TWI485790B - Fine pitch bump manufacturing method and structure thereof - Google Patents

Description

Fine pitch bump manufacturing method and structure thereof

The present invention relates to a method of manufacturing a bump, and more particularly to a method of manufacturing a fine pitch bump for preventing copper ions from being released.

In the fine pitch bump structure, since copper ions of the copper bumps are free, if the distance between adjacent copper bumps is too close, a short circuit may easily occur.

The main object of the present invention is to provide a method for manufacturing fine pitch bumps, comprising the steps of: providing a germanium substrate having a surface, a plurality of pads disposed on the surface, and a surface disposed on the surface a protective layer, the protective layer having a plurality of openings, wherein the openings expose the pads; forming a titanium-containing metal layer on the protective layer and the pads, the titanium-containing metal layer having a plurality of first And a plurality of second regions located outside the first regions; forming a photoresist layer on the titanium-containing metal layer; patterning the photoresist layer to form a plurality of trenches, the trenches should contain titanium The first regions of the metal layer; forming a plurality of copper bumps in the first regions of the titanium-containing metal layer, each of the copper bumps having a first top surface and a first ring wall; performing a heating a step of expanding the respective trenches of the photoresist layer, and the photoresist layer is formed by heat forming a plurality of body portions and a plurality of removable portions; and performing an etching step on the photoresist layer to remove the portions Removable portion and revealing the titanium-containing metal layer, and each of the sheets The rib has an inner sidewall; a plurality of bump protective layers are formed on the titanium-containing metal layer, the first top surface of each of the copper bumps, and the first annular wall, each of the bump protective layers having a bump a cover portion and a metal layer covering portion, the bump cover portion covers the first top surface of each of the copper bumps and the first ring wall, and the bump cover portion has a second top surface and a first a second ring wall having a space between the inner sidewall of the body portion and the second ring wall of the photoresist layer; plating a plurality of gold layers in each of the spaces and the second portion of each of the bump covering portions a top surface and the second annular wall and each of the gold layers has a third top surface; removing the body portions of the photoresist layer; and removing the second regions of the titanium-containing metal layer to enable Each of the first regions of the titanium-containing metal layer is formed as a under bump metal layer under each of the copper bumps, and each of the under bump metal layers has a bump carrier under each of the copper bumps. And a portion of the first ring wall protruding from each of the copper bumps, the metal layer covering portion of each of the bump protection layers covering each of the under bump metal layers The extension portion. The copper in the copper bumps can be prevented by forming the bump protection layer and the gold layers on the first metal top layer and the first top surface of the copper bumps. The ion is free to cause a short circuit, thereby improving the reliability of the fine pitch bump structure.

Referring to FIGS. 1 and 2A to 2L, which are a preferred embodiment of the present invention, a method for manufacturing a fine pitch bump includes the following steps: First, please refer to steps 11 and 2A of FIG. 1 to provide a The substrate 110 has a surface 111, a plurality of pads 112 disposed on the surface 111, and a protective layer 113 disposed on the surface 111. The protective layer 113 has a plurality of openings 113a, and the plurality of openings 113a Openings 113a expose the pads 112; then, referring to steps 12 and 2B of FIG. 1, forming a titanium-containing metal layer 200 on the protective layer 113 and the pads 112, the titanium-containing metal layer 200 Having a plurality of first zones 210 and a plurality of a second region 220 outside the first region 210; thereafter, please refer to steps 13 and 2C of FIG. 1 to form a photoresist layer 300 on the titanium-containing metal layer 200; then, refer to step 14 of FIG. 1 and 2D, the photoresist layer 300 is patterned to form a plurality of trenches 310, which are corresponding to the first regions 210 of the titanium metal layer 200; afterwards, please refer to step 15 of FIG. 1 and 2E, forming a plurality of copper bumps 120 in the first regions 210 of the titanium-containing metal layer 200, each of the copper bumps 120 having a first top surface 121 and a first ring wall 122; Referring to steps 16 and 2F of FIG. 1, a heating step is performed to enlarge each of the trenches 310 of the photoresist layer 300, and the photoresist layer 300 is formed by heat into a plurality of body portions 320 and a plurality of movable portions. In addition to the portion 330, in the present embodiment, the glass transition temperature of the heating step is between 70 and 140 °C.

Thereafter, referring to steps 17 and 2G of FIG. 1 , an etching step is performed on the photoresist layer 300 to remove the removable portions 330 and expose the titanium-containing metal layer 200, and each of the body portions The 320 series has an inner sidewall 321 . In the embodiment, the etching method used in the etching step of the photoresist layer 300 is a plasma dry etching method; then, refer to steps 18 and 2H of FIG. 1 . The plurality of bump protection layers 130 are formed on the titanium-containing metal layer 200, the first top surface 121 of each of the copper bumps 120, and the first ring wall 122. The materials of the bump protection layers 130 are selected. Each of the bump protection layers 130 has a bump covering portion 131 and a metal layer covering portion 132. The bump covering portion 131 covers the copper bumps 120. The first top surface 121 and the first annular wall 122 and the bump covering portion 131 have a second top surface 131a and a second annular wall 131b. The metal layer covering portion 132 has a first outer sidewall 132a. And the metal layer covering portion 132 protrudes from the bump covering portion 131 a second ring wall 131b, the inner side wall 321 of the main body portion 320 of the photoresist layer 300 and the second ring wall 131b have a space S; afterwards, please refer to steps 19 and 2I of FIG. A plurality of gold layers 140 are plated in each of the spaces S, the second top surface 131a and the second ring walls 131b of the bump covering portions 131, and each of the gold layers 140 has a third top surface 141 and a The second outer sidewall 142; then, referring to steps 20 and 2J of FIG. 1, a plurality of wettable layers 150 are formed on the third top surfaces 141 of the gold layers 140.

Thereafter, referring to steps 21 and 2K of FIG. 1 , the body portions 320 of the photoresist layer 300 are removed to expose the second regions 220 of the titanium-containing metal layer 200 and the gold layers 140 . The second outer sidewalls 142, the wettable layers 150, and the first outer sidewalls 132a of the metal layer covering portions 132. In this embodiment, the second outer sidewalls 142 of each of the gold layers 140. The first outer sidewalls 132a of the metal layer covering portion 132 are flush with each other; finally, referring to steps 22 and 2L of FIG. 1 , the second regions 220 of the titanium-containing metal layer 200 are removed to Each of the first regions 210 of the titanium-containing metal layer 200 is formed as a lower under bump metal layer 160 under each of the copper bumps 120. The under bump metal layer 160 is selected from titanium/tungsten. One of gold/titanium/copper or titanium/tungsten/copper, and each of the under bump metal layers 160 has a bump bearing portion 161 under each of the copper bumps 120 and a copper protruding from each of the copper bumps The extending portion 162 of the first ring wall 122 of the bump 120, the metal layer covering portion 132 of each of the bump protecting layers 130 covers the extending portion 162 of each of the under bump metal layers 160, and each of the bumps under The metal layer extending portion 162 of the system 160 having a third outer side wall 162a, 162a of the third system and the outer wall of the metal layer covering each of the first portion 132 of the outer wall 132a flush. The present invention is achieved by the titanium-containing metal layer 200 and each of the copper bumps 120. The bump protection layer 130 and the gold layer 140 are formed on the first top surface 121 and the first ring wall 122 to prevent the copper ions in the copper bumps 120 from being freed and causing a short circuit. Improve the reliability of fine pitch bump structures.

Referring to FIG. 2L, a fine pitch bump structure 100 according to a preferred embodiment of the present invention includes a germanium substrate 110, a plurality of under bump metal layers 160, a plurality of copper bumps 120, and a plurality a bump protection layer 130, a plurality of gold layers 140, and a plurality of wettable layers 150. The germanium substrate 110 has a surface 111, a plurality of pads 112 disposed on the surface 111, and a surface 112 disposed thereon. The protective layer 113 has a plurality of openings 113a, and the openings 113a expose the pads 112. The under bump metal layers 160 are formed on the pads 112, and the bumps are under the bumps The material of the metal layer 160 is selected from one of titanium/tungsten/gold, titanium/copper or titanium/tungsten/copper. Each of the under bump metal layers 160 has a bump bearing portion 161 and an extending portion 162. The copper bumps 120 are formed on the under bump metal layers 160, and each of the copper bumps 120 has a first top surface 121 and a first ring wall 122, and each of the under bump metal layers 160 The bump bearing portion 161 is located under each of the copper bumps 120, and the extending portion 162 of each of the under bump metal layers 160 protrudes from the copper The first ring wall 122 of the block 120, the bump protection layer 130 is formed on the extension portions 162 of the under bump metal layers 160, the first top surface 121 of each of the copper bumps 120, and the The first ring wall 122 has a bump covering portion 131 and a metal layer covering portion 132. The material of the bump protecting layer 130 is selected from one of nickel, palladium or gold. Each of the bump covering portions 131 covers the first top surface 121 and the first ring wall 122 of each of the copper bumps 120, and the bump covering portion 131 has a second top surface 131a and a second portion. Each of the metal layer covering portions 132 has a first outer sidewall 132a and the metal layer covering portion 132 protrudes from the bump covering portion. The second ring wall 131b of the 131 is formed on each of the metal layer covering portions 132, the second top surface 131a and the second ring wall 131b of each of the bump covering portions 131, and each of the gold layers The layer 140 has a third top surface 141 and a second outer sidewall 142. The second outer sidewall 142 is flush with the first outer sidewall 132a of each of the metal layer covering portions 132. The third layer 141 is formed on the third top surface 141 of the gold layer 140. In this embodiment, the extension portion 162 of each of the under bump metal layers 160 has a third outer sidewall 162a. The third outer sidewall 162a is flush with the first outer sidewall 132a of each of the metal layer covering portions 132.
The scope of the present invention is defined by the scope of the appended claims, and any changes and modifications made by those skilled in the art without departing from the spirit and scope of the invention are within the scope of the present invention. .

11. . . Providing a substrate

12. . . Forming a titanium-containing metal layer on the protective layer and the pads, the titanium-containing metal layer having a plurality of first regions and a plurality of second regions located outside the first regions

13. . . Forming a photoresist layer on the titanium-containing metal layer

14. . . Patterning the photoresist layer to form a plurality of trenches, the plurality of trenches being opposite to the first regions containing a titanium metal layer

15. . . Forming a plurality of copper bumps in the first regions, each of the copper bumps having a first top surface and a first ring wall

16. . . Performing a heating step to enlarge each of the grooves of the photoresist layer, and the photoresist layer is heated to form a plurality of body portions and a plurality of removable portions

17. . . Performing an etching step on the photoresist layer to remove the removable portions and reveal the titanium-containing metal layer, and each of the body portions has an inner sidewall

18. . . Forming a plurality of bump protection layers on the titanium-containing metal layer, the first top surface of each of the copper bumps, and the first ring wall

19. . . Plating multiple layers of gold

20. . . Forming a plurality of wettable layers

twenty one. . . Removing the body portions of the photoresist layer

twenty two. . . Removing the second regions of the titanium-containing metal layer such that each of the first regions of the titanium-containing metal layer is formed as a lower under bump metal layer under each of the copper bumps

100. . . Fine pitch bump structure

110. . .矽 substrate

111. . . surface

112. . . Solder pad

113. . . The protective layer

113a. . . Opening

120. . . Copper bump

121. . . First top surface

122. . . First ring wall

130. . . Bump protection layer

131. . . Bump cover

131a. . . Second top surface

131b. . . Second ring wall

132. . . Metal layer covering

132a. . . First outer side wall

140. . . Gold layer

141‧‧‧ third top surface

142‧‧‧Second outer side wall

150‧‧‧ Wettable layer

160‧‧‧ under bump metal layer

161‧‧‧Bump bearing

162‧‧‧Extension

162a‧‧‧ third outer side wall

200‧‧‧Titanium-containing metal layer

210‧‧‧First District

220‧‧‧Second District

300‧‧‧ photoresist layer

310‧‧‧ slotting

320‧‧‧ Body Department

321‧‧‧ inner side wall

330‧‧‧Removable Department

S‧‧‧ Space

Figure 1 is a flow chart showing a method of manufacturing fine pitch bumps in accordance with a preferred embodiment of the present invention.
2A to 2L are schematic cross-sectional views showing a method of manufacturing a fine pitch bump according to a preferred embodiment of the present invention.

100. . . Fine pitch bump structure

110. . .矽 substrate

112. . . Solder pad

113. . . The protective layer

120. . . Copper bump

121. . . First top surface

122. . . First ring wall

130. . . Bump protection layer

131. . . Bump cover

131a. . . Second top surface

131b. . . Second ring wall

132. . . Metal layer covering

132a. . . First outer side wall

140. . . Gold layer

141. . . Third top surface

142. . . Second outer side wall

150. . . Wettable layer

160. . . Under bump metal layer

161. . . Bump bearing

162. . . Extension

162a. . . Third outer side wall

Claims (10)

A fine pitch bump manufacturing method comprising at least the steps of: providing a germanium substrate having a surface, a plurality of pads disposed on the surface, and a protective layer disposed on the surface, the protective layer Having a plurality of openings, the openings exposing the pads; forming a titanium-containing metal layer on the protective layer and the pads, the titanium-containing metal layer having a plurality of first regions and a plurality of a second region outside the first region; forming a photoresist layer on the titanium-containing metal layer; patterning the photoresist layer to form a plurality of trenches, the plurality of trenches corresponding to the first portion of the titanium metal layer Forming a plurality of copper bumps in the first regions of the titanium-containing metal layer, each of the copper bumps having a first top surface and a first ring wall; performing a heating step to expand the photoresist Each of the layers is grooved, and the photoresist layer is formed by heat into a plurality of body portions and a plurality of removable portions; an etching step is performed on the photoresist layer to remove the removable portions and reveal The titanium-containing metal layer, and each of the body portions has an inner sidewall; The bump protection layer is disposed on the titanium-containing metal layer, the first top surface of each of the copper bumps, and the first ring wall, and each of the bump protection layers has a bump cover portion and a metal layer cover portion. The bump covering portion covers the first top surface of each of the copper bumps and the first ring wall, and the bump covering portion has a second top surface and a second ring wall, the metal layer covering portion Having a first outer sidewall and the metal layer covering portion protrudes from the second annular wall of the bump covering portion, between the inner sidewall of the body portion of the photoresist layer and the second annular wall Has a space; Electroplating a plurality of gold layers in each of the spaces, the second top surface of each of the bump covering portions, and the second ring wall, and each of the gold layers has a third top surface; removing the photoresist layer And removing the second regions of the titanium-containing metal layer such that the first regions of the titanium-containing metal layer are formed as a lower under bump metal layer under each of the copper bumps, and each The under bump metal layer has a bump bearing portion under each of the copper bumps and an extension portion of the first ring wall protruding from each of the copper bumps, and the metal of each bump protecting layer The layer covering portion covers the extension of each of the under bump metal layers. The fine pitch bump manufacturing method according to claim 1, wherein the etching method used in the etching step of the photoresist layer is a plasma dry etching method. The fine pitch bump manufacturing method of claim 1, wherein before the step of removing the body portions of the photoresist layer, a plurality of wettable layers are formed on the gold layers. The steps of the third top surface. The fine pitch bump manufacturing method of claim 1, wherein each of the gold layers further has a second outer sidewall, the first outer sidewall and the first outer sidewall of each of the metal layer covering portions Flush. The fine pitch bump manufacturing method of claim 1, wherein the extension portion of each of the under bump metal layers has a third outer sidewall, and the third outer sidewall is covered with each of the metal layer covers. The first outer sidewall is flush. The fine pitch bump manufacturing method according to claim 1, wherein the glass transition temperature of the heating step is between 70 and 140 °C. A fine pitch bump structure comprising: a germanium substrate having a surface, a plurality of pads disposed on the surface, and a protective layer disposed on the surface, the protective layer having a plurality of openings And the openings are exposed to the plurality of pads; the plurality of under bump metal layers are formed on the pads, and each of the under bump metal layers has a bump bearing portion and an extension portion; a copper bump is formed on the underlying metal layer, and each of the copper bumps has a first top surface and a first ring wall, and the bump bearing portion of each of the under bump metal layers Located under each of the copper bumps, the extension portion of each of the underlying metal layers protrudes from the first ring wall of each of the copper bumps; and a plurality of bump protection layers are formed on the bumps The protrusions of the underlying metal layer, the first top surface of each of the copper bumps, and the first ring wall, each of the bump protection layers has a bump cover portion and a metal layer cover portion, each of the The bump covering portion covers the first top surface of each of the copper bumps and the first ring wall, and the bump covering portion has a second top surface and a second ring wall, and each of the metal layer covers Having a first outer sidewall and the metal layer covering portion protrudes from the second annular wall of the bump covering portion, each of the metal layer covering portions covering each of the extending portions And a plurality of a gold layer, which is formed based on each portion of the metal layer covering the top surface of each of the second bumps and the cover portion of the second annular wall and each of the gold-based layer having a third top surface. The fine pitch bump structure of claim 7, further comprising a plurality of wettable layers formed on the third top surfaces of the gold layers. The fine pitch bump structure of claim 7, wherein each of the gold layers further has a second outer sidewall, and the second outer sidewall is flat with the first outer sidewall of each of the metal layer covering portions. Qi. The fine pitch bump structure according to claim 7, wherein the extension portion of each of the under bump metal layers has a third outer sidewall, the third The outer sidewall is flush with the first outer sidewall of each of the metal layer covering portions.