TWI300616B - Flip chip structure - Google Patents

Description

1300616 Meaning 1^117871 V. Description of invention (1) Yearly revision '[Technical field to which the invention belongs], Monthly on a flip-chip structure' and especially related to a ball that can be avoided after reflow of fresh bumps The (wafer) protective layer underneath the bottom metal layer is destroyed. a), [previous technology], in today's information society, the multimedia application market continues to expand rapidly. 'Integrated circuit packaging technology has also been digitalized, smashed, and connected to electronic devices. Use human trends to develop. In order to achieve the above requirements, electronic components must meet the requirements of high-speed processing, multi-function, integration, small size, light weight, and low cost. Therefore, the integrated circuit sealing technology is also becoming more miniaturized and high. Density development. Among them, Bal 1 Gr id Array (BGA), chip size M Chip-Scale Package (CSP), Flip C^iip (F/C), multi-chip module (Multi A M〇dule,) and other southern density integrated circuit packaging technology also came into being. Flip Chip Packaging Technology mainly uses an array of area arrays to arrange a plurality of bonding pads on the active surface of the die. A bump is formed on each of the pads, and after the wafer is flipped, the bumps on the wafer pads are electrically used (616 (^^^^^^ and mechanical (1116(:^11) [(^117) is connected to a substrate (substrate) or a mounting pad corresponding to the surface of a printed circuit board (PCB). Furthermore, since the flip chip bonding technique can be applied to the high pin count (High Pin Count) ) chip package structure, and at the same time and right

1300616 Amendment Case No. 92117871 V. Invention Description (2) Small package area and shortened signal transmission path, etc., so flip chip bonding technology has been widely used in the field of chip packaging. • The so-called wafer bump process is common in flip chip technology (fHp ch 1 p), which is mainly used to form balls on external contacts (usually metal pads) on wafers with multiple wafers. Bottom metal layer (UBM, Unde;r

Metallurgy), then forming a bump or implanting a solder ball on the bottom metal layer to serve as a connection interface for subsequent wafer-substrate electrical conduction. As mentioned above, please refer to FIG. 1 , which is a conventional flip chip structure 1 〇 〇. The flip chip structure 1 〇 has an active surface 丨〇 1, a protective layer 102, a benzocyclobutene layer (Benzocycl 〇 ene, BCB) 〇 3 and a plurality of wafer pads 104. The protective layer 102 and the wafer pads 1〇4 are formed on the active surface 101, and the protective layer 1〇2 exposes the wafer pads 1〇4. Further, a benzocyclobutene layer 1 〇 3 is formed on the wafer protective layer 丨〇 2, and the wafer pad 104 is exposed. Further, a ball-bottom metal layer 1〇6 is formed on the wafer pad 1〇4 and the benzocyclobutene layer 1〇3, and a solder bump 108 is formed on the ball-bottom metal layer 1〇6. The ball metal layer 106 is disposed between the pad pads 1〇4 and the solder bumps 108 to serve as a bonding interface between the pad pads 1〇4 and the solder bumps 1〇8. Referring to FIG. 1 again, the conventional ball bottom metal layer 〇6 mainly includes an adhesion layer 〇6a, a barrier layer 106b, and a wettable layer 106c. The adhesive layer 16a is used to increase the bonding strength between the wafer pad 104 and the barrier layer 16b, and is made of a metal such as sinter or titanium. The barrier layer 1 Q β b is used to prevent diffusion of metal on the upper and lower sides of the barrier layer 1 Q β b , and the commonly used materials are, for example, nickel-star alloy, nickel-copper alloy, and nickel. . In addition, the wetting layer

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Page 7 1300616 - Case No. 921 871 Description of Invention (3) 106c is used to increase the adhesion of the ball-bottom metal layer 106 to the solder bumps 108. Common materials include metals such as copper. It is worth noting that due to the better soldering characteristics of tin-tin alloys, the material of solder bumps 8 is often tin-alloyed, but lead has a great influence on the natural environment, so lead-free solder (lead free s〇ider) The birth of lead-containing or lead-free solders consists of tin. Referring to FIG. 1 again, during the reflow process, the solder bumps 108 are often caused by the cohesive force of the solder bumps 1 〇 8 so that the spheroidized solder bumps 08 pull the periphery of the sphere metal layer 106 upward. The benzocyclobutene layer (BCB Uyer) 103 and the wafer soldering solder bumps 108 are pressed under the spherical metal layer. However, since the benzocyclobutene layer 丨〇3 is larger (in other words, it is harder), it often causes the #=pressure benzocyclobutene layer m under the protective layer ι〇2 two of it Squeeze and rupture. Furthermore, it also causes a phenomenon in which the benzocyclobutene layer (10) i ay er ) 1 〇 3 is stripped and detached below the periphery of the metal layer G6. [Invention] The structure of the material bump layer is divided into the lower layer. In view of this, the object of the present invention is Φ ^ ^ ^ ', which is caused by the spheroidization of a flip chip wafer resulting in ": In the case of Reflow, due to the under-conformation, the periphery of the metal layer of the ball and the periphery of the metal layer at the bottom of the ball are too small to lead to the phenomenon of peeling off and separating between the bottom and the bottom of the ball; This / wide ring of olefin layer (B c B benzocyclobutene layer, and into a calf, so the bottom of the bottom of the metal layer 4 is bad. V squeeze the protective layer to protect

Page 8 1300616 曰 曰 Amendment 17871 V. OBJECT DESCRIPTION OF THE INVENTION (4) For the above purposes, the present invention proposes a number of wafers of fresh enamel, a protective layer, a poly-Asia, and Layer, a plurality of ball bottom metal layers and a plurality of solder bumps. And, the protective layer is formed on the active surface of the flip chip and soldered to the 'polyimide layer and the benzocyclobutene layer: formed on the protective layer and simultaneously exposed the solder pad. Further, a layer is formed on the solder tab to provide a flip chip structure as a phase layer of the solder bump and the solder bump. The system includes a bump bump. Wherein the wafer protective layer is formed on the cover and exposes the wafer pads, and the polyimide is formed directly on the protective layer while exposing the discharged wafer. Further, the bottom metal layer is formed on the wafer slab as a transition layer between the solder bumps and the solder pads. /, with a few acres: Ya! The amine layer is formed between the stupid and cyclobutene layer and the wafer layer or directly between the bottom metal layer and the wafer protective layer, and the acoustic modulus of the layer is less than the stupid and thin layer and protection: That is, the water-Asian makeup layer is composed of a relatively soft material, so it can be used as a buffer layer for the external protective layer of the protective layer to prevent the solder bump ball from pulling the periphery of the metal layer of the ball. The protective layer below the peripheral portion is squeezed to break the deformation. , ° (four), [implementation]

1300616

Referring to Figure 2, there is shown a cross-sectional view of a comparative structure in accordance with the present invention. Only the case of flip-chip MM 92117871 V. Description of the invention (5) Crystal wafer structure. I would like to: 3, please refer to Figure 2, which shows the neighboring eight communities of the flip chip structure 200. The flip chip structure 20 has a j 〇〇 ^ knife junction jie Lei drawer f input, a first " electrical layer (dielectric protective layer) 205, a 208 electric protective layer) 2 ° 6, - ball bottom Metal layer m and solder bumps 208. Wherein, the protective layer 2〇2 is disposed on the active surface 201 of the active+convex no-structure m and exposes the wafer pad=protecting into/forming the first dielectric layer (dielectric protective layer) 205 and the second The dielectric acoustic layer i 620 is on the protective layer 202 and exposes the wafer solder (four) 曰4. The second two-in-one dielectric layer (dielectric protective layer) 205 has a modulus of elasticity less than = drag layer) 2 ° 6 elastic modulus and protective layer 2 ° 2 of the bomb into the Lei Ju / ί 二之, A dielectric layer (dielectric protective layer) 205 is composed of a material that is softer than the second layer (dielectric protective layer) 206 and the protective layer 2〇2. In general, the protective layer may be a material such as cerium oxide (siHc〇n ο-. 'silicori nitride, ph〇Sph〇Silicate glass (PSG). Preferably, ♦ ^ The layer (dielectric protective layer) 20 6 is composed of a harder benzocyclobutene layer, and the first dielectric layer (dielectric protective layer) 2〇5 may be composed of polyamidene. Forming a ball bottom metal layer 207 on the wafer pad 204 and the second dielectric layer (dielectric protective layer) 206, and the ball bottom metal layer 2〇7 is mainly composed of an adhesive layer 207=, a barrier layer 2〇7b, The wetted layer 207c is composed of. When the wafer pad 2〇4 is an aluminum pad, the adhesive layer/barrier layer/wetting layer can preferably be aluminum/nickel-vanadium alloy/copper three-layer structure. Adhesive layer/resistance when pad 2〇4 is a copper pad

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The barrier layer/wetting layer may preferably be a titanium/nickel-vanadium alloy/copper three-layer structure f-adhesive layer, a barrier layer, and a material of the wetting layer: 隹 regardless of the material of the adhesive layer From titanium, tungsten, titanium-tungsten alloy, ^:: a material in the group of people; the material of the barrier layer is selected from the group consisting of nickel, Lu vanadium 5 gold, nickel-copper alloy and nickel-titanium alloy One of the materials: Nickel: The material of the wet layer is selected from the group consisting of copper, chrome copper and copper alloy, and the adhesive layer, the barrier layer and the wetting layer can be formed by sputtering. In addition, a solder bump 2 〇8 is disposed on the wetting layer 2 0 7c as a connecting element when the wafer structure is bonded to the substrate (not shown), which is noteworthy. The bottom metal layer 2〇7 may also extend over the second dielectric reed (human protective layer) 206 to form a line redistribution layer, and over the line 3 heavy & t layer over the other dielectric layer ( The dielectric protective layer) is used to expose part of the line = distribution layer as a bump pad. Thereafter, solder bumps are formed on the bumps. As described above, since the solder bumps 2〇8 are soldered and spheroidized, the periphery of the ball metal layer 2〇7 is pulled by the solder bumps 2〇8 to press the bottom metal layer go? That is, the first dielectric layer (dielectric protective layer) 20 5 and the second dielectric layer (dielectric protective layer) 2 〇 6 under the peripheral portion; only the second dielectric layer (dielectric protective layer) 20 The mutual system is composed of a material with a low modulus of elasticity, so the second layer (dielectric protective layer) 2 can absorb the bottom metal layer 207 and be pulled to the $31 dielectric layer. The electrical protective layer) is applied to the compressive stress applied by the sub-layer as the second dielectric layer (dielectric protective layer) 20 and the buffer interface of the wafer protective layer 2 〇 2 to prevent the protective layer 2 0 2 damage and avoid causing the bottom metal layer 207

1300616 Amendment No. 92117871 V. Description of the invention (7) The second dielectric layer around the periphery of the perimeter and the bottom metal layer 207 (in the case of ^ ^ ^ ^ ^ ^ ^ t , a , a '; The service life of the flip chip structure. Next, please refer to FIG. 3, which shows a cross-sectional view of a flip chip structure according to another comparative example of the present invention. Referring to FIG. 3, the flip chip structure is shown. 3〇〇之社 ί:图入.Λ晶ί片结构3GG series has—active surface 3Gi, protective layer 302,), electrical layer (dielectric protective layer) 3〇3, #塾3〇4, one Ball bottom solder bumps 3〇8. The 'protective wide 3. 2 series is disposed on the active surface 曰r塾 30'4 for protecting the active surface 301 of the flip chip structure state and exposing the formation-dielectric layer (dielectric protective layer) 3G3 on the protective layer 302 'And violent chrome out of the wafer soldering different 302 its second layer (dielectric protective layer) 3 ° 3 elastic modulus is less than the protection, the dielectric layer (dielectric protective layer) 3 ° 3 system by the ratio of $ 濩 layer 302 is composed of a "man's material. Preferably, a dielectric protective layer" 3 0 3 may be composed of polyamidamine. 9 m and the other two metal layers 306 are formed on the dielectric layer (dielectric protective layer) And the mat 304, and the bottom metal layer 306 is mainly composed of an adhesive layer 3〇6a I1 early layer 3 0 6 b, a wetting layer 3 〇6 C. The wafer 锃埶q 牯 - - red / ^ Tianri Riyue Zinc Pad 304 is an aluminum pad 2: Yes! 曰 广 / / / Wetting layer is better can be Ming / Recording alloy / copper three 曰,,,,,,,,,,,,,,,,,,,, In the case of a copper pad, the adhesion layer/resistance/wetting layer may preferably be titanium/nickel alloy/ _2#β曰+ sound, darkening @9, fish/钔 layer, but regardless of its adhesion. F Ρ Early layer, wet layer 疋 composed of what material Generally disabilities, adhesive ^^^^ "titanium-tungsten alloy, tungsten, chromium, aluminum group consisting of

i - the material is negative; the material of the barrier layer is selected from nickel, nickel vanadium alloy

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The material consisting of nickel-copper alloy and nickel-titanium alloy is selected from the group consisting of copper, chrome-copper and copper layers, barrier layers and wetting layers, and the alloy of the wetting layer. Wherein, the method of bonding the money or the way of electroplating forms a solder bump 308 on the wetting layer 306c as a covering day and day structure and substrate (not shown in the figure) Flip bonded joint elements. It is noted that the bottom metal layer 30 6 may also extend over the dielectric layer (dielectric security layer) j03 to form a line redistribution layer, and over the line redistribution layer to cover another dielectric layer. The electrical protective layer) is used to expose a portion of the wiring redistribution layer as a bump pad. Thereafter, the solder bumps are formed on the bump pads. When the solder bumps 308 are re-sphered, the periphery of the ball metal layer 306 is pulled by the solder bumps 308 to squeeze the ball metal layer. The dielectric layer below the 3 〇6 ten central part (ie, the part outside the perimeter) (the dielectric layer (dielectric protective layer) 3 0 3 is composed of a material with a lower modulus of elasticity, so the dielectric The layer (dielectric protective layer) 303 can absorb the compressive stress applied to the protective layer 302 by the under-ball metal layer 3〇6 to serve as a dielectric layer (dielectric layer) 3 0 3 and a protective layer 3 0 . The buffer interface of 2 prevents the destruction of the protective layer 3 〇 2 and causes the peeling and detachment between the periphery of the bottom metal layer 306 and the dielectric layer (dielectric protective layer) 303 under the periphery of the ball metal layer 3Q6. The above-mentioned flip chip structure design can improve the use of the stomach life of the flip chip structure. The specific examples set forth in the detailed description of the embodiment are merely for ease of description of the technical contents of the present invention, and are not intended to be the present invention. Narrowly limited to this embodiment, therefore, without departing from the spirit of the invention The following application 1300616

1300616 _ Case No. 92117871_Year _g_Revision _ Brief description of the diagram (5), [Simplified description of the drawing] FIG. 1 is a schematic cross-sectional view of a conventional flip chip structure. Figure 2 is a cross-sectional view showing the structure of a flip chip in accordance with a preferred embodiment of the present invention. 3 is a cross-sectional view showing a structure of a flip chip according to another preferred embodiment of the present invention. Description of the component symbols: 10 0· flip chip structure 101: active surface 102: protective layer 103: benzocyclobutene layer 104: wafer pad 1 0 6 : ball metal layer 106a: adhesive layer 106b: barrier layer 106c : Wetting layer 108 : solder bump 2 0 0 · flip chip structure 201 : active surface 202 : protective layer 204 : wafer pad 205 : first dielectric layer (dielectric protective layer) (polyimine layer) 2 0 6: second dielectric layer (dielectric protective layer) (benzocyclobutene layer)

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Page 16 Case No. 92117871 Date _ Corrective Drawing Simple Description 207: Ball Metal Layer 207a: Adhesive Layer 20 7b : Barrier Layer 20 7c : Wetting Layer 208 Solder Bump 300 Flip Chip Structure 301 Active Surface 3 02 Protective layer 303 Dielectric layer (dielectric protective layer) (polyimide layer) 304 Pad 306 Bottom metal layer 3 0 6a : Adhesive layer 3 0 6b : Barrier layer 30 6c : Wetting layer 308 Fresh material Bump

Claims (1)

1300616 Correction No. 92117871 VI. Patent Application No. 1 · A flip chip structure comprising: an active surface; a plurality of pads disposed on the active surface; a protective layer disposed on the active surface And exposing the solder pads; a polyimide layer (polyimide, PI) formed on the protective layer and exposing the pads; a benzocyclobutene layer (10) (10) ^ team ... ' is formed on the polyimide layer and exposes the pads; and X plurality of ball-bottom metal layers are formed on the benzocyclobutene layer and are respectively disposed on the The wafer flip-chip structure described in the above item 1 further comprises a plurality of red germanium bumps respectively formed on the metal layer of the ball. The flip chip structure described in the above, wherein the protective mussels, and the niobium 1 contain a nitride. The recrystallized wafer structure according to the above item 1, wherein the protective wafer ', 匕Containing silicon nitride. 厣材材2, the scope of the first paragraph Polycrystalline wafer structure, wherein the said protective p SG). Mi shell comprises phosphorus silicon glass (phosphosilicate glass, Page 17 1300616 _ Case No. 92117871 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Oxide). The flip chip structure as described in claim 1, wherein the material of the bottom metal layer is selected from the group consisting of titanium, tungsten, titanium tungsten alloy, chromium, aluminum, nickel, nickel alloy, nickel copper A material consisting of alloys, nickel-titanium alloys, copper, and copper-chromium alloys. The flip chip structure as described in claim 1, wherein one of the ball bottom metal layers is a line redistribution layer, and further comprising a dielectric layer formed on the line redistribution layer and exposed The line redistribution layer is formed to form a line redistribution pad. 9. The flip chip structure as described in claim 8 further forms a solder bump on the line redistribution pad. The flip-chip structure as described in claim 1, wherein the spherical metal layer is a three-layer structure of a nickel/niobium alloy/copper. 11. The flip chip structure of claim 1, wherein the spherical metal layer is a titanium/nickel vanadium alloy/copper three-layer structure. The flip chip structure as described in claim 1, wherein the spherical metal layer is a two-layer structure of titanium/copper alloy. Page 18 1300616 Case No. VI. Patent Application Range 92117871 1 3 · a flip chip structure comprising: an active surface; a plurality of pads disposed on the active surface; itch squeezing; the soldering layer is disposed on the active surface And exposing the first dielectric layer on the protective layer and exposing the pad; a second dielectric layer formed on the first dielectric layer and exposing the 塾' and the The second dielectric layer has a modulus of elasticity greater than the first, elastic modulus; and the plurality of ball-bottom metal layers of the tantalum layer are formed on the second dielectric layer. The flip chip structure of item i3, wherein the elastic modulus of the layer is greater than the modulus of elasticity of the first dielectric layer. μ stay 1 5 · The flip chip structure described in claim 13 of the patent application, the material of the 1 φ # dielectric layer is a polyimide layer.八以弟16· As claimed in the thirteenth wafer structure described in claim 13, the material of the second dielectric layer is a benzocyclobutene layer. 〃 ^17. The flip-chip structure as described in claim 13 of the patent application, further comprising a plurality of solder bumps respectively formed on the ball-bottom metal layers. No Page 19 13 〇〇 616 Case No. 92] 178 Ή VI. Patent Application Scope Amendment 1 8 · The flip chip structure described in claim 13 of the patent application, wherein the material of the compliant layer contains nitride (nitride). The flip chip structure as described in claim i, wherein the material of the protective layer comprises silicon nitride. 2. The flip chip structure as described in claim 13 wherein the material of the thin layer comprises phosphosilicate glass (PSG). 2 1. The flip chip structure as described in claim 3, wherein the material of the thin layer comprises a Si 1 icon oxide. 2. The flip chip structure as described in claim j3, wherein the material of the bottom metal layer is selected from the group consisting of titanium, tungsten, titanium tungsten alloy, chromium, aluminum, nickel, nickel vanadium alloy, A material of a group consisting of nickel-copper alloy, nickel-titanium alloy, copper, and copper-chromium alloy. The flip chip structure as described in claim 13 wherein one of the ball bottom metal layers is a line redistribution layer, and further comprising a dielectric layer formed on the line redistribution layer The line redistribution layer is exposed to form a line redistribution pad. Page 20 13〇〇616 车月曰 Amendment ^92117871 /, 'Application for patent scope 2 4 The patent application of the flip chip structure described in item 23, further forms a dry bump on the line redistribution pad. 2 5 κ The flip chip structure described in claim 13 wherein the ball layer is a three-layer structure of a smelting/nickel alloy/copper. 2 g 广 · The flip chip structure as described in claim 3, wherein the ball & metal layer is a titanium/nickel vanadium alloy/copper three-layer structure. The crystal chip structure described in claim 13 wherein the ball & metal layer is a two-layer structure of titanium/copper alloy. 2 g • a flip chip structure comprising: an active surface; 'a plurality of solder bumps disposed on the active surface; a protective layer disposed on the active surface and exposing the solder bumps; a dielectric layer formed on the protective layer and exposing the pads, and the elastic modulus of the black layer is less than the elastic modulus of the protective layer of the wafer, and a plurality of spherical metal layers. The system is formed on the dielectric layer and is respectively disposed on the fresh enamel of the 5th. 29. The flip chip structure of claim 28, wherein the dielectric layer is made of a polyimide layer. 〃 ^ Page 21 1300616 VI. Application for Patent Scope Repairs 3 〇 · The flip chip structure described in claim 28, further comprising a plurality of solder bumps formed at the bottom of the sphere On the metal layer. The flip chip structure as described in claim 28, wherein the material of the protective layer comprises a nitride. 32. The flip chip structure of claim 28, wherein the material of the barrier layer comprises silicon nitride. The flip chip structure as described in claim 28, wherein the material of the vine layer comprises a phosphosilicate glass (PSG) 〇 3 / · as described in claim 28 The flip chip structure, wherein the material of the vine layer comprises a silicon oxide. 35. The flip-chip structure as described in claim 28, wherein the material of the spheroidal metal layer is selected from the group consisting of Qin, He, Qinhe alloy, Luo, Ming, _, nickel alloy, nickel copper A material consisting of alloys, nickel-titanium alloys, copper, and copper-chromium alloys. 36. The flip chip structure as described in claim 28, wherein one of the ball metal layers is a line redistribution layer and further comprises a dielectric layer type page 1300616 _ case number 92117871_ Amendment of the year _ _ _, the patent application scope is formed on the redistribution layer of the line and expose the line redistribution layer to form a line redistribution pad. 3 7 . The flip chip structure as described in claim 36, further forming a solder bump on the line redistribution pad. 3. The flip-chip structure as described in claim 28, wherein the spherical metal layer is a three-layer structure of indium/nickel alloy/copper. The flip-chip structure as described in claim 28, wherein the spherical metal layer is a titanium/nickel-niobium alloy/copper three-layer structure. The flip-chip structure as described in claim 28, wherein the spherical metal layer is a two-layer structure of titanium/copper alloy. Page 23