JPH10303355A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To operate a semiconductor device stably without generating a failure such as cracks in a resin when packaging the resin in an element mounting part, by forming on the rear surface side of the element mounting part a first resin joint part consisting of a number of recessed parts having projections in the periphery. SOLUTION: A semiconductor device 10 is provided with a first resin joint part consisting of a plurality of recessed parts having projections in the periphery, on the rear surface side of an element mounting part 11 as a non-mounting surface 19. Then, in the resin packaging step for manufacture of the semiconductor device 10, a melted resin 17 is filled and cured around the element mounting part 11 on which a semiconductor circuit element 15 is placed and an inner lead 12, thereby forming a body. Further, the recessed parts 21 are formed as an area array on the non-mounting surface 19 of the element mounting part 11. Thus, the generation of cracks accompanied with curing shrinkage of the resin 17 and of failure due to lack of resistive factor against fluidity to the melted resin 17 can be prevented effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufactured by resin sealing an element mounting portion on which an integrated circuit element is mounted and internal terminals (inner leads) arranged around the integrated circuit element. About.

[0002]

2. Description of the Related Art A semiconductor device formed of a resin-sealed package tends to have a higher mounting density of integrated circuit elements and to be smaller and thinner due to a demand for additional functions and improved portability. Along with this, when the resin cures and contracts, a shearing force or the like is generated between the resin and the element mounting portion, thereby causing cracks in the resin portion or heat fluctuation during use of the semiconductor device. There were problems such as damaging the resin. As a method for preventing such cracks, damages, etc., for example, Japanese Patent Publication No. 61-3100 discloses a method in which a surface on which a semiconductor pellet (integrated circuit element) is placed and bonded is made flat, and a plurality of recesses are formed on the other surface. There is described a semiconductor device having a lead frame bed (element mounting portion) in which is formed a resin integrally with a plurality of internal terminals (inner leads).

[0003]

However, the semiconductor device described in the above-mentioned Japanese Patent Publication No. 61-3100, in which a plurality of depressions are provided on the non-mounting surface of the semiconductor pellet and formed as a bed, has the following problems. Was. Since the dimensional difference between the resin-sealed bed and the resin that cures and contracts is large, an excessive shear force is generated in the resin, and cracks and the like are easily generated. Once such cracks are formed, moisture, impurities, and the like may enter the cracks and corrode the inner leads or the element mounting portions and the like, causing malfunction of the semiconductor device. Since the resistance between the cured resin and the bed, especially the tensile force in the direction perpendicular to the joint surface, is small, the resin and the bed surface are liable to peel off due to temperature fluctuations during operation, and the bonded integrated circuit element The connection portion with the inner lead is damaged, which causes troubles such as shortening of the life of the semiconductor device. Since the recess is formed by dissolving the base metal of the lead frame by an etching process or formed by a simple press working, a smooth joint surface with less unevenness is formed, and the adhesive strength between the resin and the bed surface is formed. Run out. When the depression is formed by etching, a chemical treatment step such as a preliminary treatment step and a cleaning step is required, and the production cost is increased. When filling the molten resin into the resin mold placed in the lead frame and performing resin sealing, the flow path of the molten resin formed in the resin mold has few irregularities and poor flow resistance,
Bubbles remain in the resin mold, and the curing of the resin becomes uneven, so that defects are easily generated inside the resin. The present invention has been made in view of such circumstances, and provides a semiconductor device that can be operated stably without generating defects such as cracks in the resin when sealing the inner lead and the element mounting portion with the resin. The purpose is to do.

[0004]

According to the present invention, there is provided a semiconductor device comprising:
The semiconductor device described above includes a number of inner leads around the element mounting portion, and the integrated circuit element mounted on the element mounting portion is entirely resin-bonded with the tip of the inner lead being wire-bonded. In the semiconductor device to be sealed, a first resin engaging portion is provided on the back surface side of the element mounting portion, the first resin engaging portion having a large number of depressions having a protrusion on a peripheral portion. According to a second aspect of the present invention, in the semiconductor device of the first aspect, each of the protrusions has an overhang portion projecting into the recess. Claim 3
The semiconductor device according to claim 1, wherein the depressions are arranged in an area array,
Moreover, it is formed by ultrasonic processing. A semiconductor device according to a fourth aspect of the present invention is the semiconductor device according to any one of the first to third aspects, wherein a second resin engagement is provided at an intermediate portion of the inner lead, the depression having a projection on a peripheral portion. Part is provided. The semiconductor device according to claim 5 is
5. The semiconductor device according to claim 1, wherein the element mounting portion is formed separately from the inner lead, and is joined to the inner lead. A semiconductor device according to a sixth aspect is the semiconductor device according to any one of the first to fourth aspects, wherein the element mounting portion is formed integrally with the inner lead. The area array shape refers to a state in which a plurality of depressions are arranged in a substantially lattice shape with an interval therebetween, but also includes a case where the depressions are arranged in a staggered manner at each lattice point, or a case where the depressions are irregularly arranged. It is.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. 1A and 1B are a side sectional view and an enlarged view of a main part of the semiconductor device according to the first embodiment of the present invention, and FIGS. 2A, 2B, and 2C are respectively. FIGS. 3A, 3B, and 3C are a plan view, a schematic side view, and an explanatory view of a modified example of the lead frame, respectively. FIGS. FIGS. 4A and 4B are explanatory views showing a method of manufacturing a semiconductor device, and FIGS. 5A and 5B.
3A and 3B are a plan view and a schematic side sectional view of a lead frame applied to a semiconductor device according to a second embodiment of the present invention.

Hereinafter, a semiconductor device according to a first embodiment of the present invention will be described. As shown in FIG. 1, a semiconductor device 10 includes an integrated circuit element 15 mounted on an element mounting surface 18 of an element mounting section 11, a plurality of inner leads 12 disposed around the element mounting section 11, and an integrated circuit. Element 15
And a bonding wire 16 for connecting the tip of the inner lead 12, a resin 17 for integrally sealing them, and an outer lead 13 integrally with the inner lead 12 and pulled out from the resin 17, The projection 2 is formed on the non-mounting surface 19 on the back side of the element mounting portion 11.
There is provided a first resin engaging portion composed of a number of depressions 21 having 0 in the peripheral portion.

In the resin sealing step in the manufacture of the semiconductor device 10, the molten resin 1 is formed around the element mounting portion 11 on which the integrated circuit element 15 is mounted and the inner lead 12.
7 is filled and cured to form a main body. By forming the depressions 21 in an area array on the non-mounting surface 19 of the element mounting portion 11, cracks due to curing shrinkage of the resin 17 and poor flow resistance to the molten resin 17 are caused. The generation of defects can be effectively prevented.

A method for manufacturing such a semiconductor device will be described below. The lead frame 14, which is a material for forming the element mounting portion 11, the inner lead 12, and the outer lead 13, is manufactured as follows. First, a strip-shaped sheet material made of a metal such as copper or a copper alloy is subjected to press working such as tandem processing to obtain a lead frame 14 having a pattern as shown in FIG. 2A.
The lead frame 14 includes outer frame portions 22 and 23 disposed on both sides in the width direction of the strip-shaped thin plate, an element mounting portion 11 disposed between the outer frame portions 22 and 23, and the inner lead 1.
2. An outer lead 13 formed integrally with the inner lead 12, a suspension lead 24 for connecting and supporting the element mounting portion 11 with the outer frame portions 22 and 23, and the outer lead 13 on the outer frame portions 22 and 23. Tie bar 2 for joining
5 and the like are formed. Then, the recess 21 is formed on the back surface (non-mounting surface) 19 of the element mounting surface 18 formed on the lead frame 14. Next, the integrated circuit element 15
After mounting on the element mounting portion 11 and performing resin sealing, the outer frame portions 22 and 23 and the tie bar 25 and the like between the outer leads 13 pulled out from the portion of the resin 17 are separated.
A semiconductor device 10 as shown in FIG. 1 is manufactured.

The integrated circuit element 15 is mounted on the element mounting surface 18 of the element mounting portion 11 via an adhesive such as epoxy resin or the like. 19, a large number of depressions 21 having projections 20 on the peripheral edge are arranged in an area array so that a first resin engaging portion is formed. FIG. 2 (c) shows the deformation when the element mounting portion 11a having the depression 21 formed thereon is separately formed and then connected to the main body of the lead frame 14a via the suspension lead 24a by means of ultrasonic welding or the like. An example is shown, and the following method of forming the recess 21 can be applied in the same manner as in the case of the element mounting portion 11 integrally formed in advance with the main body of the lead frame 14 as shown in FIG. .

Hereinafter, a method of forming such a depression 21 will be described in detail. First, as shown in FIG. 3A, the element mounting portion 11 is placed on the processing substrate 29 with the element mounting surface 18 facing down.
Is placed, and the back end (non-mounting surface) 19 of the element mounting surface 18 is pressed against the tip end of a piercing tool 26 to be ultrasonically vibrated. A transducer 27 for ultrasonically oscillating the piercing tool 26 is disposed on a side portion of the piercing tool 26 so as to transmit a vibration force in a direction substantially perpendicular to the pressing direction of the piercing tool 26. By applying a high frequency voltage to the transducer 27 via the oscillator 28, the drilling tool 26 can be laterally vibrated at a required frequency and vibration intensity (amplitude). Note that, if necessary, abrasive grains for grinding can be interposed between the drilling tool 23 and the non-mounting surface 19 that is the drilling surface, and in this case, grinding can be performed more efficiently. . In the present embodiment, the tip of the drilling tool 26 is pressed against the non-mounting surface 19 with a predetermined pressure, and the punching tool 26 is ultrasonically vibrated, so that the thickness L of the lead frame 14 (0.15 to 0.15).
0.2 mm), a square-shaped depression 21 having a depth D of about 1/5 to 2/3 and a side length of 1 to 2 mm is formed in an area array. As a result, as shown in FIG. 3A, the outer peripheral portion of the piercing tool 26, that is, the peripheral edge of the recess 21 is deposited with metal chips cut by the ultrasonic vibration in the lateral direction, and the metal chips are deposited or fused. And the protrusions 20 protruding to have a height H from the original non-mounting surface 19 can be effectively formed.

Next, as shown in FIG. 3 (b), in a state where the element mounting portion 11 on which the projections 20 are formed is mounted on a processing substrate 29, if necessary, a pressing die 30 of a press machine is used.
The protrusion 20 is plastically deformed to adjust it to a required shape by pressing from above. FIG. 3 (c) shows the shape pattern of the projections 20 and the depressions 21 shaped in this way, and is adjusted to the necessary shape pattern as appropriate according to the shape of the pressing surface of the press machine, the pressing method, and the like. It is possible to The shape pattern shows an example in which the projection 20 is formed without being pressed by a press machine, and there is an advantage that the number of steps for forming the depression 21 can be reduced. The shape pattern is an example in which the upper portion of the protrusion 20 is formed by plastically deforming the protrusion flatly, and has an advantage that the dimensions of the resin at the time of resin sealing can be appropriately controlled. The shape pattern presses a part of the projection 20 toward the recess 21 to form the overhang portion 31 and imparts a coupling force by mechanical fastening between the resin and the non-mounting surface 19 when the resin is sealed. it can. Although FIG. 3 shows a case where the depressions 21 are formed one by one, a plurality or all of the depressions may be formed by a plurality of drilling tools 2.
Alternatively, the processing may be performed using an ultrasonic processing machine having 6 and a press processing machine that simultaneously presses a plurality of protrusions. Further, the shape of the tip of the drilling tool 26 on the pressing surface may be a shape other than a square, and may be appropriately selected from shapes such as a triangle, a pentagon, a hexagon, a heptagon, an octagon, and a circle. You can choose.

Next, a procedure for manufacturing the semiconductor device 10 using the lead frame 14 will be described with reference to FIG. First, as shown in FIG. 4A, after the integrated circuit element 15 is fixed to the element mounting portion 11 of the lead frame 14, the integrated circuit element 15 and the inner leads 12 are connected by bonding wires 16. Next, as shown in FIG. 4B, the resin mold 32 is disposed so as to be sandwiched from the upper and lower surfaces of the lead frame 14, and the resin 17 melted through the resin supply holes 33 provided in the resin mold 32 is removed. 32. At this time, the molten resin 17 having high fluidity flows on the depression 21 formed on the back surface side of the element mounting surface 18, but since the depression 21 has the protrusion 20 on the peripheral edge thereof,
The flow resistance of the resin 17 at this portion increases. For this reason, while the molten resin 17 is uniformly dispersed, the supply speed of the resin 17 is suppressed, and it is possible to reduce the entrapment of air bubbles and the like.
The resin is discharged from a discharge hole 34 provided at a position opposite to the resin supply hole 33. When the molten resin 17 is cured,
Although the resin 17 shrinks, the cured resin 17 is securely held by the projections 20 formed on the peripheral edge of the depression 21. Can be suppressed.
Thus, as shown in FIG.
7 can be obtained, the durability of the semiconductor device 10 can be maintained, and the degree of mechanical joining between the resin 17 and the non-mounting surface 19 can be increased by the projections 20. Thus, the semiconductor device 10 having high resistance to such factors can be obtained.

Next, a semiconductor device according to a second embodiment of the present invention will be described. Parts having the same functions as those of the semiconductor device 10 described in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 5, a lead frame 40 used for a semiconductor device is provided with outer frames 41 and 42 arranged at both ends in the width direction of a strip-shaped sheet material, and hanging leads 47 between the outer frames 41 and 42. An element mounting portion 43 to be supported, an inner lead 44 connected to the integrated circuit element 15 of the element mounting portion 43 by a bonding wire 16, and an outer lead 45 following the inner lead 44 are formed. A recess 21 having a projection 20 protruding from the non-mounting surface 19 on the non-mounting surface 19 of the element mounting portion 43 in the peripheral edge portion.
Are arranged to form a first resin engaging portion,
In addition, a second resin engaging portion composed of a depression 21 having a projection 20 on the periphery is also formed in a dimple forming region 46 indicated by oblique lines, which is an intermediate portion of the inner lead 44.
In addition, in FIG.
Is shown on the side of the non-mounting surface 19, but the depression 21 is also formed on the side of the element mounting surface 18 to further strengthen the adhesiveness between the hardening resin 17 and the inner lead 12. It is also possible.

By forming the first and second resin engaging portions including the recesses 21 arranged in the area array, the element mounting portion 11 on which the integrated circuit element 15 is mounted and the inner lead are formed. When the semiconductor device is formed by filling the molten resin 17 around the substrate 12 and
Cracks due to curing shrinkage of the resin and defects due to poor flow resistance to the molten resin are effectively prevented. Since the method of forming the depression 21 is substantially the same as the method using the ultrasonic processing shown in the first embodiment, FIG.
An operation content for realizing the ultrasonic processing method will be described.

In the second embodiment, FIG.
By controlling the frequency, amplitude, etc. of the ultrasonic vibration applied to the drilling tool 26 for each depth D to be pressed, the surface roughness on the inner surface of the depression 21 and the inclination angle of the inner surface of the depression 21 It is possible to adjust θ and the like. For example, when the depth D is shallow, the frequency and amplitude are increased by the high-frequency oscillator 28, and the frequency and the like are decreased as the depth D increases. And the height H of the projections 20 formed by cuttings, plastic deformations, and the like generated during cutting can be adjusted. In addition, by setting the vibration frequency and amplitude at the time of lifting the tip of the piercing tool 26 from the recess 21 to be larger than those at the time of pressing the piercing tool 26, it is possible to increase the surface roughness of the inner surface of the recess 21. Thereby, the flow resistance when the non-mounting surface 19 of the element mounting portion 43 and the portion of the inner lead 44 are sealed with resin, and the adhesiveness between the surface of the resin 17 and the inner lead 44 after resin sealing, By controlling the peeling resistance and the like, troubles such as malfunctions occurring in the semiconductor device can be prevented.

The embodiments of the present invention have been described above.
The present invention is not limited to these embodiments, and all changes in conditions without departing from the gist are within the scope of the present invention. For example, in the present embodiment, the case where the depression is formed only on the non-mounting surface side of the element mounting portion has been described. However, the depression can be arranged on the element mounting surface side as needed. In addition, by appropriately changing the shape, size, and the like of the drilling tool to be ultrasonically vibrated, the adhesion between the lead frame and the resin can be maintained more appropriately.

[0017]

According to the semiconductor device of the present invention, a plurality of inner leads are provided around the element mounting portion, and the integrated circuit element mounted on the element mounting portion is connected to the tip of the inner lead by a wire. In a semiconductor device which is entirely resin-sealed in a bonded state, the first resin engaging portion composed of a number of depressions having projections on the periphery is provided on the back surface side of the element mounting portion. Further, it is possible to prevent the occurrence of cracks due to the curing shrinkage of the resin when the resin is sealed. In addition, since flow resistance at the time of filling the resin is provided, defects generated inside the resin can be suppressed, and troubles such as malfunction of the semiconductor device during use can be prevented. In particular, in the semiconductor device according to the second aspect, since each of the protrusions has an overhang portion projecting into the recess, the degree of mechanical coupling between the resin, the element mounting portion, and the inner lead increases. , Curing shrinkage of resin during resin sealing,
Further, generation of cracks due to temperature fluctuation during use can be more effectively prevented.

In the semiconductor device according to the third aspect, since the depressions are arranged in an area array and formed by ultrasonic processing, the depressions having projections on the peripheral edge can be efficiently formed by a simple operation. Can be formed. As a result, a resin-sealed semiconductor device with few defects can be manufactured, and its reliability can be improved. Claim 4
In the semiconductor device described above, since the second resin engaging portion composed of a recess having a protrusion on the peripheral portion is also provided in the middle portion of the inner lead, the bonding between the resin and the inner lead to be resin-sealed is performed. And the reliability as a semiconductor device can be further improved. In the semiconductor device according to the fifth aspect, the element mounting portion is formed separately from the inner lead and is joined to the inner lead, so that the recess for forming the resin engaging portion is more precisely formed.
And it can be formed efficiently. In the semiconductor device according to the sixth aspect, since the element mounting portion is formed integrally with the inner lead, positioning between the element mounting portion and the inner lead can be accurately performed by press molding using a mold. .

[Brief description of the drawings]

FIGS. 1A and 1B are a side sectional view and a main part enlarged view of a semiconductor device according to a first embodiment of the present invention, respectively.

FIGS. 2A, 2B, and 2C are a plan view, a schematic side sectional view, and an explanatory view of a modified example of a lead frame, respectively.

FIGS. 3A, 3B, and 3C are explanatory diagrams of a method of forming a depression in a lead frame, and explanatory diagrams of a method of forming a depression, respectively;
It is explanatory drawing which shows the kind of depression.

FIGS. 4A and 4B are explanatory diagrams illustrating a method for manufacturing a semiconductor device.

FIGS. 5A and 5B are a plan view and a schematic side sectional view, respectively, of a lead frame applied to a semiconductor device according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Semiconductor device 11 Element mounting part 11a Element mounting part 12 Inner lead 13 Outer lead 14 Lead frame 14a Lead frame 15 Integrated circuit element 16 Bonding wire 17 Resin 18 Element mounting surface 19 Non-mounting surface (back surface) 20 Projection 21 Depression 22 Outer frame Part 23 Outer frame part 24 Suspended lead 24a Suspended lead 25 Tie bar 26 Drilling tool 27 Transducer 28 High frequency oscillator 29 Processing board 30 Pressing type 31 Overhang part 32 Resin type 33 Resin supply hole 34 Discharge hole 40 Lead frame 41 Outer frame part 42 Outer frame part 43 Element mounting part 44 Inner lead 45 Outer lead 46 Dimple formation area 47 Suspension lead

Claims (6)

[Claims] An integrated circuit device mounted on the element mounting portion is provided with a plurality of inner leads around the element mounting portion, and the whole of the integrated circuit element is wire-bonded to a tip portion of the inner lead. In the semiconductor device to be stopped, a first resin engaging portion including a large number of depressions having a protrusion on a peripheral portion is provided on a back surface side of the element mounting portion. 2. The semiconductor device according to claim 1, wherein each of said projections has an overhang portion projecting into said recess. 3. The semiconductor device according to claim 1, wherein the depressions are arranged in an area array and formed by ultrasonic processing. 4. The method according to claim 1, wherein a second resin engaging portion formed of a recess having a protrusion on a peripheral portion is provided also at an intermediate portion of the inner lead. 3. The semiconductor device according to claim 1. 5. The semiconductor device according to claim 1, wherein said element mounting portion is formed separately from said inner lead and is joined to said inner lead. . 6. The device according to claim 1, wherein the element mounting portion is formed integrally with the inner lead.
The semiconductor device according to claim 1.