KR100860445B1 - Semiconductor device and manufacturing method of conductive pad - Google Patents

Abstract

A semiconductor device and a manufacturing method of a bond pad are provided to prevent a short effect between a bond pad and a conductive layer or a lead frame by forming an outermost layer of a bond pad as a nickel layer. A semiconductor die(110) includes a semiconductor substrate(111) and an active region(112). An insulating layer(120) is formed to cover an outer circumference of the semiconductor die in order to expose the active region of the semiconductor die. A bond pad(130) is formed on the active region exposed through the insulating layer. The bond pad is composed of a lamination of a molybdenum layer(131), an aluminum layer(132), and a nickel layer(133). The nickel layer is formed to cover the molybdenum layer and a lateral surface of the aluminum layer.

Description

Technical Field [0001] The present invention relates to a semiconductor device and a method of manufacturing the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing a bond pad. More particularly, the present invention relates to a semiconductor device capable of preventing a short circuit phenomenon due to excessive remelting of a solder deposited on a bond pad and a leakage current phenomenon caused by metal peeling And a method of manufacturing a bond pad.

1 is a cross-sectional view showing a conventional semiconductor device.

As shown, a conventional semiconductor device 100 'includes a semiconductor die (not shown) having a semiconductor substrate 111' and an active region 112 'formed thereon (an epi layer 112a' and a doped region 112b ' An insulating layer 120 'covering a predetermined portion of the active region 112' of the semiconductor die 110 'and an active region 112' exposed through the insulating layer 120 ' And a formed bond pad 130 '.

Here, a certain amount of solder 140 '(for example, Pb-Sn-Ag alloy) may be deposited on the bond pad 130' so that a conductive connection member or the like can be easily electrically connected during the packaging process. In addition, a conductive layer 150 'may be formed on the lower surface of the semiconductor die 110' so as to be electrically connected to the lead frame 160 'during the packaging process.

The bond pad 130 'typically includes a molybdenum (Mo) layer 131', an aluminum (Al) layer 132 'formed by sputtering, evaporation and photo processes, , A nickel (Ni) layer 133 'and a gold (Au) layer 134'. In addition, the conductive layer 150 'includes a vanadium (V) layer 151', a nickel layer 152 ', and a gold layer 153'.

However, in the conventional semiconductor device 100 ', since the solder 140' formed on the bond pad 130 'is excessively re-melted during the manufacturing process, the solder 140' There is a problem that a phenomenon that the bond pad 130 'and the conductive layer 150' or the lead frame 160 'are electrically short-circuited frequently occurs due to the downward flow along the side surface of the lead frame 110'.

That is, in the conventional semiconductor device 100 ', the solder 140' is welded to the gold layer 134 'of the bond pad 130', so that the gold layer 134 'and the solder 140' If the gold layer 134 'and the solder 140' are subjected to interlayer metal bonding, the re-melting temperature may be lowered to about 235 ° C. Accordingly, in the semiconductor manufacturing process in which the process temperature is approximately 235 ° C or higher, the solder 140 'is excessively re-melted, resulting in a shot phenomenon as described above. For example, in a reflow process in which a conductive connection member is connected to the solder 140 ', the solder 140' is excessively remelted such that the solder 140 'contacts the semiconductor die 110' To the lower conductive layer 150 'and the lead frame 160' along the side surface of the lead frame 160 '.

1 shows a state in which the solder 140 'is excessively remelted and shorted to the lower conductive layer 150' and the lead frame 160 'along the side surface of the semiconductor die 110' . Referring to FIG. 2A, there is shown a photograph of solder 140 'formed on a bond pad in a conventional semiconductor device taken down to the side of semiconductor die 110'. In addition, referring to FIG. 2B, there is shown a photograph of a solder 140 'that is over-melted at the bond pad 130'.

In addition, the conventional bond pad 130 'is formed by forming a molybdenum layer 131' and an aluminum layer 132 'using a sputtering and photolithography process and further forming a nickel layer 133' and a gold layer 134 ' Is formed by using a deposition and photolithography process. Thus, as shown in the photographs of FIGS. 1A and 2C, each layer of the bond pad 130 'is exposed to the side. That is, the molybdenum layer 131 ', the aluminum layer 132', the nickel layer 133 ', and the gold layer 134' are both exposed to the outside through the side portions. Therefore, impurities easily penetrate through the interface between the molybdenum layer 131 'and the insulating layer 120' or between the molybdenum layer 131 'and the active region 112'. Accordingly, the molybdenum layer 131 'is apt to be peeled from the active region 112'. Further, there is a problem that the leakage current increases due to the metal peeling phenomenon.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor device and a method of manufacturing a bond pad capable of preventing an excessive remelting phenomenon of a solder deposited on a bond pad of a semiconductor chip .

Another object of the present invention is to provide a semiconductor device capable of suppressing a leak current generated by filling a molybdenum layer in an active region by preventing an interface between a molybdenum layer forming a bond pad and an active region from being exposed to the outside, And a method of manufacturing a bond pad.

A semiconductor device according to the present invention includes a semiconductor die having an active region formed on a semiconductor substrate, an insulating layer covering the outer periphery of the semiconductor die to expose an active region of the semiconductor die, and a bond pad formed on the active region exposed through the insulating layer The bond pad is formed such that a molybdenum layer, an aluminum layer, and a nickel layer are sequentially stacked, and the nickel layer covers the molybdenum layer and the aluminum layer.

Here, the molybdenum layer and the aluminum layer are formed by a sputtering and a photo process, and the nickel layer is formed by a plating process. Also, the nickel layer is formed by plating with a thickness of 1 to 3 탆, and the solder is further formed on the bond pad. In addition, the solder is remelted at a temperature of 300 to 320 ° C. Furthermore, a conductive layer is formed on the lower surface of the semiconductor substrate, and the conductive layer is formed of a vanadium layer, a nickel layer, a gold layer, or a nickel layer. Also, the conductive layer may be formed by plating a nickel layer to a thickness of 1 to 3 탆.

A method of manufacturing a bond pad for a semiconductor device according to the present invention includes the steps of: forming an aluminum layer having a plurality of microprojections in an active region of a semiconductor die; and performing zincate treatment on the aluminum layer, A step of stripping the zinc particles partially stripping the zinc particles from the aluminum layer, and a step of zincating the surface of the aluminum layer and the zinc particles to form the aluminum And a nickel layer forming step of forming a nickel layer on the surface of the aluminum layer and the zinc layer.

The nickel layer forming step is performed by electroless plating nickel on the surfaces of the aluminum layer and the zinc layer.

As described above, in the semiconductor device and the method of manufacturing a bond pad according to the present invention, the outermost layer of the bond pads becomes a nickel layer, so that the solder bonds with nickel rather than gold. When the solder is subjected to interlayer metal bonding with nickel, the re-melting temperature of the solder rises to about 320 ° C. Therefore, in the subsequent semiconductor manufacturing process, there is no process of rising to a temperature of about 320 DEG C or more, so that an excessive re-melting phenomenon of the solder can be prevented and, as a result, the short circuit between the bond pad and the conductive layer or the lead frame The phenomenon can be prevented.

As described above, in the semiconductor device and the method of manufacturing a bond pad according to the present invention, the molybdenum layer and the aluminum layer constituting the bond pad are formed by sputtering and photolithography, but the outermost nickel layer is plated Process, the nickel layer also covers the side surfaces of the molybdenum layer and the aluminum layer. That is, the interface between the molybdenum layer and the active region is covered with the nickel layer and is not exposed to the outside. Therefore, it is possible to prevent impurities from penetrating through the interface between the molybdenum layer and the active region, thereby suppressing metal peeling and leakage current phenomena.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the present invention.

3 is a cross-sectional view showing a semiconductor device according to the present invention.

3, a semiconductor device 100 according to the present invention includes a semiconductor die 110, an insulating layer 120, and a bond pad 130, The nickel layer 133 is formed so as to cover the side surfaces of the molybdenum layer 131 and the aluminum layer 132 in order that the nickel layer 133, the aluminum layer 132, and the nickel layer 133 are sequentially laminated. . In addition, solder 140 may be formed on the bond pad 130, and a conductive layer 150 may be formed on the bottom surface of the semiconductor die 110. Furthermore, the conductive layer 150 may be electrically connected to the lead frame 160.

The semiconductor die 110 includes a conventional semiconductor substrate 111 and an active region 112 formed on the surface thereof (for example, an epi layer 112a and a doped region 112b).

The insulating layer 120 covers the peripheral edge of the semiconductor die 110 so that the active area 112 is exposed to the outside. The insulating layer 120 may be any one selected from the oxide film, the nitride film and the equivalent film, but the material thereof is not limited thereto.

The bond pad 130 is formed in the active region 112 exposed through the insulating layer 120. That is, the bond pad 130 is formed by sequentially laminating a molybdenum layer 131, an aluminum layer 132, and a nickel layer 133. Here, the molybdenum layer 131 and the aluminum layer 132 are formed by sputtering and photolithography, and the nickel layer 133 is formed by a plating process. For example, the nickel layer 133 is formed by an electroless plating process. Therefore, the nickel layer 133 covers both sides of the molybdenum layer 131 and the aluminum layer 132. Of course, the interface between the molybdenum layer 131 and the active region 112 is also completely covered with the nickel layer 133. With this structure, impurity penetration through the interface between the molybdenum layer 131 and the active region 112 can be prevented originally, and the metal filling phenomenon and the leakage current can be suppressed.

Here, the molybdenum layer 131 has a thickness of about 0.5 mu m as in the prior art, and the aluminum layer 132 has a thickness of about 4 mu m as in the conventional case. However, the nickel layer 133 is formed by plating with a thickness of approximately 1 to 3 탆, unlike the conventional (approximately 0.3 탆). When the thickness of the nickel layer 133 is 1 탆 or less, the solder 140 can form an interface directly with the aluminum layer 132 due to the interlayer metal bond thickness formed by the solder 140. The solder 140 and the aluminum layer 132 have poor bonding characteristics to each other, so that the solder 140 may easily peel off from the aluminum layer 132. When the thickness of the nickel layer 133 is not less than 3 탆, the thickness of the interlayer metal bond formed by the solder 140 is not more than the thickness of the interlayer metal bond, and thus the electroless plating process takes too long.

The solder 140 is welded to the bond pad 130. That is, the solder 140 is welded to the nickel layer 133. Thus, an interlayer metal bond is formed between the solder 140 and the nickel layer 133. When the solder 140 and the nickel layer 133 are subjected to the interlayer metal bonding, the re-melting temperature of the solder 140 increases to about 300 to 320 ° C. or more. In other words, the interlayer metal bonding region of the solder 140 and the nickel layer 133 is remelted when a temperature of about 320 DEG C or higher is provided. Therefore, in the subsequent semiconductor manufacturing process, there is no process of providing a temperature of about 320 DEG C or more, so that an excessive remelting phenomenon of the solder 140 is prevented, and the bond pad 130 and the conductive layer 150 or the lead frame 160 is prevented.

The conductive layer 150 is formed on the lower surface of the semiconductor substrate 111 of the semiconductor die 110. The conductive layer 150 may be formed of a vanadium layer, a nickel layer, and a gold layer, or may be formed of a nickel layer alone. Here, since the outermost layer of the bond pad 130 is formed of the nickel layer 133, if the nickel layer alone is formed also as the conductive layer 150, the number of processes can be significantly reduced. Of course, the thickness of the nickel layer alone formed as the conductive layer 150 also has a thickness of 1 to 3 占 퐉.

The lead frame 160 is located on the lower surface of the semiconductor die 110 and is electrically connected to the semiconductor die 110 through the conductive layer 150. The lead frame 160 is typically made of copper, a copper-nickel alloy, and the like. The lead frame 160 stably supports the semiconductor die 110 to be positioned on the external circuit board and electrically connects the semiconductor die 110 and the external circuit board.

FIG. 4A is a photograph of a bond pad taken in a semiconductor device according to the present invention, and FIG. 4B is a photograph of a solder remelted in a bond pad. FIG.

As shown in FIG. 4A, the bond pad 130 is covered with the nickel layer 133 at its outermost portion. That is, conventionally, a molybdenum layer and an aluminum layer are formed by a sputtering and a photolithography process, and a nickel layer and a gold layer are formed by a deposition and a photolithography process, whereby the side surfaces of the molybdenum layer and the aluminum layer are exposed to the outside. However, in the present invention, since the nickel layer 133 is formed by the plating process, the nickel layer 133 covers both sides of the molybdenum layer and the aluminum layer. In this manner, the interface between the molybdenum layer and the active region is covered with the nickel layer 133, thereby preventing the impurities from penetrating into the interface and the metal peeling phenomenon.

In addition, as shown in FIG. 4B, the remelting diameter of the solder 140 formed on the bond pad 130 is considerably smaller than that of the prior art. That is, conventionally, the solder 140 and the gold layer have an interlaminar metal bond, and the melting point is about 235 DEG C, and thus the melting diameter of the solder material is 1389 to 1600 mu m. However, in the present invention, the solder 140 and the nickel layer 133 are formed by interlaminar metal bonding to have a melting point of 320 ° C, and thus the melting diameter of the solder material is 432 to 584 μm. Accordingly, the solder 140 is prevented from flowing to the lower side along the side surface of the semiconductor die 110 by re-melting to cause the conductive layer 150 and the lead frame 160 to be short-circuited.

5A and 5B are a plan and X-ray photographs of a semiconductor device according to the present invention in a packaged state.

As shown, the semiconductor package 1 includes a die paddle 3 having a first lead 2, a semiconductor die 110 electrically connected to the die paddle 3 by a conductive layer 150, A solder 140 positioned on a bond pad 130 provided on an upper surface of the semiconductor die 110, a conductive connection member 4 connected to the solder 140, 2 leads 5 and an encapsulating material 6 surrounding the die paddle 3, the semiconductor die 110, the solder 140 and the connecting member 4. The solder 140 serves to interconnect the bond pads 130 of the semiconductor die 110 and the connection member 4. The solder 140 is used for connecting the connection member 4, Or is not excessively remelted in the mounting process of the semiconductor package. Particularly, since the solder 140 is not over-melted in the connecting process of the connecting member 4, the solder 140 flows downward along the side surface of the semiconductor die 110 as in the prior art, So that it is possible to prevent the occurrence of the phenomenon. Here, the first lead 2, the die paddle 3, the second lead 5, and the like are generally referred to as a lead frame.

6 is a flowchart showing a method of manufacturing a bond pad according to the present invention.

6, a method of manufacturing a bond pad according to the present invention includes forming an aluminum layer (S1), a first zincate treatment step (S2), a zinc particle stripping step (S3) A zincate treatment step S4, and a nickel layer formation step S5.

First, in the aluminum layer forming step S1, an aluminum layer 132 having a predetermined thickness is formed on the molybdenum layer (not shown) formed in advance in the active region of the semiconductor die using a normal sputtering and a photo process . At this time, fine protrusions 132a are formed naturally on the surface of the aluminum layer 132. That is, the fine protrusions 132a are not formed by any special process, but are spontaneously formed during the sputtering of aluminum and the photolithography process.

Subsequently, in the first zincate treatment step (S2), the aluminum layer 132 is subjected to a zincate treatment so that the zinc particles 132b adhere to the fine protrusions 132a. Here, the fine protrusions 132a are protruded upward by a predetermined length, so that the zinc particles 132b are easily attached. However, such zinc particles 132b are not adhered to the fine protrusions 132a sufficiently to form a layer.

Subsequently, in the zinc particle stripping step (S3), the zinc particles 132b are partially stripped from the aluminum layer 132. For example, a part of the zinc particles 132b formed on the fine protrusions 132a of the aluminum layer 132 is partially removed through an etching process. By this process, the zinc particles 132b become approximately flat.

Subsequently, in the second zincate treatment step (S4), the surfaces of the aluminum layer 132 and the zinc particles 132b are subjected to zincate treatment so that the zinc layer 132b is formed on the aluminum layer 132 . By such a process, the zinc layer 132b in a unit of nm is formed flat on the surface of the aluminum layer 132.

Lastly, in the nickel layer forming step S5, a nickel layer 133 is formed on the surfaces of the aluminum layer 132 and the zinc layer 132b. That is, a predetermined thickness of nickel is electrolessly plated on the surface of the zinc layer 132b to form a nickel layer 133 having a predetermined thickness.

1 is a cross-sectional view showing a conventional semiconductor device.

FIG. 2A is a photograph of a solder formed on a bond pad in a conventional semiconductor device taken on the side, FIG. 2B is a photograph of a solder being melted excessively in a bond pad, FIG. It's a picture.

3 is a cross-sectional view showing a semiconductor device according to the present invention.

FIG. 4A is a photograph of a bond pad taken in a semiconductor device according to the present invention, and FIG. 4B is a photograph of molten solder taken in a bond pad. FIG.

5A and 5B are a plan and X-ray photographs of a semiconductor device according to the present invention in a packaged state.

6 is a flowchart showing a method of manufacturing a bond pad according to the present invention.

7A to 7E are sectional views sequentially illustrating a method of manufacturing a bond pad according to the present invention.

Description of the Related Art

100; A semiconductor device according to the present invention.

110; Semiconductor die 111; Semiconductor substrate

112; Active area 112a; Epi layer

112b; Doping region 120; Insulating layer

130; Bond pads 131; Molybdenum layer

132; An aluminum layer 133; Nickel layer

140; Solder 150; Conductive layer

160; Lead frame

Claims (10)

A semiconductor die on which an active region is formed, An insulating layer covering the outer periphery of the semiconductor die so as to expose the active region; And a bond pad formed in an active region exposed through the insulating layer, Wherein the bond pad is formed so that a molybdenum layer, an aluminum layer, and a nickel layer are sequentially stacked, and the nickel layer covers the side surfaces of the molybdenum layer and the aluminum layer. The semiconductor device according to claim 1, wherein the molybdenum layer and the aluminum layer are formed by a sputtering and a photo process, and the nickel layer is formed by a plating process. The semiconductor device according to claim 1, wherein the nickel layer is plated to a thickness of 1 to 3 탆. The semiconductor device according to claim 1, wherein solder is further formed on the bond pad. The semiconductor device according to claim 3, wherein the solder is remelted at a temperature of 300 to 320 ° C. The semiconductor device according to claim 1, wherein a conductive layer is formed on a lower surface of the semiconductor substrate. The semiconductor device according to claim 6, wherein the conductive layer comprises a vanadium layer, a nickel layer, and a gold layer, or a nickel layer. The semiconductor device according to claim 6, wherein the conductive layer is formed by plating a nickel layer to a thickness of 1 to 3 탆. A method of manufacturing a bond pad for a semiconductor device, An aluminum layer forming step of forming an aluminum layer having a plurality of fine projections in an active region of a semiconductor die; A first zincate treatment step of applying a zincate treatment to the aluminum layer to adhere the zinc particles to the microprojections; A step of stripping the zinc particles partially stripping the zinc particles from the aluminum layer; A second zincate treatment step in which a zinc layer is formed on the aluminum layer by treating the surfaces of the aluminum layer and the zinc particles with a zincate treatment; And And forming a nickel layer on a surface of the aluminum layer and the zinc layer. 10. The method of claim 9, wherein the forming of the nickel layer is performed by electroless plating of nickel on the surfaces of the aluminum layer and the zinc layer.

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