MAP type lead frame

Abstract

This invention provides a MAP-type lead frame and its products that can improve the reliability of semiconductor devices and the like. [Solution] By manufacturing semiconductor devices and other products using a lead frame of the MAP type that includes leads, in which intrusion prevention means, which are two or more stepped recesses that prevent flux and moisture from entering, are provided on the leads or suspension leads, the reliability of semiconductor devices and other products can be dramatically improved.

Description

Technical Field

[0001] The present invention relates to a MAP type lead frame useful for semiconductor devices and the like, and products thereof.

Background Art

[0002] Conventionally, various studies have been made on the manufacturing method and the like of a MAP type lead frame used for semiconductor devices and the like because it greatly affects the reliability of semiconductor devices and the like.

[0003] In recent years, a method for manufacturing a lead frame used for a non-leaded semiconductor device has been studied. In a non-leaded semiconductor device such as a QFN (Quad Flat Non-Leaded Package) that exposes the lower surface (external electrode terminal) of a lead on the mounting surface side of the package (the lower surface side of the resin sealing body), a retaining portion is formed in a part of the lower surface of the lead, and the sealing resin wraps around below the retaining portion to form a mold lock portion so that the lead does not fall off from the resin sealing body (package). (For example, refer to Patent Document 1)

[0004] However, none of the conventional methods can sufficiently prevent the intrusion of flux and moisture, and the reliability of semiconductor devices and the like is still not satisfactory.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

Means for Solving the Problems

[0007] As a result of diligent research to achieve the above objective, the inventors have found that a lead frame having a recessed or convex portion on a part of the sealing resin contact surface of the lead or suspension lead can efficiently prevent flux and moisture from entering, and can also achieve excellent adhesion, thus solving the above-mentioned conventional problems all at once. Furthermore, after obtaining the above findings, the inventors conducted further studies and completed the present invention.

[0008] In other words, the present invention relates to the following invention. [1] A MAP type lead frame, characterized in that a part of the sealing resin contact surface of the lead or suspension lead is provided with an uneven surface consisting of a recess or a protrusion. [2] The lead frame according to [1], wherein a plurality of the aforementioned protrusions and indentations are provided. [3] The lead frame according to [1], wherein the uneven portion has a stepped shape of two or more steps. [4] The lead frame according to [1], wherein the uneven portion is located within the sealing resin. [5] The lead frame according to [1], wherein the uneven portion is shaped by deforming a part of the lead or suspension lead within the sealing resin. [6] The lead frame according to [1], wherein the uneven portion is a processed portion obtained by processing a part of the lead or suspension lead within the sealing resin. [7] An electronic device including a lead frame, wherein the lead frame is the lead frame described in [1]. [8] An electronic component including a lead frame, wherein the lead frame is the lead frame described in [1]. [9] A product comprising 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 drawing]

[0010] [Figure 1] This is a schematic diagram showing an example of a preferred MAP-type lead frame of the present invention. [Figure 2] This is a cross-sectional view along line aa in Figure 1. [Figure 3] Figure 2 shows a modified example of the lead, part 1. [Figure 4] Figure 2 shows a modified example of the lead. [Figure 5] This is a modified example 3 of the lead shown in Figure 2. [Figure 6] This is a modified example 4 of the lead shown in Figure 2. [Modes for carrying out the invention]

[0011] The lead frame of the present invention is a MAP-type lead frame, characterized in that a portion of the sealing resin contact surface of the lead or suspension lead is provided with an uneven surface consisting of a recess or a protrusion. In the present invention, it is preferable that there are multiple such uneven surfaces. This preferred range allows for more efficient prevention of the intrusion of flux, moisture, and the like. Furthermore, in the present invention, it is preferable that the uneven surfaces have a stepped shape of two or more steps. This preferred range allows for easier prevention of the intrusion of flux, moisture, and the like while maintaining good adhesion. In the present invention, having the uneven surfaces within the sealing resin allows for more effective prevention of the intrusion of flux, moisture, and the like. The aforementioned lead is not particularly limited as long as it is a lead used in a MAP-type lead frame, and may be a known lead. Similarly, the aforementioned suspension lead is not particularly limited as long as it is a suspension lead used in a MAP-type lead frame, and may be a known suspension lead.

[0012] In the present invention, it is preferable that the concavo-convex portion further includes a concavo-convex portion formed by a concave portion or a convex portion. The concavo-convex portion is not particularly limited as long as it is composed of a concave portion or a convex portion, and it may be a concavo-convex portion composed of a convex portion or a concavo-convex portion composed of a concave portion. Further, the concavo-convex portion does not have to have a regular shape and may have a shape such as a substantially triangular shape, a substantially quadrilateral shape (e.g., a substantially square shape, a substantially rectangular shape, or a substantially trapezoidal shape, etc.), a substantially pentagonal shape, a substantially hexagonal shape, etc., a substantially circular shape, a substantially elliptical shape, etc. Further, the cross-sectional shape of the concave portion or the convex portion of the concavo-convex portion is not particularly limited, and examples thereof include a substantially U-shaped cross-section, a substantially inverted U-shaped cross-section, and a substantially rectangular cross-section.

[0013] In the present invention, it is preferable that the concavo-convex portion is within the sealing resin. According to such a preferable range, the reliability of the semiconductor device can be more efficiently improved.

[0014] Examples of the sealing resin include thermosetting resins, and more specifically, epoxy resins, silicone resins, etc. are often used. When an epoxy resin is used, the sealing resin is formed by a transfer molding method or the like. When a thermoplastic resin is used as the sealing resin, the sealing resin is formed by an injection molding method or the like. A semiconductor element on which a semiconductor component is mounted is usually connected by a lead frame and bonding wires.

[0015] In addition, metals such as gold, copper, and aluminum are used as the materials used for the bonding wires used in the present invention. As the bonding wire, for example, a gold wire, an aluminum wire, a copper wire, etc. are used. The temperature at the time of wire bonding may be within the range of 80 to 250°C or 80 to 220°C. The heating time may be several seconds to several minutes. Wire bonding may be performed by a combination of vibration energy by ultrasonic waves and pressure bonding energy by applied pressure while being heated within the above temperature range.

[0016] In addition, metals such as copper alloys and iron alloys are used as the materials used for the lead frames used in the present invention.

[0017] Further, in the present invention, it is preferable that the concavo-convex portion has a shape obtained by deforming a part of the lead or the suspension lead in the sealing resin. According to such a preferable range, intrusion of flux, moisture, etc. can be more efficiently prevented, and the adhesion between the lead and the sealing resin can be made better.

[0018] Also, in the present invention, it is preferable that the concavo-convex portion is a processed portion obtained by processing a part of the lead or the suspension lead in the sealing resin. According to such a preferable range, intrusion of flux, moisture, etc. can be more efficiently prevented, and the reliability of the semiconductor device can be significantly improved.

[0019] Hereinafter, preferred embodiments of the present invention will be described more specifically with reference to the drawings, but the present invention is not limited to these specific examples. All of the preferred embodiments of the present invention shown below have a plurality of the concavo-convex portions, the concavo-convex portions have a stepped shape of two or more steps, the concavo-convex portions are in the sealing resin, the concavo-convex portions have a shape obtained by deforming a part of the lead or the suspension lead in the sealing resin, and the concavo-convex portions are processed portions obtained by processing a part of the lead or the suspension lead in the sealing resin.

[0020] FIG. 1 is a schematic configuration diagram of a preferred MAP type lead frame of the present invention, in which concavo-convex portions are provided at the ends of the leads and the suspension leads. The lead frame of FIG. 1 includes a lead 1, a suspension lead 2, a first concavo-convex portion 3, a second concavo-convex portion 4, a sealing resin 6, a die pad 7, a semiconductor chip 8, and a bonding wire 9. Figure 2 is a cross-sectional view along line aa shown in Figure 1, and the lead 1 is provided with a first uneven portion 3 and a second uneven portion 4. The first uneven portion 3 and the second uneven portion 4 are formed by creating two or more steps in the lead 1 inside the sealing resin 6, and this configuration efficiently prevents the intrusion of flux and moisture. The processing means for the stepping is not particularly limited as long as it does not hinder the objective of the present invention and may be known processing means. The width and depth or height of the recesses or protrusions of the first uneven portion 3 and the recesses or protrusions of the second uneven portion 4 are not particularly limited as long as they do not hinder the objective of the present invention, but in the present invention, the width is preferably 1 μm to 10 mm, and the depth or height is preferably 1 μm to 10 mm. According to these preferred ranges, better adhesion can be achieved and the intrusion of flux and moisture can be prevented more efficiently.

[0021] Figure 3 shows Modification 1 of the lead shown in Figure 2. In Modification 1, the lead 1 is provided with a first uneven portion 3 and a second uneven portion 4. This improves the adhesion between the lead and the sealing resin, and more efficiently prevents the intrusion of flux and moisture. The width and depth or height of the recesses or protrusions of the first uneven portion 3 and the recesses or protrusions of the second uneven portion 4 are not particularly limited as long as they do not hinder the purpose of the present invention, but in the present invention, the width is preferably 1 μm to 10 mm, and the depth or height is preferably 1 μm to 10 mm. According to these preferred ranges, better adhesion can be achieved, and the intrusion of flux and moisture can be prevented more efficiently.

[0022] Figure 4 shows a modified example 2 of the lead shown in Figure 2. In modified example 2, the lead 1 is provided with a first uneven portion 3, a second uneven portion 4, and a third uneven portion 5. This further increases the bonding area between the lead and the sealing resin, making it possible to more efficiently prevent the intrusion of flux and moisture. The width and depth or height of the recesses or protrusions of the first uneven portion 3, the recesses or protrusions of the second uneven portion 4, and the recesses or protrusions of the third uneven portion 5 are not particularly limited as long as they do not hinder the purpose of the present invention, but in the present invention, the width is preferably 1 μm to 10 mm, and the depth or height is preferably 1 μm to 10 mm. According to these preferred ranges, better adhesion can be achieved, and the intrusion of flux and moisture can be more efficiently prevented.

[0023] Figure 5 shows a modified example 3 of the lead shown in Figure 2. In modified example 3, the lead 1 is provided with a first uneven portion 3, a second uneven portion 4, and a third uneven portion 5. This further improves the adhesion between the lead and the sealing resin, and more efficiently prevents the intrusion of flux and moisture. The width and depth or height of the recesses or protrusions of the first uneven portion 3, the recesses or protrusions of the second uneven portion 4, and the recesses or protrusions of the third uneven portion 5 are not particularly limited as long as they do not hinder the purpose of the present invention, but in the present invention, the width is preferably 1 μm to 10 mm, and the depth or height is preferably 1 μm to 10 mm. According to these preferred ranges, better adhesion can be achieved, and the intrusion of flux and moisture can be prevented more efficiently.

[0024] Figure 6 shows Modification 4 of the lead shown in Figure 2. In Modification 4, the lead 1 is provided with a first uneven portion 3, a second uneven portion 4, and a third uneven portion 5. This further increases the bonding area between the lead and the sealing resin, making it possible to more efficiently prevent the intrusion of flux and moisture. The width and depth or height of the recesses or protrusions of the first uneven portion 3, the recesses or protrusions of the second uneven portion 4, and the recesses or protrusions of the third uneven portion 5 are not particularly limited as long as they do not hinder the purpose of the present invention, but in the present invention, the width is preferably 1 μm to 10 mm, and the depth or height is preferably 1 μm to 10 mm. According to these preferred ranges, better adhesion can be achieved, and the intrusion of flux and moisture can be more efficiently prevented.

[0025] (Example 1) A prototype MAP-type lead frame with the lead shown in Figure 1 was fabricated, and its resistance to flux and moisture intrusion and improvement in reliability after packaging were evaluated. As a comparative example, a prototype lead frame with a retaining portion formed on the lead, as described in Patent Document 1, was fabricated, and its resistance to flux and moisture intrusion and improvement in reliability after packaging were similarly evaluated. As a result, the present invention product was able to significantly prevent the intrusion of flux and moisture, and improved reliability was also observed. On the other hand, the comparative example product was unable to prevent the intrusion of flux and moisture, and no improvement in reliability was observed. [Industrial applicability]

[0026] The MAP-type lead frame of the present invention is useful for semiconductor devices and the like. [Explanation of symbols]

[0027] 1 Lead 2 Suspension Leads 3. First uneven portion 4. Second uneven area 5. Third uneven area 6 Sealing resin 7 Die Pad 8 Semiconductor chips 9 Bonding wire

Claims

1. A MAP-type lead frame, characterized in that a portion of the sealing resin contact surface of the lead or suspension lead is provided with an uneven surface consisting of a recess or a protrusion.

2. The lead frame according to claim 1, wherein a plurality of the aforementioned protrusions and recesses are provided.

3. The lead frame according to claim 1, wherein the aforementioned uneven portion has a stepped shape of two or more steps.

4. The lead frame according to claim 1, wherein the aforementioned uneven portion is located within the sealing resin.

5. The lead frame according to claim 1, wherein the uneven portion is shaped by deforming a part of the lead or suspension lead within the sealing resin.

6. The lead frame according to claim 1, wherein the uneven portion is a processed portion obtained by processing a part of the lead or suspension lead within the sealing resin.

7. An electronic device including a lead frame, wherein the lead frame is the lead frame described in claim 1.

8. An electronic component including a lead frame, wherein the lead frame is the lead frame described in claim 1.

9. A product comprising a lead frame, wherein the lead frame is the lead frame described in claim 1.

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