JPH0746707B2 - Semiconductor mounting substrate and manufacturing method thereof - Google Patents

Description

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

In particular, the present invention provides a semiconductor substrate excellent in heat dissipation from a mounted semiconductor element and a method for manufacturing the same, including an internal substrate for cameras, watches, chip carriers, pin grid arrays. , Advantageously used for hybrid substrates.

[Conventional technology]

The material of the conventional semiconductor mounting substrate on which a semiconductor element is directly mounted is plastics or ceramics, and plastics are most widely used because they are easy to process and relatively low in cost. In general, semiconductor mounting substrates using plastics such as glass epoxy have excellent dimensional accuracy and mechanical strength superior to ceramic substrates such as alumina, but their thermal conductivity is about 1/60 that of alumina, which is extremely small. For this reason, the conventional plastic substrate has not yet been sufficiently satisfied as a substrate on which an IC with a high degree of integration and a semiconductor element with high 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.

FIG. 7 and FIG. 8 show 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 the case where a metal plate is bonded to the periphery of the opening on the back surface side of the substrate through an adhesive layer as shown in FIG. 7, the semiconductor mounting recess is formed. It is very difficult to completely eliminate the protrusion of the adhesive used to bond the substrate and the metal plate around the bottom surface of the opening, and it is very difficult to remove the adhesive from the outside of the semiconductor mounting part as compared with the outer size of the semiconductor element to be mounted. If the size of the device must be increased in advance and the size of the device becomes large, or if the amount of protrusion of the adhesive material becomes large, it may not be possible to place the semiconductor element at a proper position. Further, in the substrate as shown in FIG. 8, after the metal plate is joined to the back surface of the substrate, the opening is cut and the protruding portion of the adhesive is removed so as to reach the metal plate from the front surface of the substrate, It is difficult to process the surface of the excavated metal plate in a completely smooth manner, and stable quality cannot be obtained, leading to cost increase.
Alternatively, there is a defect that the semiconductor element may not be mounted in a regular position or shape.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor mounting substrate which is excellent in heat dissipation and has high reliability, high reliability, high density wiring formation, and easy miniaturization of a device, and a method for manufacturing the same, in which the drawbacks of the above-mentioned conventional techniques are improved. To do.

[Means to solve the problem and its action]

Hereinafter, the present invention will be described in detail with reference to the drawings. Fig. 1 ~
FIG. 2 is a vertical sectional view of a semiconductor mounting substrate according to the present invention. In FIG. 1, an opening penetrating from the front surface to the back surface of a substrate (1) having an upper surface made of a plastic material such as glass-epoxy resin, glass-modified triazine resin, or glass-polyimide resin and having a metal foil (2) attached thereto. (3)
Is formed, and the metal plate (4) is bonded to the substrate rear surface side of the opening (3) via the adhesive layer (5) so as to close the opening, whereby the semiconductor mounting recess (6) is formed. 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).

By the way, when the substrate (1) and the metal plate (7) are joined, the adhesive may protrude. In order to prevent the adhesive from protruding, the adhesive is attached to the opening (3) side. There is a method of retreating inward from the wall. However, since the bonding area between the substrate (1) and the metal plate (4) is reduced in that method, the adhesive force is insufficient, and an adhesive material for the sealing resin used for protecting the mounted semiconductor element is used. Since it has a drawback in that it does not easily go around to the retracted portion and a void is likely to occur, it is not the best means for solving the above-mentioned problems.

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 (10), the surface from the substrate (1) forming the semiconductor mounting recess side wall to the metal plate (4) was made smooth, 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 shows a vertical cross-sectional view of the structure of a sun for another implementation of the semiconductor mounting substrate according to the present invention. Unlike FIG. 1, it has a recess (9) 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 smooth from the adhesive substrate (1) to the metal plate (4) as in the substrate according to the present invention shown in FIG. Since the surface is formed and the machining of the bottom surface of the semiconductor mounting recess can be limited to the periphery of the bottom surface, the surface of the metal plate (4) at the bottom part for directly fixing the semiconductor element is a metal flat plate made of a material. The surface shape can be exposed as it is, and a smooth surface can be easily formed. The semiconductor mounting substrate in FIG. 2 is the first
It is possible to make the entire substrate thinner than that shown in the figure.

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 they are excellent in adhesiveness, heat resistance, durability and electric insulation. As the metal plate, copper, aluminum,
It is possible to effectively use iron or alloys thereof, and further, those having relatively high thermal conductivity such as those obtained by plating the metal plate with nickel, gold or the like.

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 vertical sectional views of the semiconductor mounting substrate of the present invention showing the order of manufacturing steps. As shown in FIG. 3A, a conductor circuit (8) is formed on a substrate (1) having a metal foil adhered to its upper surface or upper and lower surfaces. Next, as shown in FIG. 2B, an opening (3) penetrating the substrate (1) is formed by cutting or punching. Next, as shown in FIG. 3C, a metal plate (4) is provided on the back surface side of the substrate of the opening so as to close the opening (3) through the substrate (1) and an adhesive layer (5). Bonding is performed to form a semiconductor mounting recess (6). Next, as shown in FIG. 4D, the side wall of the opening (3), the adhesive layer (5) and the surface of the metal plate (4) are simultaneously cut, and the protruding portion of the adhesive layer (5) is cut. In addition, the present invention has an object to form a groove (7) having an outer peripheral portion continuous with the side surface of the semiconductor mounting recess (6) over the entire circumference of the bottom surface of the semiconductor mounting recess (6) by cutting. The substrate can be obtained.

After being processed in this manner, the semiconductor element is mounted in the semiconductor mounting substrate recess (6) via silver paste or the like. According to the above-described manufacturing method, even if the amount of the adhesive layer (5) for joining the substrate (1) and the metal plate (4) flowing out is relatively large, the adhesive layer (5) can be removed by cutting after joining, so the conditions in the joining step There is an advantage that there are few restrictions such as.

FIGS. 4A to 4C are views showing another method of manufacturing the semiconductor mounting substrate of the present invention in the order of steps. As shown in FIG. 4A, a conductor circuit (8) is formed on a substrate (1) having a metal foil (2) attached to the upper surface or the upper and lower surfaces of the substrate. Next, as shown in FIG. 2B, a metal plate (4) is provided on the back surface of the substrate (1) and an adhesive layer (5) is formed only on the peripheral region of the semiconductor mounting portion.
Are joined through. Next, as shown in FIG. 3C, a portion corresponding to the periphery of the semiconductor mounting portion on the surface of the substrate (1) is subjected to grooving by an end mill so as to reach the inside of the metal plate (4). At the same time as forming the mounting recess (6), a continuous groove (7) is formed around the bottom surface of the semiconductor mounting recess (6). That is, a part of the substrate (1) and the protruding portion of the adhesive layer (5) are removed by performing continuous grooving processing that reaches the inside of the metal plate (4) around the semiconductor mounting area of the substrate (1). Forming a semiconductor mounting recess (6) and simultaneously forming a groove (7) having an outer peripheral portion continuous with the side surface of the semiconductor mounting recess (6) over the entire bottom surface of the semiconductor mounting recess (6). Thus, the substrate intended by the present invention can be obtained.

After being processed in this way, the semiconductor element is mounted in the semiconductor mounting recess (6) via silver paste or the like. According to the above-described manufacturing method, the semiconductor mounting recess (6) and the groove (7) around the entire bottom surface of the semiconductor mounting recess (6) can be formed in the substrate at the same time, which shortens the process. To have.

5 (a) to 5 (e) are views showing the manufacturing steps of another embodiment of the semiconductor mounting substrate of the present invention in the order of steps. As shown in FIG. 5 (a), a conductor circuit (8) is attached to a substrate (1) having a metal foil (2) adhered to the upper surface or the upper and lower surfaces of the substrate.
To form. Next, as shown in FIG. 2B, the opening (3) penetrating the substrate (1) is formed by punching or cutting. Next, as shown in FIG. 3C, a recess (9) is formed by cutting in the peripheral region of the opening (3) on the back surface side of the substrate. Next, as shown in FIG. 3D, a metal plate (4) is bonded to the recess (9) via an adhesive layer (5) so as to close the opening (3), and a semiconductor mounting recess is formed. (6) is formed. Next, as shown in FIG. 7E, the side wall of the opening (3), the adhesive layer (5) and the surface of the metal plate (4) are simultaneously cut, and the protruding portion of the adhesive layer (5) is cut. At the same time, by forming a groove (7) having an outer peripheral portion continuous with the side surface of the semiconductor mounting recess (6) over the entire circumference of the bottom surface of the semiconductor mounting recess (6), the substrate intended by the present invention can be obtained. it can.

FIGS. 6A to 6D are views showing another manufacturing process of the embodiment of the semiconductor mounting substrate of the present invention in process order. FIG. 6 is a vertical cross-sectional view showing a state where a conductor circuit (8) is formed on a substrate (1) in which a metal foil (2) is attached to the upper and lower surfaces of the substrate as shown in FIG. 6 (a). . Next, a recess (9) is formed on the back surface of the substrate (1) using an end mill as shown in FIG.

Next, as shown in FIG. 3C, the metal plate (4) is bonded to the bottom surface of the recess (9) only in the peripheral region of the semiconductor mounting portion via the adhesive layer (5). Next, as shown in FIG. 3D, a portion corresponding to the periphery of the semiconductor mounting portion on the surface of the substrate (1) is subjected to grooving by an end mill so as to reach the inside of the metal plate (4). By forming the mounting recess (6) and at the same time forming the continuous groove (7) around the bottom surface of the semiconductor mounting recess, the substrate intended by the present invention can be obtained.

Further description will be given below based on examples.

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 copper plating is applied to the surface of the substrate (1). After that, a photosensitive resin film was adhered, exposed and developed to form a circuit pattern, etching was performed, and the conductor surface was nickel-plated and gold-plated to form a conductor circuit (8). Next, an opening (3) was formed in the substrate (1) by punching. After that, an aluminum plate was bonded to the back surface side of the substrate (1) via an adhesive layer (5) made of an epoxy resin. After that, the substrate (1) constituting the inner surface of the opening (3), the adhesive layer (5), and the surface of the metal plate (4) are simultaneously cut using an end mill to mount the semiconductor according to the present invention. I made a substrate.

Example 2 In FIG. 2, copper foil (2) is attached to the upper and lower surfaces of a substrate made of glass-modified triazine resin, and the entire surface of the substrate (1) is plated with copper and then the substrate surface is coated. A photosensitive resin film is attached, exposed and developed so that the photosensitive resin film is left in a portion other than the desired circuit pattern, and copper plating or solder plating is applied only on the desired circuit pattern, and the solder plating is used as an etching resist. The conductor circuit (8) was formed by etching and then nickel-plating and gold-plating the conductor surface. Next, an opening (3) was formed in the substrate (1) by punching. After that, a cutting process was performed on the substrate back surface side of the opening (3) using an end mill to form a recess (9). After that, a phosphor bronze plate (4) previously plated with nickel and gold was bonded to the recess (9) through an adhesive layer (5) made of a modified triazine resin. Further, the substrate (1) and the adhesive layer (5) which constitute the inner surface of the opening (3),
A semiconductor mounting substrate according to the present invention was manufactured by simultaneously cutting and the surface of the metal plate (4) with an end mill.

Example 3 In FIG. 2, a copper foil (2) is attached to the upper and lower surfaces of a substrate (1) made of glass-polyimide resin, and the whole surface of the substrate (1) is plated with copper and then the substrate is formed. A photosensitive resin film was attached to the surface, exposed and developed to form a circuit pattern, which was then etched to form a conductor circuit (8) by solder plating on the conductor surface. Next, a cutting process was performed on the back surface side of the substrate (1) using an end mill to form a recess (9). After that, the Kovar plate (4) was joined to the inside of the recess (9) through an adhesive sheet (5) made of a polyimide resin which was hollowed into a rectangular shape. After that, a rectangular groove is formed from the surface of the substrate (1) by an end mill to a depth reaching the Kovar plate (4), and a part of the substrate (1) and a protruding part of the adhesive layer are removed to form a semiconductor mounting recess. The semiconductor mounting substrate according to the present invention was manufactured by simultaneously forming (6) and the groove (7) over the entire bottom surface of the recess (6).

FIG. 9 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. 10 is a perspective view of 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 (16) is mounted in the semiconductor mounting recess (6) of the semiconductor mounting substrate (1) of the present invention, and then the periphery is covered with epoxy resin (1).
It is sealed with 8). Moreover, the metal plate (4) of the substrate (1)
The frame plate (12) for the sealing resin is on the side opposite to the adhesive layer (13).
And the conductor pin (15) for external connection is fixed to the through hole (14) electrically connected to the conductor circuit while penetrating through the sealing resin frame plate (12). There is.

〔The invention's effect〕

As described above, in the semiconductor mounting substrate according to the present invention, the substrate and the metal are formed by forming the groove having the outer peripheral portion continuous with the side surface of the semiconductor mounting recess over the entire bottom surface of the semiconductor mounting recess. Since the protruding portion of the adhesive material to the semiconductor mounting portion generated when joining the plates is completely removed, it can be effectively used as having the semiconductor mounting recess, and the semiconductor mounting substrate can be easily miniaturized.

Further, since it is possible to limit the cutting work of the bottom surface of the semiconductor mounting recess to only the periphery of the bottom surface, the surface of the metal plate at the bottom portion for directly fixing the semiconductor element exposes the surface shape of the metal flat plate as a material. Since it is possible to use it, that is, it is easy to finish the bottom surface of the semiconductor mounting recess smoothly, the positional accuracy of the mounted semiconductor element is improved,
And it is possible to reduce the cost by obtaining the substrate with stable quality.

[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. 3 and 4 are views showing a longitudinal section of a semiconductor mounting substrate according to the present invention in the order of steps, and FIGS. 5 and 6 show longitudinal sections of another embodiment of the semiconductor mounting substrate of the present invention. It is the figure which showed each different process order. FIG. 7 and FIG. 8 are vertical sectional views of a conventional semiconductor mounting substrate, respectively. FIG. 9 is a perspective view of a substrate showing an example of a pin grid array manufactured using the semiconductor mounting substrate of the present invention when viewed from the back side, and FIG. 10 is a plan view of the substrate shown in FIG. It is a longitudinal cross-sectional view cut along a line. DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Copper foil, 3 ... Opening, 4 ... Metal plate, 5 ... Adhesive layer, 6 ... Semiconductor mounting recess, 7 ... Groove, 8 ... Conductor circuit, 9 ... Recess, 10 … Protruding part of adhesive, 11… Concavo-convex on bottom surface of semiconductor mounting recess, 12… Frame plate for sealing resin, 13… Adhesive layer, 14… Through hole, 15… Conductor pin, 16… Flange of conductor pin, 17… Semiconductor element, 18 ... Bonding wire, 19 ...
Sealing resin.

Claims (6)

[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. 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 forming a conductor circuit on a semiconductor mounting substrate made of a plastic material; (b) a step of forming an opening penetrating from a front surface to a back surface of the substrate in a semiconductor mounting area of the substrate; A step of forming a semiconductor mounting recess by bonding a metal plate to the substrate rear surface side of the opening via an adhesive layer so as to close the opening; (d) a sidewall of the opening, an adhesive layer, and a metal. A step of simultaneously cutting the surface of the plate to cut the protruding portion of the adhesive layer and forming a groove having an outer peripheral portion continuous with the side surface of the semiconductor mounting recess over the entire bottom surface of the semiconductor mounting recess. 4. A method for manufacturing a semiconductor mounting substrate comprising the steps (a) to (c) below. (A) A step of forming a conductor circuit on a semiconductor mounting substrate made of a plastic material; (b) A metal plate is bonded to the back side of the substrate through an adhesive layer provided only around the semiconductor mounting region of the substrate. Step; (c) For semiconductor mounting by performing a continuous grooving process that reaches the inside of the metal plate around the semiconductor mounting region of the substrate to remove a part of the substrate and a protruding part of the adhesive layer. A step of forming a groove having an outer peripheral portion which is continuous with the side surface of the semiconductor mounting recess over the entire bottom surface of the semiconductor mounting recess at the same time of forming the recess. 5. A method for manufacturing a semiconductor mounting substrate, which comprises the following steps (a) to (e): (A) a step of forming a conductor circuit on a semiconductor mounting substrate made of a plastic material; (b) a step of forming an opening penetrating from a front surface to a back surface of the substrate in a semiconductor mounting area of the substrate; A step of forming a recess in the peripheral region of the opening on the back surface side of the substrate; (d) forming a semiconductor mounting recess by bonding a metal plate to the recess via an adhesive layer so as to close the opening. (E) The side wall of the opening, the adhesive layer, and the surface of the metal plate are simultaneously cut to cut the protruding portion of the adhesive layer, and at the same time, the semiconductor mounting recess is entirely covered with the semiconductor mounting recess. A step of forming a groove having an outer peripheral portion continuous with the side surface of the recess. 6. A method for manufacturing a semiconductor mounting substrate comprising the steps (a) to (d) below. (A) A step of forming a conductor circuit on a semiconductor mounting substrate made of a plastic material; (b) A step of forming a recess on the back surface of the semiconductor mounting region of the substrate; (c) A semiconductor mounting on the bottom surface of the recess. A step of joining a metal plate through an adhesive layer provided only on the periphery of the region; (d) by subjecting the periphery of the semiconductor mounting region on the substrate surface to continuous grooving reaching the inside of the metal plate, A part of the substrate and a protruding portion of the adhesive layer are removed to form a semiconductor mounting recess, and at the same time, a groove having an outer peripheral portion continuous with the side surface of the semiconductor mounting recess over the entire bottom surface of the semiconductor mounting recess. Forming process.