Method of manufacturing a lead frame

Abstract: In a method for manufacturing a lead frame, a pre-determined pattern is formed on a matrix (10) by a resist (12), an electro-deposition portion (13) is provided in a cavity formed in the resist patterns (12) and the electro-deposition pattern (13) is separated from the matrix (10). The resist pattern is formed on the matrix (10) so that a cavity portion (17) connecting a plurality of cavity (16) ends for inner lead formation can be included in the resist pattern, and an electro-deposition portion is provided into the cavity portion (17) so that the electro-deposition pattern (13) can be formed into a configuration in which the tip ends of inner leads (22) are connected by a connecting piece (21), and the electro-deposition pattern (13) is separated from the matrix (10) while the tip ends of the inner leads (22) are connected by the connecting piece (21). Alternatively the tip ends are connected by a fixing member such as an adhesive tape. The electro-deposited material (13) may be plated whilst still held by the matrix (10) to reduce distortion. A connection between the leads may also be formed as a dam bar which again provides mutual support during lead frame processing. Various parts of the lead frame may be made thicker by selectively applying multi-layer plating. At least one of the multi-layers may be a reinforcing layer.

Description: The present invention relates to a lead frame adapted to be used for a semiconductor device and a method for manufacturinq the same. In general, lead frames for use in semiconductor devices are manufactured by punching or etching metallic materials. However, in the case of punching or etching, the minimum processing width is approximately the same as the material thickness so that the processing range is limited, and there is a limit to forming a fine pattern from a material of a predetermined thickness. On the other hand, as well known, there is provided a method for manufacturing lead frames by means of electro-forming (disclosed in Japanese Examined Patent Publication (Kokoku) No. 48-39867). This known electro-forming process is shown in Figs. 7(a), (b), (c), (d) and (e), and will be described below: A resist 11 is coated or adhered on a matrix 10 made of conductive material such as stainless steel, as shown in Fig. 7(a); pattern printing is conducted, as shown in Fig. 7(b); developing is conducted so as to form a resist pattern 12, as shown in Fig. 7(c); when this resist pattern is used as s mask, an electro-deposition pattern 13 is formed on the matrix 10 by means of plating, as shown in Fig. 7(d); the resist pattern 12 is removed; and further the electro-deposition pattern 13 is separated from the matrix 10, as shown in Fig. 7(e). Next, the electro-deposition pattern 13 is subjected to necessary plating. In this way, a lead frame is manufactured. In some cases, after the resist pattern 12 has been removed from the matrix 10, a surface of the electro-deposition pattern 13 is ground so that the thickness of the electro-deposition pattern 13 can be made uniform. According to this electro-forming process, a lead frame having a very fine pattern, the section of which is rectangular, can be accurately manufactured. In the above manufacturing process of lead frames, the following problems may be encountered: When the electro-deposition pattern 13 is separated from the matrix 10 in the electro-forming process, the electro-deposition pattern 13 may be deformed. Also, the electro-deposition pattern 13 may be deformed in the process conducted after electro-forming, for example, in the process of plating. Further, in the case where the electro-deposition pattern 13 is ground, the electro-deposition pattern 13 tends to be deformed. Such a deformation of the electro-deposition pattern 13 may become remarkable when the pattern is fine. Also, if the inner lead pattern becomes finer, the resist pattern 12 for the mask must become finer and, therefore, the electro-deposition pattern 13 must be developed in such narrow recesses of the resist pattern 12. When an electro-forming is conducted, hydrogen is generated due to a negative pole reaction. If the resist pattern 12 is narrow as mentioned above, the hydrogen particles in small bubbles would be attached to the inner walls of the resist pattern 12 because the plating liquid does not smoothly flow. Therefore, a good plated film would not be formed, but small pits or holes would be formed in the electro-deposition pattern 13. JP-A-42-80661 discloses a method of making a lead frame in which the tips of the inner heads are linked by a linking piece. This linking piece protects against deformation of the inner leads. JP-A-6306190 discloses an inner lead which has a trapezoid cross-section to increase the strength of the lead to prevent crosswise deformation. The present invention has been achieved to solve the above problems. It is an object of the present invention to provide a method for manufacturing a lead frame by which the electro-deposition pattern is not deformed in the processes conducted after the electro-forming process, for example, in the process of plating. In order to solve the above problems, the present invention is provided with the following construction. That is, the present invention is to provide a method for manufacturing a lead frame comprising the steps of: forming a resist pattern on said major surface of said conductive material, the resist pattern having therein a cavity, corresponding to a pattern of the lead frame, and a connection cavity connecting tip ends of a plurality of inner lead cavities, said inner lead cavities having a trapezoidal cross-section in a plane perpendicular to the major surface of the conductive material and in which the edge of the inner lead cavity adjacent the major surface of the conductive material is greater in dimension than the edge of the inner lead cavity on the side thereof remote from the major surface of the conductive material, the tapered cavities being formed by exposing the resist to a beam of light of a relatively low intensity in order to form a tapered surface in said resist; depositing a metallic layer by electro-deposition to form said lead frame such that tip ends of inner leads, formed in the inner lead cavities, are connected by a connecting piece formed in the connection cavity; and separating said lead frame from said cavities of said resist and from said conductive material while the tip ends of said inner leads are connected by said connecting piece. It is preferable to provide a method for manufacturing a lead frame which further comprises the steps of: conducting required processes including a plating process after the separation of the electro-deposition pattern while the tip ends of the inner leads are connected by the connecting piece; and then removing and separating the connecting piece from said electro-deposition pattern. According to the above, the electro-deposition pattern is formed so that the tip ends of the inner leads can be connected with the connecting piece. Therefore, deformation of the inner leads can be prevented when the electro-deposition pattern is separated from the matrix and also when the electro-deposition pattern is subjected to the processes such as plating after that. Even when the electro-deposition pattern is ground in the electro-forming process, deformation can be prevented to the utmost since the fore ends of the inner lead are connected by the connecting piece. Also, according to the present invention, since there is a recess for the connecting piece for connecting a plurality of inner leads, the plating liquid can smoothly flow and therefore hydrogen generated due to the negative pole reaction liquid would not be attached to the inner walls of the resist pattern. Thus, a generation of small pits or holes in the electro-deposition pattern would be prevented. Under the condition that the inner leads are fixed by the fixing member, and the outer leads are fixed by the dam bar, the electro-deposition pattern is separated from the matrix. Therefore, the deformation of the leads can be prevented when the electro-deposition pattern is separated from the matrix. Also, there is provided a lead frame comprising a predetermined pattern which is formed by providing a plated coat on a matrix by means of electro-forming, characterized in that: a stage portion of said lead frame on which a semiconductor element is to be mounted is formed thicker than inner leads by a multi-layer plated coat. Since the stage portion is formed thicker than the inner leads from a multi-layer plating coat, a lead frame having high radiating properties can be obtained. Said stage portion may be formed from a multilayer composed of plated coats made of different metals. If the stage portion is a multi-layer plating coat made of different metals, a lead frame having sufficient radiating properties and mechanical strength can be obtained. There is also provided a lead frame, wherein tip ends of predetermined inner leads surrounding a stage portion, and said stage portion are connected by a thin connecting portion of a plated coat protruded from the tip ends of the inner leads and an outer periphery of the stage portion. If the tip ends of the inner leads for ground connection and the stage portion are connected by a thin connecting portion, and also if a stage support bar and the stage portion are connected by the thin connecting portion, the connection can be easily conducted, and an excessive force is not given in the case of depressing in which the stage portion is depressed with respect to the inner lead surface. Therefore, the deformation of the inner leads can be prevented. A plurality of dimples may be provided on a surface opposite to a surface of said stage portion on which a semiconductor element is mounted, and said dimples are formed in such a manner that the diameter thereof is extended as it advances to the inside from the opposite surface. If the dimples are formed in the stage portion, adhesion can be improved with respect to the resin for sealing. There is also provided a lead frame formed by electro-forming, characterized in that an outer lead of said lead frame is formed into a multi-layer. The multi-layer portion of said lead frame may be composed of a metallic layer and a reinforcing layer formed on one side or both sides of said metallic layer. Said metallic layer may be made of copper or copper alloy; and said reinforcing layer may be made of iron, nickel or alloy of these metals. Also, there is provided a method for manufacturing a lead frame by electro-forming, characterized in that: a metallic layer is formed on a matrix in accordance with a pattern of said lead frame; and a reinforcing layer is formed at least on the pattern of an outer lead portion on said metallic layer. Also, there is provided a method for manufacturing a lead frame by electro-forming, characterized in that: a reinforcing layer is formed on a matrix in accordance with at least a pattern of an outer lead portion in a pattern of the lead frame; a metallic layer is formed on said reinforcing layer in accordance with the pattern of said lead frame; and a reinforcing layer is formed at least on a pattern of the outer lead portion of said metallic layer. If the main body portion of a lead frame is formed by electro-forming, it is possible to manufacture the lead frame easily when the inner leads and the like are formed into a very fine pattern. Also, if the main body portion of the lead frame is made of copper or copper alloy, a lead frame product excellent in the radiating properties and electric characteristics can be provided. Whereas the reinforcing layer is formed in the outer lead portion, a product having mechanical strength necessary to allow bending of the lead can be obtained, and a highly reliable product can be provided. Particular embodiments of the various aspects of the present invention will now be described with reference to the accompanying drawings, in which:- Figs. 1(a) to 1(h) show a process that is helpful for understanding this invention; Fig. 2 is a schematic illustration showing a resist pattern; Fig. 3 is a schematic illustration showing an example in which a thin portion is formed in a connecting base portion of the inner lead and the connecting piece; Figs. 4(a) and 4(b) are schematic illustrations showing an example in which the resist pattern in Fig. 3 is formed; Fig. 5 is a schematic illustration showing a first embodiment for the formation of the inner lead; Fig. 6 is a sectional view showing another embodiment of the connecting piece; Figs. 7(a) to 7(e) show a process of a conventional method for manufacturing a lead frame; Figs. 8(a) to 8(d) show still another embodiment of the present invention; Figs. 9(a) to 9(c) show still another embodiment of the present invention; Fig. 10 shows an embodiment of the present invention including a dam bar; The electro-deposition processes shown in Figs. 1(a), 1(b), 1(c) and 1(d) are the same as the conventional electro-deposition processes shown in Fig. 7(a) to 7(d) respectively. Therefore, the explanation of these processes of the electro-deposition will be omitted here. In order to make the thickness of the deposition pattern 13 uniform, the electro-deposition pattern 13 is appropriately ground. As shown in Fig. 1(h), the electro-deposition pattern 13 is formed in such a manner that the tip ends of inner leads 22 are connected by a connecting piece 21. In order to form this connecting piece 21, a cavity portion is formed for connecting the tip ends of a plurality of cavities for inner lead formation, and the electro-deposition portion is also provided in this cavity portion for the connecting piece 21, so that the connecting piece 21 is formed. Next, while the resist pattern 12 is left, the electro-deposition pattern 13 is subjected to necessary plating such as silver plating so as to form a plating layer 14, as shown in Fig. 1(e). Next, the resist pattern 12 is removed, as shown in Fig. 1(f). Finally, the electro-deposition pattern 13 is removed from the matrix 10. In this way, the lead frame is completed, as shown in Fig. 1(g). After that, in order to make a stage surface (not shown) lower compared to the inner lead surface, a stage support bar (not shown) is subjected to depressing formation by which a step is provided on the stage support bar. Then, after the inner leads 22 are fastened by a tape piece (not shown) to prevent movement, the connecting piece 21 is removed. The processes of depressing, fixing by a tape piece, and removing the connecting piece 21 may be conducted in an order different from that described above. That is, the order may be changed in accordance with the configuration of the lead frame. The above-mentioned stage is used for mounting thereon a semiconductor chip. The electro-deposition pattern 13 is formed under the condition that the tip ends of the inner leads 22 are connected with the connecting piece 21. Accordingly, deformation of the inner leads 22 can be prevented, when the surface of the electro-deposition pattern 13 is ground, when the electro-deposition pattern 13 is separated from the matrix 10, or when the electro-deposition pattern 13 is handled, or in any process after that. Plating is conducted while the resist pattern 12 is left, so that the deformation of the electro-deposition pattern 13 can be prevented, and a plating layer is not formed on the side of the electro-deposition pattern (i.e., lead) 13 of the obtained lead frame, so that a short circuit caused between the leads by the migration and peeling of a plating layer can be prevented. In this connection, the electro-deposition pattern 13 may be ground to make the thickness of the electro-deposition pattern 13 uniform after the removal of the resist pattern 12, and then the electro-deposition pattern 13 may be subjected to plating. Also, in this case, the deformation of the electro-deposition pattern 13 can be prevented since the electro-deposition pattern 13 is subjected to plating under the condition that it is supported by the matrix 10. Further, plating may be conducted after the electro-deposition pattern 13 is peeled off from the matrix 10. In this case, since the inner leads 22 are connected with the connecting piece 21, the deformation of the inner leads 22 can also be prevented. Due to the foregoing, after electro-forming has been completed, the electro-deposition pattern 13 is subjected to plating. Therefore, a conventional plating process of lead frames can be carried out. Therefore, advantageously, it is not necessary to change the conventional apparatus therefor. Further, after the electro-deposition pattern 13 has been peeled off, plating is conducted. Accordingly, it is advantageous that a flat surface which has been closely contacted with the matrix 10 can be used as a wire bonding surface. In this connection, in the case of a lead frame in which plating is not required at all, of course, the plating process is omitted. Fig. 2 shows a further example in which the resist pattern 12 is formed by leaving a resist portion 18, the height of which is smaller than that of other resist portions, in a boundary between the tip end of a cavity 16 for the formation of the inner lead 22 and a cavity portion 17 for the formation of the connecting piece 21, and plating is carried out on the resist pattern 12. Due to the foregoing, as illustrated in Fig. 3, electro-deposition portions on the side of the cavity 16 for inner lead formation, and that on the side of the cavity 17 for connecting piece formation can be connected in a bridge form astride the resist portion 18 having a lower thickness. In this way, a thin portion 23 is formed in a connecting base portion with which the connecting piece 21 of the tip ends of the inner leads 22 are connected. As the thin portion 23 is formed in the above manner, the connecting piece 21 can be easily removed. In this case, the connecting piece 21 is removed after a piece of tape has been stuck on the inner lead 22 to fix the lead frame. It is preferable that such a resist portion 18 having a lower thickness is formed on the resist pattern 12 in the following manner. First, as illustrated in Fig. 4(a), the resist portion 18 having a lower thickness is formed at a predetermined position. Then, as illustrated in Fig. 4(b), a resist is further coated on the resist portion 18 which has already been formed, and then the pattern is plated and developed. Fig. 5 shows an embodiment of this invention. In the resist pattern 12 of this embodiment, a section of the cavity 16 for the formation of the inner leads is formed into a trapezoid in which the matrix 10 side is wider as illustrated in the drawing. Due to the foregoing, a section of the inner lead 22 growing in the cavity 16 for the formation of the inner lead is formed into a trapezoid. When a side closely contacting with the matrix 10 side is used as a bonding surface as described above, a wide bonding area can be ensured. In order to form the section of the cavity 16 for the inner lead formation into a trapezoid, the following method is employed. In the case of exposure of a negative type resist, it is exposed to a beam of light, the intensity of which is relatively low. Then, the inside is exposed to light less than the surface as illustrated in the drawing. Due to the foregoing, the grade of sensitization is inclined, so that a tapered surface can be formed in the development as described above. Reference numeral 15 denotes a mask. In order to form a section of the cavity 16 for the formation of the inner lead into a reverse trapezoid, sensitization processing may be conducted opposite to the aforementioned manner. In this case, when a grinding surface side of the electro-deposition pattern 13 is used as a bonding surface, a wide bonding area can be ensured. In this connecting, a connecting base portion with which the connecting piece 21 of the inner lead 22 is connected, may be formed narrow so that the connecting piece 21 can be easily removed. Fig. 6 shows another embodiment of this invention. This embodiment shows an example of manufacture of the lead frame having a stage on which a semiconductor chip is to be mounted. In this embodiment, electro-deposition is conducted in such a manner that a tip end of the inner lead 22 of the electro-deposition pattern 13 is connected with a wide connecting piece 25 including a stage 24. As described above, under the condition that the tip ends of the inner lead 22 are connected with the connecting piece 25, the following processes are carried out in the same manner as described above. A process for peeling the electro-deposition pattern 13 from the matrix; a plating process; a process for fixing the inner lead 22 with a piece of tape; and a process for forming the tip end of the inner lead 22, stage support bar, and the stage 24 by means of punching. Also, in this embodiment, under the condition that the inner leads 22 are connected with the connecting piece 25, the inner leads 22 are subjected to a peeling process for peeling the inner leads 22 from the matrix 10, and a plating process. Therefore, the deformation of the inner leads 22 can be prevented. The connecting portion 25a is removed in the later stage by cutting along the lines 26. In the above embodiments, as the connecting piece 21 (or 25) is formed, the thickness of the electro-deposition pattern 13 electrically deposited on the matrix 10 can be also made uniform. That is, the inner lead 22 is narrower compared to the stage. Therefore, when the electro-deposition pattern 13 is formed by means of plating, the electric current density is increased, so that the thickness of a plating layer tends to increase compared to other portions. However, as the connecting piece 21 (or 25) is formed, a portion of the connecting piece 21 (or 25) acts as a dump land, and the concentration of electric current density on the tip ends of the inner lead 22 can be avoided. Therefore, the thickness of the electro-deposition pattern 13 can be made uniform. As a result, stress generated in the process of plating can be reduced, and looseness of the inner leads 22 can be prevented. According to the above-mentioned several embodiments, the electro-deposition pattern is formed so that the tip ends of the inner lead is connected with the connecting piece. Therefore, the deformation of the inner lead can be prevented in an electro-forming process and after processes such as plating. Particularly, according to the above-mentioned embodiments, a flow of the plating liquid can be improved due to the connecting piece 21, so that the thickness of the tips of the inner leads 22 can be prevented from being diminished. Figs. 8(a) to 8(g) show another embodiment of this invention. The continuous processes as shown in Figs. 1(a) to 1(g) can also be applied to this embodiment. That is, while the resist pattern 12 is left, the electro-deposition pattern 13 is subjected to plating, as shown in Fig. 8(a), and then the resist pattern 12 is removed, as showin in Fig. 8(b). Alternatively, after the resist pattern 12 has been removed, the electro-deposition pattern 13 can be subjected to plating. Next, in this embodiment, the fixing member 31 such as a tape is fixed onto a portion of the electro-deposition pattern 13 where the leads are dense, that is, the fixing member 31 is fixed onto the inner leads, as shown in Fig. 8(c). Next, under the condition that the leads are fixed by the fixing member 31, the electro-deposition pattern 13 is separated from the matrix 10, as shown in Fig. 8(d). In this embodiment, as the electro-deposition pattern 13 is separated from the matrix 10 under the condition that the portions between the inner leads are fixed by the fixing member 31, the deformation of the inner leads can be prevented when they are separated from the matrix 10 or when they are handled after that. Various materials can be used for the fixing member 31, such as an adhesive tape, a resin sheet, a photosensitive dry film, or a sheet on which a resist is coated by means of printing and then dried. Figs. 9(a) to 9(c) show a still another embodiment of this invention. In this embodiment, after the electro-deposition process as shown in Fig. 1(d) has been completed, the resist pattern 12 is removed without conducting a plating process, as shown in Fig. 9(a). Next, the inner lead portion is fixed by the fixing member 31, as shown in Fig. 9(b). The electro-deposition pattern 13 is separated from the matrix 10, as shown in Fig. 9(c). After that, plating is performed if necessary. In this way, the manufacture of the lead frame is completed. Also, in this embodiment, the deformation of the inner leads can be effectively prevented in the case where the electro-deposition pattern 13 is separated from the matrix 10 and after that. In the above embodiment, the fixing member 31 is used only for fixing the inner leads. However, like a lead frame of what is called an LOC (lead on chip) or a COL (chip on lead) type, the fixing member 31 may be a tape which fixes the inner leads and mounts a semiconductor element. Accordingly, this embodiment can be advantageously applied to LOC or COL type semiconductor devices. Fig. 10 shows another embodiment of this invention, in this embodiment, a dam bar 32 is formed in a base portion of the outer leads. The dam bar 32 is provided for the purpose of preventing the leakage of resin (not shown) from gaps between the outer leads in the case where: the semiconductor chip or element (not shown) is sealed with resin after a semiconductor element has been mounted on the lead frame and subjected to wire-bonding. Therefore, the dam bar 32 is provided for filling the gaps between the outer leads. The dam bar 32 is formed in the same manner as that of the formation of the fixing member 31 in the previous embodiment. That is, after the process of plating, the dam bar 32 is formed in the base portion of the outer leads in the same manner as that of the fixing member 31 in the previous embodiment, shown in Figs. 8(a) to 8(d). Alternatively, in the same manner as that of the embodiment, shown in Figs. 9(a) to 9(c), the dam bar 32 is formed and the electro-deposition pattern 13 is separated from the matrix 10. After that, the electro-deposition pattern 13 is subjected to plating if necessary. When the dam bar 32 is formed in the base portion of the outer leads as described above, the outer lead portion can be fixed by the dam bar 32 in the same manner as that of the aforementioned fixing member 31. Accordingly the deformation of the pattern 13 can be prevented when the electro-deposition pattern 13 is separated from the matrix 10, or when the electro-deposition pattern 13 is handled in the plating process after the electro-deposition pattern has been separated from the matrix 10. The dam bar 32 may be formed by means of electro-deposition, however, it becomes difficult to trim the dumb bar when the outer leads are formed into a fine pattern. When the dam bar 32 is made of a different insulating member like this embodiment, it is not necessary to conduct trimming. Since the dam bar 32 is fixed before the separation of the electro-deposition pattern 13, there is no possibility that the electro-deposition pattern is deformed in the formation of the dam bar. The dam bar 32 may be formed in the following manner: As illustrated in Fig. 10, an adhesive tape 33 is pressed against the outer lead base portion so as to be adhered, so that the adhesive is filled in the gaps between the outer leads. Alternatively, a photosensitive resist is filled in the gaps between the leads of the outer lead base portion by means of screen printing, and then the resist is dried and hardened so as to form a dam bar (not shown). The dam bar 32 is formed when the photosensitive resist is filled in the gaps between the leads closed by the matrix 10. Therefore, it becomes easy to fill the gaps with the photosensitive resist. However, it is necessary to use a dam bar 32, the separability of which is high with respect to the matrix 10. For this reason, as illustrated in Fig. 10, it is preferable to provide a coating 34, the separability of which is high, on a portion of the matrix 10 corresponding to the dam bar 32. In the above embodiments, the fixing member 31 and the dam bar 32 are separately provided. However, it is a matter of course that both the fixing member 31 for fixing the inner lead portion, and the dam bar 32 for fixing the outer leads are provided. When both the inner leads and the outer leads are fixed, the deformation can be more effectively prevented in the separation from the matrix 10 and in the process of plating. In the above embodiments, in the case where the electro-deposition pattern 13 is subjected to plating after it has been separated from the matrix 10, it is preferable that a flat surface of the electro-deposition pattern 13 on the matrix 10 side is formed into a bonding surface.

Claims: A method of manufacturing a lead frame on a major surface of a conductive material, comprising the steps of: forming a resist pattern on said major surface of said conductive material, the resist pattern having therein a cavity, corresponding to a pattern of the lead frame, and a connection cavity connecting tip ends of a plurality of inner lead cavities, said inner lead cavities having a trapezoidal cross-section in a plane perpendicular to the major surface of the conductive material and in which the edge of the inner lead cavity adjacent the major surface of the conductive material is greater in dimension than the edge of the inner lead cavity on the side thereof remote from the major surface of the conductive material, the tapered cavities being formed by exposing the resist to a beam of light of a relatively low intensity in order to form a tapered surface in said resist; depositing a metallic layer by electro-deposition to form said lead frame such that tip ends of inner leads, formed in the inner lead cavities, are connected by a connecting piece formed in the connection cavity; and separating said lead frame from said cavities of said resist and from said conductive material while the tip ends of said inner leads are connected by said connecting piece. A method of manufacturing a lead frame according to claim 1, said method further comprising the steps of: conducting a plating process, after the separation of said lead frame from the conductive material but while maintaining the tip ends of said inner leads connected by said connecting piece; and removing said connecting piece from said inner leads of said lead frame. A method of manufacturing a lead frame according to claim 1, further comprising the step of providing said resist pattern with a reduced height resist portion, relatively to the height of the remainder of the resist pattern, in respective locations between the tip ends of said inner lead cavities and said connection cavity. A method of manufacturing a lead frame as recited in claim 1, further comprising the steps of: prior to the separating step, forming a plated coat on said lead frame after said lead frame has been formed on said conductive material; and then separating said lead frame, with said plated coat formed thereon, from said conductive material. A method for manufacturing a lead frame as recited in claim 1, further comprising the steps of: removing said resist pattern after said lead frame has been formed; fixing the inner leads of said lead frame with a fixing member; and separating said lead frame from said conductive material while maintaining said fixing member fixed to said inner leads of said lead frame. A method for manufacturing a lead frame according to claim 5, wherein said fixing member comprises an adhesive tape. A method of manufacturing a lead frame as recited in claims 1 or 5, further comprising the steps of: providing a dam bar in base portions of outer leads of said lead frame for preventing leakage of resin in the process of moulding and also for fixing said outer leads; and separating said lead frame from said conductive material while said outer leads remain fixed by said dam bar.

Inventors: FUKASE KATSUYA, IIJIMA TAKAHIRO, NAKAZAWA MASAO, WAKABAYASHI SHINICHI, FUKASE, KATSUYA, IIJIMA, TAKAHIRO, NAKAZAWA, MASAO, WAKABAYASHI, SHINICHI, FUKASE, KATSUYA, C/O SHINKO ELECTRIC IND., IIJIMA, TAKAHIRO, C/O SHINKO ELECTRIC IND., NAKAZAWA, MASAO, C/O SHINKO ELECTRIC IND., WAKABAYASHI, SHINICHI, C/O SHINKO ELECTRIC IND.
Applicants: SHINKO ELECTRIC IND CO, SHINKO ELECTRIC INDUSTRIES CO. LTD.
Application year: 1993
Main classification: H01L23
IPC codes: H01L21, H01L23, H05K3