JP6326647B2 - Lead frame for mounting a semiconductor element and manufacturing method thereof - Google Patents

Description

  The present invention relates to a semiconductor device mounting lead frame and a method for manufacturing the same.

  Semiconductor packages come in various types such as BGA (Ball Grid Array) packages using solder balls and CSP (Chip Size Package) in which outer leads are arranged under the semiconductor elements, in response to demands for multi-pin, miniaturization and thinning. Packages have been proposed and used.

  Among them, a QFN (Quad Flat Non-lead) type package using a lead frame that is a metal material is known as a method that is relatively inexpensive and can meet the above-described requirements.

  A QFN type semiconductor package uses a metal material, a semiconductor element is mounted on a die pad portion formed in the center, and lead portions are arranged in an area array around the die pad portion. The semiconductor package becomes an internal connection part connected at the back, and the back side thereof becomes an external connection part. By using the upper and lower (front and back) surfaces of the lead part for the internal connection part and the external connection terminal part, respectively, a large number of pins, miniaturization and thinning are realized.

  Patent Document 1 discloses a step of plating a noble metal on a copper material for a lead frame as a metal material, and after forming an etching resistant resist film on the back surface, half-etching is performed using the plating layer on the surface as an etching mask. A step of mounting a predetermined semiconductor element on the lead frame material, wire bonding the semiconductor element and the metal plating layer, a step of resin sealing, and a step of removing the etching resistant resist formed on the back surface of the lead frame material And a step of etching the back surface using the noble metal plating layer as an etching mask and making the external connection portion independent, showing a method for manufacturing a semiconductor package.

  Similarly, in Patent Document 2, a semiconductor element mounting lead frame having a half etching process on the front surface side is used to mount a semiconductor element on the front surface side and encapsulate the resin, and then etching the back surface side to form a semiconductor. A semiconductor package manufactured by removing an unnecessary portion of an element mounting lead frame is described.

JP 2011-1000089 A JP 2014-165242 A

  By the way, in a general semiconductor package lead frame such as QFN, a die pad portion for mounting a semiconductor element, a lead portion for wire bonding, and a frame portion of the lead frame are connected by a connecting piece, and the die pad portion and the lead portion are leads. It is necessary to prevent dropping from the outer frame.

  However, in the semiconductor package described in Patent Document 1, a columnar shape is formed by half-etching on the element mounting surface side, and the opposite surface is not etched and remains as the material surface. The part does not need to be connected to the outer frame of the lead frame, and can be freely arranged. Therefore, in patent document 1, only the die pad part and lead part which are required for a semiconductor package are arrange | positioned, and the several package is arrange | positioned at the space | interval of the minimum cutting width. There are packages that do not require a die pad.

  For example, in Patent Document 1, as shown in FIG. 2, a semiconductor element region and leads around it are arranged to form one semiconductor package, and a plurality of semiconductor packages are arranged in one resin-encapsulated block. ing. In FIG. 2 of Patent Document 1, a total of 16 semiconductor packages of 4 rows × 4 stages are arranged in one block, 4 blocks are arranged in one lead frame, and a total of 64 semiconductors in one lead frame. The package is arranged.

  By the way, in recent years, semiconductor packages have been reduced in thickness and size, and cost reduction has been required at the same time. Along with this, there are naturally similar demands for lead frames used in these semiconductor packages. Specifically, the arrangement is higher density and the lead frame thickness is reduced with respect to one lead frame.

  As described above, the lead frame of the type described in Patent Literature 1 forms columnar die pad portions and lead portions by half-etching from the semiconductor element mounting surface. The back side is not etched and remains the entire material surface, so although it is relatively stronger than a general lead frame, semiconductor packages are arranged in high density and the lead frame plate thickness is very thin In some cases, depending on the setting, deformation may occur such that the central portion of the block of the lead frame is warped downward during processing of the lead frame. Such deformation may interfere with the production of the lead frame, and the same problem naturally occurs during processing and conveyance in the subsequent die bonding process and wire bonding process.

  Therefore, the present invention can be applied during the processing of the lead frame even when the die pad portion and the lead portion are arranged at a high density with respect to a single lead frame or the lead frame plate thickness is extremely thin. It is an object of the present invention to provide a lead frame for mounting a semiconductor element and a method for manufacturing the same, which can prevent the lead frame from being deformed such as warping during processing and conveyance.

In order to achieve the above object, a lead frame for mounting a semiconductor element according to one aspect of the present invention has a columnar die pad portion and a lead portion formed by forming a recessed portion on the surface side of a metal plate. A semiconductor device formed by mounting a semiconductor element on the die pad portion and connecting a bonding wire on the lead portion to seal the surface side with resin, and then removing unnecessary portions of the metal plate from the back side. A lead frame for mounting a semiconductor element used as a component of a package,
A plurality of sets of die pad portions and lead portions are provided so that a plurality of the semiconductor packages can be formed in one block for performing the resin sealing, and on a cutting line between adjacent pairs of the die pad portions and the lead portions. A columnar reinforcing piece is provided.

  According to another aspect of the present invention, there is provided a method of manufacturing a lead frame for mounting a semiconductor element, wherein the surface of a metal plate is half-etched, and a die pad part for mounting a semiconductor element is disposed around the die pad part, A lead portion serving as a connection terminal of a bonding wire electrically connected to the semiconductor element, and a reinforcing piece provided on at least a part of a cutting line provided between the adjacent die pad portion and the set of the lead portions; Has a half-etching step of forming a columnar shape.

  According to the present invention, even when semiconductor packages are arranged at a high density with respect to a single lead frame, or when the lead frame plate thickness is extremely thin, during the processing of the lead frame, the post-processing is performed. It is possible to prevent deformation such as warping of the lead frame during or during conveyance.

It is the figure which showed an example of the lead frame for semiconductor element mounting concerning the 1st Embodiment of this invention. FIG. 1A is a cross-sectional view showing an example of a semiconductor element mounting lead frame according to the first embodiment of the present invention. FIG. 1B is a view showing an example of a semiconductor package using the lead frame according to the first embodiment of the present invention. FIG. 1C is a plan view of an example of a semiconductor element mounting lead frame according to the first embodiment of the present invention. It is the figure which showed the plane structure of an example of the resin sealing block of the lead frame which concerns on the 1st Embodiment of this invention. It is the figure which showed the process of the first half of an example of the manufacturing method of the lead frame for semiconductor element mounting concerning the 1st Embodiment of this invention. FIG. 3A is a diagram showing an example of a metal plate preparation process. FIG. 3B is a diagram showing an example of a resist layer forming process. FIG. 3C is a diagram illustrating an example of a first resist mask forming process. FIG. 3D is a diagram showing an example of the plating process. It is the figure which showed the process of the second half of an example of the manufacturing method of the lead frame for semiconductor element mounting concerning the 1st Embodiment of this invention. FIG. 4A shows an example of a second resist mask forming process. FIG. 4B is a diagram showing an example of a half etching process. FIG. 4C is a diagram illustrating an example of a resist mask peeling process. It is the figure which showed the planar structure of an example of the lead frame 100a for semiconductor element mounting concerning the 2nd Embodiment of this invention. It is the figure which showed an example of the lead frame 100b for semiconductor element mounting concerning the 3rd Embodiment of this invention. FIG. 6A is a cross-sectional view showing an example of a semiconductor element mounting lead frame according to the third embodiment of the present invention. FIG. 6B is a view showing an example of a semiconductor package using the lead frame according to the third embodiment of the present invention. FIG. 6C is a plan view of an example of a semiconductor element mounting lead frame according to the third embodiment of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing an example of a lead frame for mounting a semiconductor device according to the first embodiment of the present invention. FIG. 1A is a cross-sectional view showing an example of a semiconductor device mounting lead frame according to the first embodiment of the present invention, and FIG. 1B is a diagram according to the first embodiment of the present invention. It is the figure which showed an example of the semiconductor package using a lead frame. FIG. 1C is a plan view of an example of a semiconductor element mounting lead frame according to the first embodiment of the present invention. 1A and 1B are cross-sectional views taken along the line AA ′ in FIG.

  As shown in FIG. 1A, the semiconductor element mounting lead frame 100 according to the first embodiment is configured using a metal plate 10. The metal plate 10 may be composed of various metal materials, but may be composed of, for example, copper or a copper alloy having a thickness of 0.1 mm to 0.15 mm.

  The semiconductor element mounting lead frame 100 according to the present embodiment includes a die pad portion 20, a lead portion 30, a reinforcing piece 40, and plating layers 70 and 71.

  The die pad portion 20 is a region for mounting a semiconductor element. In FIG. 1B, a semiconductor element 110 is mounted on the surface of the die pad portion 20 to constitute a semiconductor package 150 as a whole. As shown in FIG. 1B, one die pad part 20 is usually formed for one semiconductor package 150. The die pad unit 20 is often formed in the central region of the semiconductor package 150. Since the metal plate 10 is made of a single metal material, the metal plate 10 itself does not have a front surface and a back surface, but in this embodiment, for convenience, a semiconductor element on which the semiconductor element 110 is mounted. The mounting surface is referred to as the front surface or the front surface side, and the opposite surface is referred to as the back surface or the back surface side. In FIGS. 1A and 1B, the upper surface is the front surface and the lower surface is the back surface. A semiconductor element is mounted on the surface side of the die pad portion 20.

  The lead portion 30 is a connection terminal that is formed around the die pad portion 20 and is electrically connected from the terminal of the semiconductor element 110 using the bonding wire 120. In general, a plurality of lead portions 30 are provided around one die pad portion 20 and serve to electrically connect the terminals of the semiconductor element 110 to the outside. As shown in FIGS. 1B and 1C, the lead portion 30 is provided in a double annular shape including an inner lead portion 30 that is closer to the die pad portion 20 and a lead portion 30 that is slightly separated from the die pad portion 20. May be.

  As shown in FIG. 1A, the die pad portion 20 and the lead portion 30 are configured to have a columnar shape by forming a hollow shape portion 60 by half etching. That is, a half-etched die pad that is not half-etched is formed by removing a part from the surface of the metal plate 10 without passing through the metal plate 10 and forming a hollow portion 60 leaving the remaining portion 61. The part 20 and the lead part 30 have a shape protruding relatively in a columnar shape. Since the die pad portion 20 and the lead portion 30 are connected to each other and the metal plate 10 via the remaining portion 61, there is no possibility of detachment from the metal plate 10. That is, the semiconductor element mounting lead frame 100 forms the die pad portion 20 and the lead portion 30 in a columnar shape by half-etching processing on the front surface side, but the back surface side is not etched and remains on the material surface. In the state of 100, the die pad part 20 and the lead part 30 do not need to be connected to the outer frame of the lead frame 100, and can be freely arranged. Therefore, the die pad portion 20 and the lead portion 30 can be configured to have a free planar shape, and the die pad portion 20 and the lead portion 30 can be arranged at high density. For this reason, it is possible to dispose only the die pad portion 20 and the lead portion 30 necessary for the semiconductor package 150 and dispose a plurality of semiconductor packages 150 with a minimum cutting width interval.

  As shown in FIG. 1B, the remaining portion 61 is removed at the stage of manufacturing the semiconductor package 150 in a later step, and the die pad portion 20 and the lead portion 30 are not connected to each other but are sealed. It is fixed by the resin 130.

  Further, as shown in FIGS. 1A to 1C, plating layers 70 and 71 are formed on the front surface side and the back surface side of the die pad portion 20 and the lead portion 30, respectively. As shown in FIG. 1B, the die pad portion 20 mounts a semiconductor element, the front surface side of the lead portion 30 functions as a connection terminal for internal wiring of the semiconductor package 150, and the back surface side is externally connected from the outside. Functions as a connection terminal. Therefore, the plating layers 70 and 71 are formed on both surfaces of the die pad portion 20 and the lead portion 30. The plating layers 70 and 71 are generally composed of a noble metal such as gold (Au), silver (Ag), palladium (Pd), platinum (Pt), and are formed by performing noble metal plating.

  As shown in FIG. 1A, a reinforcing piece 40 is formed on the outer side of the outer lead portion 30. Similar to the die pad portion 20 and the lead portion 30, the reinforcing piece 40 is formed by half-etching and has a columnar shape. As shown in FIG. 1B, the reinforcing piece 40 does not function as a connection terminal. Therefore, the plating layers 70 and 71 are not formed on both the front side and the back side of the reinforcing piece 40. The reinforcing piece 40 is a structure provided to reinforce the lead frame 100 and is provided to prevent the lead frame 100 from being warped and deformed. That is, as described above, the die pad portion 20 and the lead portion 30 are connected to each other through the remaining portion 61 and are also connected to the metal plate 10. However, due to the recent demand for thinning, the thickness of the remaining portion 61 is increased. The manufacturer of the semiconductor package 150 may require about 10 to 30% of the metal plate 10 (etching depth of about 90 to 70%). That is, the manufacturer of the semiconductor package 150 may receive such a request from the viewpoint of reducing the etching amount after resin sealing as much as possible. If the thickness of the metal plate 10 is 0.1 mm to 0.15 mm, for example, 10% is 10 to 15 μm. When the thickness is 10 to 15 μm, the strength of the remaining portion 61 is not sufficient, and the lead frame 100 may be deformed such that the remaining portion 61 warps. Although depending on the arrangement and cutting width of the semiconductor package, the deformation is more likely to occur as the lead frame 100 is thinner and the half-etching depth is deeper. In particular, when the plate thickness is 0.1 mm or 0.125 mm and the half etching is 70% to 90%, the remaining thickness of the half etched portion is 0.01 m to 0.0375 mm, and deformation tends to occur frequently.

  In such a case, by providing the reinforcing piece 40 so as to form a frame outside the lead portion 30, the lead frame 100 can be reinforced and the occurrence of warpage can be prevented or reduced. Therefore, the reinforcing piece 40 is formed with a sufficient thickness and is configured to have the same thickness as at least one of the die pad portion 20 and the lead portion 30. Therefore, when the die pad portion 20 and the lead portion 30 have the same thickness, the reinforcing piece 40 is configured to have the same thickness as both. By providing such a reinforcing piece 40, deformation due to warping of the lead frame 40 during processing of the lead frame 100, during processing of the semiconductor package 150, or during transportation can be prevented, and the request for thinning can be sufficiently met.

  The reinforcing piece 40 is provided on the cutting line 50 of the semiconductor package 150. In the semiconductor package 150, the semiconductor element 110 is mounted on the surface of the die pad portion 20 of the lead frame 100, the terminals of the semiconductor element 110 are connected to the lead portion 30 by wire bonding, and then sealed with a sealing resin 130. It is formed. After the resin sealing is completed, the remaining portion 61 is removed by etching and separated into semiconductor packages 150 as shown in FIG. 1B, but the reinforcing pieces 40 are adjacent to the adjacent semiconductor packages 150. It is provided on a cutting line 50 provided between them. As shown in FIG. 1B, the exposed portion on the back surface side of the reinforcing piece 40 is removed by etching, but the front surface portion sealed with resin remains in the semiconductor package 150. However, the reinforcing piece 40 is necessary from the viewpoint of preventing warpage during the manufacture of the lead frame 100 and the semiconductor package 150, but is an unnecessary metal piece that does not play any role after the semiconductor package 150 is manufactured. is there. Therefore, in the present embodiment, the reinforcing piece 40 is provided on the cutting line 50 when the semiconductor package 150 is singulated, and most or all of the reinforcing piece 40 is cut when the semiconductor package 150 is singulated. The configuration is removable. Thereby, the semiconductor package 150 can be completed without leaving the reinforcing piece 40 in the separated semiconductor package 150.

  As shown in FIGS. 1A to 1C, the reinforcing piece 40 is preferably configured to have a width narrower than the width of the cutting line 50. Thereby, the reinforcing piece 40 can be reliably removed when the semiconductor package 150 is separated. However, it is not always essential that the reinforcing piece 40 is narrower than the width of the cutting line 50. Even when the reinforcing piece 40 is wider than the width of the cutting line 50, as long as the reinforcing piece 40 is provided on the cutting line 50, when the semiconductor package 150 is singulated, most of the reinforcing piece 40 is This is because only a part of the reinforcing piece 40 is removed and remains in the semiconductor package 150, and there is no particular adverse effect. However, as described above, the width of the reinforcing piece 40 is preferably narrower than the width of the cutting line 50. Therefore, in the following example, the example in which the width of the reinforcing piece 40 is narrower than the width of the cutting line 50 will be mainly described. I will explain. However, this is not intended to exclude an embodiment in which the width of the reinforcing piece 40 is wider than the width of the cutting line 50.

  FIG. 2 is a diagram illustrating a planar configuration of an example of a resin sealing block of the lead frame according to the first embodiment of the present invention. As shown in FIG. 2, a plurality of one lead frame 80 having a set of the die pad portion 20 and the lead portion 30 corresponding to one semiconductor package 150 are arranged to constitute a collective lead frame 100 as a whole. ing. Lead frames 80 are two-dimensionally arranged in a matrix, and a lead frame 100 as an aggregate is configured.

  In FIG. 2, a total of 16 lead frames 80 of 4 vertical and 4 horizontal are shown, but this 4 × 4 = 16 lead frames 80 are one resin-sealed block. The resin sealing is continuously performed so as to cover the entire 16 lead frames 80. In the resin sealing block 90, the reinforcing piece 40 is provided on the cutting line 50 between the adjacent lead frames 80. Although the cutting line 50 is not illustrated in FIG. 2, the cutting line 50 is provided so as to include the reinforcing piece 40 as described in FIGS. 1A to 1C. The reinforcing pieces 40 are provided in both the width direction (vertical direction in FIG. 2) and the longitudinal direction (horizontal direction in FIG. 2) of the metal plate 10, and the reinforcing pieces 40 are arranged in a lattice shape. That is, the reinforcing pieces 40 are provided vertically and horizontally on the cutting line 50 between all the adjacent lead frames 80 in the resin sealing block 90. Thereby, the strength of the lead frame 100 can be maintained and the lead frame 100 can be prevented from being deformed. In addition, the frame-shaped part 11 of the metal plate 10 is provided around the resin sealing block 90 and holds the entire resin sealing block 90 from the outside. A plurality of resin sealing blocks 90 may be continuously arranged along the longitudinal direction of the metal plate 10, and each resin sealing block 90 may have the same configuration.

  The upper limit of the width of the reinforcing piece 40 is (the width of the cutting line 50−0.05 mm), and the lower limit is 0.05 mm. If the width of the reinforcing piece 40 exceeds (the width of the cutting line 50−0.05 mm), the reinforcing piece 40 may remain on the semiconductor package 150 side as a burr at the time of cutting. On the other hand, if the width of the reinforcing piece 40 is less than 0.05 mm, the effect of the reinforcing piece 40 is not obtained, and problems and deformations due to warpage occur. Therefore, the width of the reinforcing piece 40 is preferably about (the width of the cutting line 50−0.1 mm).

  Next, a method for manufacturing a lead frame for mounting a semiconductor device according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a diagram illustrating the first half of an example of a method for manufacturing a semiconductor device mounting lead frame according to the first embodiment of the present invention, and FIG. 4 is related to the first embodiment of the present invention. It is the figure which showed the process of the second half of an example of the manufacturing method of the lead frame for semiconductor element mounting.

  FIG. 3A is a diagram showing an example of a metal plate preparation process. In the metal plate preparation step, a metal plate 10 that is a material for the semiconductor element mounting lead frame 100 is prepared. As the metal plate 10, various plate-like metal materials may be used depending on the application. For example, a metal plate 10 made of copper or a copper alloy having a thickness of 0.1 mm to 0.15 mm may be used. .

  FIG. 3B is a diagram showing an example of a resist layer forming process. In the resist layer forming step, first, pretreatment for removing foreign matters and impurities on the surface of the metal plate 10 is performed to form resist layers 140 and 141 on both sides. Usually, a commercially available dry film resist is stuck with a laminator.

  FIG. 3C is a diagram illustrating an example of a first resist mask forming process. In the first resist mask forming step, resist masks 144 and 145 for forming necessary plating on the front surface side (semiconductor element mounting surface side) and the back surface side (external connection portion side) are formed. The formation of the resist masks 144 and 145 is a general method, and the resist layers 140 and 141 are exposed and developed using an exposure mask on which a predetermined pattern is formed, so that the openings 142 and 143 are formed. Then, resist masks 144 and 145 are formed on both sides.

  FIG. 3D is a diagram showing an example of the plating process. In the plating step, the necessary plating layers 70 and 71 are formed on the metal plate 10 exposed from the openings 142 and 143 of the formed resist masks 144 and 145 after performing general plating pretreatment, and the resist is formed. The masks 144 and 145 are peeled off. Although various metal materials may be used for the plating layers 70 and 71, noble metals such as gold (Au), silver (Ag), palladium (Pd), and platinum (Pt) may be used as the plating layers 70 and 71. .

  Next, with reference to FIG. 4, the latter half of the process for producing the semiconductor element mounting lead frame according to the first embodiment will be described.

  FIG. 4A shows an example of a second resist mask forming process. In the second resist mask formation step, resist layers 146 and 147 are formed again on both surfaces of the metal plate 10 on which the plating layers 70 and 71 are formed in the same manner as in FIGS. 3B and 3C, and exposure and development are performed. As a result, a resist mask 149 is formed on the front surface side, which is a pattern of the semiconductor element mounting lead frame 100 and covers a wider area than the formed plating layer 70. Note that the resist mask 149 is formed by forming an opening 148 in the resist layer 146. On the back side, a resist mask 147 is formed to cover the entire surface.

  Here, the portion of the resist layer 146 to be the lead portion 30 to be wire-bonded and the portion of the resist layer 146 to be the die pad portion 20 are already formed when the metal plate 10 is dissolved by half etching. In addition, the surface of the metal plate 10 is set wider than the plating layer 70 of the die pad portion 20. By doing so, it can prevent that a part of plating layer 70 becomes a burr | flash or lose | deletes, and produces a malfunction in a post process.

  In addition, the resist layer 146 is left as a part of the pattern of the resist mask 149 also in the region that becomes the cutting line 50 between the individual lead frames 80 formed of the die pad portion 20 and the lead portion 30. The reinforcing piece 40 is formed in such a region. As shown in FIG. 2, the reinforcing piece 40 is formed on the cutting line 50 between the adjacent lead frames 80 and is formed in a lattice shape so as to surround the periphery of the die pad portion 20 and the lead portion 30. The resist layer 146 is set so that the resist mask 149 for etching has the width of the reinforcing piece 40.

  Note that the resist layer 146 is not formed on the surface of the metal plate 10 on which the plating layer 70 is formed, and a resist mask 147 covering the entire surface is formed on the back side, and the plating layer 70 on the surface is used as an etching mask. Is also possible. In this case, a resist layer (resist mask) 147 may be formed only on the back surface. Further, the plating layer 70 on the front surface side may be formed in the same pattern as the resist layer 146 so as to cover the same region as the resist mask 149. In this case, the upper surface of the formation part of the reinforcing piece 40 becomes an opening in the process of FIG. 3C, and the plating layer 70 is formed in the process of FIG.

  FIG. 4B is a diagram showing an example of a half etching process. In the half etching process, half etching is performed using the formed resist masks 147 and 149 as etching masks. In the half etching step, half etching is performed from about half the thickness of the metal plate 10 to a depth of about 90%. The degree of this half-etching can be arbitrarily selected in consideration of the etching from the back side that is performed in a later step.

  By performing half-etching processing of the metal plate 10 from the front surface side, a portion to be the lead portion 30 is formed in a columnar shape having a recessed portion 60 on the side surface. The upper surface of the lead part 30 has a configuration in which a plating layer 70 for wire bonding is formed in an area smaller than the planar shape of the upper surface, and the lower surface has a configuration in which a plating layer 71 for external connection is formed. Function.

  Similarly, the portion that becomes the die pad portion 20 is also a region for mounting the semiconductor element 110 having a columnar shape with the recessed portion 60 formed on the side surface and the plating layer 70 formed on the upper surface. In this way, the die pad portion 20 and the lead portion 30 having a columnar shape are formed by half etching.

  Moreover, the location used as the reinforcement piece 40 is also comprised by the columnar shape in which the hollow shape part 60 was formed in the side surface. Since the reinforcing piece 40 does not need a function as a terminal, it is different from the lead part 30 in that the plating layer 70 is not formed on the surface. However, the reinforcing piece 40 is formed by half-etching like the lead part 30. A columnar shape similar to the lead portion 30 is formed. However, since the width of the reinforcing piece 40 is preferably included in the cutting line 50, the width is determined in relation to the width of the cutting line 50. Generally, it has a width smaller than the width or diameter of the lead portion 30.

  FIG. 4C is a diagram illustrating an example of a resist mask peeling process. In the resist mask peeling step, the front-side resist mask 149 and the back-side resist mask 147 are peeled to complete the semiconductor element mounting lead frame 100 according to the first embodiment. Note that the resist masks 147 and 149 may be peeled using a predetermined stripping solution.

  The completed semiconductor element mounting lead frame 100 is used as a component for manufacturing the semiconductor package 150 in a subsequent process. Specifically, in the post-process, the semiconductor element 110 is mounted on the die pad portion 20, wire bonding is performed with the bonding wire 120, sealing is performed with the sealing resin 130, and etching is performed from the back side to form a columnar shape. The lead portion 30 and the substantially prismatic die pad portion 20 are made independent. Then, the semiconductor package 150 is obtained by cutting into individual semiconductor packages 150. At this time, the reinforcing piece 40 formed on the cutting line 50 is removed, and the reinforcing piece 40 does not remain in the completed semiconductor package 150.

  In addition, there is a semiconductor package 150 in which only the lead part 30 is arranged and a die pad is not required after securing the area of the die pad part 20, and the semiconductor element mounting lead frame 100 is also used for such a semiconductor package 150. it can.

  According to the lead frame 100 for mounting a semiconductor element and the manufacturing method thereof according to the first embodiment of the present invention, the reinforcing piece 40 can be formed at the same time when the die pad portion 20 and the lead portion 30 are formed. The deformation of the semiconductor element mounting lead frame 100 can be prevented without increasing the number. Further, since the reinforcing piece 40 is provided between all adjacent lead frames 80 in the same resin sealing block 90, the strength of the lead frame 100 for mounting a semiconductor element can be reliably increased. It is possible to reliably prevent deformation such as warping during processing and conveyance.

[Second Embodiment]
FIG. 5 is a diagram showing a planar configuration of an example of a semiconductor element mounting lead frame 100a according to the second embodiment of the present invention.

  As shown in FIG. 5, the lead frame 100a for a semiconductor device according to the second embodiment is the first embodiment in that the reinforcing pieces 40a are not in a lattice shape but are provided only in the width direction of the metal plate 10. This is different from the semiconductor element mounting lead frame 100 according to the embodiment. As described above, the reinforcing piece 40a may be arranged only in the short direction (width direction) of the metal plate 10 depending on the thickness of the metal plate 10 and the setting of half etching, the arrangement of the individual lead frames 80, and the like. . When the lead frame 100a is processed or transported, or when the lead frame 100a is cut into a sheet, inspection, packaging, or the like may be applied with a pinching force in the short direction (width direction). May occur. The same applies to the process of mounting the semiconductor element 110, the bonding process, and the like. It is effective to arrange such a lead frame 100a only in the short direction (width direction).

  The manufacturing method of the semiconductor element mounting lead frame 100a according to the second embodiment is substantially the same as the manufacturing method of the semiconductor element mounting lead frame 100 according to the first embodiment, but will be described with reference to FIG. In the second resist mask forming step, the pattern of the opening 148 of the resist mask 149 for forming the reinforcing piece 40 may be formed in a linear pattern in the width direction as shown in FIG. . The remaining steps may be performed in the same manner as the manufacturing method of the semiconductor element mounting lead frame 100 according to the first embodiment, and the description thereof is omitted.

  According to the semiconductor element mounting lead frame 100a and the manufacturing method thereof according to the second embodiment, the semiconductor element mounting lead frame 100a is effectively and efficiently applied when a particularly large force is applied in the width direction of the metal plate 10. Can be reinforced.

[Third Embodiment]
FIG. 6 is a diagram showing an example of a semiconductor element mounting lead frame 100b according to the third embodiment of the present invention. FIG. 6A is a cross-sectional view showing an example of a semiconductor element mounting lead frame according to the third embodiment of the present invention, and FIG. 6B is a diagram according to the third embodiment of the present invention. It is the figure which showed an example of the semiconductor package using a lead frame. FIG. 6C is a plan view of an example of a semiconductor element mounting lead frame according to the third embodiment of the present invention. FIGS. 6A and 6B are cross-sectional views taken along the line BB ′ of FIG. 6C.

  6A and 6B, in the lead frame 100b for mounting a semiconductor element according to the third embodiment, the height of the reinforcing piece 40b is higher than the height of the die pad portion 20 and the lead portion 30. The semiconductor device mounting lead frame 100 is different from the semiconductor device mounting lead frame 100 according to the first embodiment in that the configuration is low.

  Thus, the thickness of the reinforcing piece 40b may be set to be thinner than the die pad portion 20 and the lead portion 30 and thicker than the hollow-shaped portion 60 that has been half-etched. Preferably, the thickness of the reinforcing piece 40b is set to be 0.02 mm to 0.05 mm thicker than the half-etched hollow portion 60. In these cases, the reinforcing piece 40b is removed because the semiconductor element 110 is mounted, wire-bonded, sealed with the sealing resin 130, and etched simultaneously with the etching from the back side. Although a part remains in the sealing resin, the thickness of the reinforcing piece 40b is thin. For this reason, the load at the time of cutting | disconnecting the metal plate 10 can be reduced, and consumption of a cutting component can be suppressed. It also prevents the tool from being damaged during cutting. In particular, the type with a narrow cutting width is effective because the load during cutting is reduced and the tool is prevented from being damaged. The thickness of the reinforcing piece 40b is more preferably set to be about 0.03 mm thicker than the half-etched portion.

  Since other configurations are the same as those of the semiconductor element mounting lead frames 100 and 100a according to the first and second embodiments, description thereof will be omitted. Further, in the lead frame 100b for mounting a semiconductor element according to the third embodiment, the planar configuration of the reinforcing piece 40b may be a lattice like the lead frame 100 for mounting a semiconductor element according to the first embodiment. However, it may be configured to extend linearly only in the width direction of the metal plate 10 as in the semiconductor element mounting lead frame 100a according to the second embodiment.

  The manufacturing method of the semiconductor element mounting lead frame 100b according to the third embodiment is performed by configuring the etching resist mask 149 for forming the reinforcing piece 40b in a slit shape or a dot shape and changing the arrangement density. When the arrangement density of the slit-like or dot-like resist layer is high and the arrangement density of the openings is low, the amount of the etching solution reaching the material surface is reduced and the amount of etching is reduced. When the arrangement density of slit-like or dot-like resist layers is low and the arrangement density of the openings is high, the amount of the etching solution reaching the material surface increases, and the thickness of the openings not covered with the resist layer Get closer to. Further, the arrangement density of the slits or dots is set so that the height of the reinforcing piece 40b is appropriate in consideration of various conditions such as the concentration of the etching solution and the blowing direction of the etching solution.

  According to the semiconductor element mounting lead frame 100b and the manufacturing method thereof according to the third embodiment, it is possible to provide the semiconductor element lead frame 100b that can be easily cut when the semiconductor package is separated.

〔Example〕
Next, examples in which the semiconductor element mounting lead frame and the manufacturing method thereof according to the embodiment of the present invention are implemented will be described.

Example 1
A dry film resist (AQ-2558, manufactured by Asahi Kasei E-Materials Co., Ltd.) was laminated on both sides using a 0.1 mm-thick copper-based alloy material (EFTEC64-T manufactured by Furukawa Electric Co., Ltd.) as the metal plate.

  The plating area formed on the lead portion on the front surface side is a square shape of 0.5 mm □, the plating area formed on the semiconductor element mounting portion is a square shape of 4 mm □ with a radius of 0.2 mm, and the back surface side The plating area to be formed on the external connection part is a pattern that forms a resist mask having a square shape of 0.5 mm □ and a square shape of 4 mm □ having a radius of 0.1 mm on the die pad part. Then, the resist mask was exposed and developed to form a resist mask having openings where plating is required.

  Next, the metal plate exposed from the opening of the formed resist mask is subjected to a pre-plating process for removing an oxide film and the like, with a thickness of 1 μm for Ni, 0.07 μm for Pd, and 0.003 μm for Au. Sequential plating was performed, and the resist mask was peeled off.

  Next, the same dry film resist as described above was laminated on both surfaces of the metal plate on which plating was formed, and the back side was used as a resist mask covering the entire surface. Moreover, the surface side was made to cover 50 μm larger on one side than the formed plating. Further, a resist mask was formed where the reinforcing piece was to be placed. In this pattern, there are four blocks that are resin-sealed by one lead frame, and one semiconductor package is arranged in four rows and four stages, for a total of 16 blocks.

  Reinforcing pieces were arranged on the cutting line of the semiconductor package in three blocks in the longitudinal direction of the lead frame and three in the short direction in a grid pattern on one block. The cutting width was 0.2 mm, and the reinforcing piece width was 0.05 mm. The height of the reinforcing piece was set to the same height as the lead part and the die pad part.

  Next, using an etching solution with a liquid temperature of 40 ° C., etching is performed for 2 minutes at a spray pressure of 0.1 to 0.2 MPa, half-etching is performed from the surface side to a depth of about 70 μm, and the columnar shape that becomes the lead portion A shape and a substantially prismatic shape serving as a die pad portion for mounting a semiconductor element and a columnar shape serving as a reinforcing piece were formed.

  Then, the lead frame for mounting a semiconductor element of the present invention was obtained by peeling off the resist masks on both sides. During this time, deformation such as warpage did not occur. Moreover, there was no deformation such as warpage in the inspection process and the packaging / packing process, which are the next processes.

  A semiconductor element was mounted on the lead frame for mounting the semiconductor element using a silver paste, and the bumps of the semiconductor element and the lead portion were connected with a bonding wire having a diameter of 20 μm. Then, after sealing with an epoxy-based sealing resin, an etching process was performed using the plating layer formed on the back side with an alkaline copper etching solution as an etching mask.

  Then, it cut | disconnected to each package size at the cutting process, and the semiconductor package was obtained. No deformation such as warping occurred during processing or conveyance during this time.

(Example 2)
In Example 2, the reinforcing pieces were arranged at only three locations in the short direction of one block on the cutting line of the semiconductor package. Others are the same as the first embodiment.

  There was no occurrence of deformation such as warpage during the etching process, during conveyance, or in the next inspection process and packaging / packing process. In addition, deformation such as warping did not occur during processing or transportation until the semiconductor package was obtained by cutting from mounting the semiconductor element.

(Example 3)
In Example 3, the height of the reinforcing piece was 0.03 mm thicker than the half-etched portion. The etching resist forming the reinforcing piece is arranged in a slit shape, and the arrangement density is a portion where the height of the reinforcing piece is half-etched in consideration of various conditions such as the concentration of the etching solution and the blowing direction of the etching solution. The thickness was set to be 0.03 mm thicker. Others are the same as the first embodiment.

  There was no occurrence of deformation such as warpage during the etching process, during conveyance, or in the next inspection process and packaging / packing process. In addition, deformation such as warping did not occur during processing or transportation until the semiconductor package was obtained by cutting from mounting the semiconductor element.

  In addition, after resin sealing, at the time of etching processing from the back side, some of the reinforcing pieces remained in the sealing resin. After cutting, no semiconductor package had any reinforcing pieces attached.

Example 4
In Example 4, the height of the reinforcing piece was 0.02 mm thicker than the half-etched portion. The etching resist forming the reinforcing piece is arranged in a slit shape, and the arrangement density is a portion where the height of the reinforcing piece is half-etched in consideration of various conditions such as the concentration of the etching solution and the blowing direction of the etching solution. The thickness was set to be 0.02 mm thicker. Others are the same as the first embodiment.

  There was no occurrence of deformation such as warpage during the etching process, during conveyance, or in the next inspection process and packaging / packing process. In addition, deformation such as warping did not occur during processing or transportation until the semiconductor package was obtained by cutting from mounting the semiconductor element.

  In addition, the reinforcement piece was removed at the time of the etching process from the back side after resin sealing.

(Example 5)
In Example 5, the width of the reinforcing piece was 0.1 mm. Others are the same as the first embodiment.

  There was no occurrence of deformation such as warpage during the etching process, during conveyance, or in the next inspection process and packaging / packing process. In addition, deformation such as warping did not occur during processing or transportation until the semiconductor package was obtained by cutting from mounting the semiconductor element.

(Comparative Example 1)
The comparative example 1 is the setting which does not arrange | position a reinforcement piece, and others are the same as Example 1. FIG.

  At the time of etching processing and conveyance, the center part of the short direction of the lead frame warped downward, and a part of the apparatus contacted the part and the deformation occurred.

(Comparative Example 2)
In Comparative Example 2, the height of the reinforcing piece was made 0.01 mm thicker than the half-etched portion. The etching resist forming the reinforcing piece is arranged in a slit shape, and the arrangement density is a portion where the height of the reinforcing piece is half-etched in consideration of various conditions such as the concentration of the etching solution and the blowing direction of the etching solution. The thickness was set to be 0.01 mm thicker. Others are the same as the first embodiment.

  At the time of etching processing and conveyance, the center part of the short direction of the lead frame warped downward, and a part of the apparatus contacted the part and the deformation occurred.

  As described above, when Examples 1 to 5 and Comparative Examples 1 and 2 are compared, in Comparative Examples 1 and 2, the etching process caused deformation of the lead frame during conveyance, whereas in Examples 1 to 5, In the etching process, deformation such as warping of the lead frame did not occur during transportation. Thereby, according to the lead frame which concerns on Examples 1-5 which provided the reinforcement piece, it was shown that generation | occurrence | production of deformation | transformation, such as curvature of a lead frame, can be prevented.

  As described above, according to the lead frame for mounting a semiconductor element and the method for manufacturing the same according to the embodiment of the present invention, one columnar reinforcing piece is disposed along the cutting line of the adjacent semiconductor package. Due to the high density of the semiconductor package with respect to the lead frame or the thinning of the lead frame thickness, the center part of the lead frame block during the processing of the lead frame, during the post-processing, or during transportation is on the lower side. Warping deformation can be prevented.

  By setting the reinforcing piece to be narrower than the cutting width, the reinforcing piece is removed at the same time when the semiconductor package is cut, so that it does not remain in the semiconductor package.

  Also, the thickness of the reinforcing piece is set to be thinner than the material plate thickness and thicker than the half-etched part, and after the resin is sealed, when the back side is etched, the reinforcing piece is simultaneously etched and removed. If the height is set to a height that can be cut, the load during cutting can be reduced, and consumption of cut parts can be suppressed. It also prevents the tool from being damaged during cutting.

  The preferred embodiments and examples of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments and examples, and the above-described embodiments and examples can be performed without departing from the scope of the present invention. Various modifications and substitutions can be made to the embodiments.

DESCRIPTION OF SYMBOLS 10 Metal plate 11 Frame-shaped part 20 Die pad part 30 Lead part 40, 40a, 40b Reinforcing piece 50 Cutting line 60 Indented part 70, 71 Plating layer 80, 100 Lead frame 90 Resin sealing block 110 Semiconductor element 120 Bonding wire 130 Sealing Resin 140 to 149 Resist mask 150 Semiconductor package

Claims (13)

It has a column-shaped die pad part and a lead part formed by forming a hollow part on the surface side of the metal plate, and a semiconductor element is mounted on the die pad part and a bonding wire is connected on the lead part. A semiconductor element mounting lead frame used as a component of a semiconductor package formed by removing unnecessary portions of the metal plate from the back surface side after resin sealing the front surface side,
A plurality of sets of die pad portions and lead portions are provided so that a plurality of the semiconductor packages can be formed in one block for performing the resin sealing, and on a cutting line between adjacent pairs of the die pad portions and the lead portions. A semiconductor element mounting lead frame provided with columnar reinforcing pieces.   The lead frame for mounting a semiconductor element according to claim 1, wherein the reinforcing piece is provided only on the cutting line extending in the width direction of the metal plate.   2. The lead frame for mounting a semiconductor element according to claim 1, wherein the reinforcing pieces are provided in a lattice shape on both the cutting line extending in the width direction of the metal plate and the cutting line extending in the longitudinal direction of the metal plate.   The lead frame for mounting a semiconductor element according to any one of claims 1 to 3, wherein the reinforcing piece has a width narrower than a width of the cutting line.   5. The lead frame for mounting a semiconductor element according to claim 1, wherein a thickness of the reinforcing piece is the same as a thickness of at least one of the die pad portion and the lead portion.   5. The lead frame for mounting a semiconductor element according to claim 1, wherein the reinforcing piece is thinner than the die pad portion and the lead portion and thicker than the hollow portion. A manufacturing method of a lead frame for mounting a semiconductor element,
A die pad portion for mounting a semiconductor element by half-etching the surface of the metal plate, and a lead portion which is disposed around the die pad portion and serves as a connection terminal of a bonding wire electrically connected to the semiconductor element; A method of manufacturing a lead frame for mounting a semiconductor element, comprising: a half-etching step of forming a reinforcing piece provided in at least a part on a cutting line provided between the adjacent die pad part and the pair of lead parts in a columnar shape .   The method of manufacturing a lead frame for mounting a semiconductor element according to claim 7, wherein a width of the reinforcing piece is formed narrower than a width of the cutting line.   9. The method of manufacturing a lead frame for mounting a semiconductor element according to claim 7, wherein the reinforcing piece is formed only on the cutting line in the width direction of the metal plate.   9. The method of manufacturing a lead frame for mounting a semiconductor element according to claim 7, wherein the reinforcing pieces are formed both on the cutting line in the width direction of the metal plate and on the cutting line in the longitudinal direction of the metal plate. .   The method for manufacturing a lead frame for mounting a semiconductor element according to any one of claims 7 to 10, further comprising a plating step of forming plating layers on the front and back surfaces of the die pad portion and the lead portion.   The plating step is performed before the half etching step, and the half etching step is performed by using the plating layer formed on the surface of the die pad part and the lead part as an etching mask on the surface side. A method of manufacturing a lead frame for mounting a semiconductor device according to claim 11.   The forming region of the die pad part and the lead part is covered with a resist layer, the forming part of the reinforcing piece is covered with a slit-like or dot-like resist layer, the half-etching process is performed, and the reinforcing piece is The method for manufacturing a lead frame for mounting a semiconductor element according to claim 7, wherein the lead frame is formed in a columnar shape lower than the die pad portion and the lead portion.

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