CN101887877A - Lead frame, semiconductor device, and method for manufacturing lead frame - Google Patents

Abstract

The present invention provides a lead frame, a semiconductor device, and a method for manufacturing a lead frame that can ensure roughening quality and can be provided at low cost. The lead frame (1) of the present invention is provided with a base material (10) made of a metal material, an element mounting portion (20) provided on a part of the base material (10) and capable of mounting a semiconductor element, as the base material (10) A roughened surface (30) provided on at least a part of a part of the surface of the sealing element mounting part (20) and at least a part of a region in contact with the sealing material of the semiconductor element mounted on the sealing element mounting part (20).

Description

Lead frame, semiconductor device, and method for manufacturing lead frame

technical field

The present invention relates to a lead frame, a semiconductor device, and a method of manufacturing the lead frame. More particularly, the present invention relates to a roughened lead frame, a semiconductor device using the lead frame, and a method of manufacturing the lead frame.

Background technique

In recent years, in order to improve the reliability of semiconductor packages, there has been an increasing demand for improving the adhesiveness between the lead frame and the resin in which the surface of the lead frame has been roughened. Such a lead frame is known to be composed of a pad portion on which a semiconductor element is mounted and a lead portion electrically connected to the semiconductor. In a predetermined area including the pad portion and the lead portion, a plurality of tiny pins on the surface are provided. A protruding dimple lead frame (for example, refer to Patent Document 1). In the lead frame described in Patent Document 1, after forming a lead frame having a land portion and a lead portion from a metal base plate, dimples and fine protrusions are formed on the surface of the formed lead frame.

In the lead frame described in Patent Document 1, since the dimples having a plurality of protrusions are formed on the metal base plate, the resin entering the gaps between the protrusions exhibits an anchoring effect, thereby improving the adhesion between the resin and the lead frame.

Patent Document 1: JP-A-2008-71886

Contents of the invention

However, in the lead frame described in Patent Document 1, after the shape of the lead frame is formed, dimples are formed on the surface of the lead frame, and minute protrusions are formed on the surface of the dimples. Dimples and tiny protrusions are formed one by one on a plurality of short strip-shaped lead frames. Therefore, in the lead frame described in Patent Document 1, it is difficult to reduce its manufacturing cost while maintaining a certain quality of the dimples and microprotrusions required for the lead frame.

Therefore, an object of the present invention is to provide a lead frame, a semiconductor device, and a method of manufacturing a lead frame that ensure roughening quality and can be provided at low cost.

In order to achieve the above objects, the present invention provides a lead frame comprising a base material made of a metal material, an element mounting portion provided on a part of the base material on which a semiconductor element can be mounted, and a part of the surface of the base material, A roughened surface provided on at least a part of a region in contact with the sealing material of the semiconductor element mounted on the sealing element mounting portion.

The roughened surface of the lead frame is preferably positioned closer to the inner side of the base material than the surface of the base material.

The roughened surface of the above-mentioned lead frame preferably has a roughness greater than that of the surface of the base material.

In the above-mentioned lead frame, it is preferable that a conductive layer is further provided on a part of the surface of the base material.

In addition, in order to achieve the above object, the present invention provides a semiconductor device including a base material made of a metal material, a semiconductor element mounted on an element mounting portion provided on a part of the base material, and a seal for sealing the semiconductor element. A sealing portion and a roughened surface provided on at least a part of a region that is in contact with the sealing portion as part of the surface of the base material.

The roughened surface of the above-mentioned semiconductor device is preferably positioned closer to the inside of the substrate than the surface of the substrate.

The roughened surface of the aforementioned semiconductor device preferably has a roughness greater than that of the surface of the substrate.

The semiconductor device described above preferably further includes a conductive layer on a part of the surface of the substrate.

In addition, in order to achieve the above object, the present invention also provides a method for producing a lead frame, which includes a base material preparation step of preparing a base material made of a metal material, and a step of providing a mask member in a predetermined area on the surface of the base material. A masking step, a roughening step of roughening the surface of the substrate using a mask member as a mask to form a roughened substrate, and a press working step of performing a press treatment on the roughened substrate.

In the roughening step of the above method for producing a lead frame, it is preferable to form a roughened surface located on the inner side of the base material than the base material surface on a part of the base material surface.

In the roughening step of the above-mentioned method for producing a lead frame, it is preferable to form a roughened surface having a roughness greater than that of the base material surface.

In the above-mentioned method for producing a lead frame, the masking step is preferably performed by a roll-to-roll plating device (リ-ルテつき device) in which a mask member is provided on the surface of the base material, and the roughening step is preferably performed in the roll-to-roll plating device. .

In the above method for producing a lead frame, a conductive layer forming step of forming a conductive layer on a part of the surface of the base material may be further included.

In the base material preparation step in the above-mentioned method for producing a lead frame, the base material may be prepared by winding the base material into a reel shape, and the base material after the roughening treatment of the punching process after the punching process is wound into a reel shape. Reel-shaped winding process.

According to the lead frame, semiconductor device, and lead frame manufacturing method of the present invention, it is possible to provide a lead frame, a semiconductor device, and a lead frame manufacturing method that ensure roughening quality and can be provided at low cost.

Description of drawings

FIG. 1 is a cross-sectional view of a lead frame according to a first embodiment of the present invention.

Fig. 2 is an enlarged cross-sectional view of a part of a substrate surface and a roughened surface according to the first embodiment of the present invention.

3A is a schematic diagram of the manufacturing process of the lead frame according to the first embodiment of the present invention.

3B is a schematic diagram of the manufacturing process of the lead frame according to the first embodiment of the present invention.

3C is a schematic view of the manufacturing process of the lead frame according to the first embodiment of the present invention.

4 is a cross-sectional view of a lead frame according to a second embodiment of the present invention.

5A is a schematic diagram of a manufacturing process of a lead frame according to a second embodiment of the present invention.

5B(a) and (b) are schematic cross-sectional views of a lead frame according to a modified example of the second embodiment of the present invention.

6 is a cross-sectional view of a semiconductor device according to a third embodiment of the present invention.

Fig. 7 is a schematic diagram of a resin coupling test performed on a copper material having a roughened surface in an example.

Figure 8 is a graph showing the results of coupling experiments.

Fig. 9 is a schematic diagram of a plan view of a substrate subjected to press working.

FIG. 10 is a comparison diagram of SEM observations of a region in contact with a die of a punching machine and a region not in contact with a die of a punching machine after a roughening treatment is applied to a part of the surface of a base material when press processing is applied.

Symbol Description

1, 1a: lead frame; 2: semiconductor device; 3: copper material with roughened surface; 5: sheet lead frame; 7: roll lead frame; 10, 11: base material; 10a, 10b: base material surface ;11a, 11b: area; 15: copper strip; 15a, 15b: surface; 17: copper strip after roughening; 20: element mounting part; 30, 31: roughened surface; 30a: convex part; 30b: concave part; 31a : area; 40: lead wire; 50: sealing part; 55: resin; 60: mask; 70: conductive layer; 74: plating layer; 80: semiconductor element; 85: die bonding material; 90: wire; 100: roll pair Coil plating device; 110: punching machine; 112: part; 115: punching section; 120: hot plate; 125: stopper.

Detailed ways

first embodiment

FIG. 1 shows an example of a schematic cross-section of a lead frame according to a first embodiment of the present invention, and FIG. 2 shows an example of a schematic enlarged cross-section of a part of a substrate surface and a roughened surface according to a first embodiment of the present invention.

Outline of structure of lead frame 1

The lead frame of the first embodiment has: a base material 10 made of a metal material used as a raw material of the lead frame; The roughened surface 30 is provided on at least a part of a predetermined area in contact with a part of the encapsulating material sealing the semiconductor element mounted on the element mounting portion. Further, in the lead frame 1 , lead wires 40 capable of supplying electric power to the semiconductor element are provided at a position at a predetermined distance from the outer edge of the element mounting portion 20 . The area indicated by the dashed-two dotted line in FIG. 1 shows an example of the area where the sealing portion 50 is formed when the sealing material is provided on the lead frame 1 .

Substrate 10

The base material 10 is formed, for example, of a thin plate (thickness of 0.08 to 3.00 mm as an example) made of a metal material having predetermined thermal conductivity and predetermined electric conductivity according to the characteristics of the semiconductor element used. As the metal material, copper, copper alloy, aluminum or aluminum alloy, etc. can be used. Furthermore, in order for the lead frame 1 to exhibit properties such as predetermined strength and predetermined heat resistance, a predetermined amount of additive elements such as iron, zinc, phosphorus, tin, and nickel may be added to the metal material. In addition, as the base material 10 , a material in which thin plates made of a predetermined metal material are metal-bonded to both surfaces of a thin plate made of a predetermined metal material can also be used. As an example, the substrate 10 in the present embodiment is formed to have a substantially square-shaped region and an end portion including the lead wire 40 as seen from a plan view of the element mounting portion 20 described later. Moreover, the surface of the base material 10 includes the surface 10a on the side where the element mounting part 20 is provided, and the surface 10b on the opposite side to the surface 10a.

Component mounting part 20

The element mounting portion 20 is provided in a predetermined region of the surface 10 a of the base material 10 . The area where the element mounting portion 20 is provided is determined by the shape of the semiconductor element mounted on the element mounting portion 20 . Examples of semiconductor elements mounted on the element mounting portion 20 include integrated circuits such as IC and LSI, light emitting elements, light receiving elements, small signal transistors, power transistors, and the like.

Roughened surface 30

The roughened surface 30 is formed on the inner side of the base material 10 than the surface of the base material 10 . Specifically, refer to FIG. 2 . The roughened surface 30 in FIG. 2 is formed at a lower position than the surface 10a when the surface 10a is used as a reference plane. When the roughened surface 30 is formed on the surface 10b, the roughened surface 30 is formed at a lower position than the surface 10b when the surface 10b is used as a reference plane. That is, the roughened surface 30 in this embodiment is formed at a position closer to the center line A-A than the surface 10a and surface 10b of the base material 10, based on the center line A-A in the thickness direction of the base material 10. In addition, the roughened surface 30 may be provided in the area between the lead 40 and the element mounting portion 20 , near the lead 40 , etc. as long as it is in the area of the surface of the base material 10 that can be in contact with the sealing material.

In addition, the roughened surface 30 is formed to have a roughness greater than that of the surface of the substrate 10 (ie, the surface 10 a and the surface 10 b in FIG. 2 ). For example, roughened surface 30 is formed to have protrusions 30a and recesses 30b, and surface 10a and surface 10b are formed without substantial unevenness. That is, when viewed with the naked eye, the surface 10a and the surface 10b are formed to be glossy, while the roughened surface 30 is formed to be matte. In the present embodiment, "glossy" means that light is scattered on the roughened surface 30 and is "dark" when viewed with the naked eye. As long as the front end of the convex portion 30a is formed at a position closer to the centerline A-A than the surface of the substrate 10, the distance D between the surface and the convex portion 30a is not limited, but as an example, the distance D (that is, FIG. 2 The distance between the middle surface 10a and the front end of the convex portion 30a) is about 1 μm.

Lead 40

The lead wire 40 is provided at one end of the lead frame 1 . In the lead frame in the modified example of the present embodiment, it may be provided at both one end and the other end of the lead frame depending on the usage form of the lead frame. Furthermore, in another modified example of the present embodiment, a plurality of leads 40 may be provided around the lead frame.

Manufacturing method of lead frame 1

3A to 3C show an example of the outline of the manufacturing process of the lead frame according to the first embodiment of the present invention. Specifically, FIG. 3A shows an example of the outline of the process of forming the roughened surface of the lead frame of this embodiment, and FIG. 3B shows an outline of a cross section of the copper strip portion in the process of forming the roughened surface. Moreover, FIG. 3C shows the outline|summary of the press process in the manufacturing process of the lead frame in this embodiment.

First, as shown in FIG. 3A , a thin plate of a metal material is prepared to be wound into a roll-shaped metal strip. In the present embodiment, as an example, a copper strip 15 made of copper is prepared as a material of the base material (base material preparation step). Then, one end of the copper strip 15 is passed through the roll-to-roll plating apparatus 100 . The roll-to-roll plating apparatus 100 may also be called a strip plating apparatus or a front plating apparatus. In addition, before or after the substrate preparation step, a step of cleaning the surface of the substrate may be further provided. Moreover, the copper strip 15 can use any one of a flat strip with a certain thickness (that is, a copper strip with a rectangular cross section) or a special-shaped strip with different thicknesses (that is, a copper strip with a concave-convex cross-sectional shape).

Thereafter, roughening treatment is performed simultaneously with or immediately after attaching the mask member to the surface of the copper strip 15 . Specifically as shown in Figure 3B (a), in the roll-to-roll electroplating device 100, at first the masking tape (the mask 60 of Figure 3B) as the masking part is attached to the copper strip 15 as the base material. A predetermined area of the surface 15a and the surface 15b (mask process). Among them, the surface 15b is the surface on the opposite side to the surface 15a. The predetermined area is appropriately determined according to the lead frame to be manufactured. As an example, a plurality of masking tapes are attached to the surface 15 a and the surface 15 b of the copper strip 15 at predetermined intervals in the width direction of the copper strip 15 .

The masking tape is made of a material that can withstand mechanical action and chemical action in the etching process of the roughening process described later, and is formed of a polymer material such as polypropylene and polyethylene terephthalate, for example. In addition, as the mask member, a mechanical mask in which a mask made of rubber or the like is mechanically fixed to the surface 15a and surface 15b of the copper strip 15 can also be used.

Then, as shown in FIG. 3B (b), in the roll-to-roll plating apparatus 100, by using the masking tape as a mask, the surface 15a and the surface 15b of the copper strip 15 not provided with the masking tape are roughened, The roughened surface 30 is formed, and a roughened base material is manufactured (roughening process). The roughening treatment is performed using an etching solution (hereinafter referred to as "etchant") capable of etching and roughening the surface of the base material. For example, a sulfuric acid-based etchant can be used for the copper strip 15 . In this way, the roughened surface 30 at the inner side of the copper strip 15 than the surface 15a and the surface 15b of the copper strip 15 constituting the base material is formed on a part of the surface 15a and the surface 15b of the surface 15 . That is, based on the centerline in the thickness direction of copper strip 15 , roughened surface 30 is formed closer to the centerline than surface 15 a and surface 15 b of surface 15 . In addition, the roughened surface 30 formed by such roughening treatment becomes rougher than the roughness of the surface 15 a and the surface 15 b of the copper strip 15 .

Then, the masking tape is removed in the roll-to-roll plating apparatus 100 . The copper strip is discharged from the roll-to-roll electroplating device 100. At this time, the copper strip 15 is formed with a roughened surface 30 in a predetermined area, and has a surface 15a of the copper strip corresponding to a part of the area covered by the masking tape. and surface 15b (surface 15b is not shown in FIG. 3A ). Then, by winding this copper strip into a reel shape, the roughened copper strip 17 which is a roughened base material is manufactured.

Then, as shown in FIG. 3C , the roughened copper strip 17 is put into the punching machine 110 , and the roughened copper strip 17 is stamped in real time to manufacture a lead frame (pressing process). That is, in this embodiment, the press working process is implemented after a roughening process. The punching machine 110 has a die for forming a lead frame of a predetermined shape, and the roughened copper bar 17 is punched with the die. The roughened surface 30 in this embodiment is located inside the roughened copper strip 17 than the surface 15a and surface 15b of the roughened copper strip 17 other than the roughened surface 30 . Therefore, with regard to the roughened surface 30, except for a very limited portion of the outer edge of the punched portion, the die of the punching machine 110 can be suppressed from directly contacting the roughened surface 30, so the influence of the punching process on the roughened surface 30 (i.e. It is called the effect that the roughened surface 30 is damaged) is much smaller than the effect on the surface 15a and the surface 15b.

In addition, when the roughened copper strip 17 is put into the punching machine 110, in order to adjust the roughened copper strip 17 wound into a reel to be roughly horizontal, the roughened copper strip 17 may also be rolled by a leveler. 17 into the stamping machine 110. Even so, since the roughened surface 30 is located on the inner side of the roughened copper strip 17 than the surface 15a and the surface 15b, direct contact between the leveler and the roughened surface 30 can be prevented, and damage to the roughened surface 30 can be suppressed.

Next, after the press work, the roughened copper bar 17 subjected to the press work is cut for each predetermined length, and the lead frame of a predetermined shape is formed into a sheet to form the sheet lead frame 5 (cutting step). . In addition, the rolled lead frame 7 can also be produced by winding the roughened copper strip 17 subjected to the pressing process into a roll shape having a predetermined diameter after the pressing process (winding step).

In addition, when manufacturing the roll-shaped lead frame 7, when preparing the reel-shaped copper strip 15 in the substrate preparation process, the lead frame of this embodiment is manufactured by a reel-to-reel method. In addition, when the oil used in the press machine 110 adheres to the lead frame by the press process, a cleaning process may be performed after the press process.

Effects of the first embodiment

The lead frame 1 of this embodiment has the roughened surface 30 as a part of the surface 10a and the surface 10b, and is located closer to the inner side of the base material 10 than the surface 10a and the surface 10b. During the press working, it is possible to suppress damage to the roughened surface 30 in the press machine 110 as in the case where the entire surface 10a is roughened. Thus, the lead frame 1 of this embodiment can ensure the quality of the roughened surface 30 required by the lead frame 1 without changing the thickness of the base material 10 .

In addition, the lead frame 1 of the present embodiment can form the roughened surface 30 on the surface of the copper strip 15 continuously from roll to roll in the state of the raw material state, that is, the large reel-shaped copper strip 15 . Therefore, for example, an existing strip plating apparatus can be used instead, so that an increase in the cost of the roughening treatment can be suppressed. Moreover, in the present embodiment, since the roughened surface 30 is partially formed on the surface of the copper strip 15, the cost of the chemical reagents required for the roughening treatment can be reduced, and at the same time, it is possible to suppress damage to the surface of the lead frame caused by the equipment used in the manufacture of the lead frame. Contamination (the surface 10a, the surface 10b, and the roughened surface 30) can suppress, for example, a decrease in the solder wettability of the outer lead.

Furthermore, for example, when the roughened surface is conventionally formed by nickel plating or the like, the relative height of the roughened surface formed by nickel plating is higher than that of a non-roughened surface. Therefore, if the roughened surface formed by nickel plating is brought into contact with equipment such as the press machine 110, stains (fine metal powder) will be generated. On the other hand, in the lead frame 1 in this embodiment, the roughened surface 30 is locally formed on the surface of the copper strip 15, and the relative height of the roughened surface 30 with respect to the surface 15a and the surface 15b of the copper strip 15 is low. , In this embodiment, unlike the conventional ones, stains caused by the contact of the roughened surface made of the nickel plating layer with equipment such as the press machine 110 do not occur. In this manner, in the present embodiment, it is possible to prevent the manufactured lead frame 1 from being contaminated by stains.

second embodiment

FIG. 4 shows an example of a cross-sectional outline of a lead frame according to a second embodiment of the present invention. FIG. 5A shows a part of the outline of the manufacturing process of the lead frame according to the second embodiment of the present invention. In addition, FIG. 5B(a) and FIG. 5B(b) are an example of the cross-sectional outline of the lead frame of the modification of 2nd Embodiment of this invention.

Compared with the lead frame 1 of the first embodiment, the lead frame 1a of the second embodiment has basically the same structure as the lead frame 1 except that the conductive layer 70 is provided at the end of the lead 40, and is produced by basically the same manufacturing process. Manufacture, therefore, only details the differences.

The lead frame 1 a of the second embodiment further has a conductive layer 70 on at least a part of the surface of the copper strip 15 . For example, the lead frame 1a has a conductive layer 70 made of a metal material such as nickel or silver in a region in contact with wires for electrically connecting electrodes of semiconductor elements to be mounted on the lead frame 1a to the leads 40 . The conductive layer 70 can be formed on a part of the surface 15 a and the surface 15 b of the copper strip 15 by electroplating or vapor deposition (such as vacuum vapor deposition, sputtering, etc.). As an example, the conductive layer 70 is a plating layer formed of nickel plating, silver plating, or the like.

For example, by using the roll-to-roll plating apparatus 100, as shown in FIG. 5A(a), the conductive layer 70 is formed on a predetermined region of the copper strip 15 except for the roughened surface 30 to be formed (conductive layer forming step). In addition, a masking tape (mask 60 in FIG. 5A ) is provided on a predetermined area of the copper strip 15 except for the roughened surface 30, and roughening is performed on the opening area of the mask 60 as shown in FIG. 5A(b). deal with. Thereby, the roughened surface 30 and the conductive layer 70 are formed on the surface 15a of the copper strip 15, and the roughened surface 30 is formed on the surface 15b. Other steps are the same as those of the first embodiment.

Modified example of the second embodiment

As shown in FIG. 5B( a ), when the conductive layer forming step is performed first and the roughening treatment step is performed thereafter, the lead frame 1 a is formed without a roughened surface directly under the conductive layer 70 . On the other hand, as shown in FIG. 5B( b ), when roughening is first performed and then the conductive layer forming step is performed, the lead frame 1 a is formed with a roughened surface directly under the conductive layer 70 .

Effects of the second embodiment

The lead frame 1a of the second embodiment can not only form the roughened surface 30 by roll-to-roll, for example, by switching to an existing strip plating device, roughening treatment and partial plating can be implemented in the strip plating device (that is, Roughening and plating can be combined in-line within the device). Accordingly, the cost required for manufacturing the lead frame 1a can be reduced.

Furthermore, since the lead frame 1 a of the second embodiment further has the conductive layer 70 on the surface of the base material, the distance from the surface of the conductive layer 70 to the roughened surface 30 is larger than that without the conductive layer 70 . Therefore, since the height of the roughened surface 30 relative to the conductive layer 70 can be relatively reduced, damage to the roughened surface 30 during leveling by a leveler and punching can be more effectively suppressed.

third embodiment

FIG. 6 is an example schematically showing a cross section of a semiconductor device according to a third embodiment of the present invention.

The semiconductor device 2 of the third embodiment has substantially the same structure as the lead frame 1 of the first embodiment except that the semiconductor element 80 is mounted on the lead frame 1 of the first embodiment, so only the differences will be described in detail.

The semiconductor device 2 has a base material 10, an element mounting portion 20 provided on a part of the base material 10, a semiconductor element 80 mounted on the element mounting portion 20 via a die-bonding material 85, a sealing portion 50 sealing the semiconductor element 80, The roughened surface 30 provided on a part of the surface of the substrate 10 and at least a part of the region in contact with the sealing part 50 , and the lead wire 40 provided at a predetermined distance from the outer edge of the element mounting part 20 and supplies power to the semiconductor element 80 , the plated layer 75 as a conductive layer provided in a predetermined area between the lead 40 and the element mounting portion 20 , and the wire 90 electrically connecting the electrode of the semiconductor element 80 to the plated layer 75 .

The semiconductor element 80 is mounted on the element mounting portion 20 via a die-bonding material 85 which has conductivity and fixes the semiconductor element 80 on the element mounting portion 20 . For the die bonding material 85 , for example, silver paste, lead-free solder, eutectic solder, or the like can be used. In addition, the plating layer 75 can be formed of, for example, a nickel plating layer or a silver plating layer having a predetermined thickness. Also, gold wires, aluminum wires, or the like can be used for the wires 90 . Furthermore, the sealing portion 50 may be formed by covering at least the semiconductor element 80 with a resin material such as epoxy resin.

Effects of the third embodiment

The semiconductor device 2 according to the third embodiment has the roughened surface 30 only on a part of the surface of the base material 10 constituting the lead frame 1 and in a part of the region in contact with the sealing portion 50 . Therefore, when the semiconductor element 80 is modularized with a resin material, even if a burr of the resin material is formed outside the position where the sealing portion 50 should be formed, since the burr is not formed on the roughened surface 30, it is formed on the The surface of the base material 10 can be easily removed.

In addition, in the semiconductor device 2 according to the third embodiment, the sealing portion 50 is in contact with the roughened surface 30 provided on a part of the surface of the base material 10 . Moreover, the adhesion force between the roughened surface 30 and the sealing portion 50 is greater than the adhesion force between the surface of the base material 10 except the roughened surface 30 and the sealing portion 50. Therefore, compared with a lead frame without the roughened surface 30, the sealing is better. The adhesion force between the portion 50 and the base material 10 can be improved. In this way, when the semiconductor device 2 of the present embodiment is subjected to a heat cycle test in which the low temperature and the high temperature are respectively maintained for a certain period of time, even if the thermal expansion coefficient of the semiconductor element 80 is different from that of the die-bonding material 85 or the die-bonding material 85 Even when stress is generated in the die-bonding material 85 due to the difference in thermal expansion coefficient between the thermal expansion coefficient of the substrate 10 and the thermal expansion coefficient of the substrate 10, the sealing portion 50 and the substrate 10 can be firmly adhered to each other in a state covering the entire semiconductor element 80. , so the peeling of the die-bonding material 85 from the base material 10 can be suppressed.

Example

coupling test

FIG. 7 shows the summary of the resin coupling test performed on the copper material having a roughened surface in the example, and FIG. 8 shows the results of the coupling test.

Specifically, the difference in the adhesiveness of the resin with or without the roughened surface was evaluated by a coupling test. First, a roughened copper material (hereinafter referred to as "copper material 3 having a roughened surface") is prepared. Specifically, copper materials of C194, OFC (all manufactured by Hitachi Electric Cable Co., Ltd.), and MF202 (manufactured by Mitsubishi Electric Corporation) were prepared as copper materials. Then, the surface of each copper material was roughened using a sulfuric acid-based etchant, and the copper material 3 with a roughened surface was obtained. Then, a thermosetting resin for transfer molding (hereinafter referred to as "resin 55") was adhered to a part of the surface of the copper material having a roughened surface. Adhesion conditions were such that the resin 55 was placed on the hot plate 120 so as to be in contact with the surface of the copper material 3 having a roughened surface, and held at a temperature of 180° C. for 90 seconds for adhesion. Among them, the contact area between the roughened surface and the resin 55 was specified to be 10.75 cm ² .

Then, as shown in FIG. 7 , a load is applied to the resin 55 by continuously contacting a part moving in parallel on the surface of the copper material 3 with a roughened surface at a predetermined speed on the side of the resin 55, and the measurement of the thickness of the resin 55 from the roughened The load when peeling off the copper material 3 on the surface. Among them, the copper material 3 having a roughened surface is pressed against the stopper 125, and a load is applied to the side of the resin 55 to move the part in the direction where the stopper 125 exists, and the speed of the part movement is set at 50 μm/sec.

As a result, as shown in FIG. 8 , when any of C194, OFC, and MF202 was used as the copper material, the adhesion force of the resin 55 when the surface of the copper material was roughened was significantly lower than that of the flat copper surface without roughening treatment. get improved.

State of roughened surface before and after stamping

Fig. 9 shows a schematic plan view of the base material after the press process is performed, and Fig. 10 is a region in contact with the die of the press machine when the press process is performed after roughening is performed on a part of the surface of the base material composed of CIC. Comparison with SEM observations of areas without contact.

Specifically, a base material 11 having a thickness of 0.4 mm, a width of 65 mm, and a length of 100 mm was prepared, which was composed of copper/invar/copper clad material = 1:2:1 (hereinafter referred to as "CIC"). Part of the surface of the material 11 was roughened to form the roughened surface 31 , and then punched, and the surface state of the base material 11 was observed by SEM (magnification: 5000 times). The observed parts are the region 31 a of the roughened surface 31 in the portion 112 corresponding to the die of the punching machine and the punched part 115 in the burr side of the roughened surface 31 .

Among them, the stamping process is to form a 9mm square opening 11b in a predetermined area of the base material 11 (specifically, at two positions straddling the roughened surface 31 and the area 11a and the area straddling the roughened surface 31 and the area 11c). For processing, the pressure of the stamping process used is 80t. In addition, roughening treatment is performed using a sulfuric acid-based etchant. Moreover, the roughened surface 31 is strip-shaped from a plan view, specifically, from one side of the two long sides of the base material 11 to the center of the base material 11a to the center of the base material 20 mm ± 2, and from the long side of the long side. The region 11c extending from the opposite side to the center of the substrate 11 to 29 mm±2 is a region not subjected to roughening treatment.

Specifically, FIG. 10( a ) is a SEM photograph of the region 31 a, and FIG. 10( b ) is a SEM photograph of the die-cut portion 115 . Referring to FIG. 10( a ) and FIG. 10( b ), it can be seen that the roughened surface 31 in the region 31 remains rough, but most of the roughened portion in the punched portion 115 is damaged. This is considered to be that the roughened surface 31 is damaged due to the direct contact of the punching part 115, and the roughened region of the region 31a, that is, the region after etching, is formed at a lower position relative to the regions 11a and 11c. area. That is, by roughening a part of the base material 11 , the roughened surface 31 can maintain a roughened state even if press processing is applied.

The embodiments and examples of the present invention have been described above, but the above-described embodiments and examples do not limit the invention according to the claims. In addition, it should be noted that not all combinations of the features described in the embodiments and examples are necessarily means for solving the problems of the present invention.

Claims (14)

1. A lead frame comprising: Substrates made of metallic materials, an element mounting portion on which a semiconductor element can be mounted, provided on a part of the substrate, A roughened surface that is provided on at least a part of a portion of the surface of the base material that is in contact with the sealing material that seals the semiconductor element mounted on the element mounting portion. 2. The lead frame according to claim 1, wherein the roughened surface is located closer to the inner side of the base material than the surface of the base material. 3. The lead frame according to claim 2, the roughened surface has a roughness greater than that of the surface of the base material. 4. The lead frame according to claim 3, further comprising a conductive layer on a part of said surface of said substrate. 5. A semiconductor device having: Substrates made of metallic materials, a semiconductor element mounted on an element mounting portion provided on a part of the substrate, sealing the sealing portion of the semiconductor element, A roughened surface provided on at least a part of a region that is in contact with the sealing portion as part of the surface of the base material. 6. The semiconductor device according to claim 5, wherein the roughened surface is located closer to the inner side of the base material than the surface of the base material. 7. The semiconductor device according to claim 6, wherein the roughened surface has a roughness greater than that of the surface of the base material. 8. The semiconductor device according to claim 7, further comprising a conductive layer on a part of the surface of the substrate. 9. A method of manufacturing a lead frame, comprising: A substrate preparation process for preparing a substrate made of a metal material, a masking step of providing a masking member in a predetermined region of the surface of the substrate, using the mask member as a mask, performing a roughening treatment on the surface of the substrate to form a roughening process of the roughened substrate, A stamping process in which stamping is performed on the substrate after the roughening treatment. 10. The method of manufacturing a lead frame according to claim 9, wherein in the roughening step, a lead frame located closer to the surface of the base material than the surface of the base material is formed on a part of the surface of the base material. The roughened surface on the inner side of the substrate. 11. The method of manufacturing a lead frame according to claim 10, wherein in the roughening step, the roughened surface is formed to have a roughness greater than that of the surface of the base material. 12. The method of manufacturing a lead frame according to claim 11, wherein the masking step is performed by a roll-to-roll plating apparatus in which the mask member is provided on the surface of the base material, and the roll-to-roll plating The roughening step is carried out in a coil plating apparatus. 13. The method of manufacturing a lead frame according to claim 12, further comprising a conductive layer forming step of forming a conductive layer on a part of the surface of the base material. 14. The method of manufacturing a lead frame according to claim 13, further comprising: in the base material preparation step, winding the base material into a roll shape to prepare a roll-shaped base material; A winding step of winding the base material in the shape of a reel after the roughening treatment of the pressing treatment.

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