JP3805733B2 - Manufacturing method of semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device including a circuit element incorporated in a semiconductor substrate and a package for housing the semiconductor element.
[0002]
[Prior art]
A resin mold IC package in which a package for housing a semiconductor element is made of an insulating synthetic resin material is excellent in terms of compactness and easy handling of a semiconductor device.
One such IC package is a thin package (TSOP: Thin Small Outline Package). In this thin package, the end portion of the lead arranged parallel to the surface of the semiconductor element on which the electrode pad is formed is positioned on the surface of the semiconductor element in the vicinity of the electrode pad via the insulating adhesive tape.
The electrode pad and the lead are connected by a bonding wire, and the semiconductor element is sealed with an insulating synthetic resin material including a connection portion between the lead and the electrode pad.
The semiconductor element is connected to the electrode pad via a bonding wire and connected to an external circuit via a lead extending outside the resin material.
[0003]
[Problems to be solved by the invention]
By the way, in the conventional semiconductor device as described above, the bonding wire that connects the electrode pad formed on the surface of the semiconductor element and the end portion of the lead has an arc shape so that there is sufficient slack between the two connection portions. It is provided as follows.
Moreover, the connection end of the bonding wire to the lead end is located at the height of the sum of the thickness of the insulating adhesive tape and the thickness of the lead from the IC surface, and the bonding wire exceeds this height. It is provided to draw an arc shape.
Therefore, when sealing this connection portion with an insulating synthetic resin material, the insulating synthetic resin material is coated with the thickness of the insulating adhesive tape from the surface of the semiconductor element to cover the bonding wires arranged in an arc shape. In addition, a thickness dimension sufficiently exceeding the sum of the thickness dimensions of the leads is required. This is disadvantageous in reducing the thickness of the semiconductor device, and there has been a strong demand for the appearance of a technique for reducing the thickness.
[0004]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a semiconductor element having an electrode pad formed on the surface, and a distance from the semiconductor element surface toward the electrode pad from the outside of the edge on the surface side of the semiconductor element. In the semiconductor device including the lead that extends and the bonding wire that connects the lead to the electrode pad, an offset portion that is bent toward the surface of the semiconductor element is provided in the vicinity of the electrode pad of the lead, and bonding is performed at the offset portion. The wire is connected to the lead.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
FIG. 1 is a cross-sectional view partially showing a semiconductor device according to a reference example of the present invention.
A semiconductor device 10 according to a reference example of the present invention includes a semiconductor element 11 made of a semiconductor substrate in which an integrated circuit element such as a 16 Mbit DRAM is incorporated, and a large number of leads 12 for the semiconductor element.
[0006]
Electrode pads 13 for circuit elements are formed on the surface of the semiconductor element 11, and the portion excluding the electrode pads 13 on the surface of the semiconductor element 11 is, for example, a polyimide resin having a thickness of 5 to 15 μm. It is protected by an insulating protective film 14. The lead 12 is a central portion 12A that extends from the outer edge of the semiconductor element 11 toward the electrode pad 13 at a distance from the surface on which the insulating protective film 14 is disposed. It is positioned on the semiconductor element 11 by an insulating tape 15 made of a polyimide resin film coated with a resin adhesive on both sides.
[0007]
A step portion 12B that is bent toward the insulating protective film 14 is formed at a portion that is located closer to the central portion side of the semiconductor element 11 than an adhesive portion that is supported by the insulating tape 15 of the central portion 12A of the lead 12. . By this step portion 12B, an offset portion 12C that is bent toward the surface of the semiconductor element 11 is defined at the tip end portion of the lead 12 located in the vicinity of the electrode pad 13. In the illustrated example, the offset amount by the step portion 12B is substantially equal to the thickness dimension of the insulating tape 15, and the offset portion 12C at the tip of the lead 12 is pressed onto the insulating protective film 14 by the spring force of the lead 12 itself. The insulating protective film 14 protects the surface of the semiconductor element 11 from damage by mitigating impacts and the like when the offset portion 12C is pressed and the bonding wire 16 described below is connected.
[0008]
Between the lead 12 and the electrode pad 13, a bonding wire 16 for electrically connecting the two is connected. On the surface of the offset portion 12C of the lead 12, for example, a silver plating layer 17 for facilitating the bonding of the bonding wire 16 by thermal ultrasonic waves is formed, and one end of the bonding wire 16 is connected to the silver plating calendar. 17 is connected to the lead 12 at the offset portion 12C. Further, the other end of the bonding wire 16 is connected to the electrode pad 13 as in the prior art.
[0009]
A package 18 that entirely seals the semiconductor element 11 is formed by, for example, an epoxy-based resin material containing fibrous silica (60 to 100 μm) so as to cover those connection parts including these bondin wires 16. Yes. The package 18 is generally formed by clamping using an upper mold and a lower mold, but the insulating tape 15 for positioning the lead 12 on the semiconductor element 11 reduces the impact during clamping. This prevents cracks and the like from occurring in the semiconductor element 11. A metal plating layer 19 for connection to an external circuit is formed on the leg portion 12D of the lead 12 protruding from the package 18, and the electrode pad 13 of the semiconductor element 11 passes through the lead 12 and the bonding wire 16. Is connected to an external circuit.
[0010]
In the semiconductor device 10 according to the present invention, the bonding wire 16 that connects the lead 12 and the electrode pad 13 is connected to the lead 12 by the offset portion 12 </ b> C of the lead 12. The offset portion 12C to which the bondin wire 16 is connected is bent toward the insulating protective film 14 that covers the surface of the semiconductor element 11 by the thickness of the insulating tape 15 that is the bonding means. The height position of the offset portion 12C, which is a connection portion with the din wire 16, from the insulating protective film 14 is reduced.
[0011]
From this, the bondin wire 16 is wired between the offset portion 12C and the electrode pad 13 with a slack as in the prior art, but the height position from the insulating protective film 14 at the top is the offset portion. Since the offset amount is set lower by 12C, for example, as shown in FIG. 1R> 1, the top position of the bonding wire 16 is lower than the height position of the central portion 12A of the lead 12, for example 0.225-0. A value of 25 mm can be set.
[0012]
Accordingly, the height dimension H on the surface side of the semiconductor element 11 of the package 18 can be made smaller than the conventional one without exposing the top of the bondin wire 16, and thus the thickness dimension T of the main body portion of the package 18 can be reduced. The semiconductor device 10 can be reduced in thickness by reducing the thickness dimension to, for example, 1 mm or less.
[0013]
Instead of forming the offset portion 12C of the lead 12 at the tip portion of the lead 12, it can be formed at the central portion 12A, for example. However, as shown in the figure, the offset portion 12C can be easily positioned in the vicinity of the electrode pad 13 by forming the offset portion 12C at the tip of the lead 12. Therefore, in order to shorten the bonding wire 16 by reducing the size of the bonding wire 16, it is desirable to provide the offset portion 12 </ b> C at the tip of the lead 12.
[0014]
2 and 3 are cross-sectional views partially showing other reference examples according to the present invention. Components having the same functions as those shown in FIG. 1 are denoted by the same reference numerals. In FIG. 2, the back surface of the semiconductor element 11 is exposed from the package 18 to the atmosphere in order to improve the heat dissipation of the semiconductor device 10. Regarding the exposure of the back surface of the semiconductor element 11, so-called burrs caused by the protrusion of the resin material from the upper mold for the package 18 cause a reduction in heat dissipation. Therefore, it is desirable that the upper half portion 18 </ b> A of the package 18 be smaller than the surface of the semiconductor element 11 in order to reliably prevent burrs due to the wraparound of the resin material to the back surface of the semiconductor element 11.
[0015]
In addition, by disposing the insulating tape 15 serving as a contact means so as to protrude outward from the edge of the semiconductor element 11, when the insulating tape 15 is heated and bonded, the melted portion of the adhesive causes the semiconductor element 11 to melt. A fillet 20 covering the edge portion can be formed.
The fillet 20 acts to suppress the occurrence of cracks in the vicinity of the edge portion against a periodic temperature change such as a temperature cycle test performed after the completion of the semiconductor device 10.
[0016]
As shown in FIG. 2, by exposing the back surface of the semiconductor element 11 from the package 18 to the atmosphere, the heat dissipation of the semiconductor device 10 can be improved, and it is not necessary to cover the back surface of the semiconductor element 11 with a resin material. Therefore, since the thickness dimension of the semiconductor device 10 can be reduced by the thickness, it is more advantageous in reducing the thickness.
[0017]
As shown in FIG. 3, the back surface and the peripheral surface of the semiconductor element 11 can be exposed from the package 18 to the atmosphere, thereby further improving heat dissipation. Further, as shown in FIG. 3, the surface of the synthetic resin material constituting the package 18 is positioned substantially on the same plane as the surface of the central portion 12A excluding the offset portion 12C of the lead 12, so that an electrode is formed in the package 18. With the pad 12, the bonding wire 16, and the offset portion 12 </ b> C following the stepped portion 12 </ b> B of the lead 12 being embedded, the thickness of the package 18 can be further reduced, thereby further reducing the thickness of the semiconductor device 10. become.
[0018]
FIG. 4 is a plan view showing an embodiment of the present invention .
FIG. 5 is a cross-sectional view taken along line AA shown in FIG.
The plan view shown in FIG. 4 is basically the same as that in the example shown in FIG. 3, but the lead 12 is shown in FIGS. 1 to 3 as clearly shown in FIG. The leg portion 12D is not provided.
In the semiconductor device 10 shown in FIGS. 4 and 5, the central portion 12A of the lead 12 exposed from the package 18 is disposed so as to face the circuit board, and, for example, a bump electrode or the like is provided on the circuit board at the exposed surface of the central portion 12A. Can be connected directly.
[0019]
A method for manufacturing such a semiconductor device will be described with reference to FIGS. 6 (a) to 6 (c) and FIGS. 7 (a) to 7 (d).
FIG. 6 shows the shape before resin sealing. 6A is a top view, FIG. 6B is an AA sectional view, and FIG. 6C is a CC sectional view.
In FIG. 6A, a frame-shaped dam bar 21 larger than the size of the semiconductor element 11 is formed on the frame by an etching method or a stamping method.
In this dam bar 21, leads 12 are formed as external terminals connected to the dam bar 21. After the metal plating is applied to the bonding portion, the frame-like insulating tape 15 connected from the leads 22 to the dam bar 21 is attached. Glue. The inner side of the insulating tape 15 reaches a position on the semiconductor element 11. Further, the lead tip portion where the insulating tape 15 is not bonded is bent by the thickness of the insulating tape.
Thereafter, after the semiconductor element 11 is bonded and mounted on the insulating tape portion, the electrode pad of the semiconductor element and the offset portion which is the lead tip portion are connected by a bonding wire, and then a mold resin is injected and the individual cutting process is started. At this time, since the insulating tape 15 exists up to the bottom of the dam bar 21, the resin does not flow out to the side surface of the semiconductor element 11.
[0020]
FIGS. 7A to 7B and 7C to 7D are views showing cut portions corresponding to the AA and CC sectional views in FIG. 6, respectively.
As shown in FIG. 6, after the semiconductor device is bonded to the lead and sealed with resin, the lead 12 between the end surface of the semiconductor device 11 and the inner end surface of the dam bar 21, the insulating tape 15, and the mold resin 18 are cut by the individual punching blades 23. Punch out.
[0021]
In the example shown in FIGS. 4 and 5, by exposing the back surface and the peripheral surface of the semiconductor element 11 from the package 18 to the atmosphere, heat dissipation is improved and the leg portion 12 </ b> D of the lead 12 is not required. Therefore, an ultra-thin chip size semiconductor device having a thickness dimension of 0.5 mm or less can be realized.
[0022]
FIG. 8 is an explanatory view showing another embodiment of the present invention, and FIGS. 8A and 8B are views showing cut sections corresponding to the AA sectional view and the CC sectional view in FIG. 6, respectively. It is.
In this embodiment, a recess 24 of about half the thickness of the lead is provided in advance on the surface of the lead 12, and resin is used by using mold dies 25 and 26 in which protrusions are provided at the same position as the recess 24. Perform the mold. Here, the protrusion of the mold is provided not only on the lead portion but also on the portion to be cut. After the mold resin is injected by the molds 25 and 26, the mold resin is cut by the individual cutting blades 23 in accordance with the recessed portions.
Since the recesses are provided in the lead and resin portion of the semiconductor device as described above, it is difficult to apply stress to the semiconductor device when cutting out the individual pieces, and the flatness of the cross section after cutting is obtained, thereby improving the reliability.
[0023]
The present invention is not limited to the above embodiments. As the bonding means, a liquid adhesive can be used instead of the insulating tape. However, it may be desirable to secure a predetermined distance between the central portion 12A, which is the support portion of the lead 12, and the surface of the semiconductor element from the viewpoint of capacitance or the like. In that case, an insulating tape is used. Thus, a predetermined interval can be secured.
Further, the present invention has been described with respect to an example of a resin-encapsulated semiconductor device in which the package is made of an electrically insulating synthetic resin material. However, a ceramic type including a package made of ceramic provided with a cavity for housing a semiconductor element, and a package made of metal. The present invention can be applied to a semiconductor device having various packages other than the metal type provided.
[0024]
【The invention's effect】
In the semiconductor device of the present invention described above, the connection end of the bonding wire connecting the lead and the electrode pad to the lead is connected by the offset portion formed on the lead and bent toward the surface of the semiconductor element. The
Therefore, according to the present invention, the height offset from the surface of the semiconductor element at the top of the bondin wire can be reduced by the lead offset, thereby reducing the thickness of the entire semiconductor device. Thus, it is possible to reduce the thickness of the semiconductor device.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view partially showing a semiconductor device (part 1) according to a reference example of the present invention.
FIG. 2 is a cross-sectional view partially showing a semiconductor device (part 2) according to a reference example of the present invention;
FIG. 3 is a cross-sectional view partially showing a semiconductor device (part 3) according to a reference example of the present invention;
FIG. 4 is a plan view showing a semiconductor device (No. 4) according to the present invention.
5 is a cross-sectional view taken along line AA of the semiconductor device (part 4) shown in FIG. 4;
6 is a view showing a method of manufacturing the semiconductor device (No. 4) shown in FIG. 4; FIG.
7 is a view showing a method of manufacturing the semiconductor device (No. 4) shown in FIG. 4; FIG.
8 is a view showing a modification of the semiconductor device (part 4) shown in FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Semiconductor device 11 Semiconductor element 12 Lead 12C Offset part 13 Electrode pad 15 (Access means) Insulation tape 16 Bonding wire

Claims (1)

Preparing a semiconductor element having an electrode pad formed on the surface;
Preparing each lead frame connected by a dam bar and having a lead frame having an offset portion extending toward the surface of the semiconductor element in the vicinity of the electrode pad;
A step of disposing the offset portion on the surface of the semiconductor element without interposing the adhesive layer by fixing the lead frame to the semiconductor element via an adhesive layer applied to the dam bar;
A method of manufacturing a semiconductor device, comprising: a step of resin-sealing the surface of the semiconductor element; and a step of cutting an inner region from the dam bar after resin sealing.

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