting recess. Forming a groove having an outer peripheral portion continuous with the side surface of the recess for use. 4. A method of manufacturing a semiconductor mounting substrate, which comprises the following steps (a) to (e). (A) A step of forming a recess on the back surface of the semiconductor mounting region of a semiconductor mounting substrate made of a plastic material; (b) Metal with an adhesive layer provided only on the periphery of the semiconductor mounting region on the bottom surface of the recess. A step of joining the plates; (c) a step of plating the outer surfaces of the metal plate and the substrate; (d) a step of forming a conductor circuit on the substrate; (e) the step around the semiconductor mounting area of the substrate By performing a continuous grooving process that reaches the inside of the metal plate from the surface of the substrate, a part of the substrate and the protruding portion of the adhesive layer are removed to form a semiconductor mounting recess, and at the same time, the metal plate is formed. A step of cutting to form a groove having an outer peripheral portion continuous with the side surface of the semiconductor mounting recess over the entire circumference of the bottom surface of the semiconductor mounting recess.