TWI265589B - Method to form a shallow trench insulation - Google Patents

Abstract

This invention discloses a method to form the insulation of a shallow trench. After the etching process of a shallow trench is carried out, one nitrogenous oxide layer process is additionally introduced in order to nitrogenize a lining oxide layer and the cushion oxide layer exposed on the lateral wall of the shallow trench, so a nitrogenized oxide silicon layer can be formed, so the growth ability of the oxide layer can be inhibited, so the beak at the upper edge on the shallow trench can be restricted in order to meet the need when the dimension of the following fabricated device is required to be miniaturized.

Description

1265589 A7 B7 V. INSTRUCTIONS () Field of the Invention: (Please read the note on the back and then fill out this page) The present invention relates to a method of semiconductor manufacturing, and in particular to After the trench is etched, a F j ^ layer nitridation step is added to form a shallow trench isolation manufacturing method. BACKGROUND OF THE INVENTION: In the integrated circuit technology, 'metal oxide semiconductors (Μ^1 〇_ Semiconductors; M0S) transistors are the most important basic electrons and bodies. Typically, a complete integrated circuit consists of thousands of MOS transistors. Therefore, it is necessary to add an isolation structure for electrical gland between adjacent transistors to prevent the size of the adjacent elements of the adjacent transistors from being shortened, and the isolation structure between the elements must also be reduced. Component isolation techniques also add to the difficulty of shrinking the isolation structure between components. Various methods of component isolation have been developed, especially in the sub-half micron integrated circuit process, which is most widely used by Shallow Trench Isolation (STI). Printed by the Intellectual Property Office of the Ministry of Economic Affairs and the Consumer Cooperatives. Please refer to Figures 1 to 5, which are shown as the manufacturing process of the conventional shallow trench isolation. Please refer to Figure 1 for illustration. A semiconductor substrate 1 is provided, typically a germanium substrate. In an oxygen-containing environment, on a substrate of 10 2, the paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) 1265589 A7 B7 5. The invention description () forms a layer of pad oxide layer 12 (pad oxide). The pad oxide layer 12 is preferably formed of cerium oxide. Thereafter, a layer of tantalum nitride (Si3N4) 14 is deposited on the pad oxide layer 12 using low pressure chemical vapor deposition (LPCVD) or other deposition method. The entire wafer will then be subjected to a lithography process. Referring to FIG. 2, after the tantalum nitride layer 14 is formed, a photoresist is defined to expose the nitride layer 14. On the wafer, the mask pattern of the desired trench 20 is transferred to the photoresist using a conventional lithography process to form a photoresist layer 16. Thereafter, the entire wafer is subjected to an etching process. Referring to FIG. 3, when the photoresist layer 16 is formed, it can be used as a mask to carry out a process. The underlying nitride layer 14, the pad oxide layer 12 and the substrate 1 are sequentially etched by wet etching or dry etching. Thereafter, the desired trench 20 is formed in the substrate 10. (Please read the notes on the back and fill out this page again)

Ordered by the Intellectual Property Office of the Ministry of Economic Affairs, the Consumer Cooperatives Printed After the etching has been dug up to the proper depth and the required trenches 2 are formed in the substrate, the sidewalls of the pad oxide layer 12 are exposed in subsequent processes. Therefore, when the etching process for rounding the upper edge of the shallow trench is performed, the area of the bare oxide film 12 is larger, and the bird's beak is easily formed. Next, the photoresist layer 16 is removed, for example, by an ashing step. Please refer to Figure 4. Then, a thermal oxidation step is performed to form a liner oxide layer 18 on the surface of the trench 20 to repair the surface layer to which the trench 20 is etched. Then, using chemical vapor deposition or other deposition methods, fill the trench 2〇 with yttrium oxide to form a yttrium oxide line. ♦ This paper scale applies to the Chinese National Standard (CNS) A4 specification (210X297 public Chu) 1265589

V. Description of the invention () c Please read the precautions on the back and then fill out this page > Then, using a chemical mechanical polishing (CMp) method or other grinding method to remove the tantalum nitride layer 14 above the substrate 10, a portion of the tantalum oxide layer 22, and the tantalum oxide layer 12' leaving only the trench 2 Another portion of the ruthenium oxide layer 22 is shown in Figure 5. It is known from the above that in the shallow trench isolation process, the tantalum oxide layer 12 at the upper edge of the shallow trench is formed by a circular etching process, so that the exposed area becomes large, and the bird's beak phenomenon is easily formed. The size of this beak easily occupies the active area and the component size is not easily reduced. In addition, there is an improved method for suppressing the formation of bird's beak by utilizing the area where the oxide layer is etched back. However, when filling with ruthenium deposits, it is not easy to control, leaving voids, which affect the electrical properties of the components. Therefore, an effective method is needed to solve this problem. OBJECTS AND OVERVIEW OF THE INVENTION: Ministry of Economic Affairs, Intellectual Property Office, Staff Consumption Cooperative Printing In view of the above-mentioned invention background, the traditional shallow trench isolation process makes the exposed area of the tantalum oxide layer change. Large, and easy to form a bird's beak. Therefore, it is easy to occupy the active area so that the size of the element is not easily reduced. And, when filled with crushed deposits, it is not easy to control, leaving voids to affect the electrical properties of the components. Accordingly, the main object of the present invention is to provide a shallow trench isolation for the present invention. 4 The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) 1265589

The method of formation. First, a ^ tuL.. _ gas / channel is formed on a substrate. Then, using furnace tube nitriding or tempering temperature nitriding, the oxidation and m butyl rolling layer nitriding step is performed to make the lining oxide layer (please read the back sheet of the precautions and then fill in the page > layer, ma emulsified layer 虱And forming a nitrogen oxynitride as a barrier layer. 7 A further object of the invention is to provide a shallow trench isolation method. The invention utilizes furnace tube nitriding or rapid temperature gasification to carry out (4): "匕 step : Make the oxide layer and the oxygen in the upper edge of the shallow trench...disintegrate and form the nitrogen oxide dream layer, which can prevent the oxidation from continuing below, and can limit the phenomenon of the black mouth. First, on a f material Forming a tantalum oxide layer, a nitride layer, and a photoresist layer. The box performs a lithography and (four) step to form a shallow trench in the semiconductor substrate. Then the photoresist layer is removed. Thereafter, the furnace tube nitrogen is utilized. Or rapidly warming, performing an oxide layer nitridation step 'so that the liner oxide layer and the pad oxide layer adjacent to the shallow trenches' are nitrided and form a oxynitride layer. An oxygen-cut layer is formed to fill Ditch. Then, proceed to flat = base: Forming a shallow trench isolation structure. Printing by the Intellectual Property Office of the Ministry of Economic Affairs, Employees' Consumption Cooperatives According to the above-mentioned purposes, the present invention provides a method for forming shallow trench isolation. After the shallow trench is etched, an oxidation layer nitridation step is added. The lining oxide layer and the exposed oxide layer on the upper edge of the sidewall of the shallow trench are nitrided to form a yttria layer. Therefore, the regeneration ability of the oxide layer is reduced, and the black mouth of the upper edge of the shallow trench is suppressed while preventing In the case of filling the paper with the deposition, the Chinese National Standard (CNS) A4 specification (210x297 public) 1265589 A7 B7 is applied. 5. When the invention is described (the component is electrically affected) to provide the demand for future component size reduction. Brief Description: The preferred embodiment of the present invention will be explained in more detail in the following description with the following figures, wherein: Figures 1 to 5 show the manufacturing flow chart of the conventional shallow trench isolation. And Figures 6 through 11 illustrate a manufacturing flow chart for shallow trench isolation in accordance with a preferred embodiment of the present invention. Note Complete this page and then read it back)

I-booking · Ministry of Economic Affairs Intellectual Property Bureau employee consumption cooperative printing 10 substrate 12 pad oxide layer 14 tantalum nitride layer 16 photoresist layer 18 lining oxide layer 20 trench 22 yttrium oxide layer 110 substrate 112 pad oxide layer 114 nitriding矽 layer 116 photoresist layer 118 lining oxide layer 120 trench 122 ruthenium oxide layer 6 This paper scale is applicable to China National Standard (CNS) A4 specification (210X 297 mm) 1265589

V. Description of the Invention (Detailed Description of the Invention: The present invention discloses a method for forming shallow trench isolation. After the shallow trench is etched, an oxidation layer nitridation step is added to make the lining oxide layer and the upper edge of the shallow trench sidewall exposed. The ruthenium oxide layer is nitrided and forms a nitrogen oxide dream layer, whereby the bird's beak on the upper edge of the shallow trench is suppressed. Please refer to Fig. 6 to Fig. 11 for the green display of the shallow trench isolation method of the present invention. A preferred embodiment is shown in Fig. 6. A semiconductor substrate 110, such as a germanium substrate, is provided. In an oxygen-containing environment, a pad oxide layer 112 is formed on the substrate 110 by heating. The oxide layer 112 is preferably formed of hafnium oxide. Thereafter, a layer of tantalum nitride 1 14 is deposited on the pad oxide layer 112, for example, using low pressure chemical vapor deposition (LPCVD) or other deposition methods. Then, the entire wafer will The lithography process is performed. Referring to FIG. 7, after the tantalum nitride layer 114 is formed, the photoresist is defined to expose the tantalum nitride layer 11. On the wafer, the conventional lithography process is used to Ditch diagram of the trench 1 2 0 And transferred to the photoresist to form a wide photoresist layer 116. After that, the entire wafer is further subjected to an etching process. Referring to FIG. 8, when the photoresist layer 116 is formed, it can be etched as a mask. Process, and sequentially etch the underlying tantalum nitride layer 114, the paper size is applicable to the Chinese National Standard (CNS) A4 specification (210x297 mm) (please read the note on the back and fill out this page) - Booking · % Economy Ministry of Intellectual Property Office Staff Consumer Cooperatives Ministry of Printing and Economy Ministry Intellectual Property Bureau Staff Consumer Cooperatives Printed 1265589

5. Description of the Invention (Oxide layer 112 and substrate 11G. (4) Process, preferably in wet mode (4), however, the present invention is not used herein, the etching process of the present invention can also be dry etched into 4 The desired trench is formed in the material 110. Referring to Figure 9, after the proper depth is dug and the desired trench 120 is formed in the substrate 110, the photoresist layer m is removed, for example, by an ashing step. Then, a thermal oxidation step is performed to form a "layer oxide layer 118 on the surface of the trench 12" for repairing the surface of the trench 12, which is etched, and then performing a nitridation step so that the upper edge of the sidewall of the trench 12 is bare. The oxide layer 112' is nitrided and forms an oxynitride layer. The method of nitriding the oxide layer is preferably performed by gasification of the furnace tube or rapid temperature nitridation, wherein the furnace tube is nitrided or the gas is rapidly heated and nitrided. It is a gas (N2), nitrogen oxide (10), nitrous oxide (NH3) or ammonia (NH3). However, the present invention is not limited thereto, and other gases which can be used in the nitriding step are applicable to the present invention. In the nitriding step, the liner oxide layer 118 is also nitrided into a hafnium oxynitride layer. According to the description of 帛 10 ® , then, using chemical vapor deposition or other deposition methods, (4) 120 is filled with yttrium oxide, and a yttrium oxide layer 122 is formed. Then, the entire wafer is subjected to a polishing step. Please refer to FIG. It is illustrated that the cerium nitride layer 114, the yttrium oxide layer 122, and the pad oxide layer 112 above the substrate 110 are removed by a chemical mechanical polishing (CMp) method or by other methods of grinding, leaving only in the trench 12 Oxidation 8 (please read the notes on the back and fill out this page)

1265589

V. INSTRUCTION DESCRIPTION () 矽 层 122 In summary of the above, the present invention discloses a method of manufacturing several trenches. After the shallow trench is etched, a ^ ^ and oxide layer nitridation step is added to form the exposed oxide layer of the upper edge of the sidewall of the shallow trench and a lining layer to form the oxynitride layer. Therefore, the beak of the upper edge of the shallow trench is suppressed while preventing the electrical properties of the component from being affected to provide a demand for future component size reduction. The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention as defined by the present invention; Modifications or modifications are intended to be included in the scope of the claims below. (Please read the notes on the back and fill out this page.) Printed by the Ministry of Economic Affairs, Intellectual Property Office, Staff and Consumer Cooperatives. 9 This paper size applies to the Chinese National Standard (CNS) A4 specification (210X297 mm).

Claims (1)

1265589 A8 B8 C8 D8 VI. Patent Application Scope of Application: (Please read the note on the back and fill out this page) 1. A method for manufacturing shallow trench isolation, including at least: forming a trench on a substrate, where The substrate further includes a pad oxide layer and a tantalum nitride layer sequentially stacked; forming a liner oxide layer on one sidewall of the trench; and performing a thermal nitridation step to cause the liner oxide layer and the trench sidewall The exposed pad oxide layer is nitrided and forms a hafnium oxynitride layer, respectively. 2. The method of claim 1, wherein the thermal nitridation step utilizes a furnace tube nitridation step. 3. The method of claim 2, wherein the gas used in the furnace tube nitriding step further comprises a nitrogen (NO, nitrogen oxide (N〇), nitrous oxide (乂0) or A group consisting of ammonia (NH3), etc. 4. The method of claim 2, wherein the thermal nitridation step utilizes a rapid temperature nitridation step. 5. The method of claim 4, wherein the gas used in the rapid temperature nitridation step further comprises a nitrogen (NO, nitrogen oxide (NO), nitrous oxide (沁0) or A group of ammonia (Nh3), etc. 10 This paper scale applies to China National Standard (CNS) A4 specification (210X297 mm) 1265589 Α8 Β8 C8 D8 VI. Patent application scope Ministry of Economic Affairs Intellectual Property Bureau employee consumption cooperative print 6 The method for manufacturing a shallow trench isolation includes at least: forming a trench on a substrate, wherein the substrate further comprises a tantalum oxide layer and a nitride layer stacked in sequence; forming an oxide layer on the trench On one side wall; carry out a heat The nitriding step is such that the lining oxide layer and the exposed pad oxide layer on the sidewall of the trench are nitrided and form a yttrium oxynitride layer, and a ruthenium oxide layer is formed to fill the trench. The method of claim 6, wherein the method for forming the trench comprises: sequentially forming the pad oxide layer, the nitride layer and a photoresist layer on the substrate; performing a lithography and surname step The method of forming the trench in the substrate; and removing the photoresist layer. The method of claim 6, wherein the thermal nitriding step utilizes a furnace tube nitriding step. The method of claim 8, wherein the gas used in the furnace tube nitriding step further comprises a nitrogen (NO, nitrogen oxide (ν〇), nitrous oxide (Ν2〇) or ammonia (ΝΗ3) ) (1) Please read the following notes on the back page and fill in the page. Patent application scope 10. If the patent application scope is the sixth item The method of the present invention, wherein the thermal nitridation step utilizes a rapid temperature nitridation step. The method of claim 1, wherein the gas used in the rapid temperature nitridation step further comprises A group consisting of nitrogen (NO, nitrogen oxide (NO), nitrous oxide (N2〇) or ammonia. 1 2. A method for manufacturing shallow trench isolation, including at least: on a semiconductor substrate Forming a pad oxide layer and a tantalum nitride layer; performing a lithography step to form a trench in the semiconductor substrate; forming a liner oxide layer on one sidewall of the trench; performing a thermal nitridation step, The pad oxide layer and the pad oxide layer on the sidewall of the trench are nitrided and respectively formed into a hafnium oxynitride layer; a niobium oxide layer is formed to fill the trench; and a planarization step is performed. 13. The method of claim 12, wherein the thermal nitriding step utilizes a furnace tube nitridation step. The Ministry of Economic Affairs, the Intellectual Property Office, and the Employees' Cooperatives Co., Ltd. prints the method described in the patent scope of 513, wherein the gas used in the nitrogen production step of the furnace tube is further selected from nitrogen (8) and nitrogen oxide ( N〇), emulsified nitrous oxide (Να) or ammonia (NH3), etc. - group. 12 1265589 A8 B8 C8 D8, Patent Application No. 1 5 - The method of claim 12, wherein the thermal nitridation step utilizes a rapid temperature nitridation step. 1 6 · The method of claim 1 顼 wherein the gas used in the rapid temperature nitridation step is further selected from the group consisting of nitrogen (N2), nitrogen oxides (NO), and nitrous oxide (N2). 〇) or ammonia (NH3) and other groups of people. (Please read the notes on the back and fill out this page.) Printed by the Consumer Intellectual Property Office of the Intellectual Property Office of the Ministry of Economic Affairs. This paper scale applies to China National Standard (CNS) A4 specification (210X297 mm)