JPH0437050A - Resin seal type semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the disconnection of a covered wire, by a method wherein, in a resin seal type semiconductor device using a pellet, leads and covered wires, an aperture is formed around a tab so as to penetrate the tab from the surface to the rear. CONSTITUTION:A single crystal silicon substrate 2A is used as a main body, thereby forming a pellet 2. A system circuit is mounted on the surface of the substrate 2A. A wiring layer is formed on the surface of a substrate 2A so as to interpose an interlayer insulating film 2B. The semiconductor pellet 2 is fixed on the surface of a tab 4A so as to interpose an adhesive layer 3. A flat slit type aperture 4D stretching slenderly along the periphery is formed in the tab 4A. The aperture 4D is constituted as a hole penetrating the tab 4A from the surface side to the rear side, and connects resin 6 on the surface side and the rear side of the tab 4A, on the periphery of the tab 4A. Thereby the movement of resin caused by the temperature cycle of the peripheral part of the tab is reduced, and the stress generated in the covered wire can be decreased. As the result, the disconnection of covered wire can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor device, and particularly to a technique that is effective when applied to a resin-sealed semiconductor device using a covered wire.

[Conventional technology]

Resin-molded semiconductor devices such as QFP (Quad Flat Package) can be formed at a lower cost than ceramic-encapsulated semiconductor devices, and are in high demand.

In this type of resin-sealed semiconductor device, the external terminals (ponding pads) of the semiconductor pellet and the inner leads of the leads are connected by wires. Semiconductor pellets are typically mounted on the surface of the tab. This semiconductor pellet, tab,
The inner leads and wires are hermetically sealed with resin (resin mold). For example, epoxy resin is used as the resin.

The resin-sealed semiconductor device currently being developed by the present inventor was patented in 1986.
-200561 is adopted. This coated wire is a metal wire whose surface is coated with an insulator. The metal wire of the coated wire is gold (Au),
Copper (Cu) or aluminum (AQ) is used. As the insulator, a resin-based insulating material such as polyurethane resin or polyimide resin is used.

A resin-sealed semiconductor device using this coated wire is superior to a resin-sealed semiconductor device using a so-called bare wire formed of a metal wire in the following points.

(1) Since the covered wire covers the metal wire with an insulator, there are no short circuits between adjacent covered wires, short circuits between covered wire tabs, and short circuits between covered wire semiconductor pellets. Therefore, the reliability of the resin-sealed semiconductor device can be improved.

(2) Based on the above (1), the loop of the covered wire during bonding can be allowed to come into contact with the periphery (etch) of the tab, increasing the degree of freedom in bonding. In other words, since semiconductor pellets of different sizes can be freely mounted on one type of lead frame, the number of types of lead frames can be reduced. Also.

So-called cross bonding, in which covered wires are crossed, can be freely performed, and there is no need to develop a lead frame every time the type of semiconductor pellet is improved, so the types of lead frames can be similarly reduced.

(3) Based on the above (1), since the arrangement interval of the covered wires can be reduced, the number of bottles of the resin-sealed semiconductor device can be increased.

[Problem to be solved by the invention]

However, prior to developing a resin-sealed semiconductor device using the above-mentioned coated wire, the inventor conducted a temperature cycle test (accelerated test) and found the following problems.

The joint between the tab and the resin of the resin-sealed semiconductor device is a joint between metal chips and resin, and thus has poor adhesion. When a temperature cycle test is performed, each of the tab and resin repeatedly expands and contracts along the radial direction around the semiconductor pellet. This expansion and contraction substantially maximizes the amount of relative movement of the resin with respect to the tab based on the difference in thermal expansion coefficient in the peripheral portion of the tab, and peels the resin from the surface of the tab. On the other hand, since the insulator of the covered wire is made of a resin material as described above, it has high adhesion to the resin as the sealing material. In other words, the covered wire placed opposite the surface of the tab moves as the resin expands and contracts around the tab. On the other hand, on the outside of the tab on the inner lead side, the resin serving as the sealing material moves less due to temperature cycles.

In other words, most of the space between the tab and the inner lead is filled with resin, and the resin on the front side (semiconductor pellet mounting side) and back side of the tab are connected, and the resin in this area is Movement in the vertical direction is suppressed by the peripheral edge of the tab. Furthermore, in the region where the inner leads are arranged, the contact area between one inner lead and the resin is smaller than that in the tab.

Since the resin on the upper side and the lower flange of this inner lead are connected to each other, the movement of the resin in this region in the radial direction is also small. For this reason, in the resin-sealed semiconductor device, tensile stress and compressive stress are repeatedly generated in the covered wire in the peripheral portion of the tab due to temperature cycles, and Wir line defects of the covered wire occur in this region. The present inventor considers that such a wire breakage failure does not occur with so-called bare wires, but is unique to resin-sealed semiconductor devices that use coated wires.

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique capable of preventing disconnection of a covered wire in a resin-sealed semiconductor device using a covered wire.

Another object of the present invention is to provide a technique that can improve the reliability of a resin-sealed semiconductor device using covered wire.

Another object of the present invention is to provide a technique capable of achieving the above object and reducing the adverse effects of achieving this object.

The above and other objects and novel features of the present invention will become clear from the description of the present specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

(1) External terminal of semiconductor pellet mounted on tab,
In a resin-sealed semiconductor device in which each lead is connected with a coated wire whose surface is coated with an insulator, and the tab, semiconductor pellet, lead, and coated wire are sealed with resin, this resin is placed around the tab. Provide an opening that penetrates from the front surface to the back surface of the tab.

(2) The opening provided around the tab of the means (1) has a slit-like planar shape that extends long and narrow along the periphery of the tab.

(3) A plurality of openings provided around the tab of the means (1) are arranged along the periphery of the tab.

(4) The external terminals and leads of the semiconductor pellet mounted on the tab that connect the tab hanging leads around the surroundings are connected by coated wires in which the surface of the metal wire is coated with an insulator. In a resin-sealed semiconductor device in which a coated wire is sealed with resin, an opening is provided around the tab, excluding a connecting portion between the tab and a tab suspension lead, and penetrating from the front surface to the back surface of the tab.

[For production]

According to the above-mentioned means (1), the resin on the front side (semiconductor pellet mounting surface side) and the back side of the tab are connected at the peripheral part of the tab, and the tab and the resin are connected at the peripheral part of the tab. Since the adhesion of the tab can be improved, the movement of the resin due to temperature cycles around the tab can be reduced, and the stress generated in the coated wire can be reduced. As a result, breakage of the covered wire can be prevented, and reliability based on temperature cycles of the resin-sealed semiconductor device can be improved.

According to the above-mentioned means (2), the opening area of the opening in the peripheral portion of the tab can be increased, and the connection area of the resin on the front side and the back side of the tab can be increased in the peripheral portion of the tab. It is possible to further improve the adhesion between the peripheral portion of the tab and the resin, thereby further improving the reliability of the resin-sealed semiconductor device.

According to the above-mentioned means (3), the area of the area connecting the inner side (semiconductor pellet side) and the outer side (inner lead side) of the opening of the tab is increased in the peripheral portion of the tab,
The mechanical strength of the tab itself can be improved.

According to the above-mentioned means (4), in addition to the effect of the above-mentioned means (1), the mechanical strength of the region of the tab connected to the tab suspension lead can be improved.

Below, regarding the configuration of the present invention, Q
An embodiment in which the present invention is applied to a resin-sealed semiconductor device having an FP structure will be described.

In addition, in all the figures for explaining the embodiment, parts having the same functions are given the same reference numerals, and repeated explanations thereof will be omitted.

[Embodiments of the invention]

(Example I) The structure of a resin-sealed semiconductor device having a QFP structure, which is Example I of the present invention, is shown in FIG. 1 (cross-sectional view of main parts) and FIG. 2 (partial plan view).

As shown in FIGS. 1 and 2, in a resin-sealed semiconductor device 1 having a QFP structure, an external terminal (ponding pad) 2C and an inner lead 4B of a semiconductor pellet 2 are connected with a covered wire 5, respectively.

The semiconductor pellet 2 is mainly composed of a single crystal silicon substrate 2A, and a system circuit is mounted on the surface (element formation surface) of the single crystal silicon substrate 2A. This system circuit is composed of semiconductor elements (not shown). A wiring layer is provided on the surface of single crystal silicon substrate 2A with interlayer insulating film 2B interposed therebetween.

Of these wiring layers, the external terminal 2C is basically formed in the same layer as the uppermost wiring layer. The external terminal 2C is made of, for example, an aluminum alloy film. On the external terminal 2C,
Although no reference numerals are given, the barrier metal film is connected through a bonding opening formed in the final protective film (final badge giant film). One end of the coated wire 5 is connected to the external terminal 2C with this barrier metal film interposed therebetween.

The semiconductor pellet 2 is fixed onto the surface of the tab 4A (on the mounting surface of the semiconductor pellet 2) with an adhesive layer 3 interposed therebetween.

As the adhesive layer 3, for example, Ag paste, Au-8i eutectic alloy, etc. are used.

The tab 4A has a rectangular planar shape as shown in FIG. This tab 4A can be freely loaded with semiconductor pellets 2 of different types and external sizes, and can be mounted on the lead frame 4.
In order to reduce the number of types of semiconductor pellets, the semiconductor pellet 2 is constructed with a larger planar size than that of the semiconductor pellet 2 shown in FIG. For example, the resin-sealed semiconductor device 1 of this embodiment (2) has a tab 4 having a planar size of 7.2×7.2 [mm]
On the surface of A, the plane size is 2. A semiconductor pellet 2 formed of IX2.1 [mm] is mounted. The tab 4A is formed of, for example, a Fe-Ni alloy (for example, an Fe-based alloy containing 42% Ni). Also, tab 4A is this F
It is not limited to the e-Ni alloy, but may be made of a Cu-based material.

As shown in FIG. 2, the tab 4A has a tab suspension lead 4E near each corner of a rectangular planar shape.
connected to. That is, the resin-sealed semiconductor device [1 of Example I] is supported by the four tab suspension leads 4E.

As shown in FIG. 2, this tab 4A has an opening 4D having a slit-shaped planar shape extending long and narrow along its periphery.
is configured. The opening 4D basically consists of a through hole penetrating from the front side of the tab 4A to the back side thereof,
At the peripheral portion of the tab 4A, the resins (6) on the front and back sides of the tab 4A are connected. Opening 4D is tab 4A
Multiple pieces are arranged along the periphery of the . In the arrangement direction of the openings 4D, the space between the openings 4D of the tabs 4A is used as a connection area for connecting the inside (semiconductor pellet 2 side) and outside (inner lead 4B side) of the openings 4D of the tabs 4A. In other words, this connecting region ensures mechanical strength on the inside and outside of the opening 4D of the tab 4A, and also ensures the mechanical strength of the tab 4A itself. Further, the opening 4D is a tab 4A.
The connection part with the tab suspension lead 4E (in Figure 2, reference numeral 4)
It is configured in an area other than the area marked with F and surrounded by a dashed line. Since the maximum stress for supporting the tab 4A is applied to the connecting portion of the tab 4A with the tab suspension lead 4E, the opening 4D is not provided for the purpose of ensuring mechanical strength.

The opening 4D is formed by a semiconductor pellet 2 having a large planar size.
The width dimension (slit width dimension) is made smaller in order to reduce the occupied area in order to make it possible to mount the slit. On the other hand, if the width of the opening 4D is too small, stress concentration will cause the tab 4A to
Since cracks will occur in the opening 4D, take these into consideration.
Set the width dimension of In the resin-sealed semiconductor device 1 of Example I, the width dimension of the opening 4D provided in the tab 4A is approximately Q,2
[mm], and the opening 4D is arranged from a position of about 1.5 [mm] inward from the end surface around the tab 4D.

In addition, since the stress generated in the covered wire 5 is large in the central portion of each side of the tab 4A having a rectangular planar shape, the openings 4D are positively arranged in this area, and the connection area between the openings 4D is not arranged. .

The coated wire 5 is constructed by coating the surface of a metal wire 5A with an insulator 5B, as shown in FIG. In this embodiment I, the metal wire 5A is made of Au.

Also, metal! ! 5A is Cu, AΩ as materials other than the above.
, AQ alloy, or the like. In this embodiment I, the insulator 5B is made of polyurethane resin or polyimide resin. Further, the insulator 5B may be formed of a resin material other than the above-mentioned materials, such as an esterimide resin or an esteramide resin.

The covered wire 5 may be bonded by a ball and wedge bonding method or a wedge and wedge bonding method, but is not limited thereto.

That is, the coated wire 5 is bonded to each of the external terminal 2C and the inner lead 4B of the semiconductor pellet 2 basically by a bonding method using thermocompression bonding in combination with ultrasonic vibration.

The inner lead 4B and outer lead 4c are each integrally constructed, and are cut and molded from the same lead frame 4 as the tab 4A.

That is, the tab 4A, inner lead 4B, outer lead 4C, and tab suspension lead 4E are each made of the same material.

The aforementioned semiconductor pellet 2. Tab 4A, tab hanging lead 4
E, inner lead 4B, and coated wire 5 are each made of resin (
It is hermetically sealed with resin) 6. As the resin 6, for example, a thermosetting or thermoplastic epoxy resin is used.

In this way, the semiconductor pellet 2 mounted on the tab 4A
The external terminal 2C and the inner lead 4B are each connected to the metal wire 5.
In the resin-sealed semiconductor device 1, the tab 4A, the semiconductor pellet 2, the inner lead 4B, and the coated wire 5 are sealed with a resin 6. This tab 4 around 4A
An opening 4D penetrating from the front surface to the back surface of A is provided. With this configuration, the resin 6 on the front side (the mounting surface side of the semiconductor pellet 2) and the back side of the tab 4A are connected at the peripheral portion of the tab 4A, and the resin 6 and the tab 4A are connected at the peripheral portion of the tab 4A. Since the adhesion with the tab 4A can be improved, the movement of the resin 6 due to temperature cycles around the tab 4A can be reduced, and the stress (tensile stress, compressive stress) generated in the covered wire 5 can be reduced. As a result, breakage of the covered wire 5 can be prevented, and the reliability of the resin-sealed semiconductor device 6 based on temperature cycles can be improved.

Further, the opening 4D provided around the tab 4A has a slit-like planar shape that extends long and narrow along the periphery of the tab 4A. With this configuration, the opening area of the opening 4D in the peripheral portion of the tab 4A can be increased, and the connection area of the resin 6 on the front side and the back side of the tab 4A can be increased in the peripheral portion of the tab 4A. The adhesion between the peripheral portion of 4A and the resin 6 can be further improved, and the reliability of the resin-sealed semiconductor device 1 can be further improved.

Further, the external terminal 2C and the inner lead 4B of the semiconductor pellet 2 mounted on the tab 4A around which the tab suspension lead 4E is connected are connected by a coated wire 5 in which the surface of the metal wire 5A is coated with an insulator 5B. , in the resin-sealed semiconductor device 1 in which the tab 4A, the semiconductor pellet 2, the inner lead 4B, and the covered wire 5 are sealed with a resin 6, a connecting portion (4F) between the tab 4A and the tab suspension lead 4E;
An opening 4D is provided around the tab 4A, penetrating from the front surface to the back surface of the tab 4A. With this configuration, in addition to the above effects, the mechanical strength of the connection region (4F) connected to the tab suspension lead 4E of the tab 4A can be improved.

Table 1 listed at the end of the specification shows the results of a temperature cycle test conducted by the present inventor. Table 1 shows the tests of the resin-sealed semiconductor device 1 in which an opening 4D is provided around the tab 4A of Example I, and the conventional resin-sealed semiconductor device that does not have an opening around the tab. In each of the resin-sealed semiconductor devices W1 shown in the results, the coated wire 5 is forcibly brought into contact with the edge around the tab 4A, and then resin-sealed.
A part of the frame 4 was cut and molded. The temperature cycle test was performed after paper reflow at -50["Cco, 155
Each temperature ['C] was applied repeatedly for 30 [minutes]. As shown in Table 1, in the conventional resin-sealed semiconductor device, there is no defective product in which the coated wire 5 is broken in 500 samples after 100 temperature cycles, but after 1000 temperature cycles. There were as many as 30 defective products. In contrast, the resin-sealed semiconductor device 1 of Example I did not produce any defective products during the temperature cycles from 100 to 1000 times.

(Example 2) This example 2 is a second example of the present invention in which the disadvantages caused by forming an opening in the peripheral portion of the tab in the resin-sealed semiconductor device of Example I are reduced.

FIG. 3 (partial plan view) shows a resin-sealed semiconductor device having a QFP structure, which is Embodiment 2 of the present invention.

The resin-sealed semiconductor device ti of this embodiment (2) is the same as that of the embodiment I
Instead of the slit-shaped opening 4D, an opening 4D having a circular planar shape is provided around the tab 4A. A plurality of openings 4D (a larger number than the number of slits described above) are arranged along each side of the planar rectangular shape of the tab 4A. opening 4
The cross-sectional structure of D is configured to penetrate from the front side to the back side of the tab 4A as described above. This frontage 4D can increase the area occupied by the connecting region between the openings 4D in the arrangement direction.

In this way, in the resin-sealed semiconductor device 1 using the coated wire 5, a plurality of openings 4D are arranged in the tab 4A along its periphery. With this configuration, the area of the connection region that connects the inside (semiconductor pellet 2 side) and outside (inner lead 4B side) of the opening 4D of the tab 4A in the peripheral portion of the tab 4A is increased, and Mechanical strength can be improved.

Note that the planar shape of the openings 4D arranged around the tab 4A is not limited to a circular shape, but may be formed in a rectangular shape, an elliptical shape, or the like.

In addition, areas where the covered wire 5 may come into contact (areas that allow touch), such as the edges around the tab 4A, are chamfered or rounded to reduce stress concentration on the covered wire 5. By dispersing the wires, breakage defects in the covered wire 5 can be further prevented.

As above, the invention made by the present inventor has been specifically explained based on the above embodiments, but the present invention is not limited to the above embodiments, and can be modified in various ways without departing from the gist thereof. Of course.

For example, the present invention applies to DIP structures other than QFP structures, LC
It can be applied to resin-sealed semiconductor devices such as C structure and ZIP structure.

Furthermore, the present invention can be applied to a resin-sealed semiconductor device, such as a TAB structure, which uses a covered wire and partially seals it with resin.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

In resin-sealed semiconductor devices that use coated wire,
Breakage defects of the covered wire can be prevented.

The reliability against temperature cycles of a resin-sealed semiconductor device using covered wire can be improved.

In addition to the above-mentioned effects, the adverse effects caused by obtaining the above-mentioned effects can be reduced.

Table 1

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a resin-sealed semiconductor device having a QFP structure, which is Example I of the present invention. FIG. 2 is a partial plan view of the resin-sealed semiconductor device, and FIG. 3 is a partial plan view of the resin-sealed semiconductor device of the QFP structure, which is Embodiment (2) of the present invention. In the figure, 1...Resin-sealed semiconductor device, 2...Semiconductor pellet, 2C...External terminal, 4A...Tab, 4B
... Inner lead, 4D... Opening, 4E... Tab suspension lead, 4F... Connection area, 5... Covered wire, 6... Resin.

Claims (1)

[Claims] 1. Each of the external terminals and leads of the semiconductor pellet mounted on the tab is connected with a coated wire in which the surface of the metal wire is coated with an insulator, and the tab, the semiconductor pellet, the lead, and the coated wire What is claimed is: 1. A resin-sealed semiconductor device in which the tab is sealed with a resin, the resin-sealed semiconductor device being characterized in that an opening is provided around the tab to penetrate from the front surface to the back surface of the tab. 2. The resin-sealed semiconductor device according to claim 1, wherein the opening provided around the tab has a slit-like planar shape that extends long and narrow along the periphery of the tab. 3. The resin-sealed semiconductor device according to claim 1, wherein a plurality of openings are arranged around the tab. 4. External terminals and leads of the semiconductor pellet mounted on the tab that connect the tab hanging lead around the tab are connected to each other with a coated wire that is coated with an insulator on the surface of the metal wire, and the tab, semiconductor pellet, lead, and A resin-sealed semiconductor device in which a coated wire is sealed with resin, characterized in that an opening is provided around the tab to penetrate from the front surface to the back surface of the tab, except for the connecting portion between the tab and the tab suspension lead. A resin-sealed semiconductor device.