KR20080101207A - Mold resin effluence prevention case - Google Patents

Abstract

The crack of a semiconductor chip caused by pressure can be prevented by dispersing the pressure applied to the semiconductor package using the barrier having the elasticity. The molding resin effluence prevention case(100) comprises a groove(112) for molding resin; a body(110) for applying the pressure of the several tens to the lower surface of the back up semiconductor package(1) in the molding progress tone and for preventing the leak of the molding resin; the body for dispersing the pressure delivered from the body, having the elasticity against the pressure generated by the contact of the lower surface of the back up semiconductor package; a barrier(120) for preventing the leak of the molding resin; an up-down unit for rising and dropping the body.

Description

Molded resin effluence prevention case

1 is a cross-sectional view of a conventional molding resin spill prevention case.

2B is an exploded perspective view of the molding resin leakage preventing case and the preliminary semiconductor package according to the present invention.

FIG. 2B is an enlarged view of a portion A shown in FIG. 2A.

3A is a cross-sectional view illustrating a state in which the molding resin leakage preventing case illustrated in FIG. 2A is in close contact with a preliminary semiconductor package.

3B is an enlarged view of a portion B shown in FIG. 3A.

The present invention relates to a molding resin leakage preventing case, and more particularly, to prevent molding resin flowing out through a window for electrically connecting a semiconductor chip and a substrate to a ball land and preventing cracks in the semiconductor chip. It relates to a molded resin spill prevention case prevented.

A general semiconductor device is manufactured through a semiconductor chip manufacturing process for manufacturing a semiconductor chip on a silicon wafer made of high purity silicon, a die sorting process for electrically inspecting the semiconductor chip, and a semiconductor packaging process for selecting and packaging good semiconductor chips.

The semiconductor packaging process is generally a step of die attaching a semiconductor chip manufactured through a semiconductor device manufacturing process onto a substrate (or lead frame), and a wire bonding process of bonding bumps of the semiconductor chip and bonding pads formed on the substrate with conductive wires. And a sealing step of sealing the semiconductor chip and the conductive wire with an epoxy resin or the like.

Recently, as the types of semiconductor packages are diversified and process technologies are developed, semiconductor packages in which a semiconductor chip in which bonding pads are arranged in the center are electrically connected to the bond fingers of the substrate using conductive wires have also been developed.

However, in the above-described semiconductor package, when the bonding pads arranged in the center of the semiconductor chip and the bond fingers of the substrate are wire-bonded with the conductive wire, the length of the conductive wire is lengthened, resulting in the wetting of the conductive wires during the encapsulation process. As a result, problems such as electrically shorting of the conductive wires are generated.

In order to prevent such conductive wires from pulling out, conventionally, a process of disposing a flowable material on a lower semiconductor chip, allowing a part of the conductive wire to be buried in the flowable material, and then curing the flowable material to fix the conductive wire so as not to be pulled out is further performed. Proceed. Therefore, there is a problem that the manufacturing process of the semiconductor package is complicated, and the defect occurrence rate is also increased.

1 is a cross-sectional view of a conventional molding resin spill prevention case.

In order to improve the above-mentioned problems, namely, the pulling of the conductive wires and further processing to prevent them, recently, the bonding pads 12 of the semiconductor chip 10 have been fabricated as shown in FIG. A window 22 is formed in the substrate 20 to expose the bottom surface of the 20, and the semiconductor chip 10 and the substrate 20 are aligned so that the bonding pads 12 are located in the window 22. The surface on which the bonding pads 12 of the semiconductor chip 10 are formed is bonded to the substrate 20 through the adhesive 15.

Subsequently, among the lower surfaces of the substrate 20, the bond fingers 24 arranged on the outer side of the window 22 and the bonding pads 22 of the semiconductor chip 10 exposed through the window 22 are connected to the conductive wire 30. ). In this case, even if the bonding pads 12 are arranged in the center of the semiconductor chip 10, the length of the conductive wire 30 is short, so that the pulling phenomenon can be prevented and the pulling of the conductive wire 30 is prevented. The manufacturing process is simplified because the additional processes do not have to be performed.

As such, when the bonding pads 12 arranged in the center of the semiconductor chip 10 and the bond fingers 24 formed on the lower surface of the substrate 20 are electrically connected through the wire bonding process, the semiconductor chip 10 may be connected. Molding part 40 for protecting the semiconductor chip 10 and the conductive wires 30 from the external environment by wrapping the entire upper surface of the substrate 20 including the surroundings and around the window 22 including the conductive wires 30 with a molding resin. To form.

At this time, the flowable molding resin flows through the window 22 toward the lower surface of the substrate 20, passes through the bond fingers 24 and is arranged on the lower surface of the substrate 20, and is used as an external connection terminal. In order to prevent the cover land 26 to be attached (not shown) to be attached, the molding resin leakage preventing case 50 is positioned on the lower surface side of the substrate 20.

Referring to FIG. 1, the molding resin leakage preventing case 50 may be made of metal, and may be wrapped from a portion corresponding to the window 22 to a portion slightly passing through the position where the bond fingers 24 are arranged, through the window 22. The molding resin accommodating groove 52 containing the flown molding resin and the molding resin accommodating groove 52 are formed so as to protrude to the outside of the molding resin accommodating groove 52 at a predetermined height to be contained in the molding resin accommodating groove 52. Auxiliary accommodating grooves which are formed near the center of the contact portion 54 and the contact portion 54 in contact with the substrate 20 to prevent the resin from flowing into the ball land 26 and contain the molding resin discharged from the molding resin accommodating groove 52. And 56.

Here, when the preliminary semiconductor package completed until the wire bonding process is put into a molding apparatus for forming the molding part 40, a pressure of tens of tons (Ton) is applied to the molding resin leakage preventing case 50 having the above-described configuration, thereby molding the molding resin. The contact portion 54 of the spill prevention case 50 is brought into close contact with the lower surface of the substrate 20 of the preliminary semiconductor package, and an imported ton pressure is applied from the lower surface of the preliminary semiconductor package toward the upper surface of the preliminary semiconductor package.

However, the pressure applied to the molding resin leakage preventing case 50 is several tens of tons, and as shown in FIG. 1, the width of the contact portion 54 in close contact with the lower surface of the substrate 20 is narrow. Excessive force is applied to the center portion of the preliminary semiconductor package to which 54 is in close contact. In addition, when the inlet pressure of the molding resin applied to the preliminary semiconductor package is added to the preliminary semiconductor package in the molding apparatus, cracks frequently occur in the center portion of the semiconductor chip 10 that is thin and exposed to the outside of the substrate 20 through the window 22. Is generated. As a result, there is a problem that the reliability and productivity of the product is lowered.

An object of the present invention is to buffer the pressure applied to the lower surface of the substrate in order to prevent the molding resin flowed through the window in the molding process toward the ball land, and evenly distributes the pressure on the front surface of the substrate to crack the semiconductor chip The present invention provides a molding resin leakage preventing case which prevents occurrence and prevents the molding resin from flowing into the ball land.

Molding resin spill prevention case for implementing the object of the present invention is a surface of the semiconductor chip with the bonding pads arranged in the center is attached to the upper surface of the substrate, the lower surface of the substrate through a window formed on the substrate corresponding to the bonding pads Pressing the substrate when the molding process proceeds to the preliminary semiconductor package electrically connected to the bond fingers arranged on the outer side of the window through the conductive wire, and accommodates the bond fingers including the window and contains the molding resin discharged through the window. It includes a body having a resin receiving groove is formed in the remaining portion except the molding resin receiving groove of the upper surface of the body facing the lower surface of the substrate, the barrier having elasticity that is contracted by pressure when contacting the substrate.

Hereinafter, a molding resin leakage preventing case according to embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to the following embodiments, and has a general knowledge in the art. It will be apparent to those skilled in the art that the present invention may be embodied in various other forms without departing from the spirit of the invention.

FIG. 2B is an exploded perspective view of the molding resin leakage preventing case and the preliminary semiconductor package according to the present invention, and FIG. 2B is an enlarged view of a portion A shown in FIG. 2A. 3A is a cross-sectional view illustrating a state in which the molding resin leakage preventing case illustrated in FIG. 2A is in close contact with the preliminary semiconductor package, and FIG. 3B is an enlarged view of part B illustrated in FIG. 3A.

2A and 3A, the molding resin leakage preventing case 100 includes a molding resin accommodating groove 112 and applies several tens of tons of pressure to the lower surface of the preliminary semiconductor package 1 during the molding process. Body 110 to prevent the leakage of the, has a resilient that is contracted by the pressure when in contact with the lower surface of the preliminary semiconductor package 1 to distribute and buffer the pressure transmitted from the body 110 and Together with the barrier 120 and the body 110 to prevent the outflow of the molding resin up and down unit (not shown) is included.

For convenience of description, before describing the molding resin leakage preventing case having the above-described configuration, a preliminary semiconductor package introduced into the molding process will be schematically described with reference to FIG. 2A.

Referring to FIG. 2A, the preliminary semiconductor package 1 may include a semiconductor chip 10 having bonding pads 12 arranged at a center of one surface thereof, and an adhesive 15 having one surface where bonding pads 12 are arranged among semiconductor chips 10. Is attached to the upper surface by the substrate 20 and the conductive wire 30 electrically connecting the semiconductor chip 10 and the substrate 20 to which the solder balls (not shown) connected to the upper surface are connected. ).

Among the substrate 20, a bond finger electrically connected to the bonding pads 12 by the window 22 and the conductive wire 30 to expose the bonding pads 12 to the bottom surface of the substrate 20. Ball lands 26 are formed to which 24 and solder balls are connected and electrically connected to bond fingers 24.

The window 22 is formed long in the direction in which the bonding pads 12 are arranged in the vicinity corresponding to the bonding pads 12. The bond fingers 24 and the ball lands 26 are arranged on the bottom surface of the substrate 20, where the bond fingers 24 are spaced apart from the window 22 and located outside the window 22, the bonding pads ( 12) are arranged in the arranged direction. The ball lands 26 are spaced apart from the bond fingers 24 and arranged in a plurality of columns and rows outside the bond fingers 24. Here, the ball lands 26 and the bond fingers 24 are electrically connected by circuit patterns (not shown) formed on the lower surface of the substrate 20.

When the preliminary semiconductor package 1 configured as described above is introduced into a molding apparatus (not shown), the above-described molding resin leakage preventing case 100 contacts the lower surface of the preliminary semiconductor package 1 and flows through the window 22. It accommodates the lowered molding resin and prevents the ball lands 26 from being covered by the molding resin.

2A and 3B, the body 110 of the molding resin leakage preventing case 100 is made of metal, and the upper surface of the body 110, that is, the surface facing the substrate 20 is formed flat. . The molding resin accommodating groove 112 formed in the body 110 is elongated in the direction in which the window 22 is formed, and the width of the molding resin accommodating groove 112 is bonded from the portion corresponding to the window 22. ) Is formed so as to cover a portion passing through the arranged portion to contain a molding resin flowing through the window 22.

Preferably, the ball of the body 110 in order to prevent the molding resin from excessively flowing out of the molding resin receiving groove 112 to overflow the molding resin to the ball land 26 on the surface of the barrier 120 An auxiliary receiving groove 114 is formed at a portion between the land 24 and the molding resin receiving groove 112.

The auxiliary accommodating groove 114 is also formed long in the direction in which the window 22 is formed, and the auxiliary accommodating groove 114 has a letter “V” at both sides of the molding resin accommodating groove 112 based on the molding resin accommodating groove 112. It is formed into a shape. Preferably, the area and depth of the auxiliary receiving groove 114 is less than the area and depth of the molding resin receiving groove 112, the most preferred depth from the top surface of the body 110 to the bottom of the auxiliary receiving groove 114. Is 120 μm as shown in FIG. 2B.

The barrier 120 is disposed in the entirety of the upper surface of the body 110 except for the molding resin accommodating groove 112 and the auxiliary accommodating groove 114. The barrier 120 is disposed on the adhesive layer 122 attached to the upper surface of the body 110, the elastic layer 124 disposed on the upper surface of the adhesive layer 122 and compressed by elasticity when pressure is applied to the body 110. ), The coating layer 126 is coated on the surface of the elastic layer 124 to prevent foreign matter from being pressed on the elastic layer 124 by heat generated in the molding process.

Preferably, the coating layer 126 is formed of Teflon.

Preferably, the thickness of the barrier 120 before the pressure is applied to the body 110, that is, the thickness of the coating layer 126 to the upper surface of the body 110 is 9.5㎛ ~ 28.5㎛, pressure on the body 110 After this is applied, the bayer 120 has a thickness of 5.5 μm to 8.5 μm by compressing the elastic layer 124.

That is, the thicknesses of the coating layer 126 and the adhesive layer 122 are 1 µm to 3 µm, respectively, and the thickness before the pressure is applied to the elastic layer 124 is 7.5 µm to 22.5 µm, and the pressure is applied to the elastic layer 124. After this addition, the elastic layer 124 has a thickness of 1.5 µm to 4.5 µm.

The most preferable coating layer 126 and the adhesive layer 122 is 2 μm, respectively, as shown in FIGS. 2B and 3B, and the thickness before the pressure is applied to the elastic layer 124 is 15 μm, and the elastic layer ( After pressure is applied to the 124, the thickness of the elastic layer 124 is 3 μm.

Referring to Figures 2a and 3a schematically illustrating the operation of the molding resin leakage prevention case according to the present invention.

As shown in FIG. 2A, when the preliminary semiconductor package 1 is inserted into the molding apparatus, the up / down unit of the molding resin leakage preventing case 100 disposed under the preliminary semiconductor package 1 operates to operate the body 110. ) Is raised toward the bottom surface of the preliminary semiconductor package 1, that is, toward the bottom surface of the substrate 20.

Then, as shown in FIG. 3A, the body 110 of the molding resin leakage preventing case 100 is in contact with the lower surface of the substrate 20, and the body 110 is pressed at a desired pressure, that is, several tens of tons. When contacted with the lower surface of the 20, the elastic layer 124 of the barrier 120 is in close contact with the lower surface of the substrate 20 while being compressed by the pressure applied to the body (110).

Here, the barrier 120 is attached to the entire upper surface of the body 110, except the molding resin receiving groove 112 and the auxiliary receiving groove 114, because the front surface of the barrier 120 is in contact with the substrate 20 The pressure applied to the body 110 is evenly distributed and the pressure applied to the preliminary semiconductor package 1 is buffered. Therefore, when the molding process is performed, cracks may be minimized in the central portion of the semiconductor chip 10 which is most vulnerable to impact due to the high pressure and thin thickness in the preliminary semiconductor package 1.

As shown in FIG. 3A, when the molding resin leakage preventing case 100 is in close contact with the lower surface of the preliminary semiconductor package 1, the molding resin flows into the molding apparatus to form an upper portion of the substrate 20 including the semiconductor chip 10. A molding resin is wrapped around the surface and a portion of the lower surface of the substrate 10 including the conductive wire 30 and the bond finger 24 to form the molding part 40. At this time, the flowable molding resin flows down toward the molding resin leakage preventing case 100 through the window 22 of the substrate 20, and flows into the molding resin receiving groove 112 of the molding resin leakage preventing case 100. The down molding resin is filled.

In addition, when the flowing molding resin completely fills the molding resin accommodating groove 112, the molding resin tends to overflow to the side of the molding resin accommodating groove 112, wherein the barrier 120 having elasticity is the substrate 20. It is hard to overflow the molding resin because it is in close contact with the bend of the c).

If the molding resin overflows from the molding resin accommodating groove 112, the molding resin accommodating groove 112 is disposed outside the molding resin accommodating groove 112, and the auxiliary storage groove 114 having a deeper depth than the conventional resin completely accommodates the overflowing molding resin. Therefore, the molding resin cannot cover the ball land 26.

Although the detailed description of the present invention has been described with reference to the embodiments of the present invention, those skilled in the art or those skilled in the art will have the spirit and scope of the present invention as set forth in the claims below. It will be appreciated that various modifications and variations can be made in the present invention without departing from the scope of the art.

As described in detail above, when the elastic barrier is attached to the upper surface of the body, the pressure applied to the preliminary semiconductor package is evenly distributed and buffered, thereby preventing cracks in the semiconductor chip due to the pressure. Product productivity and reliability can be improved.

In addition, the ball land is prevented from being covered by the molding resin by completely blocking the molding resin overflowed from the molding resin receiving groove by the deep receiving auxiliary groove formed outside the barrier and the molding resin receiving groove. .

Claims (8)

One side of a semiconductor chip having bonding pads arranged at a center thereof is attached to an upper surface of the substrate, and bond fingers arranged outside the window among the lower surfaces of the substrate through windows formed on the substrate corresponding to the bonding pads; In the molding resin leakage prevention case for pressing the substrate when the molding process proceeds to the preliminary semiconductor package electrically connected via a conductive wire, A body formed with a molding resin receiving groove accommodating the bond fingers including the window and containing the molding resin flowing through the window; And Molding resin spill prevention case disposed on the remaining portion of the upper surface of the body facing the lower surface of the substrate except for the molding resin receiving groove, and includes a barrier having an elastic contraction by pressure when contacting the substrate . 2. The body of claim 1, further comprising an auxiliary receiving groove spaced apart from the molding resin receiving groove and containing the molding resin flowing out of the molding resin receiving groove on both sides of the molding resin receiving groove in a direction in which the bond fingers are formed. Molding resin spill prevention case, characterized in that. The molding resin leakage preventing case of claim 2, wherein a depth of the auxiliary receiving groove is lower than a depth of the molding resin receiving groove and is formed in a “V” shape. The molding resin spill prevention case according to claim 3, wherein a depth from an upper surface of the body to a bottom of the auxiliary receiving groove is 120 μm. The barrier of claim 1, wherein the barrier comprises: an adhesive layer attached to an upper surface of the body; An elastic layer disposed on an upper surface of the adhesive layer and compressed by elasticity when the pressure is applied; Molding resin leakage prevention case characterized in that it comprises a coating layer which is coated on the surface of the elastic layer to prevent foreign matter from being pressed to the elastic layer by heat. The case of claim 5, wherein the coating layer is formed of Teflon. The thickness of the coating layer and the adhesive layer is 1 μm to 3 μm, respectively, and the thickness before the pressure is applied to the elastic layer is 7.5 μm to 22.5 μm, and the elasticity is applied after the pressure is applied to the elastic layer. The thickness of a layer is 1.5 micrometers-4.5 micrometers, The molding resin spill prevention case characterized by the above-mentioned. According to claim 7, wherein the thickness of the coating layer and the adhesive layer is 2㎛, the thickness before the pressure is applied to the elastic layer is 15㎛, the thickness of the elastic layer after the pressure is applied to the elastic layer is 3㎛ Molding resin spill prevention case, characterized in that.

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