JPS5821362A - Lead frame - Google Patents

Abstract

PURPOSE:To prevent the deformation of the lead frame generated when sealed with resin by forming a notch to the frame base section of a unit lead frame in the direction crossing with the longitudinal direction. CONSTITUTION:One notches 38 shaped to the frame base section 36 from the outsides toward other end surfaces from the end surfaces of the frame base section and two ones from the lead side at the inside are alternately formed in parallel and in bilateral symmetrical shape in the frame of the unit lead frame. The width of the notches may be approximately treble of the thickness of the lead frame, length and extent exceeding the center of the width of the frame base section 36, the mutual shortest distance approximately treble of plate thickness and the number of the notches approximately three. When the lead frame according to this constitution is sealed with resin, the notches are expanded and contracted to external stress due to the shrinkage of the resin, the frame base section is deformed only in the longitudinal direction of the lead frame, compressive stress generated at the frame base section is buffered while the tensile stress of external connecting leads is also buffered simultaneously, and deformation is completely prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lead frame, and particularly to a lead frame
The present invention relates to a structure of a lead frame that can prevent deformation of the lead frame that occurs when a 4I4I4 is used in the production of resin-sealed electronic components such as conductor devices.

Conventionally, lead frames for resin-sealed semiconductor devices in which unit shapes are regularly and continuously formed in a band-like manner are designed to buffer the tensile stress applied to the external leads during resin encapsulation. A structure has been proposed in which a through hole is formed in the longitudinal direction of the flexible member that connects the external leads of the unit lead frame.Such a structure is shown in Figure 1. Stage support bar, 8 is internal lead, 4
is the outside m * continuation lead, S is the first sexy girl, 6 is m
s safe scene par, 7 is the base of the 7th frame, and 8 is the guide hole. A through hole 9 is provided in the S-th sexy pumper 6 in its longitudinal direction. In addition, in the figure, the area marked by a single dot chain indicates a unit lead frame (qh conductor device - divided frame).

In this case, the outer S connection lead 4 is pulled in its longitudinal direction due to the tensile stress caused by the shrinkage of the resin during resin sealing, and the width of the through hole 90 provided in the seven cylinder 6 is expanded, thereby buffering the tensile stress. However, even if the deformation t-a in the length direction of the strip-shaped lead frame is corrected, there is a drawback that deflection occurs in the thickness direction.

In addition, as shown in No. 34, each S of the unit lead frame
Connecting lead and the outside of the unit lead frame that matches this
If the rt7t lead frame is directly connected to the B connection lead, the shrinkage of the resin during resin sealing will cause tensile stress in the external loose thread lead, and compressive stress will occur in the Since there is no means for stress relief, the entire lead frame is deformed. In addition, Th781 diagram>
tn, the same parts as those shown in the first #IA are given the same reference numerals.

In this way, in the conventional lead claim, the 7th leg and the outer lead bend and have a click feeling, resulting in an equilibrium state at 7t, so it is necessary to apply strong tensile stress to the outer lead at the same time as trying to flatten it. This leads to loosening of the 1st resin sealing part, which impairs airtightness, and also allows moisture to enter during the processing process after resin sealing, causing a great deal of trouble. When a foreshadowing lead frame with residual stress such as tensile stress remaining in the processing process is treated with a hydrochloric acid solution, stress corrosion cracking (8trHs
This phenomenon is called erosion (oracktng), where the erosion progresses to an extreme extent in some parts and causes breakage, which causes trouble in the plating process after resin sealing.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lead frame having a structure that prevents deformation of the lead frame after resin sealing by providing a notch-like groove in the frame portion of the lead frame.

Therefore, according to the present invention, a lead frame is provided in which a notch is provided at the base of the seven frames in a direction intersecting the length direction of the lead frame.

In other words, the present invention focused on the fact that tensile stress is generated in the external leads of the lead frame due to contraction of the resin after resin sealing, and conversely, flattening stress is generated in the frame portion parallel to the external leads. Compressive stress occurs and the frame Sj
! I! Notches t"7 formed from the surface toward the other mriii- are provided alternately from the outside @ direction and the inside jliill of the 7th layer, and the effect of the notches aS expanding and contracting in response to external stress causes the IIi fat sealing. The 4L is designed to buffer the compressive stress generated in the frame portion of the stopper, and also buffers the tensile stress generated in the external lead to prevent deformation of the lead frame.

The present invention will be explained in detail below with reference to an embodiment. Figure 8 shows an embodiment of the lead 7v-me according to the present invention.

In PJm, 81 is a die stage (semiconductor element bottom layer), 8B is a stage support bar, and 88 is a circular part (lead).
%84 is an external pattern lead, 85 is a sexy amber, aS
The ti frame base 87 is a guide hole.

, and according to the present invention, according to the lead frame, the seven-layer base 86 has the seven-layer base 86. 1s8
Notches 'ties are disposed in a direction perpendicular to the longitudinal direction of 6.

In Figure 1, the area between the dot chain layers indicates the unit lead frame (lead frame for one semiconductor device) bond area.
1i1L1 g(am)2)41186←lOJ (D
It is formed by pressing a strip of iron/nickel alloy containing x-y'lk. This jj6 meeting, frame j1ifi1$86ri so fL&! 1 (1f
In a lead frame having a length of 36 degrees, the notch 88 provided in the frame base 86 is the same as the notch 88 formed in the frame base 86, which is formed so as to face from the frame jlt part jIi11 direction of the unit lead frame to the other direction side. Three parallel notches, one from the outer direction and two from the inner lead side #1 surface, were provided at symmetrical positions on the frame base of each unit lead frame.

Notch! The width of 88 is 0.8 [deception] binding 1, the length is 1.5 (41111), the shape of the tip 1m part is circular arc, and the IIk short distance S between the notches is 1G (u
)・The width of the notch 88 is approximately 8 times the ridge thickness of the lead frame.
The problem is that the shortest distance between the notches is about 8 times the thickness of the plate, and the number of notches is three in one place. It is true.

In addition, the notches shown in - do not need to be provided in a direction perpendicular to the longitudinal direction of the 7-ray 5jIi, and are rarely provided in a diagonal view. The Iia notch 'fi may be placed at the Jll elevation of the unit lead frame if it does not result in a decrease in the rigidity of the lead frame.

Resin sealing is simultaneously performed on the resin sealing area of the lead frame in a state where the unit lead frames are 1*atS connected. Epoxy resin or the like is used for the sealing am.

When the lead frame is attached to the resin sealing jig, it is fixed by a guide hole provided in the frame part, and the position of the lead frame is determined in a straight state and the lead frame is sealed with resin. Resin sealing is performed by heating to 160-180 L°C (usually 160-180 L°C), and after the resin is assimilated, it is taken out from the resin sealing process.

In this resin sealing process, the sealing resin has a large yield compared to the lead 7 layer during the cooling process from the heated state during sealing to room temperature and the subsequent ringing process. This contraction of the sealing resin acts simultaneously on the center of each unit lead frame.

In other words, the shrinkage of the sealing resin acts on the outer S* connection lead as a tensile force, and at the same time, the compressive stress acts on the frame base as a reaction to the tensile stress of the outer fluorocarbon lead. arises as

However, in the lead frame according to the present invention, a notch i is provided in the frame base, and due to the effect of this notch expanding and contracting in response to external stress, the frame base deforms only in the longitudinal direction of the lead frame. At the same time, it can buffer the negative energy of 7 Les 5 Kis and Q9 compression.
The tensile stress of the external connection leads in a relative relationship can also be buffered at the same time.The lead frame according to the present invention thus formed and the conventional lead frame are sealed with resin under the same conditions. When using the conventional lead frame shown in S-, the condition was as shown in Fig. 4, and when the lead frame of the present invention was used, the foreshadowing as shown in Fig. 511 was obtained.・FIG. 5 11iVhzn is also 7 after resin sealing, and is a view IIjA as seen from the direction side of one piece. death certificate 4
In the case of the conventional lead frame shown in Fig. 5 and Fig. 5, 41.51 indicates resin sealing.In other words, in the case of the conventional lead frame shown in Fig. 1, the outer S folds are hardly deformed, but the frame base It transformed into L as shown in Figure 4.

If you try to correct the deformation of the lead frame in this state, a slight external force will cause a clicking sensation and the top will warp and reverse. At this time, it was found that a large tensile stress was temporarily generated on the outer connecting lead 4. 90 On the other hand, in the case of the lead frame of the present invention, macroscopic deformation does not occur in both the L and outer S connection leads 84.7 V and F in Fig. 5, and the nine notched holes installed at 1 mH of the frame base do not occur. No. 88 was only deformed in the longitudinal direction of the lead frame, and no deformation in the thickness direction of the lead frame was observed.

Furthermore, the conventional lead frame shown in FIG.
In this case, after resin sealing, it was observed that the external Iik wire lead 4 was moving in the direction where the hole with a width of 9 (LO) in the center of the sector /... (-) became wider. It was also observed that the lead frame of ``Sexy Idiom <-6'' itself was deformed by bending in the direction of the thickness of the lead frame, and it was observed that it had a slight click feeling.

The deformation of the dangerous conventional glue board 7 frame shown in Figure 1 is #
Although it is in better condition than the conventional lead frame shown in Figure III, there is some deformation in the thickness direction around the lead frame (-6). Since the leads are moved so that the hole e becomes wider, an adverse effect 1# will be exerted on the resin-sealed semiconductor element.

When a conventional lead frame is used for 15%/h, deformation is observed in the lead frame, but when the lead frame of the present invention is used, the notch provided in the flange part is By deforming only in one direction, the stress generated during resin sealing is completely alleviated, providing an effect not found in conventional lead frames.

According to the present invention, the resin sealing part and the external lead do not become loose or fall out, which is caused by the deformation of the lead frame during the processing process after resin sealing, and the airtightness is not impaired. There is no problem with handling during the process.Furthermore, since the internal stress that occurs during EMI sealing is completely buffered, it is also possible to prevent the phenomenon of stress A-11ij that occurs during plating processing, etc.

Figure 46 is a drawing showing another 14h example of the present invention.In this embodiment, the die stage 61t is arranged at the center, and leads 68 extend outward in the vicinity L of the die stage 61t. 6s is connected to the frame base 68 and the sexy member 64, and the die stage 61 is connected to the stage support par 6.
5 to 19 frame bases 68 is a lead frame connected to a sexy member 64.F: A lead frame having 19 frames is also provided with 14 notches 65 in the frame base 68 according to the present invention. By providing the lead frame in the sexy member 64, it is possible to prevent deformation of the lead frame and obtain the same effect as in the above embodiment. Not only the Y-D7 frame but also an independent ``lead frame''.
,,:“It goes without saying that the same applies to m-uses. Also, the shape, direction, installation location, number, etc. of the notched pegs of the present invention can be arbitrarily selected within the range that can buffer the stress. Further, in the above embodiment, the notches are provided alternately from five directions, and the notches may be provided only from one of the four sides.
Although two installation locations per unit lead frame were installed at symmetrical positions, the effects of the present invention can be expected even if installed at asymmetrical positions or only at one location, but in order to achieve a well-balanced stress buffering, it is necessary to install at both sides of the 7 frame direction. It is preferable to provide the notch cages according to the present invention alternately and at the same time in symmetrical positions.In addition, the notch cages according to the present invention may be provided at the unit lead frame location of the lead frame shown in Figure 1 above. In this case, a notch may be provided, for example, at the boundary of the unit lead frame (at the top of the chain).

According to the present invention, in a lead frame for a resin-sealed electronic S product, the deformation of the lead frame due to contraction of the resin during resin sealing is avoided by eliminating deformation in the thickness direction of the lead frame due to the notch provided in the frame part. This buffer prevents the resin-sealed semiconductor elements from being adversely affected, such as loosening, disconnection, and loss of airtightness between the resin-sealed part and the leads, and also prevents problems in the processing process after resin-sealing. It has the effect of making you stop writing. Therefore, the present invention is not limited to resin-sealed layer semiconductor devices, but can be effectively applied to other resin-sealed electronic products.

[Brief explanation of the drawing]

1 and 8 are views showing the configuration of a conventional lead frame 7, FIG. Figure S shows the state after resin sealing, and Figure S shows the state after resin sealing of the 14 lead frame according to the present invention shown in Fig. 8.
Figure iJ and Figure 6 are front views showing other embodiments of the present invention.・・・・・・・・・・・・・・・
・Internal lead 4.44・・・・・・・・・・・・・・・
...Outer fs connection lead 7eJ16*6g...
...6...Frame base 88e@5...
・・・・・・・・・・・・Notch 1 Concave VZ Turning 3 Figure % 4 Figure 5 and a half. ' 8 Procedural amendment (method) 1985 1" 8 a Title of the invention Lead frame a Person making the amendment a Date of amendment order January 26, 1985 ζ 1". 6 Number of inventions increased due to amendment None L Specification J
Correct "Figure 2" in the 9th line of the 13th member as shown in F below. “Figure 3” Agent: Hiroshi Matsuoka, patent attorney f, me −＋ψ(−ni゛

Claims (1)

[Claims] A lead frame for a resin-sealed electronic component, characterized in that a notch *1 is provided at the base of the unit lead frame in a direction intersecting the length direction of the lead frame.