JP5083348B2 - Mold package manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing a mold package in which an electronic component is enclosed in a mold material and leads are provided on the bottom surface.

  In general, a semiconductor module composed of a plurality of semiconductor chips (electronic components) has a structure of a mold package in which a structure in which these semiconductor chips are mounted on a substrate is enclosed in a mold material composed of resin or the like. Often done. Leads serving as electrical terminals in the mold package are formed on the surface of the mold material and connected to internal semiconductor elements and the like. There are various types of mold packages. Among them, there is a package known as a non-lead type, for example, a SON (Small Outline Non-lead) type. FIG. 5 is a diagram showing an appearance of the SON type package 10 as an example. 5, (a) is a side view thereof, (b) is a top view, (c) is a front view, (d) is a bottom view, and (e) is a perspective view. A feature of this package is that it has a rectangular shape and is provided with a plurality of leads 12 serving as electrical terminals at the left and right ends of the bottom surface of the molding material 11 in which a semiconductor chip is incorporated. Each lead 12 is made of a metal such as copper that is electrically connected to a terminal of a semiconductor chip sealed in the molding material 11 and can be soldered. The semiconductor chip is mounted on a lead frame 13 made of the same material as each lead and provided on the same plane as each lead, and is sealed in the molding material 11. In this configuration, each of the leads 12 on the bottom surface is joined to the substrate with solder, whereby the SON type package 10 can be fixed on the substrate and the substrate and the semiconductor chip can be electrically joined. The feature of such a non-lead type package is that this connection can be made only between the bottom surface and the substrate, and therefore requires an area significantly larger than the bottom area of the SON type package 10 for electrical connection. This is a point that can be mounted with high density. A typical size of the SON type package 10 is, for example, about 10 mm × 20 mm.

  However, when mounting the SON type package 10 on the substrate, the operator must check whether each lead 12 is sufficiently soldered (attached) by visual inspection or an appearance inspection device. Is required. Therefore, in practice, as shown in FIG. 5, each lead 12 is slightly protruded from the side surface of the molding material 11, and the presence or absence of solder is confirmed by observing the protruding portion. Yes. That is, in the actual SON type package 10, each lead 12 is slightly protruded from the side surface of the molding material 11. It should be noted that this protruding portion is not used for electrical connection, but is used only for checking the presence or absence of solder, so that the protruding amount is less than 1 mm. Therefore, this structure does not become an obstacle when the SON type package 10 is mounted at a high density.

  Such a SON type package is generally obtained by manufacturing a structure in which a plurality of SON type packages are arranged and cutting and separating them. For this reason, a metal pattern corresponding to the structure in which the lead frame 13 and the leads 12 in a plurality of SON type packages are arranged is used. FIG. 6A is a diagram showing a configuration corresponding to a single SON type package in this case. Leads 12 are arranged around the lead frame 13 on the same plane. FIG. 6B is a diagram showing the configuration of the metal pattern 100 in a form in which it is arranged. Each SON type package 10 is obtained by mounting each semiconductor chip on the metal pattern 100 and sealing the whole in the mold material 11 and then cutting the boundary portion between adjacent SON type packages. In the metal pattern 100, a section bar 101 and a lead frame fixing bar 102 are used to integrate the patterns constituting the metal pattern 100. The thickness of the section bar 101 and the lead frame fixing bar 102 is appropriately set so that the mechanical strength of the entire metal pattern 100 is maintained. When the boundary portion between adjacent SON type packages is cut and separated, the section bar 101 and the lead frame fixing bar 102 are cut.

  Here, a region K surrounded by a dotted line in FIG. 6B is a portion where the leads 12 of two adjacent SON type packages are formed by being divided, and is a portion where the section bar 101 is formed. is there. The region extending in the horizontal direction perpendicular to the section bar 101 at this location is the common lead 103, and the lead in the SON type package 10 formed on the left and right of the section bar 101 by dividing the common lead 103 in the left and right direction. 12 are formed on each. In this structure, a plurality of common leads 103 are formed in parallel, and a straight section bar 101 orthogonal to these is formed integrally therewith.

  The shape seen from the side, upper surface, front, and lower surface of this portion when this processing method is executed is FIG. 7, and FIG. 8 is a perspective view corresponding thereto. Here, in order to form this structure, cutting using a blade (cutting blade) is performed twice.

  First, as shown in FIGS. 7A and 8A, after a semiconductor chip is mounted and bonded onto the metal pattern 100, the surface on which the semiconductor chip is mounted (the upper surface in the figure). ) The whole is sealed in the molding material 11. With respect to this form, as shown in FIG. 7B and FIG. 8B, a wide mold material cutting blade 211 is used, and cutting processing is performed on the mold material 11 from the upper surface side. This cutting is performed at a depth until the mold material cutting blade 211 comes into contact with the metal pattern 100.

  As a result, as shown in FIGS. 7C and 8C, a groove having a depth reaching the surface of the metal pattern 100 (section bar 101, common lead 103) is formed in the molding material 11. . The width of this groove corresponds to the thickness of the mold material cutting blade 211. Next, as shown in FIGS. 7D and 8D, the central portion of the groove is cut using a cutting blade 212 that is thinner than the molding material cutting blade 211. This cutting is performed until the structure shown in FIGS. 7C and 8C is completely divided, that is, the mold material 11 and the metal pattern 100 at the cutting location are cut down in the drawing. Thereby, a shape divided into right and left as shown in FIG. 7E is obtained. FIG. 8E shows one of the divided shapes. Here, the section bar 101 is removed, and the common lead 103 is also divided on the left and right. Leads 12 formed by dividing the common lead 103 protrude from the mold material 11 on both sides of the divided portion. This shape is the shape of the lead 12 and its surroundings in FIG. 7 and 8 show the cutting in the vertical direction in FIG. 6B, but the lead frame fixing bar 102 is cut in the horizontal direction in FIG. 6B separately from this. Thereby, the individual SON type packages 10 are obtained by being divided.

  Using such a manufacturing method, it is possible to manufacture the SON package 10 having a structure in which it is easy to confirm that the solder is sufficiently on the lead 12.

  In this manufacturing method, in particular, in the second cutting process using the cutting blade 212, the section bar 101 is cut along a wide range over the entire vertical direction in FIG. Remove. At the time of cutting, the entire section bar 101 made of metal comes into contact with the cutting blade 212. For this reason, the load on the cutting blade 212 becomes extremely large, and it is difficult to increase the cutting speed, or the life of the cutting blade 212 is shortened. For this purpose, Patent Document 1 describes a technique of locally thinning a region including a section bar 101 to be removed by cutting in the metal pattern 100 in advance. As a result, the load on the cutting blade 212 can be reduced, and the above problem can be solved.

JP 2008-182175 A

  In the manufacturing method described above, it is necessary to make the molding material cutting blade 211 and the cutting blade 212 thicker than the thickness of the section bar 101, and such a thick blade is very expensive. In addition, since a thick blade tends to cause uneven wear, its life is short. Furthermore, in the case of manufacturing a plurality of types of mold packages using a plurality of types of metal patterns having different thicknesses of the section bar 101, it is necessary to prepare a plurality of types of blades having a thickness corresponding to each type. Become.

  For this reason, it was difficult to obtain a non-lead mold package at low cost by the above manufacturing method.

  The present invention has been made in view of such problems, and an object thereof is to provide an invention that solves the above problems.

In order to solve the above problems, the present invention has the following configurations.
The method of manufacturing a mold package according to the present invention includes a plurality of mold packages having a structure in which an electronic component is sealed in a mold material and a lead electrically connected to the electronic component is provided at an end of the bottom surface. obtained by cutting after constructed using a single metal pattern, a method for producing a molded package, in the metal pattern, while the portion to be the two mold package to be produced adjacent, the two One main surface of the metal pattern is formed by integrally forming a common lead that is a pattern for connecting parts to be one mold package and a linear section bar that intersects the common lead substantially orthogonally. and a plate bonding step of bonding the fixing plate, the electronic component mounted on the other main surface of the metal pattern, the common And over de with the electronic component after electrically connecting, in the other main surface, a molding step of forming a layer composed of the molding material, after said molding step, wherein adjacent to said section bar Using the first blade and the second blade that are substantially parallel to the section bar, the common lead from the other main surface side between each of the two mold package parts to be manufactured. There by half cutting a layer composed of the molding material to a depth that exposes a molding material cutting step of forming a first groove and a second groove, wherein the common lead is exposed at the bottom of each respectively, the A third blade that is substantially parallel to the section bar and thinner than the first blade, and a third blade that is substantially parallel to the section bar and thinner than the second blade. The common lead on the side opposite to the section bar as viewed from the position cut by the third blade in the first groove, and the fourth blade in the second groove, respectively. The first groove, the first groove, and the common lead on the side opposite to the section bar when viewed from the cut portion, so that each of the common leads is the lead in each of the two mold packages manufactured adjacently. A region close to the section bar in each of the second grooves is set to a depth at which the common lead is divided from the other main surface side using the third blade and the fourth blade, respectively. A cutting step for performing a cutting process, and a plate separating step for separating the fixing plate from the metal pattern after the cutting step. It is characterized by comprising.
The mold package manufacturing method of the present invention is characterized in that a plurality of the common leads are formed in parallel in the metal pattern, and the plurality of common leads are connected by the common section bar.
In the mold package manufacturing method of the present invention, the area occupied by the fixing plate is larger than the area occupied by the metal pattern.
The method for manufacturing a mold package according to the present invention is characterized in that the fixing plate provided with the marking is used.

  Since the present invention is configured as described above, a non-lead mold package can be obtained at low cost.

It is the figure which looked at the form in the process in the manufacturing method of the mold package which concerns on embodiment of this invention from the side surface, the upper surface, the front surface, and the lower surface. It is the perspective view which looked at the form in the process in the manufacturing method of the mold package which concerns on embodiment of this invention. It is the perspective view (a) and sectional drawing (b) which show the structure after the mold process in the manufacturing method of the mold package which concerns on embodiment of this invention. It is a perspective view which shows the structure of the mold package manufactured by the manufacturing method of the mold package which concerns on embodiment of this invention. They are a side view (a), a top view (b), a front view (c), a bottom view (d), and a perspective view (e) of the SON package. It is the unit structure (a) of metal pattern used when manufacturing a SON type | mold package, and the whole figure (b). It is the figure which looked at the form in the process in the manufacturing method of the conventional mold package from the side surface, the upper surface, the front surface, and the lower surface. It is the perspective view which looked at the form in the process in the manufacturing method of the conventional mold package.

  Hereinafter, a method for manufacturing a mold package according to an embodiment of the present invention will be described. This manufacturing method is suitable for manufacturing a non-lead type mold package, for example, an SON type package. The form of the SON type package manufactured by this manufacturing method is the same as that shown in FIG. Further, the structure of the lead frame and leads used for manufacturing the same and the structure of the metal pattern used are the same as those shown in FIGS. 6 (a) and 6 (b). That is, the SON type package 10 having the same configuration as the conventional one can be manufactured using the metal pattern 100 having the same configuration as the conventional one. In this SON type package, a plurality of leads 12 are provided on both side surfaces, and the leads 12 protrude slightly from the side surfaces of the molding material 11. As a result, the operation of connecting the SON package 10 to the substrate with solder can be performed reliably and easily.

  The metal pattern 100 is made of copper or copper alloy having high conductivity and high thermal conductivity. When forming the pattern shown in FIG. 6B, a method of wet etching copper or copper alloy after forming a photoresist layer having this pattern on a flat plate made of copper or copper alloy, for example. Can be used.

  In this manufacturing method, after a fixing plate is installed on the metal pattern 100, a semiconductor chip is mounted and sealed in a molding material. Then, after performing a cutting process, the fixing plate is removed. Hereinafter, this manufacturing method will be described with reference to FIGS. FIGS. 1A to 1G are a side view, a top view, a front view, and a bottom view of a form when this manufacturing method is executed in a region K surrounded by a dotted line in FIG. 6B. is there. FIGS. 2A to 2G are perspective views corresponding thereto. In this region, the section bar 101 and the common lead 103 intersect at right angles. Here, the lead 12 in the SON type package 10 formed on the left and right of the section bar 101 is formed by dividing the common lead 103 in the left-right direction.

  First, as shown in FIG. 1A and FIG. 2A, one main surface of the metal pattern 100 is fixed to a fixing plate 110 (plate bonding step). This bonding is performed using, for example, an adhesive or the like, but it is preferable to use an adhesive that can be removed using a solvent or the like in order to remove the fixing plate 110 later. Alternatively, it is possible to join using a material that melts by heating or the like. As the material for the fixing plate 110, plastic or the like can be used, and the thickness thereof is set to a thickness that can maintain a mechanical support substrate having a structure described below.

  In this state, a semiconductor chip is mounted on the surface side of the metal pattern 100 (the side opposite to the side where the fixing plate 110 is connected: the other main surface side). The semiconductor chip is bonded to the lead frame 13 in FIG. 6B using solder or an adhesive. Further, the electrode on the semiconductor chip and the end of the common lead 102 are connected using a bonding wire.

  Thereafter, as shown in FIGS. 1B and 2B, a layer made of the molding material 11 is formed on the surface side of the metal pattern 100, and a structure in which a semiconductor chip or the like is enclosed in the molding material 11 is formed. Form (molding process). This step can be performed by, for example, thermocompression bonding a sheet made of the molding material 11 and having a thickness of about 1 mm. A perspective view of the entire metal pattern 100 from the upper surface after this step is shown in FIG. 3A, and a sectional view in the AA direction is shown in FIG. A semiconductor chip 14 is mounted on each lead frame 13, and an end portion of the common lead 103 and a bonding pad on the semiconductor chip 14 are connected by a bonding wire 15. The entire structure on the metal pattern 100 is sealed in the molding material 11. In the perspective view (FIG. 3A), the description of the molding material 11 and the fixing plate 110 is omitted.

  Next, as shown in FIG. 1C and FIG. 2C, two regions on both outer sides of the section bar 101 are parallel to the section bar 101, respectively, and a molding material cutting blade (first A half-cut process is performed using a blade 201 and a mold material cutting blade (second blade) 202 (mold material cutting step). This cutting depth is from the surface side (the side where the molding material 11 is present) until the molding material cutting blades 201 and 202 come into contact with the metal pattern 100 (common lead 103). For this reason, only the molding material 11 is cut here. The cutting using the mold material cutting blades 201 and 202 can be performed simultaneously or separately. The blade thickness of the mold material cutting blades 201 and 202 can be set to, for example, about 1.0 mm.

  As shown in FIGS. 1D and 2D, the shape after the molding material cutting step is formed with two grooves (first groove 251 and second groove 252) on both sides of the section bar 101. It becomes the shape made. The common lead 103 is exposed on the bottom surface of the groove. The widths of the first groove 251 and the second groove 252 correspond to the thickness of the blades of the mold material cutting blades 201 and 202.

  Next, as shown in FIGS. 1 (e) and 2 (e), the sides close to the section bar 101 in the first groove 251 and the second groove 252 are cut in parallel with the section bar 101. Cutting is performed using a cutting blade (third blade) 203 and a cutting blade (fourth blade) 204 (cutting step). The cutting depth is such that the metal pattern 100 (common lead 103) is completely divided from the surface side and the fixing plate 11 is not divided. The cutting process using the cutting blades 203 and 204 can be performed simultaneously or separately. The thicknesses of these blades can be made thinner than the molding material cutting blades 201 and 202, for example, about 0.5 mm.

  In the shape after the cutting step, as shown in FIGS. 1 (f) and 2 (f), the first groove 251 and the second groove 252 are further formed on the bottom surface of the groove formed by the cutting step. The fixing plate 110 is exposed. Next to that, there is an area where the common lead 103 is exposed.

  Thereafter, the fixing plate 110 is separated by dissolving the adhesive using a solvent or the like (plate separation step). The shape after this is shown in FIG. 1 (g). Since the fixing plate 110 that has become the support substrate is removed, the central portion including the section bar 101 is easily removed, and the portions on both sides thereof are divided. The A perspective view of this one form is shown in FIG. 2 (g), and this shape is the shape of the side surface of the SON type package 10 shown in FIG.

  In the above description, the cutting process in the vertical direction (direction parallel to the section bar 101) in FIG. Actually, apart from this, there is also a step of cutting in the horizontal direction (direction perpendicular to the section bar 101) at the upper and lower portions of the lead frame 13 in FIG. 6B between the plate joining step and the plate separating step. is necessary. As a result, each SON type package 10 having the shape shown in FIG. 5 is obtained by being divided in the horizontal direction and the vertical direction in FIG.

  In the above manufacturing method, the molding material 11 is cut in the molding material cutting step. In the subsequent cutting step, the common lead 103 and the molding material 11 exposed on the bottom surface of the groove formed in the molding material cutting step are cut. Here, the section bar 101 itself having a shape extending in the vertical direction in FIG. 6B is not cut. For this reason, in both the molding material cutting step and the cutting step, the load on the blade is reduced, and the cutting speed can be increased, or the life of the blade can be extended. Further, the molding material cutting blades 201 and 202 need to be thicker than the cutting blades 203 and 204, respectively, but can be thinner than the width of the section bar 101. For this reason, it is possible to use a thin blade with less uneven wear as compared with the conventional manufacturing method described in FIGS. At this time, it is not necessary to locally reduce the thickness of the metal pattern 100 as in the technique described in Patent Document 1.

  Alternatively, when a plurality of types of mold packages having different patterns are manufactured by the above-described manufacturing method and the thickness of the section bar 101 is different in each metal pattern, the same mold material cutting is used for any mold package. Blades 201 and 202 and cutting blades 203 and 204 can be used, respectively. In this case, the interval between the mold material cutting blades 201 and 202 may be adjusted in the molding material cutting step, and the interval between the cutting blades 203 and 204 may be adjusted in the cutting step. On the other hand, in the case of the conventional manufacturing method shown in FIGS. 7 and 8, when the thickness of the section bar 101 is different, the thicknesses of the molding material cutting blade 211 and the cutting blade 212 are set to the section bar. It is necessary to change according to the thickness of 101 or the like.

  As described above, in the above manufacturing method, the life of the blade is reduced by reducing the load of the blade to be used, and the same blade can be used when manufacturing different types of mold packages. Therefore, a non-lead mold package can be obtained at low cost.

  In particular, in the cutting process (FIGS. 1 (f) and 2 (f)), the metal pattern 100 (common lead 103) made of metal is cut from the upper side to the lower side. , Burrs are formed downward. Obviously, it is not preferable that such burrs remain. However, since these burrs adhere to the fixing plate 110 side, they are removed at the same time as the fixing plate 110 in a subsequent plate separation step. For this reason, the influence of the burr | flash which generate | occur | produces in a cutting process can also be reduced.

  Further, the shape of the fixing plate 110 is arbitrary as long as the above-described structure formed on the metal pattern 100 can be mounted. From the plate joining process to the plate separating process, the operator can handle the above structure together with the fixing plate 110. For this reason, an operator can perform especially easily said process or the other process performed between a plate joining process and a plate separation process. In particular, various operations can be performed without directly contacting the mold material 11, the metal pattern 100, or the like. Further, for example, a marking for identification can be provided on the back surface of the fixing plate 110 (the surface opposite to the side to which the metal pattern 100 is connected). This makes it possible to perform the above operation easily and reliably.

  The size of the fixing plate 110 is set such that the metal pattern 100 can be fixed on one main surface. However, since the handling of this structure in the processes after the plate joining process is performed by contacting the fixing plate 110, the area occupied by the fixing plate 110 should be sufficiently larger than the area occupied by the metal pattern 100. Is preferred. In this case, it is possible to join a plurality of metal patterns 100 on one fixing plate 110 as long as the molding material cutting step and the cutting step can be performed simultaneously.

  FIG. 4 is a perspective view from the upper surface of the internal structure in the SON type package obtained by the above manufacturing method. This structure is the same as a general SON type package. In FIG. 4, a region surrounded by a broken line corresponds to the shape of the molding material 11. This structure is a shape obtained by dividing the shape of FIG.

  In the above example, the molding process is performed after the plate joining process. However, as long as the semiconductor chip 14 and the like are mounted on the metal pattern 100 and then sealed in the molding material 11 can be realized. It is also possible to reverse this order.

  Also, the thickness of the molding material cutting blade (first blade) 201 and the molding material cutting blade (second blade) 202, the cutting blade (third blade) 203 and the cutting blade (fourth blade). ) 204 need not be equal in thickness. However, the exposed length of the lead 12 is set by the difference in thickness between the molding material cutting blade 201 and the cutting blade 203 and the difference in thickness between the molding material cutting blade 202 and the cutting blade 204. . For this reason, these thicknesses are appropriately set depending on the length of the lead 12 exposed.

  In the above example, a plurality of SON type packages having the same configuration are obtained after cutting, but the present invention is not limited to this. As long as the above-described plate joining process, molding process, molding material cutting process, cutting process, and plate separation process can be performed, for example, using a metal pattern in which SON type packages having different configurations of the lead frame are arranged, An SON type package can also be obtained.

  In the above example, the internal structure of the SON package is shown in FIG. 4, but it is obvious that the above manufacturing method can be applied to other structures as well. For example, the same applies to a configuration in which a plurality of lead frames and a plurality of semiconductor chips are provided in one package. The same applies when electronic components other than semiconductor chips are mounted on the lead frame.

  The same applies to components that do not exist in the manufactured SON package, such as a section bar and a lead frame fixing bar, or that do not have a function even if they exist. For example, in the above example, the lead frame fixing bar 102 is used, but even if this is not used, the above manufacturing method can be similarly applied as long as the structure is integrated as a metal pattern.

  Further, although the common lead and the section bar are set to be orthogonal, it is not necessary to be strictly orthogonal as long as the above structure can be manufactured. Similarly, each common lead need not be strictly parallel. Similarly, the cutting direction in the molding material cutting process or the cutting process does not have to be strictly parallel to the section bar.

  In addition, a mold package having another structure in which leads are formed on the bottom end portion made of a mold material, for example, a QFN (Quad Flat Non-lead) type package can be manufactured in the same manner. The section bar and the common lead having the above-described structure are formed not only in the horizontal direction with respect to the lead frame 13 in FIG. If it carries out, the QFN type package provided with the lead of the same composition can be obtained.

10 SON type package (mold package)
11 Mold material 12 Lead 13 Lead frame 14 Semiconductor chip 15 Bonding wire 100 Metal pattern 101 Section bar 102 Lead frame fixing bar 103 Common lead 110 Fixing plate 201 Mold material cutting blade (first blade)
202 Blade for cutting mold material (second blade)
203 Cutting blade (third blade)
204 Blade for cutting (fourth blade)
211 Mold material cutting blade 212 Cutting blade 251 First groove 252 Second groove

Claims (4)

A plurality of mold packages having a structure in which an electronic component is sealed in a mold material and leads electrically connected to the electronic component are provided at the end of the bottom surface are configured using a single metal pattern. A method of manufacturing a mold package obtained by cutting later,
In the metal pattern, a common lead that is a pattern for connecting the two mold packages to be adjacent to each other and two mold packages that are manufactured adjacent to each other intersect with the common lead substantially orthogonally. A straight section bar is integrally molded,
A plate joining step for joining one main surface of the metal pattern to a fixing plate;
After mounting the electronic component on the other main surface of the metal pattern and electrically connecting the common lead and the electronic component , a layer made of the molding material is formed on the other main surface side. Mold process to perform,
After the molding step, a first blade and a second blade that are substantially parallel to the section bar are provided between the section bar and each of the two parts to be manufactured adjacent to each other. The first groove and the second groove in which the common lead is exposed at each bottom by half-cutting the layer made of the molding material from the other main surface side to the depth at which the common lead is exposed . A mold material cutting step for forming the grooves, and
Using a third blade that is substantially parallel to the section bar and thinner than the first blade, and a fourth blade that is substantially parallel to the section bar and thinner than the second blade, respectively.
The common lead on the opposite side of the section bar as viewed from the portion cut by the third blade in the first groove, and the portion cut by the fourth blade in the second groove. In each of the first groove and the second groove, each of the common leads on the side opposite to the section bar becomes the lead in each of the two adjacently manufactured mold packages. A cutting step of cutting a region on the side close to the section bar to a depth at which the common lead is divided from the other main surface side using the third blade and the fourth blade, respectively. ,
After the cutting step, a plate separating step for separating the fixing plate from the metal pattern;
A mold package manufacturing method comprising: In the metal pattern,
The method of manufacturing a mold package according to claim 1, wherein the plurality of common leads are formed in parallel, and the plurality of common leads are connected by the common section bar.   The method for manufacturing a mold package according to claim 1, wherein an area occupied by the fixing plate is larger than an area occupied by the metal pattern. The method for manufacturing a mold package according to any one of claims 1 to 3, wherein the fixing plate on which marking is applied is used.