Lead frame

Abstract

To provide a lead frame capable of improving the reliability of a semiconductor device or the like, and a product thereof.SOLUTION: To remarkably improve the reliability of a product such as a semiconductor device by manufacturing the product such as the semiconductor device by using a lead frame including a suspension lead connected to a die pad and having an intrusion preventing means such as a barrier part for preventing the intrusion of flux.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a lead frame useful for semiconductor devices and the like, and to a product thereof. [Background technology]

[0002] The lead frames used in conventional semiconductor devices have a large effect on the reliability of the semiconductor devices, and therefore various investigations have been carried out into the manufacturing methods thereof.

[0003] In recent years, various methods for manufacturing lead frames for use in non-leaded semiconductor devices have been investigated. In non-leaded semiconductor devices, such as QFN (Quad Flat Non-Leaded Package), in which the undersides of the leads (external electrode terminals) are exposed on the mounting surface side of the package (the underside of the resin encapsulant), a mold lock is formed by half-etching a portion of the underside of the inner lead of the lead, for example, the tip. When encapsulating with resin, a portion of the resin is caused to wrap around the tip of the underside of the inner lead, thereby forming a mold lock. This prevents the lead from falling off the resin encapsulant (see, for example, Patent Document 1). However, adding a half-etching process to lead frame manufacturing reduces the productivity of the lead frame and increases the manufacturing cost of the lead frame. Therefore, as a method for manufacturing lead frames inexpensively and with high productivity, a taper is formed by stamping (punching) the corners of the leads on the mounting surface side of the lead, thereby narrowing the width of the leads exposed on the mounting surface side of the resin encapsulant, thereby preventing the leads from falling off the resin encapsulant (see, for example, Patent Document 2). Also, by stamping, the cross-sectional shape of the lead whose underside is exposed on the mounting surface side of the resin encapsulant is made into an inverted trapezoid, and the width of the lead located inside the resin encapsulant is made wider than the width of the lead exposed on the mounting surface side of the resin encapsulant, thereby preventing the lead from falling off from the resin encapsulant (see, for example, Patent Document 3). Furthermore, a partial crushing press process is performed on the upper surface of a lead molded to a rectangular cross section, providing protrusions on both upper sides of the lead, and the protrusions are embedded in the resin when the resin encapsulant is formed, thereby preventing the lead from falling off from the resin encapsulant (see, for example, Patent Document 4). Also, a method has been considered in which the lead is molded to a rectangular cross section, and after performing a chamfering process to press the lower corners of the lead, the upper corners of the lead are crushed to form lower protrusions on both lower sides of the lead and upper protrusions on both upper sides of the lead, thereby performing mold locking (see, for example, Patent Document 5).

[0004] However, none of the conventional methods has been able to sufficiently improve the reliability of semiconductor devices and the like, and has not yet been satisfactory. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-22725 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-15668 [Patent Document 3] WO2002 / 061835 publication [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-73570 [Patent Document 5] Japanese Patent Application Laid-Open No. 2012-222335 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a lead frame and a product thereof that can improve the reliability of semiconductor devices and the like. [Means for solving the problem]

[0007] As a result of intensive research to achieve the above-mentioned object, the inventors have discovered that a lead frame including a suspension lead connected to a die pad, in which an intrusion prevention means for preventing flux from entering is provided on the suspension lead within the sealing resin, can dramatically improve the reliability of semiconductor devices and the like, and have found that such a lead frame can solve the above-mentioned conventional problems in one fell swoop. Furthermore, after obtaining the above findings, the present inventors conducted further studies and completed the present invention.

[0008] That is, the present invention relates to the following inventions. [1] A lead frame including a suspension lead connected to a die pad, characterized in that the suspension lead is provided with an intrusion prevention means for preventing flux from infiltrating. [2] The lead frame according to [1], wherein the intrusion prevention means is a barrier portion for preventing the intrusion of the flux. [3] The lead frame according to [2], wherein the barrier portion is within a sealing resin. [4] The lead frame according to [1], wherein the intrusion prevention means is a shape obtained by deforming a part of the suspension lead within the sealing resin. [5] The lead frame according to [1], wherein the intrusion prevention means is a processed portion of the suspension lead in the sealing resin. [6] An electronic device including a lead frame, wherein the lead frame is the lead frame described in [1]. [7] An electronic component including a lead frame, wherein the lead frame is the lead frame described in [1]. [8] A product including a lead frame, wherein the lead frame is the lead frame described in [1]. [Effects of the Invention]

[0009] The lead frame of the present invention can improve the reliability of semiconductor devices and the like. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing an example of a preferred lead frame of the present invention; [Figure 2] 2A and 2B are four trigonometric views of the lead frame of FIG. 1. (A) is a plan view, (B) is a front view, (C) is a bottom view, and (D) is a right side view. DETAILED DESCRIPTION OF THE INVENTION

[0011] The lead frame of the present invention is a lead frame including a suspension lead connected to a die pad, characterized in that the suspension lead is provided with an intrusion prevention means for preventing the intrusion of flux. The die pad is not particularly limited as long as it does not impede the object of the present invention, and may be a known die pad. The suspension lead may be any known suspension lead as long as it is provided with an intrusion prevention means for preventing the intrusion of flux.

[0012] In the present invention, it is preferable that a barrier portion for preventing the intrusion of the flux is used as the intrusion prevention means. According to such a preferable range, the intrusion of the flux can be prevented more efficiently. The barrier portion is not particularly limited as long as it can prevent the intrusion of the flux. For example, a means for preventing the intrusion of the flux in the suspension lead with an obstacle can be used.

[0013] In the present invention, the barrier portion is preferably located within the sealing resin. According to this preferred range, the reliability of the semiconductor device can be improved more efficiently.

[0014] The sealing resin may be a thermosetting resin, and more specifically, epoxy resin, silicone resin, etc. are often used. When an epoxy resin is used, the sealing resin is molded by a method such as transfer molding. When a thermoplastic resin is used as the sealing resin, the sealing resin is molded by a method such as injection molding. A semiconductor element equipped with semiconductor components is usually connected to a lead frame by bonding wires.

[0015] The bonding wire used in the present invention is made of metals such as gold, copper, and aluminum. Examples of bonding wires include gold wire, aluminum wire, and copper wire. The temperature during wire bonding may be within a range of 80 to 250°C or 80 to 220°C. The heating time may be from a few seconds to a few minutes. Wire bonding may be performed by combining ultrasonic vibration energy and pressure-bonding energy by applying pressure while the wire is heated within the above temperature range.

[0016] The lead frame used in the present invention is made of a metal such as a copper alloy or an iron alloy.

[0017] In the present invention, the intrusion prevention means is preferably a shape obtained by deforming a part of the suspension lead within the sealing resin. According to this preferred range, the intrusion of flux can be prevented more efficiently and the adhesion between the lead and the sealing resin can be improved.

[0018] In the present invention, the intrusion prevention means is preferably a processed portion formed by processing a part of the suspension lead within the sealing resin. According to this preferred range, the intrusion of flux can be more efficiently prevented and the reliability of the semiconductor device (especially the LED) can be dramatically improved.

[0019] Preferred embodiments of the present invention will be described in more detail below with reference to the drawings, but the present invention is not limited to these specific examples.

[0020] FIG. 1 is a schematic diagram of a preferred lead frame of the present invention. FIG. 2 is a four-sided trigonometric view of the lead frame of FIG. 1. The lead frame of FIGS. 1 and 2 is formed from a die pad 1 and a suspension lead 2, and a barrier portion 3 is provided on the suspension lead 2. The barrier portion 3 is formed by chipping the suspension lead 2 inside the encapsulation resin, and this configuration efficiently prevents the intrusion of flux. The chipping may be a crushing process, and such a processing method is not particularly limited as long as it does not impede the object of the present invention, and may be any known processing method.

[0021] Example 1 The lead frame shown in Figures 1 and 2 was fabricated as a prototype and evaluated for the presence or absence of flux and whether or not reliability improved after packaging. Furthermore, as a comparative example, the lead frame described in Patent Document 5 was fabricated as a prototype and similarly evaluated for the presence or absence of flux and whether or not reliability improved after packaging. As a result, the product of the present invention was able to significantly prevent flux penetration, and improved reliability was also observed. On the other hand, the comparative example was unable to prevent flux penetration, and no improvement in reliability was observed. [Industrial Applicability]

[0022] The lead frame of the present invention is useful for semiconductor devices and the like. [Explanation of symbols]

[0023] 1 die pad 2 Hanging leads 3 Barrier section 4 Sealing resin

Claims

1. A lead frame including a suspension lead connected to a die pad, characterized in that the suspension lead is provided with an intrusion prevention means for preventing flux from intruding.

2. 2. The lead frame according to claim 1, wherein the intrusion prevention means comprises a barrier portion for preventing the intrusion of the flux.

3. 3. The lead frame according to claim 2, wherein the barrier portion is located within a sealing resin.

4. 2. The lead frame according to claim 1, wherein said intrusion prevention means is a shape obtained by deforming a part of said suspension lead within said sealing resin.

5. 2. The lead frame according to claim 1, wherein said intrusion prevention means is a processed portion formed by processing a part of said suspension lead within said sealing resin.

6. 10. An electronic device including a lead frame, said lead frame being the lead frame of claim 1.

7. 10. An electronic component including a lead frame, wherein said lead frame is the lead frame according to claim 1.

8. 10. An article of manufacture including a lead frame, said lead frame being the lead frame of claim 1.

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