JPH0982846A - Resin-sealed semiconductor device, manufacture thereof and lead frame to be used for that - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply a highly reliable semiconductor device to a general market and to enhance the reliability of an equipment using this device by a method wherein in a resin-sealed semiconductor device of a structure (an LOC structure), wherein the inner leads of a lead frame are placed on a semiconductor chip, a void is prevented from being generated in an adhesive material, which bonds the inner leads to the chip, at the time of the adhesion of the inner leads to the chip. SOLUTION: A resin-sealed semiconductor device consists of a semiconductor substrate 1 with a plurality of connection electrodes formed on the main surface, inner leads 7 and outer leads 6 which are continuously connected with these inner leads. A plurality of leads with these inner leads secured on the main surface of substrate 1, bonding wires 4 for connecting electrically the inner leads with the electrodes 10 and the inner leads provided with a resin-sealing material 2 for resin-sealing the substrate 1, the inner leads and the wires 4 are secured on the main surface of the substrate 1 with at least one spherical connecting material 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-encapsulated semiconductor device having a LOC (Lead On Chip) structure capable of stable resin encapsulation.

[0002]

2. Description of the Related Art Conventionally, I having multiple pins or multiple terminals
In a semiconductor device such as C or LSI, a wire bonding method and a wireless bonding method are known as means for electrically connecting a semiconductor element (semiconductor chip) and an external lead. The wire bonding method is a method of connecting a connection electrode such as a bonding pad formed on a semiconductor chip and an external lead with a fine metal wire such as aluminum or gold. As a joining means, there are a thermocompression bonding method, an ultrasonic bonding method, and a method of using both of them. On the other hand, the wireless bonding method is a method in which all connection electrodes on a semiconductor chip are connected to external terminals at once by specific bumps or metal leads, and tape carrier method, flip semiconductor chip method, beam lead method, etc. are known. ing. FIG. 19 shows a semiconductor device formed by conventional wire bonding, which is protected by a resin sealing body. The resin-encapsulated semiconductor device by the wire bonding method is configured such that a semiconductor chip is mounted on a lead frame, both are electrically connected by a bonding wire, and these are resin-encapsulated.

A lead frame 3 made of a metal such as Fe-42Ni alloy or Cu integrally has a die pad 5, an inner lead 7 and an outer lead 6. A semiconductor chip 1 such as a silicon semiconductor is bonded onto the die pad 5 with a conductive adhesive 8 or the like. The tips of the inner leads 7 face the semiconductor chip 1, and the semiconductor chips 1 and the inner leads 7 are connected by the bonding wires 4.
The bonding wire 4 is connected to a connection electrode (not shown) such as a pad electrode formed on the main surface of the semiconductor chip 1. The semiconductor chip 1, the bonding wires 4, the die pad 5, and the inner leads 7 are sealed with a resin sealing body 2 such as an epoxy resin. As shown in FIG. 19, the connection electrodes of the semiconductor chip inside the resin-sealed body and the inner lead tips forming the lead frame are separated by a predetermined distance. Therefore, the resin sealing body has a wasteful space corresponding to the distance, and this wasteful space hinders the miniaturization of the semiconductor device. Therefore, a method has been adopted in which the tips of the inner leads are placed on the main surface of the semiconductor chip on which the connection electrodes are formed to eliminate the wasted space and the size of the semiconductor chip can be increased accordingly. This is a LOC structure semiconductor device.

A resin-encapsulated semiconductor device having a LOC structure using a conventional technique will be described with reference to FIGS. FIG. 20 is a transparent plan view of the resin-sealed semiconductor device, and FIG.
FIG. 21 is a sectional view of a portion taken along the line AA ′ in FIG. 20. The lead frame 3 including the outer leads 6 and the inner leads 7 is connected to the semiconductor chip 1 by an adhesive layer 9. The adhesive layer 9 fixes the tip of the inner lead 7 to the main surface of the semiconductor chip 1. Adhesive layer 9
For example, an electrically insulating polymer material such as a polyimide tape is used. Pad electrodes 10 are formed on the surface of the semiconductor chip 1 for electrically connecting an integrated circuit formed inside the semiconductor chip 1 and an external circuit. The inner lead 7 of the lead frame 3 and the pad electrode 10 of the semiconductor chip 1 are electrically connected by the bonding wire 4 in a desired shape depending on the application. After that, the semiconductor chip 1, the inner leads 7,
The bonding wire 4, the adhesive layer 9 and the like are sealed and protected by the resin sealing body 2. According to FIG. 21, the inner leads 7 of a large number of lead frames 3 are arranged on the semiconductor chip 1, and the adhesive layers 9 for joining the inner leads 7 to the semiconductor chip 1 are arranged in parallel. The inner leads 7 of are joined together.

[0005]

In the resin-encapsulated semiconductor device according to the prior art described above, when the inner lead 7 of the lead frame is bonded to the semiconductor chip 1 using the adhesive layer 9, the semiconductor chip 1 is heated. The inner leads 7 which were placed on the metal block thus prepared and which already had the adhesive layer 9 attached thereto were superposed with a very fine gap of several microns, and then heated from the upper surface of the inner leads 7. A general method is to press and press with a metal block. In this case, the adhesive layer 9 existing under the inner leads 7 is crushed by being applied with pressure from the semiconductor chip 1 side and the inner lead 7 side, but the adhesive layer 9 existing between the adjacent inner leads 7 is crushed. Is heated and not pressurized. Therefore, the adhesive layer 9 thermally expands and the adhesive layer 9 existing under the inner leads 7 is crushed, so that a space is formed between the surface of the semiconductor chip 1 and the adhesive layer 9. The semiconductor chip 1, the inner leads 7, the adhesive layer 9, the bonding wires 4, etc. are sealed and protected by the resin encapsulation body 2, but are formed between the surface of the semiconductor chip 1 and the adhesive layer 9. The void remains in the resin seal.

Most resin-sealed semiconductor devices are of the surface mounting type at the present time, and are heated in the mounting process. It has also been clarified that the resin encapsulant adsorbs moisture from the atmosphere and contains moisture even inside, and the moisture is concentrated at the interface between different materials. By heating in the mounting process,
Moisture contained in the semiconductor device, particularly moisture concentrated at the interface, evaporates and expands to expand, and the resin sealing body 2
Cracks in the semiconductor chip 1 and the resin encapsulant 2
It has been confirmed that peeling may occur at the interface between and to cause a problem such as deterioration of heat dissipation characteristics of the semiconductor device. As described above, when a void is generated between the adhesive layer 9 existing between the adjacent inner leads 7 and the surface of the semiconductor chip 1, the void serves as an accumulating portion of moisture that has been absorbed, and the accumulated moisture is also heated by mounting. Affirmation evaporates and vaporizes,
It may cause a malfunction. In addition, even if the mounting process does not happen to cause a problem, the semiconductor device may absorb moisture depending on the usage environment of the device using the semiconductor device, causing a problem such as electrical leakage of the adjacent inner leads 7. is there.

The width of the inner lead 7 depends on the thickness of the thin metal plate from which the lead frame is manufactured. That is, the width of the inner lead 7 is determined by the thickness of the inner lead 7. At present, a plate thickness of 0.125 mm is generally the thinnest metal thin plate used in a resin-sealed semiconductor device. Therefore, the inner lead 7 has a width of 0.125 mm and a terminal interval of 0.125 mm. And it is very finely processed. According to the current technology, the adhesive layer 9 is a single polymer material, which is an extremely soft material as compared with the metal thin plate forming the inner leads 7, and it is difficult to process it into a small piece. . The present invention has been made in view of the above circumstances. In a resin-sealed semiconductor device having a structure (LOC structure) in which an inner lead of a lead frame is mounted on a semiconductor chip, the inner lead and the semiconductor are A resin-encapsulated resin that enhances the reliability of equipment that uses the semiconductor device by providing a highly reliable semiconductor device to the general market by making the structure that adheres to the chip a structure that does not create voids during bonding Provide a semiconductor device.

[0008]

The present invention is characterized in that at least one spherical adhesive body made of a single material is preliminarily bonded to each of the inner leads constituting the lead frame. There is. The invention of claim 1 comprises a semiconductor substrate having a plurality of connection electrodes formed on its main surface, an inner lead and an outer lead continuously connected to the inner lead, and the inner lead is fixed to the main surface. A plurality of leads, a bonding wire that electrically connects the inner lead and the connection electrode,
A resin encapsulation type, comprising: a semiconductor substrate, the inner lead, and a resin encapsulant for encapsulating the bonding wire with resin, wherein the inner lead is fixed to the main surface by at least one spherical connector. Characterized by a semiconductor device. According to a second aspect of the present invention, in the resin-encapsulated semiconductor device according to the first aspect, the spherical connector is made of any one of silicon-modified polyimide, silicone adhesive, and acrylic adhesive. To do. Claim 3
According to another aspect of the present invention, in the resin-sealed semiconductor device according to claim 1, the spherical connecting body is an outer member made of a first synthetic resin having high adhesiveness, and the connecting body is connected from the first synthetic resin. And an inner member made of a second synthetic resin having a high hardness at the time temperature.
According to a fourth aspect of the present invention, in the resin-encapsulated semiconductor device according to the third aspect, the first synthetic resin is made of silicon-modified polyimide, and the second synthetic resin is made of polyimide. To do.

According to a fifth aspect of the present invention, a lead portion having a plurality of leads including an inner lead and an outer lead continuously connected to the inner lead, a frame portion supporting the plurality of leads, and the inner lead At least one spherical adhesive body bonded to each of them, and the spherical adhesive body is characterized by a lead frame for bonding the inner lead to a semiconductor substrate. According to a sixth aspect of the present invention, in the lead frame according to the fifth aspect, the spherical connector is made of any one of silicon modified polyimide, silicone adhesive, and acrylic adhesive. The invention of claim 7 is the invention of claim 5.
In the lead frame described in (1) above, the spherical connecting body includes an outer member made of a first synthetic resin having high adhesiveness, and a second member having a hardness higher than that of the first synthetic resin at a temperature at the time of connecting the connecting body. And an inner member made of synthetic resin. According to an eighth aspect of the present invention, in the lead frame according to the fifth aspect, the first synthetic resin is made of silicon-modified polyimide and the second synthetic resin is used.
The synthetic resin of is made of polyimide.
According to a ninth aspect of the present invention, in the lead frame according to the seventh aspect, a recess is formed in a region of the inner lead to which the spherical connection body is joined. According to a tenth aspect of the present invention, in the lead frame according to any one of the fifth to eighth aspects, a region of the inner lead to which the spherical connection body is joined is roughened. .

According to a tenth aspect of the present invention, there is provided a step of bonding at least one spherical adhesive to an inner lead forming a lead frame, and a semiconductor substrate having a plurality of connection electrodes exposed on the main surface of the lead frame. The step of placing,
A step of bringing the spherical connecting body joined to the inner lead into contact with the main surface of the semiconductor substrate, applying pressure and heating to connect the inner lead and the main surface of the semiconductor substrate, and the inner lead A resin-sealed semiconductor device including a step of electrically connecting the connection electrode with a bonding wire, and a step of resin-sealing the semiconductor substrate, the spherical connection body, the inner lead and the bonding wire. Is characterized by its manufacturing method.

According to the present invention, in a resin-sealed semiconductor device having a structure (LOC structure) in which inner leads of a lead frame are mounted on a semiconductor chip, each inner lead is used as a semiconductor chip. By allowing at least one spherical adhesive body to be fixed to be individually present in an independent shape, it is possible to supply a highly reliable semiconductor device to the general market and enhance the reliability of equipment using the semiconductor device. Furthermore, since the resin is sufficiently filled between the adhesive bodies, the airtightness of the resin sealing body can be increased. Further, the spherical adhesive bonded to the respective inner lead tips of the lead frame can bond the inner leads and the semiconductor chip together so that no void is generated during bonding. The spherical adhesive body at the tip of the inner lead may have a spherical bonding surface with the semiconductor chip, and the bonding surface with the inner lead may be flat. Therefore, a hemispherical adhesive may be used.
The joining method in which the adhesive body is spherical is a very effective technique in which the adhesive body can be selectively arranged only in a necessary portion.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a transparent plan view of a resin-encapsulated semiconductor device having a LOC structure, and FIG.
FIG. 3 is a sectional view of a portion taken along the line A ′, and FIG. 3 is a sectional view of a portion taken along the line BB ′ in FIG. 1. In the semiconductor chip 1, the lead frame 3 including the outer leads 6 and the inner leads 7 is connected to the semiconductor chip by, for example, a spherical adhesive body 20 such as silicon modified polyimide. This adhesive body 20 fixes each tip of each inner lead 7 to the main surface of the semiconductor chip 1. For the adhesive body 20, a polymer material having electrical insulation such as silicon-modified polyimide is used. The adhesive body 20 has a spherical shape, but since it is heated and pressure-bonded when the semiconductor chip 1 and the inner lead 7 are connected, it is a flat film after the adhesion. In the present invention, in addition to the modified polyimide, a silicone adhesive or an acrylic adhesive can be used. On the main surface of the semiconductor chip 1, a plurality of connection electrodes (pad electrodes) 10 for electrically connecting the integrated circuit formed inside the semiconductor chip 1 and an external circuit are formed. The inner lead 7 of the lead frame 3 and the pad electrode 10 of the semiconductor chip 1 are electrically connected by a bonding wire 4 in a desired shape depending on the application.

After that, the semiconductor chip 1, the inner leads 7, the bonding wires 4, the adhesive 20 and the like are sealed and protected by the resin sealing body 2. Semiconductor chip 1
A large number of inner leads 7 are arranged on the upper side, and a large number of adhesive bodies 20 that bond the inner leads 7 to the semiconductor chip 1 individually bond the large numbers of parallel inner leads 7. When the lead frame 3 is bonded to the semiconductor chip 1 with the adhesive 20, the semiconductor chip 1
Was placed on a heated metal block, and then the lead frames 3 to which the adhesive 20 had already been attached were superposed with a very fine gap of several microns, and then heated from above the lead frame 3. A method of pressurizing and pressure bonding with a metal block is generally used. In the resin-sealed semiconductor device having the LOC structure, the lead frame and the semiconductor chip are exposed pad electrodes 1 arranged on the semiconductor chip for connecting to an external circuit.
The lead frame 3 and the pad electrode 10 are connected by a bonding wire 4 so that they are placed apart from each other by a predetermined distance. Since the adhesive body thus closely connects the semiconductor chip and the inner lead, a highly reliable resin-sealed semiconductor device is obtained, and further, since the adhesive body is not arranged between the inner leads, The fluid resin penetrates between them without a gap to form a highly hermetic resin encapsulant.

Next, a method of manufacturing the above-mentioned resin-sealed semiconductor device will be described with reference to FIGS. FIG.
7 is a flow chart showing the manufacturing process, FIG. 5 is a plan view of a lead frame used in this resin-sealed semiconductor device, FIG. 6 is a cross-sectional view of an inner lead bonding device, and FIG.
FIG. 8 is a cross-sectional view of a manufacturing process for joining inner leads to a semiconductor chip, FIG. 8 is a cross-sectional view of a semiconductor substrate for explaining a wire bonding process, and FIG. 9 is a cross-sectional view of a resin mold forming a resin sealing body. . As shown in FIG. 4, a wafer such as a silicon semiconductor is prepared, and a probing operation and a dicing operation are sequentially performed on the wafer to manufacture semiconductor chips (wafer forming step). In addition, metal materials such as Cu, Cu alloy, Fe-42Ni, etc. are prepared in parallel with these, and a photo-patterning operation, an etching operation, a plating operation, and an adhesive body bonding operation are sequentially performed on this material to form a spherical material. A lead frame having an adhesive body is manufactured (lead frame manufacturing process). Next, a lead frame is placed on the semiconductor chip and held so that the inner leads are arranged at predetermined positions on the semiconductor chip (lead frame mounting step). Next, the inner leads are joined to the semiconductor chip (inner lead joining step). Next, the inner lead and the pad electrode of the semiconductor chip are electrically connected with a bonding wire (wire bonding step).

After that, the semiconductor chip, the inner leads,
A bonding wire, an adhesive body, and the like are resin-sealed with a synthetic resin such as an epoxy resin using a transfer molding method or the like (resin sealing step). Thereafter, an exterior treatment process and an outer lead foam process are sequentially performed, and thus the resin-sealed semiconductor device shown in FIG. 1 is manufactured. After that, a product inspection is performed on the resin-sealed semiconductor device. Next, the lead frame mounting step to the resin sealing step will be described in detail with reference to FIGS. The lead frame 3 used in this resin-sealed semiconductor device is
For example, as shown in FIG. 5, Fe-42% Ni alloy or Cu
It is composed of a strip-shaped metal plate. The lead frame 3 includes an inner lead 7 and an outer lead 6.
And a lead portion 32 having a plurality of leads, a frame portion 31 for supporting the plurality of leads, and a feed hole 33 for moving the lead frame. The inner leads 7 are arranged such that the inner lead rows face each other, and the facing portions are placed on the main surface of the semiconductor chip.

In order to bond the inner lead to the semiconductor chip, a heating bonder for holding and heating the lead frame and the semiconductor chip is used (FIG. 6). The semiconductor chip 1 is mounted on a metal die 11 which is a heating bonder, and is held and fixed by a vacuum chuck provided on the metal die 11. The main surface of the semiconductor chip 1 made of a silicon semiconductor or the like is protected by a passivation film (not shown) made of an insulating film such as SiO ₂ . The passivation film is formed on the semiconductor substrate 1 and is an integrated circuit (not shown) formed inside the semiconductor substrate.
A metal wiring such as Al (not shown) electrically connected to the wiring is covered and protected. A pad electrode 10 is formed on the tip portion of the metal wiring, and this portion is exposed from the passivation film. On the other hand, the inner lead 7
It is held and fixed to the metal block 12 which is a heating bonder. The metal die 11 and the metal block 12 move up and down, and first, the metal die 11 is moved up so that the adhesive body 20 and the semiconductor attached to the tip of the inner lead 7 held by the metal block 12 and the semiconductor. The distance from the main surface of the chip 1 is close to about 2 to 3 μm. In this state,
The metal die 11 and the metal block 12 are heated to the bonding temperature. Then, the metal block 12 is moved downward, the adhesive body 20 is heated for about 1 to 3 seconds and pressure-bonded to the inner lead 7
Are fixed to the semiconductor chip 1 (inner lead bonding step).

In this embodiment, since silicon-denatured polyimide is used as the material of the adhesive 20, the adhesive temperature is set to 425 ° C. This material has a bonding temperature of 2
100-500 ° C is suitable. If the material of the adhesive is a silicone-based adhesive, a suitable adhesion temperature is about 300 ° C, and if it is an acrylic-based adhesive, about 250 ° C is preferable. In order to heat the adhesive body first, it is necessary to heat it from both sides thereof, and therefore it is preferable to heat it uniformly from both sides of the metal die 11 and the metal block 12. Referring to FIG.
The state of the bonded body during this bonding will be described. The surface of the adhesive body 20 held by the inner lead 7 has a spherical shape before coming into contact with the semiconductor chip 1 (FIG. 7A). Then, the adhesive body 20 lands on the semiconductor chip 1 and the surface becomes flat (FIG. 7B). Since the initial surface state of the adhesive body 20 is spherical, the air between the adhesive body 20 and the semiconductor chip 1 is constantly pushed out to the outside between the time when the semiconductor chip 1 is contacted and the time when the semiconductor chip 1 becomes flat. There is no stopping. Therefore, the adhesive body 20 after both have been completely bonded becomes an airtight and flat adhesive layer without bubbles (FIG. 7C).

Next, the tip portion of the inner lead 7 fixed to the semiconductor chip 1 and the pad electrode 10 formed on the main surface of the semiconductor chip 1 are electrically connected by a bonding wire 4 made of a fine metal wire such as Au. Connecting. Bonding is performed from the pad electrode 10 to the tips of the inner leads 7 while moving the wire bonder 13 (FIG. 8). After wire bonding is completed, the semiconductor chip is sealed with resin (FIG. 9). The resin encapsulant 2 includes an upper mold 15 inside a resin mold 14.
In the cavity formed by the lower die 16 and the lower die 16, for example, a transfer molding method is used. The resin injection conditions in this case are such that the injected resin is an epoxy resin, which is fluidized to have a viscosity of 15 ± 5 Pa · s. The injection time is approximately 10 ± 1 seconds. The resin tablet supplied to the pot 25 attached to the mold is fluidized and is supplied to the gate 17 at the cavity inlet through the cull, the cull and the runner by the descent of the plunger.
It is supplied from the gate 17 into the cavity. The flow of the flowing resin enters the cavity from the gate 17 and fills the cavity to form the resin sealing body 2. The resin-sealed semiconductor device completes a product through a post process.

Next, a method of manufacturing a spherical adhesive body and a method of joining the spherical adhesive body to a lead frame will be described with reference to FIGS. FIG. 10 is a manufacturing process perspective view showing a process of joining a spherical adhesive body to the inner lead of the lead frame. For example, NMP
A silicon-modified polyimide solution containing a solvent such as (normal methyl pyrrolylone) is stored in a tank (not shown). Silicon modified polyimide solution in the tank
It is adapted to be dripped from the nozzle 18 through a pipe. This silicon-modified polyimide solution is dropped onto the inner lead 7 from the nozzle 18 (FIG. 10A). One drop 19 ejected from the nozzle 18 is dropped on the inner lead 7 and is cured into a spherical shape by surface tension to form a spherical adhesive body 20 bonded to the inner lead 7 (FIG. 10).
(B)). In order to firmly bond the spherical adhesive body 20, the connection portion of the spherical adhesive body of the inner lead 7 can be treated. FIG. 11 is a perspective view and a sectional view of an inner lead that has been subjected to such a treatment. In the inner lead 7 shown in FIG. 11A, a recess 21 is formed in a portion to which the spherical adhesive body is joined, so that the spherical adhesive body is firmly joined. The inner lead 7 shown in FIG. 11 (b) has a roughened surface at the portion to which the spherical adhesive is joined.

This roughened region 22 also firmly joins the spherical adhesive. The inner lead 7 shown in FIG.
A hemispherical recess 23 is formed in a portion where the spherical adhesive body is joined. Since the spherical adhesive body 20 is in close contact with the recess 23, a stronger joint can be achieved. The size of the spherical adhesive body is determined by the width of the inner lead. It is preferable that the diameter of the inner lead having a width of 0.125 mm is slightly smaller than that of 0.1 mm, for example. It is preferable to use a spherical adhesive having a diameter of 0.1 to 0.15 mm for the inner lead having a width of 0.125 to 0.15 mm. FIG. 12 is a cross-sectional view and a perspective view illustrating a method of forming a spherical adhesive body and then mounting the spherical adhesive body on the inner lead. Container 2
4 is filled with a curing accelerator or a curing acceleration solution 25, and the silicon-modified polyimide solution 19 discharged from the nozzle 18 is dropped therein, the silicon-modified polyimide solution 19 is solidified into a spherical shape due to the surface tension, and the adhesive body 20 is formed. (FIG. 12A). Next, when a large amount of the formed spherical adhesive body 20 is sprinkled on the lead frame, the spherical adhesive body 20 enters the recess 21 of the inner lead 7. This spherical adhesive body 20 is partially heated and fused,
It is fixed to the depression 21 (FIG. 12B). This depression is
The hemispherical depression 23 shown in FIG. 11 (c) has high adhesion. Furthermore, if the radius of the depression 23 and the radius of the spherical adhesive body 20 are equal, the adhesion is further improved.

FIG. 13 shows a method in which a spherical adhesive is directly formed on the inner leads as in the method shown in FIG. The figure is a perspective view for explaining the method. An adhesive layer 9 of, for example, silicon-modified polyimide is attached over the aligned inner leads 7 (FIG. 13A). Next, the lead frame and the adhesive layer 9 are 700 to 800 ° C.
Heat to a degree. The adhesive layer 9 is melted and bonded onto each inner lead 7 as an individual spherical adhesive body 20 (FIG. 13B). The surface of the inner lead may be subjected to a water repellent treatment to form a well-shaped spherical adhesive body.

Next, a second embodiment will be described with reference to FIGS. 14 to 16. When the inner lead and the semiconductor chip are bonded using a spherical adhesive, for example, a silicon-modified polyimide adhesive reaches 425 ° C. At such a high temperature, the adhesive body may be excessively deformed, and the semiconductor chip and the inner lead may be too close to each other, causing a problem. This embodiment is characterized in that a material which does not decrease in hardness even at the joining temperature is interposed in the spherical adhesive to prevent the above-mentioned close proximity. That is, the spherical adhesive body 20 has a two-layer structure in which a silicone-modified polyimide is used for the adhesive outer member 201 and the polyimide tape material used for the conventional adhesive layer is included in the inner member 202 having a high hardness at the joining temperature. (Fig. 14
(A)). FIG. 14B is a characteristic diagram showing the temperature dependence of the hardness of the polymer material used as the adhesive material. The vertical axis represents the hardness (no unit) of the polymer material, and the horizontal axis represents the bonding temperature when used as an adhesive. A curve A is a hardness-bonding temperature curve of polyimide, and a curve B is a hardness-bonding temperature curve of silicon-modified polyimide. When the bonding temperature is 200 ° C., the outer member 201 and the inner member 2
The hardness of 02 is not so different. However, 425 ° C
, The outer member 201 is softened, but the inner member is
Does not soften much. Therefore, the spherical adhesive does not deform significantly at the time of joining and the semiconductor chip and the inner lead do not abnormally come close to each other, and an appropriate distance can be maintained.

FIG. 15 shows the difference in hardness when the above-mentioned joining is performed.
A method for producing a spherical adhesive body having a layered structure and a method for connecting the spherical adhesive body to the inner leads will be described. For example, a silicon-modified polyimide solution and a polyimide solution containing a solvent such as NMP are supplied from a tank (not shown) and dropped from a nozzle 26 through a pipe. The nozzle 26 is composed of an outer nozzle 27 that drops the silicon-modified polyimide and an inner nozzle 28 that drops the polyimide, and forms a mass of the silicon-modified polyimide in which the polyimide is arranged.
This mass drops from the nozzle 26 onto the inner lead 7,
It is cured into a spherical shape by surface tension to form a spherical adhesive body (FIG. 15 (a)). The step of forming the spherical adhesive and the step of joining the spherical adhesive to the lead frame can be integrated.
In the method of FIG. 15 (b), the lumps dropped from the nozzle 26 are put into a dilute sulfuric acid container as shown in FIG. 12 to form the spherical adhesive body 20 in advance. The spherical adhesive 20 is fixed in the recess 21 of the inner lead 7 (or the recess 23 shown in FIG. 6C), and the spherical adhesive 20 is attached to the lead frame. In addition, in the method of FIG. 16, a spherical spherical adhesive body of polyimide to be the inner member 202 is previously attached to the inner lead. Then, a silicon-modified polyimide tape 29 is placed on the inner lead 7 so as to cover the spherical adhesive.

Next, the lead frame including the inner leads 7 and the tape 29 are heated to about 700 to 800.degree. The tape 29 is melted, and the inner member 202 on each inner lead 7 is replaced by the outer member 2 of silicon modified polyimide.
01, and the layered spherical adhesive body 20 is individually formed on each inner lead 7 (FIG. 16B). The surface of the inner lead may be subjected to a water repellent treatment to form a well-shaped spherical adhesive body. The spherical adhesive does not deform significantly at the time of joining and the semiconductor chip and the inner lead do not abnormally come close to each other, and an appropriate distance can be maintained. Next, the arrangement of the spherical adhesive body on the lead frame will be described with reference to FIGS. 17 and 18. In the embodiments of the first and second inventions, one spherical adhesive is formed at the tip portion of one inner lead, but in the present invention, the number of spherical adhesives and the position on the inner lead are formed. Is not so limited. If the part of the inner lead placed on the semiconductor chip is long,
A spherical adhesive is placed on the tip portion and the root portion of the portion arranged on the semiconductor chip to stabilize the inner lead (FIG. 17A). In the case of a longer length, in addition to arranging a spherical adhesive on the tip portion and the root portion of the portion of the inner lead arranged on the semiconductor chip, a spherical adhesive is formed between the spherical adhesive formed on both ends. At least one spherical adhesive body is formed (FIG. 17B).

In this figure, one spherical adhesive is formed between the spherical adhesives to stabilize the inner leads. It is also possible to form a plurality of branch leads on one inner lead 7 and dispose the spherical adhesive body 7 at the respective tip portions (FIG. 17 (c)). Since the spherical leads are attached to each of the branch leads, the inner leads can be stabilized. In FIG. 18, power supply lines 71 (5V) and 72 (0V) are wired between the signal lines. The power supply lines 71 and 72 are connected to the plurality of pad electrodes 10 by the bonding wires 4, respectively. The spherical adhesive 20 is arranged near both ends of the portion of the inner lead 7 arranged on the semiconductor chip 1 and the portion where the bonding wire 4 is connected, and can stabilize the inner lead during bonding. . In addition, the joint area can be widened.

[0026]

Industrial Applicability According to the present invention, it is possible to obtain a highly reliable resin-sealed semiconductor device capable of hermetically sealing resin and a device using the same. Since the spherical adhesive is attached to the lead frame, there is no particular change in the subsequent process and the method of the present technology can be used, and no new equipment is required.

[Brief description of drawings]

FIG. 1 is a transparent plan view of a resin-encapsulated semiconductor device of the present invention.

FIG. 2 is a sectional view of a portion along the line AA 'in FIG.

FIG. 3 is a sectional view of a portion taken along the line BB ′ of FIG.

FIG. 4 is a flowchart showing manufacturing steps of the resin-sealed semiconductor device of the present invention.

FIG. 5 is a plan view of a lead frame used in the resin-sealed semiconductor device of the present invention.

FIG. 6 is a cross-sectional view of an inner lead bonding device for a resin-sealed semiconductor device of the present invention.

FIG. 7 is a cross-sectional view illustrating joining of inner leads of the resin-sealed semiconductor device of the present invention.

FIG. 8 is a cross-sectional view of a bonding wire bonding apparatus used in the present invention.

FIG. 9 is a cross-sectional view of a resin mold for producing a resin sealing body used in the present invention.

FIG. 10 is a perspective view illustrating a method of joining the adhesive body of the present invention to an inner lead.

11A and 11B are a perspective view and a cross-sectional view showing a region to which the adhesive body of the invention is joined.

FIG. 12 is a cross-sectional view and a perspective view showing a method for manufacturing an adhesive body and a joining method according to the present invention.

FIG. 13 is a perspective view showing a method of joining the adhesive body of the present invention to an inner lead.

FIG. 14 is a cross-sectional view of an inner lead to which the adhesive body of the invention is attached and a hardness-bonding temperature characteristic diagram illustrating the temperature dependence of the hardness of the adhesive body material.

15A and 15B are a sectional view and a perspective view showing a method for manufacturing an adhesive body and a joining method according to the present invention.

FIG. 16 is a perspective view showing a method of joining the adhesive body of the present invention to an inner lead.

17A and 17B are a cross-sectional view and a perspective view illustrating the arrangement of inner leads on the semiconductor substrate of the present invention.

FIG. 18 is a plan view illustrating the arrangement of inner leads on the semiconductor substrate of the present invention.

FIG. 19 is a sectional view of a conventional resin-encapsulated semiconductor device.

FIG. 20 is a plan view of a conventional resin-sealed semiconductor device.

21 is a cross-sectional view of a portion taken along the line AA ′ in FIG.

[Explanation of symbols]

1 ... Semiconductor substrate, 2 ... Resin encapsulant, 3 ...
・ Lead frame, 4 ... Bonding wire,
5 ... Die pad, 6 ... Outer lead, 7
... Inner lead, 8 ... Conductive adhesive, 9
... Adhesive layer, 10 ... Pad electrode, 11 ...
・ Bump electrode, 13 ・ ・ ・ Wire bonder, 14 ・
..Resin mold, 15 ... upper mold, 16 ... lower mold,
17 ... Gate, 18, 26, 27, 28 ... Nozzle, 19 ... Silicon modified polyimide solution, 2
0 ... spherical adhesive, 21 ... dent, 22 ...
-Rough surface, 23 ... Circular depression, 24 ... Sulfuric acid container, 25 ... Sulfuric acid, 29 ... Silicon modified polyimide tape, 71 ... Power supply line (VCC), 72 ...
..Power supply line (VSS), 201 ... Outer member, 202 ...
..Inner member

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[Procedure amendment]

[Submission date] January 18, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008]

The present invention is characterized in that at least one spherical adhesive body made of a single material is preliminarily bonded to each of the inner leads constituting the lead frame. There is. The invention of claim 1 comprises a semiconductor substrate having a plurality of connection electrodes formed on its main surface, an inner lead and an outer lead continuously connected to the inner lead, and the inner lead is fixed to the main surface. A plurality of leads, a bonding wire that electrically connects the inner lead and the connection electrode,
A resin encapsulation type in which the semiconductor substrate, the inner lead, and a resin encapsulant for encapsulating the bonding wire with resin are provided, and the inner lead is fixed to the main surface by at least one spherical adhesive. Characterized by a semiconductor device. According to a second aspect of the present invention, in the resin-encapsulated semiconductor device according to the first aspect, the spherical adhesive is made of silicon-modified polyimide, silicone adhesive, or acrylic adhesive. To do. Claim 3
According to another aspect of the present invention, in the resin-encapsulated semiconductor device according to claim 1, the spherical adhesive body is an outer member made of a first synthetic resin having high adhesiveness, and the adhesive body is connected by the first synthetic resin. And an inner member made of a second synthetic resin having a high hardness at the time temperature.
According to a fourth aspect of the present invention, in the resin-encapsulated semiconductor device according to the third aspect, the first synthetic resin is made of silicon-modified polyimide, and the second synthetic resin is made of polyimide. To do.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

According to a fifth aspect of the present invention, a lead portion having a plurality of leads including an inner lead and an outer lead continuously connected to the inner lead, a frame portion supporting the plurality of leads, and the inner lead At least one spherical adhesive body bonded to each of them, and the spherical adhesive body is characterized by a lead frame for bonding the inner lead to a semiconductor substrate. According to a sixth aspect of the present invention, in the lead frame according to the fifth aspect, the spherical adhesive body is made of any one of silicon modified polyimide, silicone adhesive and acrylic adhesive. The invention of claim 7 is the invention of claim 5.
In the lead frame described in (1) above, the spherical adhesive body has an outer member made of a first synthetic resin having high adhesiveness and a second member having a hardness higher than that of the first synthetic resin at a temperature when the adhesive body is connected. And an inner member made of synthetic resin. According to an eighth aspect of the present invention, in the lead frame according to the fifth aspect, the first synthetic resin is made of silicon-modified polyimide and the second synthetic resin is used.
The synthetic resin of is made of polyimide.
According to a ninth aspect of the invention, in the lead frame according to the seventh aspect, a recess is formed in a region of the inner lead to which the spherical adhesive body is joined. According to a tenth aspect of the present invention, in the lead frame according to any one of the fifth to eighth aspects, a region of the inner lead to which the spherical adhesive body is joined is roughened. .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

According to a tenth aspect of the present invention, there is provided a step of bonding at least one spherical adhesive to an inner lead forming a lead frame, and a semiconductor substrate having a plurality of connection electrodes exposed on the main surface of the lead frame. The step of placing,
A step of bringing the spherical adhesive bonded to the inner lead into contact with the main surface of the semiconductor substrate, applying pressure and heating to connect the inner lead and the main surface of the semiconductor substrate, and the inner lead A step of electrically connecting the connection electrode with a bonding wire;

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Claims (11)

[Claims] 1. A semiconductor substrate having a plurality of connection electrodes formed on a main surface thereof, an inner lead and an outer lead continuously connected to the inner lead, the plurality of inner leads fixed to the main surface. A lead; a bonding wire that electrically connects the inner lead and the connection electrode; and a resin encapsulant that seals the semiconductor substrate, the inner lead, and the bonding wire with a resin. A resin-sealed semiconductor device, wherein the resin-sealed semiconductor device is fixed to the main surface by at least one spherical connection body. 2. The resin-encapsulated semiconductor device according to claim 1, wherein the spherical connector is made of any one of silicon modified polyimide, silicone adhesive and acrylic adhesive. 3. The spherical connecting member comprises an outer member made of a first synthetic resin having high adhesiveness, and a second synthetic resin having a hardness higher than that of the first synthetic resin at a temperature at the time of connecting the connecting member. The resin-encapsulated semiconductor device according to claim 1, wherein the resin-encapsulated semiconductor device is formed of: 4. The resin type semiconductor device according to claim 3, wherein the first synthetic resin is made of silicon-modified polyimide, and the second synthetic resin is made of polyimide. 5. A lead portion having a plurality of leads including an inner lead and an outer lead continuously connected to the inner lead, a frame portion supporting the plurality of leads, and a lead portion joined to each of the inner leads. At least one spherical adhesive body, wherein the spherical adhesive body bonds the inner lead to a semiconductor substrate. 6. The lead frame according to claim 5, wherein the spherical connector is made of any one of silicon modified polyimide, silicone adhesive and acrylic adhesive. 7. The spherical connecting member is a first adhesive member having high adhesiveness.
6. An outer member made of the synthetic resin and an inner member made of a second synthetic resin having hardness higher than that of the first synthetic resin at the temperature at the time of connecting the connecting body. Lead frame described in. 8. The lead frame according to claim 7, wherein the first synthetic resin is made of silicone modified polyimide, and the second synthetic resin is made of polyimide. 9. The lead frame according to claim 5, wherein a recess is formed in a region of the inner lead to which the spherical connection body is joined. 10. The lead frame according to claim 5, wherein a region of the inner lead to which the spherical connector is joined is roughened. 11. A step of bonding at least one spherical adhesive body to an inner lead forming a lead frame, and a step of mounting the lead frame on a semiconductor substrate having a plurality of connection electrodes exposed on its main surface. A step of bringing the spherical connecting body joined to the inner lead into contact with the main surface of the semiconductor substrate, pressurizing and heating to connect the inner lead and the main surface of the semiconductor substrate, and the inner lead And a step of electrically connecting the connection electrode to the connection electrode with a bonding wire, and a step of resin-sealing the semiconductor substrate, the spherical connection body, the inner lead and the bonding wire. A method of manufacturing a resin-encapsulated semiconductor device.