Source: https://patents.google.com/patent/JP2015072946A/en
Timestamp: 2020-01-24 16:53:26
Document Index: 304299972

Matched Legal Cases: ['arts 16', 'arts 18', 'arts 16', 'art 18', 'art 51', 'arts 52', 'art 16', 'art 19']

JP2015072946A - Lead frame and manufacturing method of the same, and manufacturing method of semiconductor device - Google Patents
Lead frame and manufacturing method of the same, and manufacturing method of semiconductor device Download PDF
JP2015072946A
JP2015072946A JP2013206649A JP2013206649A JP2015072946A JP 2015072946 A JP2015072946 A JP 2015072946A JP 2013206649 A JP2013206649 A JP 2013206649A JP 2013206649 A JP2013206649 A JP 2013206649A JP 2015072946 A JP2015072946 A JP 2015072946A
JP2013206649A
JP6319644B2 (en
田 幸 治 冨
崎 聡 柴
崎 雅 樹 矢
田 昌 博 永
2013-10-01 Application filed by 大日本印刷株式会社, Dainippon Printing Co Ltd filed Critical 大日本印刷株式会社
2013-10-01 Priority to JP2013206649A priority Critical patent/JP6319644B2/en
2015-04-16 Publication of JP2015072946A publication Critical patent/JP2015072946A/en
2018-05-09 Publication of JP6319644B2 publication Critical patent/JP6319644B2/en
239000011133 lead Substances 0 abstract title 13
PROBLEM TO BE SOLVED: To provide a lead frame that can prevent generation of metal burrs in a lead part during sewing and prevent deformation in the lead part and connecting bar.SOLUTION: A pair of corresponding long lead parts 16A and a pair of corresponding short lead parts are respectively connected via a connecting bar 17 between adjacent lead frame elements 14 of a lead frame 10. The connecting bar 17 includes: a plurality of long lead connection parts 18A located between the pair of long lead parts 16A; and a plurality of short lead connection parts located between the pair of short lead parts. The long lead connection part 18A includes: a half etching concave part 51 on at least one surface of a front surface and rear surface thereof; and flat parts 52 and 54 on both surfaces of the front surface and rear surface.
The present invention relates to a lead frame, a manufacturing method thereof, and a manufacturing method of a semiconductor device.
In recent years, it has been required to reduce the size and thickness of a semiconductor device mounted on a substrate. In order to meet such demands, conventionally, a lead frame is used, and a semiconductor element mounted on the mounting surface of the lead frame is sealed with a sealing resin, and a part of the lead is exposed on the back surface side. Various so-called QFN (Quad Flat Non-lead) type semiconductor devices have been proposed.
However, in the case of a QFN having a conventional general structure, the package becomes larger as the number of terminals increases, so that there is a problem that it is difficult to ensure mounting reliability. In addition, the increase in the size of the package increases the distance between the internal terminals and the semiconductor chip, increases the amount of gold bonding wires used, and increases the manufacturing cost of the package. Further, since the bonding wire becomes long, there is a possibility that a problem may occur when the package is assembled.
On the other hand, as a technique for realizing a multi-pin QFN, a package called DR-QFN (Dual Row QFN) in which external terminals are arranged in two rows is being developed (Patent Document 1). ~ 3).
Japanese Patent No. 3732987 JP 2001-189402 A JP 2006-19767 A
In such a DR-QFN package, relatively long lead portions and relatively short lead portions are alternately arranged, and external terminals provided in each lead portion are arranged in a staggered manner when viewed from the back surface. Has been. When manufacturing a DR-QFN package, in order to prevent deformation of the external terminals and facilitate assembly of the package, each package is sealed with an individual mold (individual mold method).
On the other hand, in order to increase the manufacturing efficiency of the DR-QFN package, it is considered to manufacture a package by collectively sealing a plurality of packages with resin and then cutting (sealing) the sealing resin for each package. (MAP method). The external terminals of the DR-QFN package are arranged in a staggered manner as described above, and among these terminals, the inner terminals are held by a relatively long lead portion and connected to a connecting bar (grid lead). Further, by providing the lead portion with a half-etched portion, after the lead portion is cut, the occurrence of metal burrs around the cut portion is prevented.
However, in the DR-QFN package, the package size is large, for example, 7 mm to 14 mm square, and the number of lead parts that have been half-etched is large. Therefore, the stress on the connecting bar is larger than that of the conventional QFN package, and deformation is caused. There is a problem that it is easy to induce. For this reason, in particular, when a DR-QFN package is manufactured by the MAP method, there is a problem that the lead portion and the connecting bar are likely to be deformed.
The present invention has been made in consideration of the above points, and it is possible to prevent the occurrence of metal burrs in the lead portion during sawing and to prevent deformation of the lead portion and the connecting bar. It is an object of the present invention to provide a lead frame, a manufacturing method thereof, and a manufacturing method of a semiconductor device.
The present invention relates to a lead frame for a semiconductor device, a plurality of lead frame elements each including a die pad on which a semiconductor element is mounted, and a plurality of long lead portions and a plurality of short lead portions provided around the die pad. A pair of corresponding long lead portions and a pair of short lead portions are connected to each other between the adjacent lead frame elements via connecting bars, and the connecting bar includes the long lead portions and the short leads. The connecting bar extends in a direction perpendicular to the longitudinal direction of the plurality of portions, and the connecting bar is disposed between the corresponding pair of long lead portions and the plurality of long lead connecting portions positioned between the corresponding pair of short lead portions. A short lead connecting portion, and the long lead connecting portion has a half-edge on at least one of the front surface and the back surface. Has a half-etched recess quenching is applied to both of the surface and the back surface, a lead frame and having a flat portion where the half-etching is not performed.
In the present invention, on the surface of the long lead connecting portion, the half-etched recess is formed in the center portion in the width direction, the flat portions are formed in both ends in the width direction, and on the back surface of the long lead connecting portion, The flat portion is formed at the center, the half-etched recesses are formed at both ends in the width direction, and the half-etched recesses are formed at the center in the width direction on the surface of the short lead connecting portion. The lead frame is characterized in that the flat portion is formed respectively.
In the present invention, the flat portion is formed at the center in the width direction on the back surface of the long lead connecting portion, the half-etched recesses are formed at both ends in the width direction, and the width direction is formed on the back surface of the short lead connecting portion. The lead frame is characterized in that the flat portion is formed at the center, the half-etched recesses are formed on both sides of the flat portion, and the flat portions are formed at both ends in the width direction.
In the present invention, on the back surface of the long lead connecting portion, the half-etched recess is formed in the center portion in the width direction, the flat portions are formed on both sides of the half-etch recess portion, and the half-etched portions are formed on both ends in the width direction. The lead frame is characterized in that a recess is formed, the half-etched recess is formed at the center in the width direction on the back surface of the short lead connecting portion, and the flat portions are formed at both ends in the width direction. .
In the present invention, the flat portion is formed at the center in the width direction on the back surface of the long lead connecting portion, the half-etched recesses are formed at both ends in the width direction, and the width direction is formed on the back surface of the short lead connecting portion. The lead frame is characterized in that the half-etched recess is formed at the center and the flat portions are formed at both ends in the width direction.
In the present invention, on the surface of the long lead connecting portion, the flat portion is formed in the center portion in the width direction, the half etching recesses are formed on both sides of the flat portion, and the flat portions are respectively formed on both ends of the width direction. The half etching recess is formed at the center in the width direction on the back surface of the long lead connecting portion, the flat portions are formed on both sides of the half etching recess, and the half etching recess is formed at both ends in the width direction. The flat portion is formed at the center in the width direction on the surface of the short lead connecting portion, the half-etched recesses are formed on both sides of the flat portion, and the flat portions are formed at both ends in the width direction. The half-etched recess is formed at the center in the width direction on the back surface of the short lead connecting portion, and is formed at both ends in the width direction. A lead frame, wherein the flat portion, respectively are formed.
In the present invention, on the surface of the long lead connecting portion, the flat portion is formed in the center portion in the width direction, the half etching recesses are formed on both sides of the flat portion, and the flat portions are respectively formed on both ends of the width direction. Formed on the back surface of the long lead connecting portion, the flat portion is formed in the center portion in the width direction, the half etching recesses are formed in both ends in the width direction, and the center portion in the width direction is formed on the surface of the short lead connecting portion. The lead frame is characterized in that the flat portion is formed in the portion, the half-etched recesses are formed on both sides of the flat portion, and the flat portions are formed on both ends in the width direction.
The present invention provides a method for manufacturing a lead frame, the step of preparing a metal substrate, the step of forming an etching resist layer on each of the front and back surfaces of the metal substrate, and the metal substrate using the etching resist layer as a corrosion-resistant film. A plurality of long lead portions and a plurality of short lead portions provided on the periphery of the die pad, each of which includes a die pad for mounting a semiconductor element on the metal substrate, A step of forming the lead frame element and a step of removing the etching resist layer from the front and back surfaces of the metal substrate, and a pair of corresponding long lead portions and a pair of adjacent lead frame elements. The short lead portions of the connecting bar are connected to each other via a connecting bar. A plurality of long lead connecting portions positioned between the corresponding pair of long lead portions, and a plurality of short lead connecting portions positioned between the corresponding pair of the short lead portions, A lead frame having a half-etched recess that is half-etched on at least one of the front and back surfaces, and a flat portion that is not half-etched on both the front and back surfaces. It is a manufacturing method.
The present invention relates to a method of manufacturing a semiconductor device, the step of manufacturing a lead frame by a method of manufacturing a lead frame, the step of mounting the semiconductor element on the die pad of the lead frame, the semiconductor element and the lead frame The step of electrically connecting the long lead portion or the short lead portion with a connecting portion, and sealing the die pad, the long lead portion, the short lead portion, the semiconductor element, and the connecting portion. A method of manufacturing a semiconductor device, comprising: a step of sealing with a resin; and a step of cutting the sealing resin and the lead frame for each lead frame element along the connecting bar.
ADVANTAGE OF THE INVENTION According to this invention, it can prevent that a lead | flash part and a connecting bar generate | occur | produce a deformation | transformation while preventing a metal burr | flash from producing | generating at a lead part at the time of a sawing process.
FIG. 1 is a plan (surface) view showing a lead frame according to an embodiment of the present invention. FIG. 2 is a cross-sectional view (a cross-sectional view taken along line II-II in FIG. 1) showing a lead frame according to an embodiment of the present invention. FIG. 3 is a bottom (rear) view showing a lead frame according to an embodiment of the present invention. 4A is a cross-sectional view along the longitudinal direction of the long lead portion (cross-sectional view taken along the line IVA-IVA in FIG. 1), and FIG. 4B is a cross-sectional view along the longitudinal direction of the short lead portion (in FIG. 1). IVB-IVB sectional view). FIG. 5 is a plan (surface) view showing the semiconductor device. 6 is a cross-sectional view of the semiconductor device (a cross-sectional view taken along line VV in FIG. 5). 7A to 7G are cross-sectional views illustrating a method for manufacturing a lead frame according to an embodiment of the present invention. 8A to 8F are cross-sectional views illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 9A is a cross-sectional view along the longitudinal direction of the long lead portion according to a modification (Modification 1) of the present invention, and FIG. 9B is a cross-sectional view along the longitudinal direction of the short lead portion. FIG. 10A is a cross-sectional view along the longitudinal direction of the long lead portion according to a modification (Modification 2) of the present invention, and FIG. 10B is a cross-sectional view along the longitudinal direction of the short lead portion. FIG. 11A is a cross-sectional view along the longitudinal direction of the long lead portion according to a modification (Modification 3) of the present invention, and FIG. 11B is a cross-sectional view along the longitudinal direction of the short lead portion. 12A is a cross-sectional view along the longitudinal direction of the long lead portion according to a modification (Modification 4) of the present invention, and FIG. 12B is a cross-sectional view along the longitudinal direction of the short lead portion. FIG. 13A is a cross-sectional view along the longitudinal direction of the long lead portion according to a modification (Modification 5) of the present invention, and FIG. 13B is a cross-sectional view along the longitudinal direction of the short lead portion.
Construction of the lead frame initially, to FIG. 1 to FIG. 4, the outline of the lead frame according to the present embodiment. 1 to 4 are views showing a lead frame according to the present embodiment.
A lead frame 10 shown in FIGS. 1 to 4 is used to manufacture a semiconductor device 20 (described later), and includes a plurality of lead frame elements 14 arranged in a matrix in the vertical and horizontal directions.
Each lead frame element 14 is an area corresponding to each semiconductor device 20. The lead frame element 14 includes a die pad 15 and a plurality of long lead portions 16A and a plurality of short lead portions 16B provided around the die pad 15. In FIGS. 1 and 3, each region surrounded by a two-dot chain line corresponds to the lead frame element 14.
Each die pad 15 is for mounting a semiconductor element 21 to be described later, and has a substantially rectangular shape in plan view. The long lead portions 16A and the short lead portions 16B are connected to the semiconductor element 21 via bonding wires 22 as will be described later, and are disposed between the die pad 15 and a space. .
As shown in FIGS. 1 and 3, each long lead portion 16A and each short lead portion 16B extend along either the X direction or the Y direction, and each long lead portion 16A includes each short lead. It is configured to be longer than the portion 16B. The long lead portions 16 </ b> A and the short lead portions 16 </ b> B are alternately arranged along the periphery of the die pad 15. The long terminal portions 16A and the internal terminal portions 16a of the short lead portions 16B are provided with plating portions 25 for improving the adhesion to the bonding wires 22, respectively.
Each long lead portion 16A and each short lead portion 16B have an internal terminal portion 16a connected to the bonding wire 22 and a connecting portion 16b having a relatively narrow width. Yes. Further, on the back side of each internal terminal portion 16a, an external terminal portion 16c connected to an external wiring board (not shown) is provided (see FIG. 2). In this case, the internal terminal portions 16a are arranged in a staggered pattern on the front side (see FIG. 1), and the external terminal portions 16c are arranged in a staggered pattern on the back side (see FIG. 3).
In the present embodiment, at least the central portion of the die pad 15 is not half-etched and has a thickness equivalent to that of the metal substrate before processing. Specifically, the thickness of the central portion of the die pad 15 can be set to 0.10 mm to 0.30 mm depending on the configuration of the semiconductor device 20.
On the other hand, around the lead frame element 14, a plurality of connecting bars 17 are arranged in a lattice pattern. The width of each connecting bar 17 may be the same on the front surface and the back surface, or may be different from each other. In the latter case, the width on the front surface side of each connecting bar 17 can be set to 0.15 mm to 0.20 mm, for example, and the width on the back surface side can be set to 0.03 mm to 0.10 mm, for example.
In each lead frame element 14, the die pad 15 is connected to the connecting bar 17 via four suspension leads 43 extending from the corners of the die pad 15 and connection leads 44 connected to the suspension leads 43. ing.
Further, between adjacent lead frame elements 14, a corresponding pair of long lead portions 16 </ b> A are connected via a connecting bar 17, and a corresponding pair of short lead portions 16 </ b> B are connected via a connecting bar 17. Each connecting bar 17 extends perpendicular to the longitudinal direction of the long lead portion 16A and the short lead portion 16B connected to the connecting bar 17. For example, a plurality of long lead portions 16A and a plurality of short lead portions 16B extending in the X direction are coupled to the connecting bar 17 extending in the Y direction. Here, the corresponding pair of long lead portions 16A (short lead portions 16B) is a pair of long lead portions 16A (adjacent to the longitudinal direction of the long lead portions 16A (short lead portions 16B) via the connecting bars 17). The short lead portion 16B). For example, in FIG. 2, the corresponding pair of long lead portions 16 </ b> A refers to a pair of long lead portions 16 </ b> A adjacent in the X direction via the connecting bar 17.
In this embodiment, as shown in FIGS. 2 and 3, each connecting bar 17 has a plurality of long lead connecting portions 18 </ b> A, a plurality of short lead connecting portions 18 </ b> B, and a plurality of reinforcing portions 19. Yes.
Each of the long lead connecting portions 18A is located between the adjacent lead frame elements 14 and between the corresponding pair of long lead portions 16A. For example, as shown in FIG. 4A, the long lead connecting portion 18A is disposed between a pair of long lead portions 16A disposed on the left and right (X direction).
Each short lead connecting portion 18B is located between adjacent lead frame elements 14 and between a pair of corresponding short lead portions 16B. For example, as shown in FIG. 4B, the short lead connecting portion 18B is disposed between a pair of short lead portions 16B disposed on the left and right (X direction).
Further, as shown in FIGS. 1 and 3, each reinforcing portion 19 is located between the long lead connecting portion 18A and the short lead connecting portion 18B adjacent to each other. That is, the long lead connecting portion 18A, the reinforcing portion 19 and the short lead connecting portion 18B are arranged along the longitudinal direction of the connecting bar 17 such as the long lead connecting portion 18A, the reinforcing portion 19, the short lead connecting portion 18B, the reinforcing portion 19, The lead connecting portions 18A are arranged in this order.
In the present embodiment, the long lead connecting portion 18A has half-etched recesses 51 and 53 that are half-etched on both the front surface and the back surface, and half-etching is performed on both the front and back surfaces. The flat portions 52 and 54 are not provided.
That is, as shown in FIG. 4A, on the surface of the long lead connecting portion 18A, a half etching recess 51 is formed at the center in the width direction (X direction), and flat portions 52 are formed at both ends in the width direction. ing.
Further, as shown in FIG. 4A, on the back surface of the long lead connecting portion 18A, a flat portion 54 is formed in the center portion in the width direction, and half etching recesses 53 are formed in both end portions in the width direction. Each half-etched recess 53 extends continuously in the X direction from the long lead connecting portion 18A to the middle of the long lead portion 16A.
On the other hand, as shown in FIG. 4B, on the surface of the short lead connecting portion 18B, a half etching recess 51 is formed at the center in the width direction (X direction), and flat portions 52 are formed at both ends in the width direction. ing. Note that a flat portion 54 is formed on the entire back surface of the short lead connecting portion 18B without being half-etched.
The half-etching recesses 51 and 53 may be provided on at least one of the front and back surfaces of the long lead connecting portion 18A.
By the way, the above-described half-etching recess 51 is formed at the center in the width direction on the surface side of each connecting bar 17. This half-etching recess 51 extends linearly over the entire area of the connecting bar 17 along the longitudinal direction of the connecting bar 17 (see FIG. 1).
As described above, the half etching recess 51 is formed in the center portion in the width direction on the surface of the long lead connecting portion 18A and the surface of the short lead connecting portion 18B, and half etching is performed on both ends in the width direction on the back surface of the long lead connecting portion 18A. A recess 53 is formed. Thereby, when cutting the sealing resin portion 24 and the lead frame 10 (see the sawing process, see FIG. 8E), the cutting work can be facilitated and the occurrence of metal burrs can be suppressed.
Further, flat portions 52 are formed at both ends in the width direction on the surface of the long lead connecting portion 18A and the surface of the short lead connecting portion 18B, and the width on the back surface of the long lead connecting portion 18A and the back surface of the short lead connecting portion 18B. A flat portion 54 is formed at the center in the direction. As a result, when a stress is applied to the connecting bar 17 from the flat surface 52 side of the front surface during the sawing process, the flat surface portion 54 of the back surface is in close contact with the back tape 36 (see FIG. 8E). For this reason, it is possible to prevent the long lead portion 16A, the short lead portion 16B, and the connecting bar 17 from being deformed by the stress.
The total thickness t (FIGS. 4A and 4B) of the surface of the long lead connecting portion 18A and the short lead connecting portion 18B is the same as the thickness of the central portion of the die pad 15 described above, for example, 0.10 mm to 0.30 mm. It can be. By setting the thickness to 0.10 mm or more, the thickness of the lead frame 10 becomes too thin after half etching, and the handling becomes difficult, and the half-etched portion is too narrow to be filled with the sealing resin. Problems can be prevented. Further, by setting the thickness to 0.30 mm or less, it is possible to narrow the distance between the long lead portion 16A and the short lead portion 16B and arrange the external terminal portions 16c with high density.
In FIGS. 1 and 3, portions (half-etched recesses 51, 53, etc.) that have been subjected to half-etching are indicated by hatching. Note that half-etching means that a metal plate, which is a material to be etched, is etched halfway in the thickness direction.
Such a lead frame 10 is formed by etching one metal substrate. Examples of the material of the lead frame 10 include copper, a copper alloy, 42 alloy (Ni 42% Fe alloy), and the like.
Configuration of Semiconductor Device Next, a semiconductor device manufactured using the lead frame according to the present embodiment will be described with reference to FIGS. 5 and 6 are diagrams showing a semiconductor device manufactured using the lead frame 10 according to the present embodiment.
A semiconductor device 20 (DR-QFN (Dual Row QFN) package) shown in FIGS. 5 and 6 includes a die pad 15, a long lead portion 16A and a short lead portion 16B, and a semiconductor element 21 mounted on the die pad 15. The long lead portion 16A and the short lead portion 16B are provided with bonding wires (connection portions) 22 that electrically connect the terminal portions 21a of the semiconductor element 21.
The die pad 15, the long lead portion 16 </ b> A, the short lead portion 16 </ b> B, the semiconductor element 21, and the bonding wire 22 are sealed with a sealing resin portion 24.
The die pad 15, the long lead portion 16A and the short lead portion 16B are the same as those included in the lead frame 10 (FIGS. 1 to 4) described above, and the configuration thereof has already been described. Omitted.
Although it does not specifically limit as the semiconductor element 21, For example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode etc. can be used.
Further, the semiconductor element 21 is fixed on the die pad 15 by a fixing material 26 such as a die bonding paste. When the fixing material 26 is made of a die bonding paste, it is possible to select, for example, an epoxy resin or a silicone resin.
Each bonding wire 22 is made of a material having good conductivity, such as gold, and one end thereof is connected to each terminal portion 21a of the semiconductor element 21, and the other end is connected to each long lead portion 16A and each short lead portion 16B. It is connected.
For example, an epoxy resin or a silicone resin can be used as the sealing resin portion 24. 5, for the sake of convenience, the sealing resin portion 24 is shown as being transparent, but may be made of an opaque resin such as black.
Manufacturing Method of Lead Frame Next, a manufacturing method of the lead frame 10 shown in FIGS. 1 to 4 will be described with reference to FIGS. FIGS. 7A to 7G are cross-sectional views illustrating the lead frame manufacturing method according to the present embodiment and correspond to FIG.
First, as shown in FIG. 7A, a flat metal substrate 31 is prepared. As the metal substrate 31, a metal substrate made of copper, copper alloy, 42 alloy (Ni 42% Fe alloy) or the like can be used as described above. In addition, it is preferable to use what the metal substrate 31 performed the degreasing | defatting etc. to the both surfaces, and performed the washing process. Moreover, the thickness of the metal substrate 31 is good also as 0.10 mm-0.30 mm, for example.
Next, photosensitive resists 32a and 33a are applied to the entire front and back surfaces of the metal substrate 31, respectively, and dried (FIG. 7B). As the photosensitive resists 32a and 33a, conventionally known resists can be used.
Subsequently, the metal substrate 31 is exposed through a photomask and developed to form etching resist layers 32 and 33 having desired openings 32b and 33b (FIG. 7C).
Specifically, on the front surface side and the back surface side of the metal substrate 31, in addition to the portion where the through etching is performed, the portion where the half etching processing such as the half etching concave portions 51 and 53 is performed (the hatched portion in FIGS. 1 and 3). An opening 33b is formed at a place to be performed.
Next, the etching resist layers 32 and 33 are used as an anticorrosion film, and the metal substrate 31 is etched with an etching solution (FIG. 7D). Corrosion liquid can be suitably selected according to the material of the metal substrate 31 to be used. For example, when copper is used as the metal substrate 31, an aqueous ferric chloride solution is usually used, and this can be performed by spray etching from both surfaces of the metal substrate 31.
As a result, a plurality of lead frame elements 14 each including a die pad 15 for placing the semiconductor element 21 on the metal substrate 31 and a plurality of long lead portions 16A and a plurality of short lead portions 16B provided around the die pad 15 are provided. Is formed.
At this time, a connecting bar 17 having a long lead connecting portion 18A, a short lead connecting portion 18B, and a reinforcing portion 19 is formed between adjacent lead frame elements 14. Further, a half etching recess 51 is formed on the surface of each of the long lead portion 16A and the short lead portion 16B, and a half etching recess 53 is formed on the back surface of the long lead portion 16A.
Next, the etching resist layers 32 and 33 are peeled off and removed (FIG. 7E).
Next, in order to improve the adhesion with the bonding wire 22, the internal terminal portions 16a of the long lead portion 16A and the short lead portion 16B are respectively plated to form the plated portion 25 (FIG. 7 (f)). In this case, the type of plating selected is not limited as long as the adhesion to the bonding wire 22 can be ensured. For example, single-layer plating such as Ag or Au may be used, or Ni / Pd or Ni / Pd / Au may be used. Multi-layer plating laminated in this order may be used. Further, the plating portion 25 may be provided only on the connection portion with the bonding wire 22 in the internal terminal 15 or may be provided on the entire surface of the lead frame 10. In this way, the lead frame 10 shown in FIGS. 1 to 4 is obtained.
Next, the lead frame 10 is placed and fixed on the back tape 37 (FIG. 7G).
Manufacturing Method of Semiconductor Device Next, a manufacturing method of the semiconductor device 20 shown in FIGS. 5 and 6 will be described with reference to FIGS. 8A to 8F are cross-sectional views illustrating a method for manufacturing a semiconductor device according to the present embodiment.
First, the lead frame 10 having the die pad 15 and a plurality of long lead portions 16A and a plurality of short lead portions 16B provided around the die pad 15 by the above-described steps (FIGS. 7A to 7G). (FIG. 8A). At this time, the lead frame 10 is placed on the back tape 37.
Next, the semiconductor element 21 is mounted on the die pad 15 of the lead frame 10. In this case, the semiconductor element 21 is placed and fixed on the die pad 15 using a fixing material 26 such as a die bonding paste (die attachment step) (FIG. 8B).
Next, the terminal portion 21a of the semiconductor element 21 is electrically connected to the long lead portions 16A and the short lead portions 16B of the lead frame 10 by the bonding wires 22 (wire bonding step) (FIG. 8C). ).
Thereafter, the die pad 15, the long lead portion 16A, the short lead portion 16B, the semiconductor element 21, and the bonding wire 22 are sealed by the sealing resin portion 24 (FIG. 8D).
Subsequently, the back tape 37 is peeled off, and a new back tape 36 is attached to the back surface of the lead frame 10.
Next, the lead frame 10 is separated for each lead frame element 14 by sawing the connecting bar 17 between the lead frame elements 14 (FIG. 8E).
At this time, the connecting bar 17 and the sealing resin portion 24 between the lead frame elements 14 are cut by moving a blade 38 made of, for example, a diamond grindstone along the longitudinal direction of the connecting bar 17. In order to cut smoothly, the width of the blade 38 is preferably the same as or wider than the width of the connecting bar 17.
In this way, the semiconductor device 20 shown in FIGS. 5 and 6 can be obtained (FIG. 8F).
Effects of this Embodiment According to this embodiment, the long lead connecting portion 18A, which is a portion of the connecting bar 17 where stress deformation is likely to occur, is subjected to half-etching on at least one of its front and back surfaces. The half-etched recesses 51 and 53 are formed, and flat portions 52 and 54 that are not half-etched are provided on both the front and back surfaces.
Thus, when a stress is applied from the flat portion 52 side of the surface of the connecting bar 17 during the sawing process (see FIG. 8E), the stress is received by the flat portion 52 on the front surface and the flat portion 54 on the back surface. it can. As described above, the strength of the long lead connecting portion 18A that is prone to stress deformation is increased, so that the overall strength of the connecting bar 17 is increased, and the long lead portion 16A, the short lead portion 16B, and the connecting bar 17 are X when sawing. It is difficult to deform in any of the direction, the Y direction, and the Z direction.
Further, by providing the half etching recess 51 on the surface of the long lead connecting portion 18A and the surface of the short lead connecting portion 18B, and providing the half etching recess 53 on the back surface of the long lead connecting portion 18A, the long lead connecting portion 18A. Further, the amount of metal around the short lead connecting portion 18B can be reduced, the stress at the time of the sawing process (FIG. 8E) is reduced to improve the cutting performance, and the long lead part 16A and the short lead at the time of the sawing process are improved. The amount of burrs generated around the portion 16B can be suppressed. As a result, in the semiconductor device 20, it is possible to prevent a short circuit between the long lead portion 16A and the short lead portion 16B adjacent to each other due to burrs.
In particular, when the package size of the semiconductor device 20 is increased by increasing the number of pins (for example, 7 mm to 14 mm square), the deformation of the connecting bar 17 described above is prevented, and the long lead portion 16A and the short lead portion 16B are short-circuited. The effect of prevention can be obtained remarkably.
As described above, according to the present embodiment, it is possible to prevent deformation of the long lead portion 16A, the short lead portion 16B, and the connecting bar 17 while suppressing the occurrence of burrs during sawing.
Modified Example Next, a modified example of the lead frame according to the present embodiment will be described with reference to FIGS. Various modifications shown in FIGS. 9 to 13 are different in the configuration of the long lead portion 16A and the short lead portion 16B, and the other configurations are substantially the same as those of the above-described embodiment. 9 to 13, the same parts as those of the embodiment shown in FIGS. 1 to 8 are denoted by the same reference numerals, and detailed description thereof is omitted.
FIGS. 9A and 9B show a lead frame 10A according to a modification (modification 1) of the present embodiment. FIG. 9A is a vertical sectional view (corresponding to FIG. 4A) showing the long lead portion 16A of the lead frame 10A along the longitudinal direction, and FIG. 9B is a view of the lead frame 10A. FIG. 6 is a vertical cross-sectional view (a diagram corresponding to FIG. 4B) showing the short lead portion 16B along the longitudinal direction.
As shown in FIG. 9A, on the back surface of the long lead connecting portion 18A, a flat portion 54 is formed in the center portion in the width direction, and half-etching recesses 53 are formed in both end portions in the width direction. Each half-etching recess 53 continuously extends in the X direction from the long lead connecting portion 18A to the middle of the long lead portion 16A. A flat portion 52 is formed on the entire surface of the long lead connecting portion 18A without being half-etched.
As shown in FIG. 9B, on the back surface of the short lead connecting portion 18B, a flat portion 54 is formed in the center portion in the width direction, and half-etching recesses 53 are formed on both sides of the flat portion 54, respectively. Flat portions 54 are formed in the respective portions. A flat portion 52 is formed over the entire surface of the short lead connecting portion 18B without being half-etched.
In this case, two half-etching recesses 53 are formed in parallel on the back side of each connecting bar 17. The two half-etching recesses 53 extend linearly over the entire area of the connecting bar 17 along the longitudinal direction of the connecting bar 17. As described above, since the two half-etching recesses 53 are formed on the back surface of the connecting bar 17, the amount of metal in the connecting bar 17 is greatly reduced, and the stress during sawing is greatly reduced, thereby improving the cutting performance. Can be improved.
Further, the reinforcing part 19 of the connecting bar 17 has a trapezoidal cross section perpendicular to the longitudinal direction, and this trapezoidal shape has a wider width on the front surface than on the back surface. Thereby, the area of the vertical cross section of the connecting bar 17 can be reduced, and the amount of metal burrs generated during sawing (also called dicing) can be suppressed. In addition, substantially the same effect as the embodiment shown in FIGS. 1 to 8 can be obtained.
10A and 10B show a lead frame 10B according to a modification (modification 2) of the present embodiment. 10A is a vertical sectional view (a diagram corresponding to FIG. 4A) showing the long lead portion 16A of the lead frame 10B along the longitudinal direction, and FIG. 10B is a diagram of the lead frame 10B. FIG. 6 is a vertical cross-sectional view (a diagram corresponding to FIG. 4B) showing the short lead portion 16B along the longitudinal direction.
As shown in FIG. 10A, on the back surface of the long lead portion 16A, a half etching recess 53 is formed at the center in the width direction, and flat portions 54 are formed on both sides of the half etching recess 53, respectively. Half-etching recesses 53 are formed in the respective parts. In this case, the half etching recesses 53 located at both ends in the width direction continuously extend in the X direction from the long lead connecting portion 18A to the middle of the long lead portion 16A. A flat portion 52 is formed on the entire surface of the long lead connecting portion 18A without being half-etched.
As shown in FIG. 10B, on the back surface of the short lead connecting portion 18B, a half etching recess 53 is formed at the center in the width direction, and flat portions 54 are formed at both ends in the width direction. A flat portion 52 is formed over the entire surface of the short lead connecting portion 18B without being half-etched.
In this case, the half-etching recess 53 is formed at the center in the width direction on the back side of each connecting bar 17. The half-etching recess 53 extends linearly along the entire length of the connecting bar 17 along the longitudinal direction of the connecting bar 17.
10A and 10B, the same effects as those in the embodiment shown in FIGS. 1 to 8 can be obtained.
FIGS. 11A and 11B show a lead frame 10C according to a modification (modification 3) of the present embodiment. FIG. 11A is a vertical sectional view (corresponding to FIG. 4A) showing the long lead portion 16A of the lead frame 10C along the longitudinal direction, and FIG. 11B is a view of the lead frame 10C. FIG. 6 is a vertical cross-sectional view (a diagram corresponding to FIG. 4B) showing the short lead portion 16B along the longitudinal direction.
As shown in FIG. 11A, on the back surface of the long lead connecting portion 18A, a flat portion 54 is formed in the center portion in the width direction, and half etching recesses 53 are formed in both end portions in the width direction. In this case, each half-etched recess 53 extends continuously in the X direction from the long lead connecting portion 18A to the middle of the long lead portion 16A. A flat portion 52 is formed on the entire surface of the long lead connecting portion 18A without being half-etched.
As shown in FIG. 11B, on the back surface of the short lead connecting portion 18B, a half etching recess 53 is formed at the center in the width direction, and flat portions 54 are formed at both ends in the width direction. A flat portion 52 is formed over the entire surface of the short lead connecting portion 18B without being half-etched.
In this case, the flat portions 54 on the back surface of each long lead connecting portion 18 </ b> A are arranged at regular intervals in a dot shape along the longitudinal direction of the connecting bar 17. Further, the back surface of the reinforcing portion 19 of the connecting bar 17 is thinned by half etching.
As a result, the strength of the long lead connecting portion 18A, which is a portion of the connecting bar 17 where stress deformation is likely to occur, is increased, so that the connecting bar 17 is prevented from being deformed during the sawing process (FIG. 8E). can do. Further, by reducing the thickness of the reinforcing portion 19, it is possible to reduce the amount of metal of the connecting bar 17 and to reduce the stress during the sawing process, thereby improving the cutting performance. Further, when resin sealing is performed by the sealing resin portion 24 (FIG. 8D), an effect that the stability of resin filling can be improved is obtained. That is, the sealing resin portion 24 can smoothly flow from the bottom surface side of the connecting bar 17 while maintaining the adhesion between the connecting bar 17 and the back tape 37. In addition, substantially the same effect as the embodiment shown in FIGS. 1 to 8 can be obtained.
12A and 12B show a lead frame 10D according to a modification (Modification 4) of the present embodiment. 12A is a vertical cross-sectional view (corresponding to FIG. 4A) showing the long lead portion 16A of the lead frame 10D along the longitudinal direction, and FIG. 12B is a view of the lead frame 10D. FIG. 6 is a vertical cross-sectional view (a diagram corresponding to FIG. 4B) showing the short lead portion 16B along the longitudinal direction.
As shown in FIG. 12A, on the surface of the long lead connecting portion 18A, a flat portion 52 is formed at the center in the width direction, and half-etching recesses 51 are formed on both sides of the flat portion 52, respectively. Flat portions 52 are formed in the respective portions. Further, on the back surface of the long lead connecting portion 18A, a half etching recess 53 is formed at the center in the width direction, flat portions 54 are formed on both sides of the half etching recess 53, and half etching recess 53 is formed at both ends in the width direction. Is formed. In this case, the half etching recesses 53 located at both ends in the width direction continuously extend in the X direction from the long lead connecting portion 18A to the middle of the long lead portion 16A.
As shown in FIG. 12B, on the surface of the short lead connecting portion 18B, a flat portion 52 is formed at the center in the width direction, and half-etching recesses 51 are formed on both sides of the flat portion 52, respectively. Flat portions 52 are formed in the respective portions. Further, on the back surface of the short lead connecting portion 18B, a half etching recess 53 is formed at the center in the width direction, and flat portions 54 are formed at both ends in the width direction.
In this case, two half etching recesses 51 are formed in parallel on the surface side of each connecting bar 17. The two half-etching recesses 51 extend linearly over the entire area of the connecting bar 17 along the longitudinal direction of the connecting bar 17.
Further, the half etching recess 53 is formed in the center portion in the width direction on the back surface side of each connecting bar 17. The half-etching recess 53 extends linearly along the entire length of the connecting bar 17 along the longitudinal direction of the connecting bar 17.
In this case, the connecting bar 17 has two half-etched recesses 51 formed on the front surface and one half-etched recess 53 formed on the back surface thereof, so that the amount of metal in the connecting bar 17 is reduced. Cutting performance can be improved by reducing stress during sawing. In addition, substantially the same effect as the embodiment shown in FIGS. 1 to 8 can be obtained.
FIGS. 13A and 13B show a lead frame 10E according to a modification (modification 5) of the present embodiment. FIG. 13A is a vertical sectional view (corresponding to FIG. 4A) showing the long lead portion 16A of the lead frame 10E along the longitudinal direction, and FIG. 13B is a view of the lead frame 10E. FIG. 6 is a vertical cross-sectional view (a diagram corresponding to FIG. 4B) showing the short lead portion 16B along the longitudinal direction.
As shown in FIG. 13A, on the surface of the long lead connecting portion 18A, a flat portion 52 is formed at the center in the width direction, and half-etching recesses 51 are formed on both sides of the flat portion 52, respectively. Flat portions 52 are formed in the respective portions. Further, on the back surface of the long lead connecting portion 18A, a flat portion 54 is formed at the center in the width direction, and half-etching recesses 53 are formed at both ends in the width direction. In this case, the half etching recesses 53 located at both ends in the width direction continuously extend in the X direction from the long lead connecting portion 18A to the middle of the long lead portion 16A.
As shown in FIG. 13B, on the surface of the short lead connecting portion 18B, a flat portion 52 is formed in the center portion in the width direction, and half etching recesses 51 are formed on both sides of the flat portion 52, respectively. Flat portions 52 are formed in the respective portions. Note that a flat portion 54 is formed on the entire back surface of the short lead connecting portion 18B without being half-etched.
In this case, since two half-etched recesses 51 are formed on the surface of the connecting bar 17, the amount of metal in the connecting bar 17 is reduced, the stress during sawing is further reduced, and the cutting performance is improved. Can be made. In addition, substantially the same effect as the embodiment shown in FIGS. 1 to 8 can be obtained.
10, 10A to 10E Lead frame 14 Lead frame element 15 Die pad 16A Long lead portion 16B Short lead portion 16a Internal terminal portion 16b Connecting portion 16c External terminal portion 17 Connecting bar 18A Long lead connecting portion 18B Short lead connecting portion 19 Reinforcing portion 20 Semiconductor Device 21 Semiconductor element 21a Terminal portion 22 Bonding wire (connection portion)
24 Sealing resin portion 26 Adhering material 43 Hanging lead 44 Connecting lead 51 Half-etching recess 52 Flat portion 53 Half-etching recess 54 Flat portion
In lead frames for semiconductor devices,
A plurality of lead frame elements, each including a die pad for mounting a semiconductor element, and a plurality of long lead portions and a plurality of short lead portions provided around the die pad,
A pair of corresponding long lead portions and a pair of short lead portions are connected via connecting bars between the adjacent lead frame elements, respectively.
The connecting bar extends perpendicular to the longitudinal direction of the long lead portion and the short lead portion,
The connecting bar has a plurality of long lead connecting portions positioned between a corresponding pair of the long lead portions, and a plurality of short lead connecting portions positioned between the corresponding pair of the short lead portions,
The long lead connecting portion has a half-etched recess that is half-etched on at least one of the front and back surfaces, and has a flat portion that is not half-etched on both the front and back surfaces. Lead frame characterized by.
On the surface of the long lead connecting portion, the half-etched recess is formed in the center portion in the width direction, and the flat portions are formed in both ends in the width direction, respectively.
On the back surface of the long lead connecting portion, the flat portion is formed in the center portion in the width direction, and the half etching recesses are formed in both ends in the width direction, respectively.
2. The lead frame according to claim 1, wherein, on the surface of the short lead connecting portion, the half-etched recess is formed at the center in the width direction, and the flat portions are formed at both ends in the width direction.
On the back surface of the short lead connecting portion, the flat portion is formed at the center in the width direction, the half-etched recesses are formed on both sides of the flat portion, and the flat portions are formed at both ends in the width direction. The lead frame according to claim 1.
On the back surface of the long lead connecting portion, the half-etched recess is formed at the center in the width direction, the flat portion is formed on both sides of the half-etched recess, and the half-etched recess is formed at both ends in the width direction. ,
2. The lead frame according to claim 1, wherein, on the back surface of the short lead connecting portion, the half-etched concave portion is formed in the center portion in the width direction, and the flat portions are formed in both end portions in the width direction.
On the surface of the long lead connecting portion, the flat portion is formed in the center portion in the width direction, the half-etched recesses are formed on both sides of the flat portion, and the flat portions are formed on both ends in the width direction,
On the surface of the short lead connecting portion, the flat portion is formed in the center portion in the width direction, the half etching recesses are formed on both sides of the flat portion, and the flat portions are formed on both ends in the width direction,
On the surface of the short lead connecting portion, the flat portion is formed at the center in the width direction, the half-etched recesses are formed on both sides of the flat portion, and the flat portions are formed at both ends in the width direction. The lead frame according to claim 1.
In the lead frame manufacturing method,
Forming a resist layer for etching on the front and back of the metal substrate,
Etching is performed on the front and back surfaces of the metal substrate using the etching resist layer as an anti-corrosion film, whereby a die pad for mounting a semiconductor element on the metal substrate and a plurality of lengths provided around the die pad are provided. Forming a plurality of lead frame elements including a lead portion and a plurality of short lead portions;
A step of removing the etching resist layer from the front and back of the metal substrate,
The long lead connecting portion has a half-etched recess that is half-etched on at least one of the front and back surfaces, and has a flat portion that is not half-etched on both the front and back surfaces. A method of manufacturing a lead frame characterized by the above.
A step of producing a lead frame by the method of producing a lead frame according to claim 8;
Mounting the semiconductor element on the die pad of the lead frame;
Electrically connecting the semiconductor element and the long lead portion or the short lead portion of the lead frame by a connecting portion;
Sealing the die pad, the long lead portion, the short lead portion, the semiconductor element, and the connection portion with a sealing resin;
And a step of cutting the sealing resin and the lead frame for each lead frame element along the connecting bar.
JP2013206649A 2013-10-01 2013-10-01 Lead frame, manufacturing method thereof, and manufacturing method of semiconductor device Active JP6319644B2 (en)
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JP2013206649A Active JP6319644B2 (en) 2013-10-01 2013-10-01 Lead frame, manufacturing method thereof, and manufacturing method of semiconductor device
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