KR20020030872A - solder mask or dielectric materials coated lead frame and manufacturing method - Google Patents

Abstract

PURPOSE: A lead frame on which a solder mask is mounted is provided to fabricate a thinner package and to decrease the number of processes, by mounting the solder mask or insulating material on the lead frame of a metallic material so that an additional molding process for protecting a bonding region becomes unnecessary after a wire bonding process. CONSTITUTION: The lead frame of a metallic material as a pad(11) on which a semiconductor chip(15) is mounted, a lead(12) and a tie bar is patterned to have a radial type. A solder mask layer of an insulation material is mounted on the lead from the outside of a wire bonding region(A) to a packaging line to prevent damage to the lead when the patterned lead frame is transferred in a transfer line. A plating layer is plated in the wire bonding region and a solder region(B) of the lead frame on which the solder mask(14) is mounted. The semiconductor chip mounted on the pad and the inner lead(12a) of the lead frame are wire-bonded by a gold wire and electrically conducted. The semiconductor chip and the gold wire are prevented from being exposed to form an encapsulating unit for protecting the wire bonding region.

Description

Lead frame with solder mask and manufacturing method thereof {solder mask or dielectric materials coated lead frame and manufacturing method}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame in which a dielectric material such as a solder mask or a polyimide tape is mounted on the lead frame, and a method of manufacturing the same.

More specifically, solder mask or insulation material is attached to the lead frame made of metal, so that no soldering is required to protect the bonding area after wire bonding. It relates to a mounted lead frame and a method of manufacturing the same.

In general, a lead frame of a semiconductor package is used as a medium and thin type medium and medium for connecting electrically and electronic devices such as semiconductor chips and printed circuit boards to be electrically connected.

The semiconductor package described above may be a resin sealing package, a tape carrier package (TCP) package, a glass sealing package, a metal sealing package, or the like, according to its type. These are classified into insert type and surface mount technology type according to the mounting method for die pads. Representative packages of the insert type include DIP (dual in-line package) and PGA (pin grid array). Typical packages include quad flat package (QFP), plastic leaded chip carrier (PLCC), ceramic leaded chip carrier (CLCC), and ball grid array (BGA).

As shown in FIG. 1, a typical leadframe package according to the prior art is in the form of a dissipation type as a pad 11, a lead 12, and a tie bar on which a semiconductor chip 15 is mounted. Copper, iron, nickel, aluminum patterned so as to have a lead frame 10 of the metal material formed as these alloys, and the patterned lead frame 10 when the lead 12 is transported in the transfer line Silver plating and solder plating are respectively applied to the wire bonding area A and the solder area B of the lead frame 10 in which the tape is mounted on the outer portion of the wire bonding area A so as to prevent damage. The gold layer 16 connected to the plated layer, the semiconductor chip 15 mounted on the pad 11, and the inner lead 12a of the lead frame 10 to be electrically conductively connected, and the semiconductor chip 15. ) And gold wire (16) to protect from oxidation and corrosion It is provided with a molding section 18 for handling molded parts by the epoxy resin.

At this time, the work process of manufacturing a typical lead frame, the step of forming a pattern of the copper, copper alloy or iron alloy substrate by etching or stamping method, the semiconductor chip and the inner wire bonding Performing silver plating or gold plating for wire bonding on the inner lead, taping for protection of the lead in the transfer line and stability during downset, and Mounting a semiconductor chip on the die pad to wirebond the inner lead of the semiconductor chip and the leadframe with gold wires for electrical connection between the semiconductor chip and the leadframe, and to protect the bonding area of the leadframe. Molding the front and rear surfaces of the lead frame excluding the outlead with an epoxy-based molding agent, and selectively opening the solder mask on the rear side of the lead frame. The lead frame is manufactured by attaching a solder ball of a tin-lead component to the uneven portion.

However, when manufacturing a typical lead frame as described above has the following problems.

In the taping process described above, the front surface of the lead frame is applied as an expensive tape, and then the tape is removed again except for a certain portion (less part of the inner lid), so that the expensive tape applied to the front surface is used. Due to this rising problem and the process of applying and removing the tape, there is a problem of poor workability.

In addition, after the semiconductor chip is mounted on the pad of the lead frame by wire bonding, the overall thickness of the lead frame is increased by molding the front surface with a predetermined thickness including the bonding area, and thus the lead frame is attached to the printed circuit board. There is a problem that is limited in the design of the printed circuit board to be mounted.

In addition, since the plating applied to the wire bonding area and the solder joint is different from each other, double plating is performed by silver plating or solder plating depending on the part, and thus an external mask design and a process for controlling the same are required for selective plating according to the part. You have a problem.

Accordingly, an object of the present invention is to attach a solder mask or an insulating material to a lead frame made of metal, and perform wire bonding after exposing the front surface (PPF) to an exposed part, and to separate the bonding area to protect the bonding area after wire bonding. It is to provide a lead frame equipped with a solder mask and a method of manufacturing the same, which makes a thinner package (more than 30% improved) due to the need for no molding work and thus reduces manufacturing costs by reducing the labor time.

Another object of the present invention, the lead is equipped with a solder mask to reduce the cost and manufacturing cost is unnecessary because the tape work process is unnecessary to ensure the protection of the lead in the transfer line after pattern molding and to ensure the stability during downset It is to provide a frame and a method of manufacturing the same.

Still another object of the present invention is to reduce the manufacturing cost and wastewater treatment cost due to the reduction of the labor time by eliminating the need for a solder plating process of the outlead part as the entire surface of the lead frame is plated as a post plating. It is to provide a lead frame equipped with a solder mask and a method of manufacturing the same, which allows for environmentally friendly plating without the use of lead (Pb), which is an environmental regulation target, due to the front plating without separate solder plating after molding. .

1 is a block diagram of a typical leadframe package according to the prior art,

2 is a schematic view of a lead frame equipped with a solder mask according to the present invention;

3 is a state in which a chip is mounted on a lead frame equipped with a solder mask according to the present invention;

4 is a flowchart illustrating a method of manufacturing a lead frame having a solder mask according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10; Leadframe

11; pad

12; lead

12a; Inner lead

12b; Out lead

13; Tie bar

14; Solder mask

15; Semiconductor chip

A; Wirebonding area

B; Solder area

The object of the present invention described above is that a lead frame of a metal material patterned to have a dissipation type as pads, leads, and tie bars on which semiconductor chips are mounted, and leads are damaged when the patterned lead frame is transferred in a transfer line The solder mask layer is mounted on the lead from the outside of the wire bonding area to the packaging line to prevent it from being formed, the wire bonding area of the lead frame on which the solder mask is mounted, the plating layer which is plated on the solder area, and the pad And a gold wire that electrically connects the inner lead of the semiconductor chip and the lead frame to be electrically connected to each other, and an encapsulation part that is encapsulated to protect the wire bonding area by preventing the semiconductor chip and the gold wire from being exposed. This is accomplished by providing a leadframe with a solder mask.

According to a preferred embodiment, the polyimide tape may be mounted on the lead from the outside of the wire bonding area to the packaging line so as to prevent the lead of the above-described lead frame from being damaged during transfer in the transfer line.

According to a preferred embodiment, the solder mask layer described above is a photo-imaging method, a laser processing method using an infrared type liquid solder mask ink and an insulating material made of polyimide, plasma etching method, silk screen printing, metal mask Any one of the coating method using the coating method, the spraying and the administering method, and the coating method by the drawing method can be selected and mounted.

According to a preferred embodiment, the plating layer which is plated over the wire bonding region and the solder region of the lead frame described above may be plated by selecting any one of nickel / paradium, nickel / gold plating, gold-silver alloy plating, and nickel.

An object of the present invention described above is to pattern a lead frame made of metal so as to have a dissipation type as pads, leads, and tie bars on which semiconductor chips are mounted, and when the leaded patterned lead frame is transferred in a transfer line, Mounting a solder mask on the leads from the outside of the wire bonding area to the packaging line to prevent damage, and forcing the surface over the wire bonding area and the solder area of the lead frame on which the solder mask is mounted; Wire-bonding the inner chip of the semiconductor chip and the lead frame mounted on the wire to be electrically connected as gold wires, and forming an encapsulation portion to seal and protect the wire bonding area by preventing the semiconductor chip and the gold wire from being exposed. And trimming the single package and forming outleads of the leadframe. The solder mask is achieved by providing a method of manufacturing a lead frame for mounting.

According to a preferred embodiment, the wire bonding region of the lead frame on which the aforementioned solder mask is mounted may be partially plated as silver plating or gold plating, and the solder region of the lead frame may be partially plated as solder plating.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, which are intended to be described in detail to be easily carried out by those skilled in the art to which the present invention pertains, and thus the present invention It does not mean that the technical scope of the is limited.

2 to 4, the pad 11, the lead 12, and the tie bar 13 on which the semiconductor chip 15 is mounted are patterned to have a dissipation type. The lead frame 10 and the patterned lead frame 10 made of copper, iron, nickel, aluminum, or a metal material formed as these alloys can be prevented from damaging the lead 12 during transfer in a transfer line. The solder mask 14 mounted on the lead 12 from the outside of the wire bonding area A to the packaging line L, and the wire bonding area A of the lead frame 10 on which the solder mask 14 is mounted. And a gold layer electrically connected to each other by wire-bonding the plated layer overlying the solder region B, the semiconductor chip 15 mounted on the pad 11, and the inner lead 12a of the lead frame 10. And the epoxy so as to protect the wire bonding region by preventing the semiconductor chip 15 and the gold wire 16 from being exposed. The sealing part 17 is sealed by the resin.

At this time, the polyimide in the lead 12 from the outside of the wire bonding region (A) to the packaging line (L) to prevent the above-described lead 12 of the lead frame 10 is damaged during the transfer in the transfer line Insulating tape, such as tape (not shown), may be mounted.

In addition, the plating layer which is plated over the wire bonding region A and the solder region B of the lead frame 10 described above may be any one of nickel / palladium, nickel / gold plating, and nickel / gold-silver alloy plating. It can be plated by selecting.

Hereinafter, a method for manufacturing a lead frame equipped with a solder mask according to the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 4, the material of the lead frame 10, which is a metal material, is pretreated and cleaned (see S10).

The lead frame 10 described above has a shape of a dissipation type configured as a pad 11, a lead 12, and a tie bar on which a semiconductor chip is mounted by etching or stamping. Patterning (see S20). At this time, it is preferable that any one of copper, aluminum, a copper alloy, nickel / iron, and an iron alloy system is used as the lead frame 10.

Insulation such as solder mask or insulating tape from the outside of the bonding area A to the packaging line L to prevent the lead 12 from being damaged during transfer in the transfer line of the patterned lead frame 10. Mount the material (see S30).

In this case, it is preferable that a polyimide tape is used as a dielectric material, and the solder mask is a liquid solder mask ink of an infrared type (IR type) made of photoimaging or polyimide. laser or plasma etching using ink and insulating materials, silk screen printing, coating using metal mask, injection and dispensing It is preferable to use any one of the coating method using and the coating method by the dotting method.

The entire surface is plated with nickel / paradium, nickel / gold plating, and nickel / gold-silver alloy plating over the wire bonding area A and the solder area B of the lead frame 10 on which the solder mask 14 is mounted. (See S40).

The semiconductor chip 15 is mounted on the pad 11 on the front surface of the solder masked lead frame 12, and the semiconductor chip 15 is formed as a gold wire 16 for electrical connection between the semiconductor chip 15 and the lead frame 10. 15) and the inner lead 12a of the lead frame 10 are wire bonded (see S50).

The wire bonding region is formed to prevent the semiconductor chip 15 or the gold wire 16 from being exposed to the outside so as to protect the wire bonding region A of the lead frame 10 from external impact or corrosion. Partly encapsulation is performed by the epoxy resin to the starting point of the solder mask 14 including A) (see S60).

A trimming operation for finishing the finished single package of the lead frame 10 and a forming operation of the outlead 12b are performed (see S70).

Next, the single package is transported to a subsequent process of mounting on a mother board.

As mentioned above, according to a preferable embodiment, it has the following advantages.

It is possible to manufacture thin package by attaching solder mask or insulating material to metal lead frame, so that no separate molding work is needed to protect the bonding area after wire bonding. The cost can be significantly reduced.

In addition, in order to ensure the protection of the lead in the transfer line after pattern molding of the lead frame and to ensure the stability during downset, a tapering process is unnecessary, thereby reducing cost and manufacturing costs.

In addition, since the front surface of the masking portion of the solder masked lead frame is plated as a front plate, a work process for soldering outlead parts is unnecessary, thereby reducing manufacturing cost and wastewater treatment cost due to shortening of labor time.

Claims (5)

A lead frame made of a metal material patterned to have a dissipation type as pads, leads, and tie bars on which semiconductor chips are mounted; A solder mask layer of an insulating material mounted on a lead from an outer side of a wire bonding area to a packaging line to prevent the lead from being damaged when the patterned lead frame is transferred in a transfer line; A plated layer overlying the wire bonding region and the solder region of the lead frame on which the solder mask is mounted; Gold wires electrically connected to each other by wire-bonding the semiconductor chip mounted on the pad and the inner lead of the lead frame; And And a sealing part encapsulating the semiconductor chip and the gold wire so as to protect the wire bonding region. The solder mask-mounted lead according to claim 1, wherein any one of polyimide tape, infrared type liquid solder mask ink, photoimatable solder mask, and an insulating material is used as the insulating material of the solder mask. frame. The lead frame according to claim 1, wherein the plating layer is plated by selecting any one of nickel / palladium, nickel / gold plating, and nickel / gold-silver alloy plating. Patterning a lead frame made of metal so as to have a dissipation type as pads, leads, and tie bars on which semiconductor chips are mounted; Mounting a solder mask on a lead from an outer side of a wire bonding area to a packaging line to prevent the lead from being damaged when the patterned lead frame is transferred in a transfer line; Front plating the wire bonding area and the solder area of the lead frame on which the solder mask layer is mounted; Wire-bonding the semiconductor chip mounted on the pad and the inner lead of the lead frame to be electrically connected as gold wires; Forming an encapsulation part to prevent the semiconductor chip and the gold wire from being exposed to encapsulate and protect the wire bonding region; And The method of manufacturing a lead frame with a solder mask, characterized in that it comprises the step of trimming the single-piece package and the out lead of the lead frame. The method of claim 4, wherein the solder mask layer; Photo-imaging method, laser processing method using infrared type liquid solder mask ink and insulating material made of polyimide, plasma etching method, silk screen printing, coating method using metal mask, spray method and spray method A method of manufacturing a lead frame with a solder mask, characterized in that any one of the coating method by the drawing method is selected and mounted.