TW451280B - Method of forming a fuse structure on a dual damascene copper structure - Google Patents

Abstract

A fuse structure is formed on a dual damascene copper structure in the present invention. The method includes: providing a semiconductor substrate having the fuse layer and at least a dual damascene copper structure layer upon the fuse layer, the dual damascene copper structure being composed of a via portion and an interconnect portion, and the via portion and the interconnect portion being formed in the insulation layer; removing a part of the interconnect portion, and forming a groove portion on the interconnect portion between the insulation layers; forming a barrier layer in the groove portion on the interconnect portion; forming the passivation layer on the barrier layer and the insulation layer; forming a bonding pad connecting to the opening and a fuse opening window in the passivation layer; etching the passivation layer down to the insulation layer through the fuse opening window; forming a metal bonding pad in the opening of the bonding pad, and also forming a metal layer in the fuse opening window at the same time; and removing the bottom of the metal layer in the fuse opening window.

Description

451 2 80 V. Description of the invention α). The present invention relates to a method for manufacturing an integrated circuit (integration iC), and more particularly to a method for forming a fuse structure in a semiconductor product F. This method uses a single-buff = a marginal layer ... the opening of the I-line structure ... the same = the opening of a bonding pad is formed on 70 pieces of integrated circuit. Advances in semiconductor process technology, such as high-resolution optical microphones (= graPhy) and anisotropic engravings, have reduced the semiconductor; the feature size of components has increased its accumulation. Unfortunately, the product yield (wafer yield) of a piece has decreased due to the increase in the accumulation of the piece and the increase in the number of separated components on the wafer; for example, a circuit component that has a rise and a decrease in yield is 卯The fins generally have 64M bits on a chip; after 2000 AD, the number of memory cells is believed to increase to more than 4G bits, and the remaining units and methods of repairing " finished products are not used ' It will be more difficult to achieve high final yields. Quot " " No need to add a photomask for the integration process of the fusion welding process opening and the welding pad opening of the aluminum-steel metal structure, because the top layer of the metal structure's antireflective coating (ARC) titanium nitride Layer, which can be used as a touch barrier layer in the process of window opening in the smelting line to prevent metal structures from being invaded and contaminated. In terms of the integrated process of the fuse process opening and the bonding pad opening of the conventional copper metal structure, although the copper structure has a nitride layer as a liner or a diffusion barrier, there is no hafnium nitride layer with an anti-reflection coating. In the process of opening the window of the marriage line, it is used as a narrative barrier layer, so it is necessary to add a photomask to prevent the copper structure from being invaded and contaminated. In order to more clearly explain the conventional copper metal structure of the smelting process

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451280

V. Description of the invention (2) After the mouth and the welding pad are opened, the dry person h shall be h. First of all, as shown in the figure with reference to the detailed description, such as the conductor substrate 10 with / double, it is provided-semiconductor substrate 10, the M-layer double-embedded copper structure below this half-photograph and the metal at the uppermost metal junction. Structurally,! 5 is used as the fusible link 34 on the layer 2 metal structure, and the uppermost layer is connected with a silicon nitride layer 19 as a viewing pad or a diffusion barrier. Then, a first passivation layer (passivation lavpr, i0, «iayer) 12 such as a silicon oxide layer is comprehensively formed on the nitride layer jaiq + Lx υ 7. Afterwards, a dead state such as a nitrided dream layer is formed. Secondly, coating one light and two J, not 'defining the pad opening 16 and the fuse opening window 8 by the lithography process. Next, the nitride pad layer 19, the first passivation layer 12 and the second passivation layer 14 are etched according to the defined solder pad opening 16 and the fuse opening window 18, and then the photoresist layer is removed. The result is shown in Figure 丨 A. Then, see Figure 〖B. First, a photoresist layer (not shown) is laid out, and then the lithographic process is used to define the previous fuse opening window 18, and then open through the fuse. Window 丨 8, the silicon oxide layer 20, the silicon nitride layer 22, the silicon oxide layer 24, the silicon nitride layer 26, the silicon oxide layer 28, and the silicon nitride layer 30 are etched to expose the silicon oxide layer 32, and then the light is removed Barrier layer. This result is shown in Figure 1B. The above-mentioned conventional manufacturing process requires the addition of a photomask to prevent the steel structure from being eroded and contaminated during the subsequent formation of the fuse opening window. Therefore, an object of the present invention is to provide a method for forming a line-contained structure on a double-embedded copper structure, which utilizes a single photomask to simultaneously form a wire opening window and an opening for a welding grate. Another object of the present invention is to form a side wall insulation protection layer in the open window of the fuse line, so as to prevent the residual metal from diffusing into the side wall insulation layer and causing pollution when the fuse line is burned by laser in the future.

Page 5 451280 5. Description of the invention (3) 'The present invention also has the purpose of forming a barrier layer, or metal protective layer, such as a nitride button (TaN), chromium or chromium-copper alloy layer, on the uppermost metal structure. The mask layer is engraved to prevent the copper metal underneath from being invaded and contaminated, and because of the choice of different barrier layer materials, it is suitable for subsequent aluminum wire welding and Flip Chip processes. In order to achieve the above object, the present invention proposes a method for forming a fuse structure on a double-embedded steel structure, which forms a barrier layer on the uppermost metal structure, and uses a single photomask to simultaneously form a fuse opening window and as a welding pad. Opening, and a side wall insulation protection layer is formed in the fuse opening window. According to the present invention, a method for forming a fuse structure on a dual-embedded copper structure includes the following steps: providing a semiconductor substrate having a fuse layer and at least one double-embedded copper structure layer on the fuse layer; The copper structure is composed of a via hole portion and an inner connecting portion, and the via hole portion and the inner connecting portion are formed in an insulating layer; a part of the inner connecting portion is removed, and the inner connecting portion between the insulating layers is removed. Forming a recessed portion; forming a barrier layer on the recessed portion of the inner connecting portion; forming a passive protective layer on the barrier layer and the insulating layer; forming a solder pad connection opening and a fuse in the passive protective layer Open the window; etch the passivated protective layer to the insulating layer through the fuse; form a metal solder pad in the opening of the solder pad, and also form a metal layer in the fuse open window; and remove this The bottom of this metal layer in the fuse opening window. In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible ', a preferred embodiment is given below, and in conjunction with the accompanying drawings, the detailed description is as follows:

4512 8 0 V. Description of the invention (4) [Schematic description] Figures 1A to 1B are cross-sectional views showing the traditional manufacturing process on a double-embedded line structure. 2A to 2F are cross-sectional views of a process for forming a smelting line structure on a double-embedded copper according to an embodiment of the present invention. ί [Symbol description] 10, 100 ~ semiconductor substrate; 14 Bu copper structure; 142 ~ metal protective layer. 12, 144 ~ first passive state protective layer; 14, 146 ~ second passive state protective layer ', 150 ~ Welding pad openings M8, 152 ~ Fuse opening window; 154 ~ Side wall insulation protection layer, 156 ~ Metal welding pad; 20, 24, 28, 126, U0 ,, i34, 138 ~ Oxide stone layer; 19, 22, 26, 30, 128, i32, i36 ~ silicon nitride layer; 34, 124 ~ wide melting line. Embodiments The present invention proposes a method for forming a fuse structure on a double-embedded copper structure. A barrier layer is formed on the uppermost metal structure, and a single cover is used to simultaneously form a fuse opening window and an opening for a solder pad. A sidewall insulation protection layer is formed in the open window of the fuse. Next, a preferred embodiment is described for detailed description. The follow-up process of this method can improve the yield by repairing the finished product by burning off the fuses and removing defective component circuits, and using the spare and intact circuits. The present invention first provides a semiconductor substrate 100. The semiconductor substrate 100 has a copper fuse layer 12 and at least one pair of interspersed copper structure layers on the fuse layer 124 of the steel structure. As shown in Fig. 2a, the detailed structure of this semiconductor element is composed of a field effect transistor.

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V. Description of the invention (5)

Transistor (FET), but it is not shown in detail in the figure to simplify the illustration and the following description. In order to facilitate the description of the multilayer double-embedded copper structure of this embodiment, a seven-layer copper structure is used as an example. The number of layers of this copper structure is more than tens of layers. The via portion and the via portion are formed in a composite insulating layer including a silicon oxide layer and a silicon nitride layer. The fuse in this embodiment is described by using a copper structure located on the fifth layer as an example. Next, referring to FIG. 2B, a portion of the copper structure of 140, which is the uppermost copper structure 140, is removed by a wet etching process at about 150 A. Then, a low pressure chemical vapor deposition (LPCVD) or plasma-assisted chemical vapor deposition (pECVD) is used to comprehensively form a barrier layer with a thickness of about 500 to 1200 A, or a metal protective layer 142, such as a nitride group (TaN ), Chrome or copper alloy layer, this metal protective layer 142 will be used as an etching mask layer in the subsequent process of defining the opening of the weld and the opening of the fuse line to prevent the steel metal layer 14 from being invaded by rice or Pollution. Then, please refer to FIG. 2C. Using a planarization process, such as Chemical Mechanical Planarization (CMP), remove part of the metal protective layer 1 42 to expose the silicon carbide layer. 38, for example, in adjusting process parameters The speed of the turntable, the down pressure, the type of polishing pad, and the type of abrasive are used to control the removal rate, uniformity and selectivity in the process, and smooth the metal protective layer 142. Then, a low-pressure chemical vapor deposition or plasma is used to promote the comprehensive formation of the chemical vapor phase / child product to form a first passivation layer 1 44 ′ such as a silicon oxide layer. Later, a low-pressure chemical vapor deposition or electro-violet was also used to promote the comprehensive formation of a second passive protective layer.

4 512 8 () V. Description of the invention (6) 14 6 ′ Such as a silicon nitride layer. Secondly, please refer to FIG. 2D, and apply a second photoresist layer 148 on the second passivation layer 146. Then, the lithography process is used to define the pad opening 150 and the fuse opening window 152. Next, the first passivation layer 144 and the second passivation state are defined according to the defined solder pad openings 丨 50 and the fuse opening window 1 52 'using an anisotropic dry etching process or an anisotropic wet etching process'. Protective layer 146. Etching. Then 'open the window through the fuse line 5 2 and use an anisotropic dry etching process or an anisotropic wet etching process to sequentially order the silicon oxide layer 38, the silicon nitride layer 136, the silicon oxide layer 134, nitrogen The siliconized layer 132, the silicon oxide layer 1 30, and the silicon nitride layer 1 2 8 are etched back to expose the silicon oxide layer 26, in which the metal protective layer 142 under the opening of the solder pad is “when the etching process is performed”, It will be used as a mask to prevent the steel metal layer 14 below it from being eroded or contaminated. After the etching is completed, the first photoresist layer 148 is removed. In addition, please refer to FIG. 2E. In the opening of the solder pad 50 and the fuse opening window 1 5 2, a side wall insulation protection layer 5 4 can be selectively deposited for future use when the fuse is burned by laser. To avoid contamination caused by the remaining metal diffused into the side wall insulation layer in the area of the fuse, the side wall insulation protection layer 1 5 4 can deposit a thickness of about 300 to 500 A of tantalum nitride, and at the same time it will also be soldered 塾A protective layer 154 is deposited in the opening 150. Next, a metal bonding pad 156 'such as aluminum or UBM (under ball metallurgy) metal is formed in the solder pad opening 150, and at the same time, a metal layer 156 is formed in the fuse opening window 152. This result is shown in Figure 2E. Finally, referring to FIG. 2F, a second photoresist layer (not shown) is defined on the metal pad 156 as a reticle. Afterwards, using anisotropy

'451280 V. Description of the invention (7) Dry money engraving process or reactive ion etching (RI E) process, using a highly directional etchant, sequentially protective layer 5 4 and metal layer 156 Etching is performed to remove the bottom of the protective layer 154 and the metal layer 156. The sidewalls of the protective layer 154 and the metal layer 156 left after the etching can be used to avoid the residual metal from diffusing into the sidewall insulation layer and causing pollution when the fuse is burned by laser in the future. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to: invent the 'any person skilled in the art without departing from the essence of the present invention :: J Wai Θ' can be modified and retouched 'therefore the present invention The scope of protection ® is determined by the scope of the attached patent application.

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Claims (1)

451280 VI. Scope of patent application " " " -------- The following 1 step is a method of forming a fuse structure on a 'dual embedded copper structure, including [providing a semiconductor substrate with a fuse layer and At least one double embedded copper structure layer on the fuse layer, the double embedded copper structure is composed of a via hole portion and an inner connection portion, and the via hole portion and the inner connection portion are formed in an insulating layer; A portion of the internal connection portion, and a depression is formed on the inside between the insulation layers: Ann, the depression portion on the internal connection portion forms a barrier layer; and a passivation layer is formed on the barrier layer and the insulation layer Forming a welding pad connection opening and a fuse opening window in the pure state protective layer; opening the other protective layer to the insulating layer through the melting line opening window; forming a metal weld in the opening of the welding joint Alas, a metal layer is also formed in the open window of the smelting line; and the bottom of the metal layer in the open window of the fusible link is removed. 2. The method according to item 1 of the scope of patent application, further comprising depositing a sidewall insulation protection layer in the fuse opening window before forming the metal layer in the fuse opening window. 3. The method according to item 1 of the scope of patent application, further comprising removing the bottom of the sidewall insulation protection layer in the molten window before removing the bottom of the metal layer in the molten window. 4 · The method according to item 2 of the scope of patent application, wherein the side wall In 512,80, the scope of patent application "---; The insulating protection layer can form a tantalum nitride layer with a thickness of about 300 to 500 people. 5. The method according to item 1 of the scope of patent application, wherein the barrier layer 疋 is formed by a low-dust chemical vapor deposition or a plasma-assisted chemical vapor deposition to form a nitride button having a thickness of about 50 0 to 1 20 0 A. Layer d 6. The method as described in item 1 of the scope of the patent application, wherein the barrier layer 疋 is formed by using low pressure chemical vapor deposition or plasma to promote chemical vapor deposition to form a chromium or chromium copper having a thickness of about 500 to J 200 A. Alloy layer. 7. The method according to item 1 of the scope of patent application, wherein the passive protective layer includes a first passive protective layer and a second passive protective layer. 8. The method according to item 7 of the scope of the patent application, wherein ‘the first pure cancer protective layer is formed by a low pressure chemical vapor deposition or a plasma-assisted chemical vapor deposition to form a silicon oxide layer. 9. The method according to item 7 in the scope of the patent application, wherein ‘the second pure cancer protective layer is formed by a low-pressure chemical vapor deposition or a plasma-promoted chemical vapor deposition to form a nitrided dream layer. 10 · The method as described in item 1 of the scope of the patent application, wherein 'the formation of a pad opening and a melting line opening window within the passive protective layer' uses an anisotropic dry etching process or an anisotropic process In a wet etching process, the passivation layer is etched back. 11, The method according to item 1 of the scope of patent application, wherein the metal () welding pad and the metal layer are aluminum or metal. 1 2. The method according to item 1 of the scope of patent application, wherein the removal of the bottom of the metal layer in the open window of the fuse is performed by using an anisotropic dry etching process or a reactive ion touch etching process, using a high direction Etchants Page 12 4 5 12 8 0 Page 13