KR100493189B1 - Method for manufacturing lead frame - Google Patents

Abstract

According to the present invention, a dispenser is placed on a lead frame for a lead-on-chip (LOC) type semiconductor package having an inner lead and an outer lead, or a lead frame having an inner lead, an outer lead, and a pad. In the manufacturing method of the lead frame which apply | coats a liquid adhesive by using, the mask member from which the center part was removed is closely adhered on the said lead frame, and the application starting position of the liquid adhesive discharged from a dispenser is set to the upper surface of the said mask, Provided is a method of producing a lead frame, characterized by applying a liquid adhesive. The manufacturing method of the lead frame of the present invention has the advantage that the liquid adhesive can be prevented from flowing to the portion where the semiconductor chip is not attached to contaminate the lead frame.

Description

Lead frame manufacturing method {Method for manufacturing lead frame}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a lead frame, and more particularly, to a method of manufacturing a lead frame in which a liquid adhesive coating method used for bonding a semiconductor chip is improved.

The lead frame is one of the core components of the semiconductor package together with the semiconductor chip, and serves as a lead connecting the inside and the outside of the semiconductor package and the support of the frame supporting the semiconductor chip. Play a role. Such a semiconductor lead frame is typically manufactured by a stamping method or an etching method. The stamping method is a processing method using a mold, and is a method of punching a lead frame material using a mold. On the other hand, the etching method is a method of forming a mask of a predetermined pattern on the lead frame with a photoresist and then molding through chemical corrosion using an etching solution. After the molding process as described above, a plating process for improving wire bonding properties is included, and an adhesive coating process or a taping process for bonding the lead frame to the semiconductor chip is included.

The lead frame has various structures according to the mounting method of the semiconductor chip. For example, the lead frame may include a pad on which the semiconductor chip is mounted, an inner lead and an outer lead. That is, a rectangular pad on which the semiconductor chip is to be mounted is supported by two or four support bars at the center portion of the quadrangular substrate of the semiconductor lead frame, and around each pad of the element within the chip by wire bonding. Inner leads to which terminals and wires are connected are arranged in a manner approaching around the four sides of the pad, and the outer leads extend outside the inner leads. In another example, the lead frame has a form for a semiconductor package of lead on chip (LOC), in which the pad is removed and the semiconductor chip is attached to a predetermined position of the inner lead.

As mentioned above, the manufacture of the lead frame includes a liquid adhesive application process for adhering the semiconductor chip to the lead frame. The liquid adhesive is applied to the pad of the lead frame or the inner lead depending on the portion to which the semiconductor chip is to be bonded. The adhesive is dried after being applied in a liquid state, and the liquid adhesive is melted by mutually heat pressing the lead frame and the semiconductor chip in a subsequent semiconductor assembly process so that the adhesion of the semiconductor chip can be achieved.

Application of the liquid adhesive is performed using a so-called dispenser device. The dispenser device fills a liquid adhesive into a cylindrical inner space of a syringe and discharges it through a needle using pneumatic pressure. Device. The liquid adhesive pressurized through the needle is applied at a predetermined position on the pad or inner lead, and then dried.

Shown in FIG. 1 is a schematic perspective view of a portion of a lead frame for a LOC type semiconductor package.

Referring to the drawings, the lead frame 10 includes inner leads 11a, 11b, 11c, 11d and 11e and outer leads 12a, 12b, 12c, 12d and 12e, and these inner leads and outer leads 12 ) Is formed as each lead extending in a straight line. A liquid adhesive should be applied to the upper surface of the inner lead 11, and the adhesive application sites are denoted by reference numerals 13a, 13b, 13c, 13d and 13e, respectively. In the subsequent semiconductor package assembly process, a semiconductor chip (not shown) is disposed at an adhesive application site, and thus the adhesion of the lead frame 10 and the semiconductor chip may be performed.

As described above, a dispenser device is used to apply the liquid adhesive to the application sites 13a to 13e. The dispenser device (not shown) aligns the needle (not shown) from which the liquid adhesive is discharged to the upper portion of the application portion 13a of the first inner lead 11a, and then sprays the liquid adhesive by pneumatic pressure. The position of the needle is then moved to the application site 13b of the adjacent inner lead 11b, and then the liquid adhesive is applied while moving to the top of the application site of the next lead. That is, the needle of the dispenser discharges the liquid adhesive while moving in the width direction from the top of the inner lead.

By the way, the liquid adhesive in the application process as described above may occur a phenomenon that the needle flows to the side of the inner lead (11a) first contact. That is, the liquid adhesive is applied to the side portion indicated by the reference numeral 14 in FIG. The flow phenomenon of the liquid adhesive may be caused by various causes. For example, the needles of the dispenser eject the liquid adhesive on top of the first inner lead 11a. If the needles are not in the correct position, the liquid adhesive will flow to the side portion 14. In addition, when the diameter of the needle is larger than the width of the inner lead, the needle may flow to the side portion 14 of the first lead 11a according to the ejection amount of the liquid adhesive. In no case, however, the liquid adhesive flows to the side portions of the other inner leads 11b, 11c, 11d, and 11e, which is the surface of the application sites 13b, 13c, 13d, and 13e once the ejection of the liquid adhesive is started. This is because the surface tension of the liquid at

2 shows a schematic perspective view of a part of the lead frame with a pad.

Referring to the drawing, the lead frame 20 includes an inner lead 21 and an outer lead 22, and a pad 23 is provided at the center thereof. The pad 23 is supported by being connected to a rail (not shown) formed on the outer circumferential surface by the support bar 24. A semiconductor chip (not shown) is attached to the top of the pad 23, indicated by reference numeral 25 is a portion to which the liquid adhesive is applied.

When the application site 25 is set as a whole over the transverse direction of the pad 23 as shown in FIG. 2, the liquid adhesive ejected through the needles (not shown) of the dispenser may have the side surface 26 of the pad 23. Flows to This flow phenomenon also occurs because of the incorrect selection of the needle's initial position.

As described with reference to the examples of FIGS. 1 and 2, the flow of the liquid adhesive to the side of the inner lead or pad when the liquid adhesive is applied negatively affects the semiconductor package assembly process. That is, the liquid adhesive flowing to the side not only contaminates the lead frame, but also causes the structure of the mold to be weakened when assembling the package. In order to prevent this side flow phenomenon of the liquid adhesive, it is necessary to accurately set the initial dispensing position of the dispenser needles, which is a difficult task.

The present invention has been made to solve the above problems, it is an object of the present invention to provide a lead frame manufacturing method improved liquid adhesive coating method.

Another object of the present invention is to provide a lead frame manufacturing method for applying a liquid adhesive using a mask.

In order to achieve the above object, according to the present invention, a liquid adhesive is applied to the lead frame for lead-on-chip (LOC) type semiconductor package having an inner lead and an outer lead using a dispenser. In the manufacturing method of the lead frame to apply, the mask member from which the center part was removed is stuck in close contact with the said lead frame, and setting the application start position of the liquid adhesive discharged from a dispenser to the upper surface of the said mask and apply | coating a liquid adhesive A method for producing a lead frame is provided.

According to another feature of the invention, the spacing between the inner surface of the mask member and the side surfaces of the adjacent inner leads is equally spaced apart from the spacing between the inner leads.

According to another feature of the invention, the application end position of the liquid adhesive discharged from the dispenser is set to the upper surface of the mask.

Further, according to the present invention, in the manufacturing method of a lead frame in which a liquid adhesive is applied using a dispenser on a lead frame including an inner lead, an outer lead, and a pad on which a semiconductor chip is mounted, the center portion is removed. The mask member is brought into close contact with the lead frame, and the liquid adhesive is applied by setting the application start position of the liquid adhesive discharged from the dispenser to the upper surface of the mask.

Hereinafter, the present invention will be described in more detail with reference to an embodiment shown in the accompanying drawings.

3 illustrates a method of applying a liquid adhesive to a lead frame for a LOC type semiconductor package according to the present invention.

Referring to the drawings, the lead frame 30 is shown in a partial perspective view, and the inner leads 31a, 31b, 31c, 31d, 31e, and 31f and the outer leads 32a, 32b, 32c, 32d, respectively extending therefrom, 32e, 32f). Application areas 33a, 33b, 33c, 33d, 33e, 33f are set on each of the inner leads 31a to 31f, and the liquid adhesive should be applied only to these application areas 33a to 33f.

According to the invention, the application of the liquid adhesive is performed using the mask 35. The mask 35 is formed in a quadrangle with the center removed as shown in the figure. The mask 35 may be manufactured using, for example, metal, resin, or paper, and may be manufactured differently from the shape shown in the drawing. The mask 35 is disposed in close contact with the upper portion of the lead frame 30, wherein the inner surface 37a of the mask 35 is spaced apart from the outer surface 38a of the inner lead 31a at a predetermined interval, The other inner side surface 37b of the mask 35 is spaced apart from the outer side surface 38f of the inner lead 31f at a predetermined interval. At this time, the intervals at which the inner surfaces 37a and 37b of the mask 35 are spaced apart from the respective outer surfaces 38a and 38f of the inner leads 31a and 31f are formed to be the same as the intervals at which the respective leads are spaced apart from each other.

The operation of applying the liquid adhesive to the application sites 13a to 13e of the lead is performed using a dispenser (not shown) in a state where the mask 35 is in close contact with the lead frame 30. To apply the liquid adhesive, the initial application position is set on the upper surface of the mask 35, which is indicated by reference numeral 36a in FIG. The position where the application of the liquid adhesive by the dispenser (not shown) is finished is the upper surface of the mask 35 indicated by reference numeral 36b.

Application of the liquid adhesive using the mask 35 is to prevent the liquid adhesive from flowing to the side of the first inner lead 31a by setting the initial application position at the predetermined position 36a of the mask 35. That is, as described above, the liquid adhesive does not flow to the side of the inner lead once the application of the liquid is initiated because of surface tension, and therefore, when the starting position of the liquid adhesive application is set to the upper surface of the mask 35, the first inner lead side This can prevent the adhesive from flowing. The upper surface of the mask 35 becomes an imaginary inner lead by separating the inner surface 37a of the mask 35 from the outer surface 38a of the initial inner lead 31a to correspond to the pitch of the lead.

Figure 4 shows the application of the liquid adhesive in accordance with the present invention in a lead frame having a pad.

Referring to the drawing, the lead frame 40 includes an inner lead 41 and an outer lead 42 and a pad 43 to which a semiconductor chip (not shown) is attached. Pad 43 is supported relative to a rail (not shown) by support bar 44.

The liquid adhesive should be applied to the application site 45 extending transversely to the top surface of the pad 43. According to the present invention, the application of the liquid adhesive is performed while the mask 47 is in close contact with the lead frame 40.

The mask 47 is a square with the center removed, similar to the mask 35 used in FIG. 3. In a state where the mask 47 is in close contact with the surface of the lead frame 40, the inner surface 49a of the mask 47 is spaced apart from one side outer surface 43a of the pad 43 at predetermined intervals. The other inner side 49b of the mask 47 is also spaced apart from the other outer side 43b of the pad 43 at predetermined intervals.

To apply the liquid adhesive using the dispenser device, the initial position of the needle (not shown) is set on the upper surface of the mask 47, for example in the portion indicated by reference numeral 48a in FIG. Application is started. The needle (not shown) begins to apply a liquid adhesive from the upper surface 48a of the mask 47 to perform adhesive application to the application site 45 of the pad 43, and the top of the mask 47. Application of the adhesive on the surface 48b ends.

Applying the liquid adhesive with the mask 47 to the lead frame 40 with the pad 43 will prevent the liquid adhesive from flowing to the side 43a of the pad 43 as described above. Can reduce the difficulty of working correctly selecting the starting position of the adhesive application. At this time, the separation interval between the inner surface 49a of the mask 47 and the outer surface 43a of the pad 43 should be determined according to the discharge amount of the liquid adhesive discharged from the dispenser (not shown).

According to the present invention, a method of manufacturing a lead frame having an improved method of applying an adhesive has an advantage in that a liquid adhesive can be prevented from contaminating the lead frame by flowing to a portion where the semiconductor chip is not attached. In addition, since the needle of the dispenser eliminates the difficulty of setting the adhesive application start position on the lead frame, the ease of operation is improved. Moreover, the application of the liquid adhesive to the lead frame having a fine pitch lead can also be made easily.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, which are exemplary and will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. . Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

1 is a schematic perspective view of a portion of a lead frame for a semiconductor package in lead-on-chip form;

2 is a schematic perspective view of a portion of a lead frame with pads.

Figure 3 is a schematic illustration showing the application of a liquid adhesive to the lead frame for semiconductor packages in the form of a lead-on-chip according to the present invention.

Figure 4 is a schematic illustration showing the application of the liquid adhesive to the lead frame with a pad in accordance with the present invention.

Brief description of the main symbols in the drawings

10. Lead frames 11a-11e. Inner lead

12a-12e. Outer lead 13a-13e. Application site

20.Lead frame 21.Inner lead

22.Outer lid 23.Pad

31a-31f. Inner lead 32a ~ 32f. Outer lead

33a-33f. Application area 35. Mask

41.Inner lead 42.Outer lead

43.Pad 47.Mask

Claims (1)

In the manufacturing method of the lead frame which apply | coats a liquid adhesive using a dispenser on the lead frame for a lead-on-chip (L.O.C.) type | mold semiconductor package which has an inner lead and an outer lead, The mask member from which the center part was removed is brought into close contact with the lead frame, the application start position of the liquid adhesive discharged from the dispenser is set to the upper surface of the mask member, and the application end position of the liquid adhesive discharged from the dispenser is set to the mask. A liquid adhesive is applied by setting to an upper surface of the method, and the space between the inner surface of the mask member and the side of the adjacent inner lead is spaced equally to the space between the inner leads.

Images