TWI446468B - Bumping process and structure thereof - Google Patents

Description

Bump process and its structure

The present invention relates to a bump process, and more particularly to a bump process that prevents copper ions from escaping.

Since the current electronic products are becoming lighter and thinner, the internal circuit layout is also more and more dense. However, such a circuit layout is liable to cause a short circuit due to the proximity of adjacent electrical connection elements.

The main object of the present invention is to provide a bump process comprising 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 And having a plurality of openings, wherein the openings expose the pads; forming a titanium-containing metal layer on the germanium substrate, the titanium-containing metal layer covering the pads, and the titanium-containing metal layer has a plurality of a first region and a plurality of second regions 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 corresponding to each other The first regions of the titanium-containing metal layer and each of the trenches have an inner sidewall; a plurality of bump bottom cladding layers are formed on the trenches, and each of the bump bottom cladding layers covers the titanium-containing layer Each of the first regions of the metal layer, each of the bump bottom cladding layers has an outer sidewall and the outer sidewalls are in contact with the inner sidewalls of each of the slots; forming a plurality of copper bumps at the bottom of the bumps Each of the copper bumps has a first top surface, a ring wall and a Surface, the bottom surface of the projection system is located on the bottom cladding layer, and each of the system in contact with the annular wall of each of the inner side wall of the slot; performing a heating step to make the Each of the slits of the photoresist layer forms a reaming hole, and a first spacing is formed between the inner sidewall of each of the slots and the outer sidewall of each of the bump bottom cladding layers, and each of the slots is formed Forming a second spacing between the inner sidewall and the ring wall of each of the copper bumps; forming a plurality of bump outer cladding layers on the first pitch, the second pitches, and each of the copper bumps a first top surface and the ring wall, such that the outer cladding layer of each of the bumps is connected to each of the bump bottom cladding layers, and each of the bump outer cladding layers has a second top surface; forming a plurality of joints Laminating the second top surfaces of the outer cladding layers of the bumps; removing the photoresist layer; and removing the second regions of the titanium-containing metal layer, and causing the titanium-containing metal layers to be The first region is formed as a sub-bump metal layer under each of the bump wrap layers. Since each of the bump encapsulation layers includes the outer cladding layer of each of the bumps and the bottom cladding layer of each of the bumps, the copper ions of the copper bumps can be prevented from being detached to cause an electrical short circuit, and Further reducing the second pitch of the adjacent copper bumps, and further, by protecting the bump wrap layers, preventing the second bumps of the titanium-containing metal layer from being removed causes the copper bumps to be recessed The situation.

Referring to FIGS. 1 and 2A to 2K, which are a preferred embodiment of the present invention, a bump process system includes the following steps: First, referring to steps 11 and 2A of FIG. 1, a substrate 110 is provided. The cymbal 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 openings 113a are The solder pads 112 are exposed; then, referring to steps 12 and 2B of FIG. 1 , a titanium-containing metal layer 200 is formed on the germanium substrate 110, and the titanium-containing metal layer 200 covers the solder pads 112, and the The titanium-containing metal layer 200 has a plurality of first regions 210 and complex a plurality of second regions 220 located outside the first regions 210; thereafter, referring to steps 13 and 2C of FIG. 1, a photoresist layer 300 is formed on the titanium-containing metal layer 200; then, refer to the first Steps 14 and 2D of the figure, patterning the photoresist layer 300 to form a plurality of trenches 310 corresponding to the first regions 210 of the titanium metal layer 200 and each of the trenches 310 An inner sidewall 311 is formed; afterwards, referring to steps 15 and 2E of FIG. 1 , a plurality of bump bottom cladding layers 131 are formed on the slots 310 , and each of the bump bottom cladding layers 131 covers the Each of the first regions 210 of the titanium-containing metal layer 200 has an outer sidewall 131a and the outer sidewall 131a is in contact with the inner sidewall 311 of each of the slots 310. For example, the material of the bump bottom cladding layer 131 is selected from one of nickel, palladium or gold, and the thickness of the bump bottom cladding layer 131 is not more than 8 um.

Then, referring to steps 16 and 2F of FIG. 1 , a plurality of copper bumps 120 are formed on the bottom cladding layers 131 of the bumps. Each of the copper bumps 120 has a first top surface 131 and a ring wall. And a bottom surface 123, the bottom surface 123 is located on the bottom cover layer 131 of the bump, and each of the ring walls 122 is in contact with the inner side wall 311 of each of the slots 310. Thereafter, refer to the steps of FIG. In the 17 and 2G diagrams, a heating step is performed to form the reaming holes of the slits 310 of the photoresist layer 300, and the inner sidewalls 311 of each of the trenches 310 and the bottom cladding layer 131 of each of the bumps A first spacing D1 is formed between the outer sidewalls 131a, and a second spacing D2 is formed between the inner sidewalls 311 of the slots 310 and the annular walls 122 of the copper bumps 120. The glass transition temperature of the heating process is between 70 and 140 ° C. Next, referring to steps 18 and 2H of FIG. 1 , a plurality of bump outer cladding layers 132 are formed at the first pitches D1. The second spacing D2, the first top surface 121 of the copper bumps 120 and the ring wall 122, so that each of the bump outer cladding layers 132 is connected to each of the bump bottom cladding layers 131, so that the bumps are externally The cladding layer 132 and each of the bump bottom cladding layers 131 form a bump encapsulation layer 130 covering each of the copper bumps 120, and each of the bump encapsulation layers 130 completely covers the copper bumps 120, and Each of the bump outer cladding layers 132 has a second top surface 132a. The material of the bump outer cladding layers 132 is selected from one of nickel, palladium or gold. The thickness of 132 is not more than 2 um; after that, referring to steps 19 and 2I of FIG. 1 , a plurality of bonding layers 140 are formed on the second top surfaces 132 a of the outer cladding layers 132 of the bumps. In the example, the material of the bonding layers 140 is gold.

Next, referring to steps 20 and 2J of FIG. 1 , the photoresist layer 300 is removed to expose the bump outer cladding layer 132 and the bonding layers 140; finally, refer to step 21 of FIG. 1 . And the 2K pattern, the second regions 220 of the titanium-containing metal layer 200 are removed, and each of the first regions 210 of the titanium-containing metal layer 200 is formed as a bump under each of the bump wrap layers 130. Lower metal layer 150 to form a bump structure 100, the material of the under bump metal layer 150 is selected from titanium / tungsten / gold, titanium / copper, titanium / tungsten / copper or titanium / nickel (vanadium) / copper one of them.

Referring to FIG. 2K, a bump structure 100 according to a preferred embodiment of the present invention includes at least one germanium substrate 110, a plurality of under bump metal layers 150, a plurality of copper bumps 120, and a plurality of a bump encapsulation layer 130 and a plurality of bonding layers 140. The germanium 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 is provided. Having a plurality of openings 113a, and the openings 113a reveal the pads 112, the bumps The lower metal layer 150 is formed on the solder pads 112. The material of the under bump metal layers 150 is selected from titanium/tungsten/gold, titanium/copper, titanium/tungsten/copper or titanium/nickel (vanadium)/ One of the copper bumps 120 is formed on the under bump metal layer 150. Each of the copper bumps 120 has a first top surface 121, a ring wall 122 and a bottom surface 123. Each of the bump layers 130 includes a bump bottom cladding layer 131 and a bump outer cladding layer connecting the bump bottom cladding layer 131. Each of the bump outer cladding layers 132 is formed on the first top surface 121 and the ring wall 122 of each of the copper bumps 120, and each of the bump outer cladding layers 132 has a second top surface. 132a, each of the bump bottom cladding layers 131 is formed on each of the under bump metal layers 150, and the bottom surface 123 of each of the copper bumps 120 is located in each of the bump bottom cladding layers 131, in this embodiment. The material of the bump bottom cladding layer 131 and the bump outer cladding layer 132 is selected from one of nickel, palladium or gold, and the thickness of the bump bottom cladding layer 131 is not greater than 8um The thickness of the outer cladding layer 132 is not more than 2 um, and the bonding layers 140 are formed on the second top surfaces 132a of the outer cladding layers 132 of the bumps. In this embodiment, The material of the bonding layer 140 is gold. Since each of the bump wrap layers 130 includes the bump outer cladding layer 132 and each of the bump bottom cladding layers 131, the copper ions of the copper bumps 120 can be prevented from being freed to cause an electrical short circuit. In this case, the distance between the adjacent copper bumps 120 can be further reduced. Moreover, by the protection of the bump wrap layers 130, the removal of the second regions 220 of the titanium-containing metal layer 200 can also prevent the These copper bumps 120 create a recess.

The scope of the present invention is defined by the scope of the appended claims, and anyone skilled in the art, without departing from the spirit of the invention Any changes and modifications made within the scope of the invention are within the scope of the invention.

11‧‧‧ Providing a substrate having a surface, a plurality of pads and a protective layer

12‧‧‧ forming a titanium-containing metal layer on the germanium substrate, the titanium-containing metal layer having a plurality of first regions and a plurality of second regions

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

14‧‧‧ patterning the photoresist layer to form a plurality of slots, and each of the slots has an inner sidewall

15‧‧‧ forming a plurality of bump bottom cladding layers on the slots, each of the bump bottom cladding layers having an outer sidewall

16‧‧‧ forming a plurality of copper bumps on the bottom of each of the bumps, each of the copper bumps having a first top surface, a ring wall and a bottom surface, and each of the ring walls and each of the slots The inner side wall contact

17‧‧‧ a heating step is performed to form a reaming of each of the slits of the photoresist layer, and a gap is formed between the inner sidewall of each of the trenches and the outer sidewall of each of the bump bottom cladding layers a first spacing, and a second spacing formed between the inner sidewall of each of the slots and the annular wall of each of the copper bumps

18‧‧‧ forming a plurality of bump outer cladding layers at the first pitches, the first a second pitch, the first top surface of each of the copper bumps, and the ring wall, such that the outer cladding layer of each of the bumps is connected to the bump bottom cladding layer, and each of the bump outer cladding layers has a second top surface

19‧‧‧ forming a plurality of bonding layers on the second top surfaces of the outer cladding layers of the bumps

20‧‧‧Remove the photoresist layer

21‧‧‧ removing the second regions of the titanium-containing metal layer, and forming each of the first regions of the titanium-containing metal layer into an under bump metal layer

100‧‧‧bump structure

110‧‧‧矽 substrate

111‧‧‧ surface

112‧‧‧ solder pads

113‧‧‧Protective layer

113a‧‧‧ openings

120‧‧‧ copper bumps

121‧‧‧First top surface

122‧‧‧Circle

123‧‧‧ bottom

130‧‧‧Bump wrap

131‧‧‧Bump bottom cladding

131a‧‧‧Outer side wall

132‧‧‧Bump outer cladding

132a‧‧‧second top surface

140‧‧‧Connection layer

150‧‧‧ under bump metal layer

200‧‧‧Titanium-containing metal layer

210‧‧‧First District

220‧‧‧Second District

300‧‧‧ photoresist layer

310‧‧‧ slotting

311‧‧‧ inner side wall

D1‧‧‧first spacing

D2‧‧‧second spacing

Figure 1 is a flow chart showing a bump process in accordance with a preferred embodiment of the present invention.

2A-2K: A schematic cross-sectional view of a bump process in accordance with a preferred embodiment of the present invention.

100‧‧‧bump structure

110‧‧‧矽 substrate

111‧‧‧ surface

112‧‧‧ solder pads

113‧‧‧Protective layer

113a‧‧‧ openings

120‧‧‧ copper bumps

121‧‧‧First top surface

122‧‧‧Circle

123‧‧‧ bottom

130‧‧‧Bump wrap

131‧‧‧Bump bottom cladding

132‧‧‧Bump outer cladding

132a‧‧‧second top surface

140‧‧‧Connection layer

150‧‧‧ under bump metal layer

Claims (11)

A bump process comprising: providing a 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 solder pads; forming a titanium-containing metal layer on the germanium substrate, the titanium-containing metal layer covering the solder pads, and the titanium-containing metal layer has a plurality of first regions and a plurality of a second region outside the first regions; forming a photoresist layer on the titanium-containing metal layer; patterning the photoresist layer to form a plurality of trenches, wherein the trenches are opposite to the titanium metal layer Each of the first regions and each of the slots has an inner sidewall; a plurality of bump bottom cladding layers are formed on the slots, and each of the bump bottom cladding layers covers the titanium-containing metal layer In one region, each of the bump bottom cladding layers has an outer sidewall; a plurality of copper bumps are formed on each of the bump bottom cladding layers, each of the copper bumps having a first top surface and a ring wall a bottom surface, the bottom surface is located on the bottom cladding layer of the bump; performing a heating step, Forming a reaming in each of the slits of the photoresist layer, and forming a first spacing between the inner sidewall of each of the trenches and the outer sidewall of each of the bump bottom cladding layers, and Forming a second spacing between the inner sidewall of the trench and the ring wall of each of the copper bumps; forming a plurality of bump outer cladding layers on the first pitch, the second pitches, and each of the copper bumps The first top surface and the ring wall are such that the outer cladding layers of the bumps are connected to the bottom cladding layers of the bumps, and the outer cladding layers of the bumps and the bottom cladding layers of the bumps Forming a bump covering each of the copper bumps a plurality of the copper bumps, wherein each of the bump outer layers has a second top surface; and a plurality of bonding layers are formed on the outer cladding of the bumps The second top surface; removing the photoresist layer; and removing the second regions of the titanium-containing metal layer, and forming each of the first regions of the titanium-containing metal layer to be located at each of the convex regions The underlying metal layer of the bump under the block wrap. The bump process of claim 1, wherein the glass transition temperature of the heating process is between 70 and 140 °C. The bump process of claim 1, wherein the material of the bonding layer is gold. The bump process of claim 1, wherein the material of the under bump metal layer is selected from the group consisting of titanium/tungsten/gold, titanium/copper, titanium/tungsten/copper or titanium/nickel (vanadium). / Copper one of them. The bump process of claim 1, wherein the bump bottom cladding layer and the material of the bump outer cladding layer are selected from one of nickel, palladium or gold. The bump process of claim 1, wherein in the step of forming a plurality of bump bottom cladding layers in the slots, the outer sidewalls of each of the bump bottom cladding layers are in contact with each other The inner side wall of the slot. The bump process of claim 1, wherein in the step of forming a plurality of copper bumps on each of the bump bottom cladding layers, the ring walls of each of the copper bumps are in contact with each other. The inner side wall of the groove. A bump structure comprising at least: a substrate having a surface and a plurality of pads disposed on the surface And a protective layer disposed on the surface, the protective layer has a plurality of openings, and the openings expose the pads; a plurality of under bump metal layers are formed on the pads; the plurality of copper a bump formed on the underlying metal layer, each of the copper bumps having a first top surface, a ring wall and a bottom surface; and a plurality of bump wrap layers completely covering the copper a bump, each of the bump wrap layers includes a bump bottom cladding layer and a bump outer cladding layer connecting the bump bottom cladding layer, each of the bump bottom cladding layers being formed on each of the bumps The underlying metal layer, each of the outer cladding layers of the bump is formed on the first top surface of each of the copper bumps and the ring wall, and the bottom surface of each of the copper bumps is located at the bottom of each of the bumps Each of the bump outer cladding layers has a second top surface; and a plurality of bonding layers are formed on the second top surfaces of the outer cladding layers of the bumps. The bump structure of claim 8, wherein the material of the joint layer is gold. The bump structure of claim 8, wherein the material of the under bump metal layer is selected from the group consisting of titanium/tungsten/gold, titanium/copper, titanium/tungsten/copper or titanium/nickel (vanadium). / Copper one of them. The bump structure of claim 8 , wherein the bump bottom cladding layer and the bump outer cladding layer are selected from one of nickel, palladium or gold.