TWI828198B - Lead frame sheet, lead frame and manufacturing method thereof, electronic component and manufacturing method thereof - Google Patents

Abstract

A lead frame sheet including a die seat, a frame and a plurality of leads is provided. The frame is adjacent to the die seat. The plurality of leads extend from the frame to the die seat adjacent to the frame respectively. The lead frame sheet has an upper surface and a lower surface that oppose to each other. The upper width of a first portion of the lead on the upper surface is smaller than the lower width of the first portion of the lead on the lower surface.

Description

Lead frame sheet, lead frame and manufacturing method thereof, electronic components and manufacturing method thereof

The invention relates to a lead frame piece, a lead frame and a manufacturing method thereof, electronic components and a manufacturing method thereof.

Lead frames are generally cut from lead frame sheets. With the development of electronic component technology, the design precision of lead frame products has increased and/or the number of chip input/output (I/O) has increased, and the arrangement density of pin design has also increased. For products with fine pitch leads, the requirements for cutting accuracy are also higher.

However, during the cutting process of the lead frame blanks, burrs or stretching problems may occur due to the extension of the metal surface during cutting. This may result in insufficient space between the cut leads and/or the risk of electrical shorts.

The invention provides a lead frame piece, a lead frame and a manufacturing method thereof, electronic components and a manufacturing method thereof.

The lead frame piece of the present invention includes a chip holder, a frame and a plurality of lead pins. The frame is adjacent to the wafer mount. A plurality of lead pins respectively extend from the frame to the chip holder adjacent to the frame. The leadframe blank has upper and lower surfaces opposite each other. The first portion of the lead has an upper width on the upper surface that is smaller than a lower width on the lower surface.

In an embodiment of the invention, the first portion of the lead is connected to the frame.

In an embodiment of the invention, the lead further includes a second part connected to the first part, and in a top view, the maximum width of the second part is greater than the maximum width of the first part.

In an embodiment of the invention, the ratio of the upper width to the lower width is substantially 3:4.

In one embodiment of the present invention, the lead frame piece is made of copper, and its upper width is at least 100 microns.

The manufacturing method of the lead frame of the present invention includes the following steps: providing the lead frame piece of the previous embodiment; and removing at least the frame of the lead frame piece to form the lead frame.

The lead frame of the present invention is formed by removing the frame from the lead frame piece of the previous embodiment.

The manufacturing method of electronic components of the present invention includes the following steps: providing the lead frame blank of the aforementioned embodiment; arranging the chip on the chip holder; electrically connecting the chip to a plurality of lead pins; and removing at least the lead frame blank frame.

The electronic component of the present invention includes: a lead frame and a chip formed by removing the frame from the lead frame piece of the previous embodiment. The chip is arranged on the chip holder and electrically connected to a plurality of pins.

Based on the above, the lead frame blank of the present invention can have better quality in applications (such as manufacturing corresponding lead frames or electronic components).

The present invention will be described more fully below with reference to the drawings of this embodiment. However, the present invention may also be embodied in various forms and should not be limited to the embodiments described herein. The dimensions of layers, regions or elements in the drawings may be exaggerated for clarity. The same or similar reference numbers indicate the same or similar components, and will not be repeated one by one in the following paragraphs. In addition, the directional terms mentioned in the embodiments, such as up or down, are only for reference to the directions in the attached drawings. Accordingly, the directional terms used are illustrative and not limiting of the invention.

1A is a schematic top view of a lead frame piece according to an embodiment of the present invention. 1B is a partial top view of a lead frame piece according to an embodiment of the present invention. 1C is a partial cross-sectional view of a lead frame piece according to an embodiment of the present invention. For example, FIG. 1B may be an enlarged view corresponding to the region R1 in FIG. 1A, and/or FIG. 1C may be a schematic cross-sectional view corresponding to the I-I' line in FIG. 1B.

Referring to FIGS. 1A to 1C , the lead frame piece 100 may include a chip holder 130 , a frame 110 and a plurality of lead pins 120 . Frame 110 is adjacent to wafer mount 130 . The plurality of lead pins 120 respectively extend from the frame 110 to the wafer holder 130 adjacent to the frame 110 . The leadframe blank 100 has an upper surface S1 and a lower surface S2 opposite to each other. The upper width WS1 of the first portion 121 of the lead 120 on the upper surface S1 is smaller than the lower width WS2 on the lower surface S2.

In one embodiment, the lead frame piece 100 may be made of copper.

In one embodiment, the lead frame blank 100 may be first formed into a rough shape or pattern by stamping, laser cutting or other appropriate manufacturing methods (hereinafter referred to as: initial lead frame blank), and then, By etching (eg, wet etching), the upper width WS1 of the first portion 121 of the lead 120 on the upper surface S1 is smaller than the lower width WS2 on the lower surface S2. For example, the parts of the initial lead frame piece that are not to be etched can be covered with a protective material (such as protective glue); then, the initial lead frame piece that has been partially covered by the protective material is placed in the etchant. So that the upper width of the first part 121 of the lead 120 on the upper surface S1 is smaller than the lower width on the lower surface S2; then, the aforementioned protective material is removed to form a lead frame piece as shown in FIGS. 1A to 1C 100.

In one embodiment, the leadframe blank 100 may include an outer frame 111 (a part of the frame 110), an inner frame 112 (another part of the frame 110), a plurality of wafer holders 130, a plurality of tie bars/support bars. ) 140 and a plurality of lead pins 120. The outer frame 111 is the outermost annular frame 110 of the lead frame piece 100 . The inner frame 112 is between two adjacent wafer holders 130 . Ties 140 connect corresponding wafer holders 130 and corresponding portions of the frame 110 . Each lead 120 extends from a corresponding position of the frame 110 to a corresponding wafer base 130 adjacent thereto. In addition, for clarity of illustration, not all chip holders 130 , tie bars 140 or lead pins 120 are labeled one by one in corresponding or similar figures.

In an embodiment, the lead 120 may include a first portion 121 and a second portion 122 . In a top view (that is, viewed in a normal direction of the upper surface S1 or the lower surface S2, as shown in FIG. 1B ), the opposite ends of the first part 121 are respectively connected to the inner frame 112 and the second part 122 . The maximum width W2 of the second portion 122 is greater than the maximum width W1 of the first portion 121 . In an exemplary application, the second portion 122 with a larger width (compared to the first portion 121 with a smaller width) is suitable for being used as a wire bonding joint.

In one embodiment, the lead 120 is composed of a first part 121 and a second part 122 .

In one embodiment, the lead 120 is composed of a first part 121 and a second part 122, and any area of the second part 122 (for example, similar to that shown in FIG. 1C, any part of the second part 122 is perpendicular to the upper surface). The corresponding width on the upper surface S1 is substantially the same as the corresponding width on the lower surface S2 (viewed in cross section of S1 or lower surface S2).

In one embodiment, the ratio of the upper width WS1 to the lower width WS2 is substantially 3:4. It is worth noting that the aforementioned "basically" term of basically 3:4 can include the acceptable allowable range in production (about ±15%), such as 3:4×(1-15%)~3:4 ×(1+15%). For example, the upper width WS1 may be approximately 100 micrometer (µm), and the lower width WS2 may be approximately 150 micrometer.

In one embodiment, since the upper width WS1 of the first portion 121 on the upper surface S1 is smaller than the lower width WS2 on the lower surface S2, during the process of manufacturing the lead frame by cutting the lead frame blank 100, This reduces the possibility that adjacent leads 120 may come into contact due to metal extension (such as copper extension).

In one embodiment, the upper width WS1 is at least 100 microns. In this way, the possibility of wire breakage of the lead frame piece 100 made of copper can be reduced.

In one embodiment, the length L1 of the first portion 121 is approximately 50 microns to 200 microns. If the length is less than 50 microns, the process window may be reduced during cutting. If the length is greater than 200 microns, the application space of the second part 122 may be reduced. For example, the length L1 of the first portion 121 may be approximately 100 microns.

FIG. 2A is a schematic top view of a partial manufacturing method of a lead frame according to an embodiment of the present invention. FIG. 2B is a schematic top view of a lead frame according to an embodiment of the present invention. FIG. 2C is a partial top view of a lead frame according to an embodiment of the present invention. FIG. 2D is a partial cross-sectional view of a lead frame according to an embodiment of the present invention.

Referring to FIGS. 2A and 2B , the manufacturing method of the lead frame 200 may include the following steps: providing the lead frame piece 100 of the aforementioned embodiment; and then removing at least the frame 110 of the lead frame piece 100 to form the lead frame.

At least the step of removing the inner frame 112 may be the same or similar to the general process of cutting a lead frame sheet to make a lead frame. The difference is that the lead frame sheet 100 according to an embodiment of the present invention is used; therefore, no steps are performed here. Elaborate. For a simple example, the lead frame piece 100 can be placed on the carrier plate 290 and then cut along the cutting line CL with a cutting knife.

In one embodiment, part of the first portion 121 may also be removed during the aforementioned cutting process. Furthermore, since the upper width WS1 of the first portion 121 on the upper surface S1 is smaller than the lower width WS2 on the lower surface S2, the metal due to metal can be reduced during the process of cutting the lead frame blank 100 to produce the lead frame 200. The lead pins 120 may be in contact due to extension (such as copper extension). In addition, for simplicity of representation, even though the first part 121 of the part may also be removed, the original identification (such as the lead 120 or the first part 121) can still be quoted on the part's identification. Tie 140 can also be used.

The lead frame 200 formed after completing the foregoing cutting process can be shown in FIGS. 2B to 2D . FIG. 2C may be an enlarged view similar to or corresponding to the area R1 in FIG. 1A , and for comparison purposes (such as comparison between FIG. 2A and FIG. 2B ), the periphery of the cut and removed area is represented by a dotted line in FIG. 2C . FIG. 2D may be a schematic side view corresponding to the edge of the cutting point in FIG. 2C (eg, II-II' plane).

As shown in FIGS. 2B to 2D , after cutting to make the lead frame 200 , the edge of the cut may have cutting marks formed by metal extension (eg, copper extension). For example, as shown in FIGS. 2C and 2D , the edge of the first portion 121 where it is cut along the cutting direction D1 may have a first end point T1 and a second end point T2 opposite to each other on the upper surface S1 . , and may have a third endpoint T3 and a fourth endpoint T4 opposite to each other on the lower surface S2. The line connecting the first endpoint T1 and the third endpoint T3 has a first included angle (defined by the acute angle) θ1 between a virtual surface parallel to the upper surface S1 or the lower surface S2, and the second endpoint T2 is There is a second included angle (defined by the right angle or acute angle) θ2 between the line connecting the fourth endpoint T4 and a virtual surface parallel to the upper surface S1 or the lower surface S2, and the second included angle θ2 is greater than the first The angle between angle θ1. Also, at the edge where the first portion 121 is cut, the upper width WS3 on the upper surface S1 is smaller than the lower width WS4 on the lower surface S2.

3 is a schematic top view of a partial manufacturing method of an electronic component according to an embodiment of the present invention.

Referring to FIG. 3 , the manufacturing method of electronic components may include the following steps in any order: providing the lead frame piece 100 of the aforementioned embodiment (marked in FIG. 1A ); arranging the chip 230 on the chip holder 130 ; The chip 230 on the chip 130 is electrically connected to the plurality of leads 120; and at least the inner frame 112 of the lead frame blank 100 is removed (marked in FIG. 1A). It is worth noting that the present invention does not limit the order of the steps of disposing the chip 230 on the chip holder 130 and removing the inner frame 112 of the lead frame blank 100 .

In one embodiment, the step of disposing the chip 230 on the chip holder 130 can be performed by a method commonly used in general chip packaging manufacturing (such as a pick up and place process).

In one embodiment, the step of electrically connecting the chip 230 disposed on the chip holder 130 to the plurality of pins 120 can be performed by a method commonly used in general chip packaging manufacturing (such as a wire bonding process). conduct. For example, the chip 230 disposed on the chip holder 130 can be electrically connected to the corresponding lead 120 through the corresponding wire 320 . In addition, for clarity of illustration, not all chips 230 or wires 320 are labeled one by one in the corresponding figures.

In one embodiment, the step of removing the inner frame 112 of the lead frame piece 100 can be performed in the aforementioned manner (eg, corresponding to the manner described in FIGS. 2A to 2D ).

In one embodiment, after the chip 230 disposed on the chip holder 130 is electrically connected to the plurality of pins 120 , a molding process commonly used in general chip packaging manufacturing may be performed. For example, the chip 230 may be encapsulated with epoxy resin or other suitable molding compound.

Through the above steps and using the lead frame blank 100 of the above embodiment, electronic components can be manufactured. In one embodiment, the aforementioned electronic component may be called a Quad Flat No-Lead (QFN) package or a Dual Flat No-Lead (DFN) package. The general appearance of the aforementioned electronic components may be the same or similar to that of a common quadrilateral planar leadless package or a biplanar leadless package, and therefore will not be repeated here.

To sum up, the lead frame blank of the present invention can have better quality in applications (such as manufacturing corresponding lead frames or electronic components).

100: Lead frame blank 110:Box 111:Outer frame 112:Inner frame 120:Leader 121:Part One 122:Part 2 130:Chip holder 140:tie 200: Lead frame 230:Chip 320:Wire CL: cutting line D1: cutting direction L1:Length R1:Region S1: upper surface S2: Lower surface T1: first endpoint T2: second endpoint T3: third endpoint T4: The fourth endpoint W1, W2: maximum width WS1, WS3: upper width WS2, WS4: lower width θ1: the first included angle θ2: The second included angle

1A is a schematic top view of a lead frame piece according to an embodiment of the present invention. 1B is a partial top view of a lead frame piece according to an embodiment of the present invention. 1C is a partial cross-sectional view of a lead frame piece according to an embodiment of the present invention. FIG. 2A is a schematic top view of a partial manufacturing method of a lead frame according to an embodiment of the present invention. FIG. 2B is a schematic top view of a lead frame according to an embodiment of the present invention. FIG. 2C is a partial top view of a lead frame according to an embodiment of the present invention. FIG. 2D is a partial side view of a lead frame according to an embodiment of the present invention. 3 is a schematic top view of a partial manufacturing method of an electronic component according to an embodiment of the present invention.

S1: upper surface S2: Lower surface WS1: Top width WS2: lower width

Claims (6)

A lead frame piece includes: a chip holder; a frame adjacent to the wafer holder; and a plurality of lead pins extending from the frame to the wafer holder adjacent to the frame, the guide pins extending from the frame to the wafer holder adjacent to the frame. The foot includes a first portion and a second portion connected, wherein: the first portion of the lead pin is connected to the frame; the lead frame piece has an upper surface and a lower surface opposite to each other; the first portion is on the The upper width on the upper surface is smaller than the lower width on the lower surface. The lead frame piece is made of all copper; the upper width is at least 100 microns; and the length of the first part is 50 microns to 200 microns. . The leadframe blank as claimed in claim 1, wherein the ratio of the upper width to the lower width is substantially 3:4. A method of manufacturing a lead frame, including: providing the lead frame piece as claimed in claim 1; and removing at least the frame of the lead frame piece to form the lead frame. A lead frame, comprising: a lead frame piece as described in claim 1, which is formed by removing the frame. A method of manufacturing electronic components, including: providing the lead frame sheet as described in claim 1; disposing a chip on the chip holder; electrically connecting the chip to a plurality of the lead pins; and removing at least the frame of the leadframe blank. An electronic component, including: a lead frame formed by removing the frame from the lead frame piece as described in claim 1; and a chip arranged on the chip seat and electrically connected to a plurality of the Lead pin.

Images