TWI343621B - Method of forming composite opening and method of dual damascene process using the same - Google Patents

Description

1343621 UMCD-2006-0271 21932twf.doc/n IX. Description of the Invention: [Technical Field] The present invention relates to a semiconductor process and in particular to a method for forming a composite opening and a double metal using the same Mosaic process. [Prior Art] As the degree of integration of semiconductor elements has increased, the use of multiple metal interconnects has become more widespread. Generally, the lower the resistance of the metal layer of the multiple metal interconnect, the element

The higher the reliability of the piece, the better the performance of the component. Among metal materials, the low resistance of copper metal is very suitable for use as a multi-metal interconnect. However, since copper metal is difficult to be patterned by conventional lithography, it has been developed as a double damascene. Process. A dual damascene process is a technique for forming trenches and via openings in a dielectric layer and then backfilling the metal to form metal and vias. The dual-metal system (4) has a record, and some form a ditch in the opening of the smuggling layer window; some form a ditch first, and then form a via window.

= Forming a fine layer of pores and then forming a trench to carry out a double metal town on February 22nd. 'In the formation of a ditch of a ditch, the layer below the opening σ may also suffer side damage, resulting in damage In order to avoid the damage caused by the metal layer method under the opening of the via window, the currently known - layer window opening VI fills the window opening 110, first The media is filled with the 麻 h h 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 以避免 、 、 、 、 、 、 、 However, this method is always provided with the shadowing effect of the UMCD-2006-0271 21932 twf.d〇c/n trench fill layer 112, and after forming the trench 120 in the subsequent remainder, the opening in the via window is completed. A fence-like dielectric layer 106a remains at the corner 11〇a, causing a problem of component reliability. However, there are often many difficulties in eliminating the dielectric layer of the grid. Avoiding the formation of the dielectric layer by adjusting the height of the trench fill layer is a method that can be adopted, but at the center of the substrate due to poor etching uniformity and micr〇bading effect The thickness of the trench fill layer and the thickness of the trench fill layer at the edge of the substrate, or the thickness of the trench fill layer in the dense region and the thickness of the trench fill layer in the loose region of the substrate are often greatly different, so that the process space is 0r〇cess Wind〇w) is very small. On the other hand, 'please refer to FIG. 2, if the etchant of less polymer is used to etch the trenches in order to avoid the formation of a gate-like dielectric layer during etching, then the apex angle 120a of the trench 120 is The dielectric layer 106 is subjected to etchant destruction due to the absence of polymer protection, resulting in a rounded corner 12 of the trench 12 being rounded. When the subsequently deposited metal layer 122 is filled into the apex rounded trench, the adjacent two dual damascene structures may be bridged accordingly. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of fabricating a dual damascene structure that avoids the rounding of the apex angle of the trench and prevents bridging of adjacent two dual damascene structures. It is still another object of the present invention to provide a method of fabricating a dual damascene structure that avoids the formation of a barrier-like dielectric layer. It is still another object of the present invention to provide a method of forming a composite opening which avoids the wide opening σ apex rounding phenomenon and which avoids the narrow opening apex angle to form a grid-like projection. 1343621 UMCD-2006-0271 21932twf.doc/n The present invention proposes a dual damascene process. In this method, a dielectric layer is formed on the substrate of the underlayer, and a via is formed therein, and the surface is formed on the substrate. Next, a dielectric layer is formed in the via opening D to form a resistive layer on the bottom. Thereafter, a lithography and engraving process is performed, and a trench is formed in the layer, and the trench is left in a dome shape, wherein the etching rate of the trench material layer is greater than that in the etching process The impedance layer. After 2, the trench layer, the resistive layer and the via opening are formed to form a conductive layer in the opening of the via and the via window. Further, in the above-described double damascene process, the etching selectivity of the trench fill layer/impedance layer is 3 to 丨" in the etching process. According to the embodiment of the present invention, in the double damascene process, the etching rate of the trench fill layer is greater than the etching rate of the dielectric layer during the etching process. According to the embodiment of the invention, in the double damascene process described above, the trench fill/dielectric layer selection ratio is u to 2 during the process of the engraving process. According to an embodiment of the invention, in the double damascene process described above, the etching rate of the resistive layer is greater than the etching rate of the dielectric layer. According to an embodiment of the invention, in the double damascene process described above, the etching gas during the etching process is free of oxygen. / In accordance with an embodiment of the present invention, in the above-described dual damascene process, the gas is included in the process of cutting into the process, and the gas is included in the gas. According to the embodiment of the present invention, in the above-mentioned double metal inlay process, the gas fed into the material further includes a carrier gas. In the above-mentioned double metal inlay process, the gas used in the scorpion and spear king also includes - adjusting gas. According to the invention 1343321 UMCD-2006-0271 2l932twf.doc/n == double metal bonding process in the 'dielectric layer material including the shape of the double damascene process more includes (four) war ~ 丨 ^ open day, in the A cap layer is formed on the electrical layer. According to an embodiment of the invention, the double metal filler material described above comprises a polymer having no anti-reflective properties. In U, the method of forming the compound opening and opening of the groove material. A material f groove is formed on the substrate. Following this, an -impedance 覆 layer is formed on the substrate. Then, carry out - lithography and Jing Cheng, in the material:; = and; two = ___' and leave the trench filling in the shape of a dome ^: Ζ process, the groove _ rate is greater than the impedance layer. 1 After the filling layer and the impedance layer 'naked wide open opening, _ La H 除 沟 在 进 进 进 进 进 进 ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' 上述 上述 上述 上述The selection of the impedance layer is as follows according to the embodiment of the present invention, the formation of the composite opening is performed, and the formation of the trench is compared with that of the material layer, according to the embodiment of the present invention, During the process, the butterfly fill/material layer has a butterfly selection ratio of 1.2 to 2. According to the embodiment of the present invention, the above-mentioned composite open impedance layer has a paste rate. / ' ' In the method of forming the above-mentioned composite opening, the material of /, 曰 包括 includes a polymer having no anti-reflection property. According to an embodiment of the present invention, the above-described method for forming a composite opening UMCD-2006-0271 21932 twf.d〇c/n includes a fluorocarbon used in the process of performing a surname process. According to the embodiment of the present invention, in the method of forming the composite opening, the gas used in the etching process further includes a carrier gas. In the method for forming a composite opening according to the embodiment of the present invention, the gas used in performing the remnant process further includes an adjustment gas. The manufacturing method of the double damascene structure of the invention can avoid the phenomenon that the apex angle of the trench is rounded, prevent the phenomenon of the bridge between the two double damascene structures, and can prevent the top corner of the opening of the via window from forming a grid matte shape. Dielectric layer. The method of forming the composite opening of the present invention can avoid wide opening deuteration and can avoid the formation of gate-like projections at the narrow opening apex angle. In order to make the above and other objects, features and advantages of the present invention more apparent and in conjunction with the touch map, the details are as follows. [Embodiment] For the first embodiment, please refer to ® 3A 'This embodiment The double damascene structure is formed on a substrate 3〇0. A conductive layer is formed on the substrate 3, and the wiring layer 304 is covered on the conductive layer 3. The substrate is, for example, a semiconductor: base: !=_Upper tree substrate. The conductive layer is carried out, for example, the layer 304 of the inner ΐ f on the conductive layer 302 can be used as _, η德', the material is, for example, a layer of nitrogen cut, forming a method of female phase deposition Forming a dielectric layer 3G6 on the lining layer, a material of the number. The low dielectric constant material has a dielectric constant lower than z: = erg FSG); the shixi sesquioxide as a heart material (ydr〇) Gen Sllsesquioxnane HSQ), methyl sulfonate semi-oxidized UMCD-2006-027 丨21932twf.doc/n (Methyl silsesquioxane 'MSQ) and hybrid organic argon polymer (HOSP); aromatic carbon Aromatic hydrocarbons such as SiLK; Organosilicate glass (Organosilicate) Glass) such as black diamond (BD), 3MS, 4MS; Parylene; Fluoro-Polymer such as PFCB, CYTOP, Teflon; Poly(arylethers) PAE-2, FLARE; Porous polymer such as XLK, Nanofoam, Awrogel;

Coral et al. In an embodiment, a cap layer 3 〇 8 is further formed on the dielectric layer 3 , 6 , and the material thereof includes tantalum nitride, tantalum carbide, bismuth carbon oxide (Sic〇), tantalum carbonitride (SiCN), carbon. A method of forming cerium oxynitride (SiCN0), cerium oxynitride or the like is, for example, a chemical vapor deposition method. Thereafter, referring to FIG. 3B, a lithography and etching process is performed to form a via opening in the dielectric layer 306. The engraved gas of the engraving process is, for example, CFVAr/N2 or CHFVAr/N2. Next, a trench drapery 312 is filled in the via opening 31A. This trench fill | 312 has a good uniformity of deposition and a small difference between the dense region and the loose region. The material f of the trench fill layer 312 includes a polymer having no anti-reflection characteristics, e.g., a method of forming GF43 and DUV52, for example, a spin coating method. ★ Thereafter, referring to Fig. 3C, a portion of the trench fill layer 312 is removed, leaving a trench fill layer 312a in the via 310. The remaining trench fills can be made by a method with a flat surface or a concave surface with a high edge. Next, the resist layer 314 is formed, for example, the underlying anti-reflective layer (BARC). The height of the remaining landfill 312a' is not particularly limited and may be h or UMCD-2006-0271 21932txvf.doc/, h2 (indicated by a broken line). The grooved layer 312 has a good degree of uniformity, and is not much different from the grooved layer 312a of the loose area. Therefore, the degree of formation is good and the surface is very flat. Therefore, the subsequent lithography system = two. The south of the two-faced gentleman undulates and affects its patterned shell. A patterned photoresist layer 316 is formed on the impedance |314. The photoresist layer 316 has an opening pattern (4) 8, which is a pattern of trenches formed in the pre-charge layer 300. Thereafter, referring to FIG. 3D, the photoresist layer 316 is used as a mask, and the resist layer 3 Μ and the dielectric layer 306 ′ are used to transfer the opening pattern 318 to the dielectric layer, and the trench 320 is formed therein. The trench wo is in communication with the via opening 31. In the lateral system (4), the trench fill layer 312a has a fine rate of the resistive rate of the resistive layer 314, and the layer 312a has a 稗-like ratio greater than that of the crane. Preferably, the landfill layer 312a has a higher engraving rate than the resistive rate of the impedance 314 and the side velocity of the resistive layer 314 is greater than 3% of the dielectric layer. The side selection ratio of the trench layer 312a/impedance g 314 is, for example, 3 phantoms, and the gate selection ratio of the trench fill layer 312a/dielectric layer 306 is, for example, 丨2 to 2. In an implementation, the side process is (4) secret (four) financial (4) Yuxiang polymer money engraving gas, for example, using oxygen-free gas as an etchant, such as fluorine smoke. The gas te is selected from the group consisting of CF4, CF#, CHJ2, CFH3 and mixtures thereof. In one example, an etching process is performed at 150 mTorr with CF4 of 15 sccm and CFsH of 95 SCCm as an etching gas. In another embodiment, the etching gas used in the etching process may be, in addition to a fluorocarbon, a carrier gas such as argon. In still another embodiment, in addition to the fluorocarbon and the carrier gas, an additional adjustment gas such as nitrogen or carbon monoxide may be added. 1343621 UMCD-2006-0271 2l932twf doc/n Since the etching gas selected during the etching process is an etching gas which can form more polymer, the polymer formed during the etching process can protect the interface at the top corner of the trench. The electrical layer is not destroyed by the engraving, so there is no bridging problem caused by the rounding of the top corner of the ditch. On the other hand, since the surname ratio of the trench fill layer 312a is greater than the surname ratio of the resistive layer 314 and the dielectric layer 306, the trench fill layer 312a will be very dense once the trench fill layer 312a is exposed during the engraving process. It is etched so that the trench fill 312b left after the etching process is dome-shaped. When the height of the trench fill layer 312a is higher than the ratio, the trench fill layer 312b is left as C1; when the height of the trench fill layer 312a is low, when h2 is left, the trench fill layer 312b is left as c2 (with a dotted line) Express it). Regardless of whether the trench fill layer 312b is C1 or C2, there is no trench fill shadowing effect, and no barrier-like dielectric layer remains at the top corner of the via opening 310. Next, referring to FIG. 3E, the photoresist layer 316, the resistive layer 314, and the trench fill layer 312b are removed. In one embodiment, the photoresist layer 316' resistive layer 314 and the trench layer 312b can be removed simultaneously, for example, by tantalum plasma ashing. The liner 3〇4 exposed by the via opening 310 is then removed. Thereafter, a conductive layer 322 is formed on the substrate 300 and filled in the trench 32 and the via opening 31A. Typically, conductive layer 322 includes a metal layer 324 and a barrier layer 326. The material of the barrier layer 326 is, for example, titanium nitride or a nitrided group. The metal layer is, for example, a copper metal layer. Thereafter, referring to FIG. 3F, a portion of the conductive layer 322 is removed, leaving a trench 320 and a conductive layer 322a among the via openings 310. The conductive layer 322& includes a metal layer 324a and a barrier layer 326a. The method of removal can be by chemical mechanical polishing. During the grinding process, the cap layer 3〇8 can be used as the polishing layer 12 1343621 UMCD-2006-0271 21932 twf.doc/n termination layer to avoid the dielectric layer caused by the different polishing rate of the dense region and the loose region on the substrate 300. 306 was overgrinded. Embodiment 2 Figs. 4A to 4D are schematic cross-sectional views showing a process of forming a composite opening according to an embodiment of the present invention.

Referring to FIG. 4A, a material layer 4〇6 is formed on the substrate 400, and the material is not particularly limited. For example, a dielectric layer such as a oxidized stone layer or any material which is intended to form a composite opening is formed. The method is, for example, a chemical vapor deposition method. Thereafter, a lithography and etching process is performed to form a narrow opening 410 in the material layer 4〇6. The butterfly gas of the process is related to the material f of the dielectric layer. When the material layer is yttrium oxide, the etched gas is, for example, CF4/Ar/N2 or CHiyAr/N2. Next, a trench fill 412 is filled in the narrow opening 410. The uniformity of deposition of this trench 412 is small in the difference between the dense region and the loose region. The material of the trench fill layer 412 includes a polymer having no anti-reflection property, and a method of forming, for example, gf43 and DUV52' is, for example, a spin coating method.

Thereafter, referring to Fig. 4B, a portion of the trench fill layer 412 is removed, leaving a (4) trench fill layer 412a with a narrow opening. The sloping trench fillet 412a can be either a generally flat surface or a scarf-side high-pitched surface. The method of removing a portion of the trench fill layer 412 may employ a back-breaking method. Next, a resistive layer (BARC) 4!4 is formed on the substrate. Since there is no special smell in the height of the trench fill, it can be represented by h3 or h4〇X dotted line). The uniformity of the backfill layer 412 is good. The difference between the densely packed area and the loose area is not much different. Therefore, the subsequently formed resistive layer 414 is well-formed and the surface is very flat. The shadow material will affect the quality of the pattern due to the height and height of the silk thread. 13 1343621 WVICD-2006-0271 21932twf.doc/n. Thereafter, a layered pattern of photoresist layers is formed on the resistive layer 414. The photoresist layer 416 has an opening pattern 418 which is a pattern intended to form a wide opening in the material layer 406. Thereafter, please refer to 4C, with the photoresist layer 416 as a mask, and the resistive layer 414 and the material layer 406 to transfer the opening pattern 418 to the material layer 406 to form a wide opening 420 therein. This wide opening 42 is in communication with the narrow opening 41. During the etching process, the etch rate of the trench fill layer 412a is greater than the etch rate of the resistive layer 414 φ, and the address of the trench fill layer 412a is greater than the etch rate of the material layer 406. Preferably, the etch rate of the trench fill layer 412a is greater than the etch rate of the etch rate of the resistive layer 414 and the etch rate of the resistive layer 414 is greater than the singularity of the material layer. The etching selectivity ratio of the trench fill layer 412a/resistive layer 414 is, for example, 3 to u, and the etching selectivity ratio of the trench fill layer 412a/material layer 406 is, for example, u to 2. In one embodiment, material layer 406 is tantalum oxide. The etching process uses an etching gas that forms more polymer during the etching process, such as an oxygen-free gas as an etchant, such as a fluorocarbon. The fluorocarbon is a group selected from the group consisting of cf4, cf3H, CH2F2, CFH3, and mixtures thereof. In one example, at 250 mTorr, an etch process is performed using 155 sccm of CF4 and 95 sccm of CF3H as the engraving gas. In another embodiment, the etching gas used in the etching process may include a carrier gas such as argon in addition to the fluorocarbon. In still another embodiment, an adjustment gas such as nitrogen or carbon monoxide may be further added in addition to the fluorocarbon and the carrier gas. Since the etching gas selected during the etching process is a gas which can form more polymer, the polymer formed during the etching process can protect the material layer at the corner of the opening from the residual damage. Therefore, there is no problem that the wide opening angle is rounded. On the other hand, since the money engraving rate of the trench fill layer 412a is greater than the residual ratio of the impedance layer 414 and the material layer 406 of 14 1343621 UMCD-2006-0271 21932 twf.doc/n, therefore, in the process of the remainder, once exposed The trench fill layer 412a' trench fill layer 412a will be etched very quickly, so that the trench fill layer 412b left after the process is in the shape of a dome. When the south of the trench fill layer 412a is 'I13', the trench fill layer 412b is left as C3; when the height of the trench fillet 412a is lower, when the ratio is lower, the trench fillet 412b is left as C4 (for The dotted line indicates it). Therefore, no groove is filled in whether the trench fill layer 412b is C3 or C4.

The shadowing effect caused by the layer does not leave a barrier layer of material at the top corner of the narrow opening 410. Next, please refer to the figure ~ / D, π and increase. * v ι - ~ a few 卜 4 卜 M gully fill 412b ‘ bare narrow opening 410, which together with the wide opening 42 构成 constitute a composite open π 430. In an embodiment, the photoresist layer 416, the resistive layer 414, and the trench fill layer 412b may be simultaneously removed, such as by oxygen ashing. The above-described method of manufacturing the composite opening can be used in a process of making any opening and narrow opening. to make

The manufacturing method of the composite opening of the present invention is because the narrow opening of the prior shaft is used for the side hybrid high-resistance layer, and after the side wide opening is opened, the surface of the remaining trench filling layer is arched. Therefore, the phenomenon that the groove angle is rounded can be avoided, and the narrow opening σ apex angle can be prevented from forming the barrier. In the interlayer window opening of the woven fabric of the present invention, the side surface is higher than the impedance layer, and the surface of the groove is left after the opening is widened. The surplus can avoid the phenomenon of rounding the top corner of the ditch, and at the same time, it can be used in less than fine ore, and the butterfly shaft = bridged, the current can be smashed into a smashed _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a barrier-like dielectric layer formed in a conventional dual damascene process. FIG. 2 is a schematic view of a conventional dual damascene process trench. 3A to 3F are schematic cross-sectional views showing a dual damascene process according to an embodiment of the present invention. FIGS. 4A to 4D are diagrams showing a process of a composite opening according to an embodiment of the present invention. Schematic diagram of the process. [Main component symbol description] 1 (H, 122, 324, 324a: metal layer 106, 306: dielectric layer 106a: barrier-like dielectric layer 110, 310: via opening 110a, 120a: top Corners 112, 312, 312a: trench fills 120, 320: trench 300: substrate 302: Conductive layer 304: lining 314: resistive layer 316: photoresist layer 318: opening pattern 322, 322a: conductive layer 326, 326a: barrier layer 16 (·ς

Claims (1)

1343621 100-1, 17 Bu dd/month coffee repair (more) original ten, patent application scope: 1. A dual damascene process, comprising: • covering a substrate, the substrate has a conductive region and the a conductive layer has been formed on the substrate by a dielectric layer; a dielectric opening is formed in the dielectric layer, and the conductive region is aligned and exposed; • a trench is filled in the via opening Forming a resistive layer on the substrate, covering the Wei dielectric layer and performing a lithography and side process, so that the trench is left in a dome shape, wherein The sculpt rate of the layer is greater than the I insect engraving rate of the impedance layer; , 冓 冓 ΪΓ ΪΓ; ΪΓ 填 填 、 ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ 填 填 填 填 填 填 填 填 填 填 填 填 ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ ΪΓ - a conductive layer. 2_If the cooking process is carried out as described in item 1 of the patent application, the ditch is heavy to the inlaid process> wherein 1.1 of the rhyme-filled layer/ship anti-layer is selected as 3 I 3' In the patent range, the _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ The H-toxic filling layer "Hai dielectric layer of the money engraving selection ratio, V 1 · 2ι 17 丄丄 100-1-17 metal fiber, which is in the patent range of the first two-metal wire In the process, one of the etching gases does not contain oxygen. In the double gold 4 inlay process described in Item 1 of Patent No. 81, the qi gas includes fluorine flue gas. The 隹>% specializes in the double metal inlay described in item 7, wherein the gas used in the etching process also includes a carrier gas. In Huai Erru, she used the double damascene process described in item 8, wherein the gas used in the preparation of the crucible also includes a conditioning gas, which includes nitrogen or carbon monoxide. ω· The double damascene process described in the scope of the patent application, wherein the material of the dielectric layer comprises a low dielectric constant material. 11. The dual damascene process of claim 1, wherein a cap layer is formed on the dielectric layer before forming the via opening. 18 1 u· As claimed in the double damascene process described in claim 1, 2 /, trench filling materials include polymers without anti-reflective properties. 3 13· A method of forming a composite opening, comprising: forming a material layer on a substrate; 5 forming a narrow opening in the material layer; 6 forming a trench fill in the narrow opening; 7 forming on the substrate a resistive layer covering the material layer and the trench fill layer; 8 performing a lithography and etching process to form a wide opening D' in the material layer in communication with the narrow opening 100-1-17 port Leave the trench filled, when the rate of the trench filler; in: two = shape and the impedance layer, bare the width and the narrow opening. Method, twenty-two tlf around the 13th item The composite opening is formed in a ratio of 3 to U. In the Ding/Processing process, the groove filling layer/the impedance layer is selected by the engraving method, and the formation opening of the composite opening in the thirteenth rhyme of the range is =, and the groove is read in the process of entering the engraving process. The engraving rate is greater than the material layer method 2: =,: the ratio of the composite (four) described in item 15 is 1.2 to 2. Ding Shi 'the groove filling layer / the material layer selection method ' rr Shen anti-layer turn 2:::. The formation method of the formation method, and the gas used in the formation of the composite opening described in item 13 of the finalization in a, includes the gas. 22. The formation of the composite opening described in item 19 is as follows. The gas used in the application also includes a carrier gas. In the method of forming a composite opening according to Item 20, the adjusted gas further includes,