TW535255B - Method of preventing increase in top critical dimension of contact window with spacer - Google Patents

Abstract

This invention discloses a method of preventing increase in top critical dimension of contact with spacer. Firstly, a first dielectric layer, an etching stop layer and a photoresist pattern layer are sequentially formed on a substrate. Then, the first dielectric layer and the etching stop layer are etched using the photoresist pattern layer as a mask to form a contact window. Subsequently, a second dielectric layer is conformally formed on the etching stop layer and the surface of the contact window and oxygen, fluorocarbon and carbon oxide gases are used as etching-reaction gases to anisotropically etch the second dielectric layer to form a spacer on the sidewall of the contact window, in which the flow rates of the oxygen and fluorocarbon are in the ranges of 2-6 sccm and 4-8 sccm, respectively. Because the etching stop layer is an oxynitride layer and the above-mentioned etching-reaction gases have a low etching rate towards it, an increase in the top critical dimension can be avoided and thus device reliability is increased.

Description

^ 5255

Avoiding ί = is related to a semiconductor process, especially about inserting metal wires to produce bad electrical properties :::: The method of increasing the dead distance, and thus preventing the related technology from tiling the reliability of the components. The performance of integrated circuits must be reduced in order to increase the size of the integrated circuit. The size of the integrated circuit must be reduced. The integrati⑽ is described. In order to achieve the purpose of k, the macro of the contact window (cri u 勹 j should be reduced after it is built up), and the lclctlcal dimension (CD) is also a problem. Traditionally, it is difficult to use the ^ lithography technology. In order to solve the above = traditionally, after the contact window is formed, an extra anchor is used to form a spacer (spacer) to contact the side wall from the side wall to form a gap period. The top of the contact window = to 'contact The macro at the top of the window becomes larger. In] The metal interconnect formed at the top of the contact _ (interc ie! The macro at the top of the contact window becomes larger and will still be within specifications. ^ No r :: f See the shrinking +, the macro at the top of the contact window will become larger Causes poor electrical contact of the metal wires, which reduces the reliability of the component. Shu 51 1 Ming L To further understand the background of the present invention ^ The following with Figures 1 a to 1 d illustrates the conventional formation of contact windows with gap walls First, please refer to the second source: substrate 10 ° 'for example-a silicon wafer, a dielectric layer 102, such as a silicon oxide layer, and an opening 104a are sequentially covered on the substrate 100 surface in order. A photoresistive layer. Μ · μ population is increased. 4 This dielectric layer 102 is used as an interlayer dielectric (ILD). Next, please refer to Figure 1b for a photoresist pattern. Layer 丨 〇4 as a curtain

535255 V. Description of the invention (2) = engraved f-dielectric layer 1G2 to form-contact fiQ2a and expose the substrate ι〇〇 clothing w. As shown in Figure 1C, after stripping the photoresist pattern layer 104, the electrical compliance of the electrical layer 102 and the surface of the contact window 〇2a is formed-ίτ: 6, such as oxygen cut layer or tetraethyl A sillate oxide (oxide) layer for subsequent formation of a barrier wall. 106, most referring to the second dielectric layer engraved with anisotropy in the figure ld: a gap 106b is formed from the side wall of the window 102a to obtain a gate gap 10. "The contact window 106a. However, when the etching process is performed to form a portion ', the upper macro of the contact from the top contact window i06 becomes larger due to the over-etching of the upper surface of the first dielectric layer 102, which reduces the element reliability. Summary of the invention: The purpose of the present invention is to provide a method for preventing the macro distance on the top of the gap from increasing, by forming an etch stop layer on the dielectric layer between the metal layers, thereby blocking The dielectric used to form the gap wall prevents over-etching from happening so that the top macro will not occur, and the reliability of the part.疋 什 疋 Window ΐ ΐ ΐΐ 'The present invention provides a method for forming a spacer with the following steps: providing a substrate, the surface of the substrate is sequentially covered with a dielectric layer, an etch stop layer and A photoresist pattern layer. The photoresist pattern layer is used as a mask to etch the etch stop layer and the first dielectric layer to form a contact window and expose the surface of the substrate; a conformation is formed on the etch stop layer and the 4 south facing surface. A second dielectric layer; and an anisotropically etched second

535255 V. Description of the invention (3)-~ The dielectric layer forms a gap wall on the side wall of the contact window, in which oxygen fluorocarbon gas and carbon oxide gas are used as the etching reaction gas, and the flow rate of fluorocarbon gas is 4 ~ 8 Sccm range. The second dielectric layer is one of a silicon oxide layer and an ethyl silicate oxide layer, and the etch stop layer is a oxynitride layer having a thickness in a range of 4200 to 400 angstroms. In addition, the above-mentioned anisotropic working pressure is in the range of 80 ~ 100 mTorr, and the high-frequency work and low-frequency power used are in the range of 70 ~ 900 W and 100 ~ 300W, respectively, and the time is in the range of 20 ~ 30 second range. In addition, the flow rate of oxygen is in the range of 2 to 6 ㈣ 且, and the flow rate of the anti-oxidant gas is in the range of 50 to 100 seem. Detailed description of the preferred embodiment: The method of forming a contact window with a gap wall according to an embodiment of the present invention will be described below with reference to Figs. 2a to 2d. First, please refer to FIG. 2a, and provide a substrate 200, such as a stone evening circle. A semiconductor element is formed on the surface of the substrate 200. For simplicity, only a flat substrate is shown here. Next, a first dielectric layer 202, such as oxide, is sequentially formed on the surface of the substrate 200 by a conventional deposition technique, such as a silicon oxide layer, a stop layer 204, such as silicon oxynitride (Si 0N), and a light Resistive layer (not shown). In this embodiment, the etch stop layer 204 is also used as a "dielectric anti-reflective coating (DARC)" and has a thickness in a range of 200 to 400 angstroms, and a preferred thickness is in angstroms. Subsequently, a photoresist layer is defined using a conventional lithography process to form a photoresist pattern layer 206 having an opening 206a. Next, referring to FIG. 2b, using the photoresist pattern layer 206 as a mask, the anti-reflection layer 204 and the first dielectric layer 202 are inscribed in order to form a

0389-7478twf (n); IDF200112357; P910021; spin.ptd page 6 535255 V. Description of the invention (4) " 一 "-contact the solid 202a and chrome out the surface of the substrate 200. Subsequently, the photoresist pattern sound 20 6 is removed. … Next, please refer to FIG. 2c. Similarly, a second dielectric layer 2 having a thickness of about 80 0 to 1 500 angstroms is formed on the antireflection layer 204 and the surface of the contact window 202a by the conventional deposition technique. 〇8, for example, a silicon oxide layer or a tetraethyl silicate oxide (TEOS oxide) layer formed by a chemical vapor deposition (CVD) method. Finally, referring to FIG. 2d, the second dielectric layer 208 is anisotropically etched and the antireflection layer 204 is used as an etch stop layer for about 20 to 30 seconds to form a gap on the sidewall of the contact window 202a The contact window 208a of the wall 208b to obtain a macro (CD) smaller than the contact window 202a. In this embodiment, the remaining reaction gas used in the above-mentioned anisotropic remaining time includes: oxygen (0 2), fluorine $ reverse gas (C4F8), carbon oxide gas (CO) and as a carrier; argon of gas Gas (Ar). Among them, the flow rate of oxygen is in the range of 2 to 6 sCCffl, and the preferred flow rate is 4 sccm. The flow rate of the fluorocarbon gas is in the range of 4 to 8 sccm 'and the preferred flow rate is 6 seem. The flow rate of carbon oxide gas is 50 ~ 100 seem, and the flow rate of argon gas is 120 ~ 160 sccm. Moreover, the working pressure for this anisotropic money engraving is in the range of 80 ~ 100 mTorr, and the preferred working pressure is 90 mTorr. In addition, the south-frequency power (27 MHz) and low-frequency power (2 MHz) used in the anisotropic etching in this embodiment are in the range of 700 to 900 W and 100 to 300 W, respectively. When performing anisotropic etching under the conditions described above, since the dielectric anti-reflection layer used in the present invention can be used as a termination layer in the anisotropic money engraving process, during the formation of the gap wall, overetching the Reactive reflection layer

535255 5. Description of the invention (5) Prevents the macro on the top of the contact window from becoming larger. Compared with the conventional method, it can effectively prevent the problem of bad electrical contact of the metal wire and improve the reliability of the component. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make changes and retouching without departing from the spirit and scope of the present invention. The scope of protection shall be determined by the scope of the attached patent application.

0389-7478twf (n); IDF200112357; P910021; spin.ptd Page 8 535255 Schematic illustration of the diagram: In order to make the above-mentioned objects, features, and advantages of the present invention more obvious and understandable, the following are particularly preferred The embodiments and the accompanying drawings are described in detail as follows: Figures 1 a to 1 d are schematic cross-sectional views of a conventional contact window with a gap wall. Figures 2a to 2d are schematic cross-sectional views showing a contact window with a gap wall formed according to an embodiment of the present invention. [Symbol description] 100, 200 ~ substrate; 102, 202 ~ first dielectric layer; 102a, 106a, 202a, 208a ~ contact window; 104, 206 ~ photoresist pattern layer; 104a, 206a ~ opening; 106, 208 ~ The second dielectric layer; 106b, 208b ~ the spacer; 204 ~ the remaining stop layer.

0389-7478twf (n); IDF200112357; P910021; spin.ptd Page 9

Claims (1)

535255 A method for forming a contact window with a gap wall includes the following steps: a substrate is provided, the surface of the substrate is sequentially covered with a first dielectric layer, an etch stop layer, and a photoresist pattern layer; a person uses the photoresist pattern layer Etch the etch stop layer and the first dielectric layer 'as a mask to form a contact window and expose the substrate surface; a conformally shaped dielectric layer on the etch stop layer and the contact window surface; and an anisotropic layer The second dielectric layer is etched to form a gap wall on the sidewall of the contact window. ^ 2 The method for forming a contact window with a partition wall as described in item 1 of the scope of the patent application, wherein the first dielectric layer is a silicon oxide layer. ^ 3 The method for forming a contact window with a partition wall as described in item 1 of the scope of the patent application, wherein the second dielectric layer is one of a silicon oxide layer and a tetraethylsilicic acid oxide layer. Wind 4. The method for forming a contact window with a partition wall as described in item 1 of the scope of the patent application, wherein the etch stop layer is an anti-reflection layer. 5. The method for forming a contact window with a partition wall as described in item 1 of the scope of the patent application, wherein the etch stop layer is a silicon oxynitride layer. 6 · The method for forming a contact solid with a partition wall as described in item 1 of the scope of the patent application, wherein the anisotropic etching uses oxygen, fluorocarbon gas, and slave oxide gas as the inert reaction gas, and the random carbon gas The flow is in the range of 4 ~ 8 seem. 7 · Form a contact with a partition as described in item 6 of the scope of patent application 535255 6. Method of applying patents The method of window, wherein the reaction gas further includes argon as a carrier gas and the flow rate is in the range of 120 ~ 160 seem. 8. The method of forming a contact window with a partition wall as described in item 6 of the scope of the patent application, wherein the flow rate of the oxygen is in the range of 2 to 6 s c c m. 9. The method for forming a contact window with a partition wall as described in item 6 of the scope of the patent application, wherein the flow rate of the carbon oxide gas is in the range of 50 to 100 sccin. 10. The method for forming a contact window with a gap wall as described in item 1 of the scope of the patent application, wherein the working pressure of the anisotropic etching is in the range of 80 m to rr mTorr. 11 · The method for forming a contact window with a gap wall as described in item 丨 of the scope of patent application, wherein the high-frequency power and low-frequency power used in the anisotropy are between 70 0 ~ 90 0 W and 100, respectively. ~ 300W range. Fans with a contact thickness of ~ 30 seconds Fans with a thickness of 200 to 400 Angstroms that form contact with a gap wall 0389-7478twf (n); IDF200112357; P910021; spin.ptd Page 11