KR100651626B1 - The manufacturing method of bump of semiconductor device - Google Patents

Abstract

A method for fabricating a bump of a semiconductor device is provided to prevent a seed metal layer from being corroded by a developing solution so that the sheer strength of a bump is prevented from being decreased, by forming a diffusion blocking layer and a seed metal layer after an exposure and development process is performed. A metal pad is formed in at least a predetermined region on a substrate(S302). A passivation layer is formed on the substrate, exposing at least a partial region of the metal pad(S303). A photoresist layer is formed on the metal pad and the passivation layer(S304). A diffusion blocking layer is formed on the metal pad and the photoresist layer(S306). A seed metal layer is formed on the diffusion blocking layer(S307). A bump is formed on the seed metal layer(S308). The photoresist layer formed under the seed metal layer is eliminated(S310). The diffusion blocking layer remaining on the sidewall of the bump is removed(S311).

Description

The manufacturing method of bump device of semiconductor device

1 is a block diagram schematically showing a bump manufacturing process of a semiconductor device according to the prior art.

2A to 2I are side cross-sectional views illustrating a manufacturing process according to FIG. 1.

3 is a block diagram schematically showing a bump manufacturing process of a semiconductor device according to the present invention.

4A to 4I are side cross-sectional views illustrating a manufacturing process according to FIG. 3.

* Reference numbers for major components *

400: substrate 410: metal pad

420: passivation layer 430: photoresist layer

440: diffusion barrier layer 450: seed metal layer

460 bump

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bump manufacturing method of a semiconductor device having bumps, and more particularly, to a bump manufacturing method of a semiconductor device having bumps with enhanced shear strength.

Recently, miniaturization and high integration of the chip itself has been progressed in the semiconductor chip manufacturing field, and a new thin and simple package and its mounting method have been developed in the package field. In response to these demands, packages using flip-chip technology have emerged. In particular, tape auto-connecting for TFT-LCD driver ICs, CMOS image sensors (CIS), PDP driver ICs, etc. Bump processes, particularly gold bump manufacturing, are used for TAP (tape automated bonding) technology. Electroplating is widely used as a method for producing gold bumps.

Hereinafter, a manufacturing process of a semiconductor device according to the prior art will be described in detail with reference to the accompanying drawings.

1 is a block diagram schematically illustrating a bump fabrication process of a semiconductor device according to the related art, and FIGS. 2A to 2I are side cross-sectional views illustrating a fabrication process according to FIG. 1. In order to manufacture a bump of a semiconductor device (not shown), referring to FIGS. 1 and 2A, first, a substrate 200 is prepared (S101). The substrate 200 generally uses a silicon wafer substrate (Si substrate) on which semiconductor devices (eg, thin film transistors, capacitors, etc.) are formed. A metal pad 210 is formed on the substrate 200 (S102), and the metal pad 210 is at least partially covered with a predetermined region of both ends of the metal pad 210 on the substrate 200 on which the metal pad 210 is formed. The passivation layer 220 to be exposed is formed (S103). The passivation layer 220 is formed to protect the substrate 200 on which the semiconductor device is formed.

Next, referring to FIGS. 1 and 2B, a barrier layer 230 is formed on the metal pad 210 and the passivation layer 220 (S104). The diffusion barrier layer 230 is formed to prevent the metal bumps to be described later from being diffused to the semiconductor device side on the substrate 200 and uses a compound including titanium and titanium (eg, a titanium tungsten (TiW) thin film). Can be formed.

1 and 2C to 2G, a seed metal layer 240 is formed on the diffusion barrier layer 230 (S105). The seed metal layer 240 is formed on the diffusion barrier layer 230 for electroplating and is formed using the same metal as the bump. The photoresist layer 250 is formed on the seed metal layer 240 (S106). After the photoresist layer 250 is formed, only the photoresist layer 250 formed on the upper region of the metal pad 210 of the photoresist layer 250 is removed (S107). After the photoresist layer 250 is removed, bumps 260 are formed on the seed metal layer 240 between the remaining photoresist layers 250 (S108). The bump 260 is formed by electroplating using gold. After the bumps 260 are formed, all remaining photoresist layers 250 formed on the seed metal layer 240 are removed (S109).

After the photoresist layer 250 is removed, referring to FIGS. 1, 2H and 2I, the exposed seed metal layer 240 is removed by removing the photoresist layer 250 (S110). In this case, the seed metal layer 240 formed of the same metal as the bump 260 may be wet etching, for example, using aqua regia, which is a solution in which distilled water (DI water), hydrochloric acid, and nitric acid are mixed at a ratio of 4: 3: 1. Remove In the next step, the diffusion barrier layer 230 exposed by the removal of the seed metal layer 240 is removed (S111). At this time, the diffusion barrier layer 230 formed of TiW is removed with a hydrogen peroxide solution. By sequentially proceeding with this process, bumps (ie, gold bumps) formed by electroplating gold remain.

However, at the time of manufacturing the gold bumps described above, when the exposure and development processes are performed in a process of removing the photoresist layer 260 formed on the metal pad 210, the seed metal layer formed of a gold (Au) thin film ( The corrosion of the 240 has a problem that the shear strength of the gold bump 260 formed on the corroded seed metal layer 240 is weakened.

In addition, when the seed metal layer 240 is removed, residues of the seed metal remain on the surface of the substrate 200 by the etching solution (for example, aqua regia) used, and when bump and bump manufacturing is completed, There is a problem that an electrical short may be caused between.

Therefore, the invention designed to solve the above-mentioned problems, the object of the present invention is to suppress the corrosion of the seed metal layer to enhance the shear strength of the bumps, and by removing the seed residues generated by the removal of the seed metal layer bumps enhanced characteristics It is to provide a bump manufacturing method of a semiconductor device having a.

According to an aspect of the present invention for achieving the above object, the bump manufacturing method of the present semiconductor device comprises the steps of forming a metal pad in at least one region on the substrate; Exposing at least one region of the metal pad and forming a passivation layer on the substrate; Forming a photoresist layer on the metal pad and the passivation layer; Removing the photoresist layer formed on the metal pad; Forming a diffusion barrier layer on the metal pad and the photoresist layer; Forming a seed metal layer on the diffusion barrier layer; Forming bumps on the seed metal layer; And removing the photoresist layer formed under the seed metal layer.

Preferably, the bump manufacturing method of the semiconductor device, before the step of removing the photoresist layer, the diffusion barrier layer and the seed metal layer of the diffusion barrier layer and the seed metal layer is not interposed between the photoresist layer and the bump. It further comprises the step of removing. The bump manufacturing method of the semiconductor device may further include removing the photoresist layer and then removing the diffusion barrier layer remaining on the sidewall of the bump.

In the removing of the diffusion barrier layer and the seed metal layer, wet etching is used, and in the removing of the photoresist layer, all of the diffusion barrier layer, the seed metal layer, and the bump formed on the photoresist layer are removed. In the step of removing the photoresist layer, a lift-off process is used. In the forming of the bump and the seed metal layer, the bump and the seed metal layer are formed of the same metal. The bump is formed of gold (Au).

Hereinafter, a silicon semiconductor device and a manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic block diagram illustrating a process of manufacturing a bump of a semiconductor device according to an embodiment of the present invention, and FIGS. 4A to 4C are views illustrating a process of manufacturing a bump of a semiconductor device according to an embodiment of the present invention. It is a cross section.

3 and 4A, in order to manufacture bumps of a semiconductor device, first, a substrate 400 is prepared (S301). The substrate 400 generally uses a Si wafer on which semiconductor devices (eg, thin film transistors, capacitors, etc.) are formed. A metal pad 410 is formed on the substrate 400 (S302), and a passivation layer 420 is formed on the substrate 400 to expose the metal pad 410 while covering a predetermined region of both ends of the metal pad 410. (S303). The passivation layer 420 is formed to protect the substrate 400 on which the semiconductor device is formed. The passivation layer 420 in this embodiment covers both ends of the metal pad 410 in a predetermined region. It may be formed in contact with both ends of the (410).

3 and 4B, the photoresist layer 430 is formed on the passivation layer 420 and the metal pad 410 at a predetermined height (S304). Referring to FIG. 4C, in the next step, the photoresist layer 430 formed on the metal pad 410 in contact with the metal pad 410 of the photoresist layer 430 is removed (S305). When removing the photoresist layer 430, photolithography, which is a process of selectively removing a layer formed on the substrate 400, is used. Photolithography is a pattern on the mask is transferred to the photosensitive material applied on the substrate, generally divided into photo-exposure technology, radiation exposure technology. By using photolithography, portions which should not be removed from the etching process are protected.

3 and 4D to 4F, the diffusion barrier layer 440 is formed on the photoresist layer 430 and the metal pad 410 patterned through photolithography (S306). The diffusion barrier layer 440 is to prevent the metal bumps to be formed on the region where the remaining photoresist layer 430 and the photoresist layer 430 are removed to the semiconductor device side. The diffusion barrier layer 440 may be formed using titanium and a titanium alloy. In this embodiment, the diffusion barrier layer 440 is formed using titanium tungsten (TiW).

Next, the seed metal layer 450 is formed on the diffusion barrier layer 440 (S307, see FIG. 4E). The seed metal layer 450 is formed to easily electroplate the bump to be described later. The seed metal layer 450 may be formed using the same metal as the bump, and in this embodiment, gold (Au) is used. The seed metal layer 450 formed of gold is formed on the upper and sidewalls of the photoresist layer 430 and the metal pad 410 since the seed metal layer 450 serves as a conductor for reducing precipitation of metal ions when electroplating is performed during bump formation. do. The seed metal layer 450 is formed at room temperature so that deformation of the photoresist layer 430 does not occur during deposition, and is formed using sputtering, which is a deposition process having a high coverage. Referring to FIG. 4F, a bump 460 is formed on the seed metal layer 450 (S308). The bump 460 is formed by electroplating using gold.

Referring to FIG. 4G, portions of the diffusion barrier layer 440 and the seed metal layer 450 that are not formed between the photoresist layer 430 and the bump 460 are removed (S309). The reason for removing the A region is to easily remove the bump 460 and the photoresist layer 430 other than the bump 460 formed on the metal pad 410. The seed metal layer 450 formed of gold, which is the same metal as the bump 460, is removed with aqua regia, which is a solution of distilled water (DI water), hydrochloric acid, and nitric acid in a ratio of 4: 3: 1, and is formed of a TiW diffusion barrier layer ( 430 is removed with hydrogen peroxide solution. Referring to FIG. 4H, the photoresist layer 430 is removed (S310). The photoresist layer 430 is removed by a lift-off process, and the photoresist layer 430 is removed by a solvent capable of dissolving a solidified photoresist layer, such as acetone, in the lift-off process. . When the photoresist layer 430 is removed using acetone, the acetone penetrates into the A region in which the seed metal layer 450 and the diffusion barrier layer 440 have been previously removed, thereby making it easier to remove the photoresist layer 430. have. After the photoresist layer 430 is removed, a bump 460 formed of gold is formed on the metal pad 410. Since the seed metal layer 450 surrounding the bump 460 is the same metal, the bump 460 is formed. Equal to), and it is represented by a virtual line.

Next, referring to FIG. 4I, the diffusion barrier layer 440 remaining on the side of the bump 460 is removed (S311). The diffusion barrier layer 440 is removed by a wet etching process using a hydrogen peroxide solution or the like. Since the seed metal layer 450 and the bump 460 are the same metal, the seed metal layer 450 is regarded as the same as the bump 460, and a separate reference numeral is not disclosed in FIG. 4I.

In the case of manufacturing the bumps of the semiconductor device through the above-described bump manufacturing process, the diffusion barrier layer 440 and the seed metal layer 450 are formed by performing the exposure process and the development process of removing the photoresist layer 430. The corrosion of the seed metal layer 450 can be prevented by the developing solution used in the developing step. In addition, since the seed metal layer 450 is formed on the photoresist layer 430 rather than on the passivation layer 420, the photoresist layer 430 is lifted off, so that the bump 460 and the bump 460 are separated from each other. The generation of residues from the seed metal layer 450 can be suppressed.

Although the present invention has been described with reference to the embodiments illustrated in the accompanying drawings, it is merely an example, and those skilled in the art may understand that various modifications and equivalent other embodiments are possible. There will be.

According to the above description, the present invention prevents corrosion of the seed metal layer by the developing solution and prevents the shear strength of the bump from being weakened by forming the diffusion barrier layer and the seed metal layer after the exposure and development processes. By forming the seed metal layer on the semiconductor device having a bump that can prevent the generation of the seed metal residue due to the etching of the seed metal layer can be manufactured.

Claims (8)

In the bump manufacturing method of a semiconductor element, Forming a metal pad in at least one region on the substrate; Exposing at least one region of the metal pad and forming a passivation layer on the substrate; Forming a photoresist layer on the metal pad and the passivation layer; Removing the photoresist layer formed on the metal pad; Forming a diffusion barrier layer on the metal pad and the photoresist layer; Forming a seed metal layer on the diffusion barrier layer; Forming bumps on the seed metal layer; Removing the photoresist layer formed under the seed metal layer Bump manufacturing method of a semiconductor device comprising a. The method of claim 1, wherein before performing the step of removing the photoresist layer, And removing the diffusion barrier layer and the seed metal layer not interposed between the photoresist layer and the bump in the diffusion barrier layer and the seed metal layer. The method according to claim 1 or 2, Removing the photoresist layer, and then removing the diffusion barrier layer remaining on the sidewalls of the bumps. The method of claim 3, Removing the diffusion barrier layer and the seed metal layer by using wet etching. The method according to claim 1 or 2, And removing the photoresist layer to remove all of the diffusion barrier layer, the seed metal layer, and the bumps formed on the photoresist layer. The method of claim 5, And removing the photoresist layer using a lift-off process. The method of claim 1, In the forming of the bump and the seed metal layer, the bump and the seed metal layer may be formed of the same metal. The method of claim 7, wherein The bump is a bump manufacturing method of a semiconductor device is formed of a metal (Au).

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