TW511225B - Method for forming insulation trench - Google Patents

Abstract

A method for forming an insulation trench at least comprises: (a) forming a mask layer on a substrate, in which the mask layer comprises an opening exposing a portion of the substrate; (b) removing the substrate beneath the exposed portion to form an opening extending through into the substrate; (c) forming an insulation material on the opening in the substrate, in which the insulation material forms an insulation plug in the opening in the substrate; and (d) after the formation of the insulation plug in the opening, removing the mask layer and a portion of the insulation plug so as to expose the surface of the substrate and to ensure that the residual insulation plug is located only in the substrate.

Description

511225 V. Description of the invention (1) 5-1 Field of the invention: The present invention relates to a method for forming an insulation trench, and more particularly to a method for forming an insulation trench without generating parasitic elements due to a gap between adjacent insulation trenches. 5-2 Background of the Invention: With the wide application of semiconductor components, a large number of independent components are mounted on a single semiconductor substrate. Many independent components need to be isolated from each other. One of the commonly used methods to achieve this is to form a trench isolation between adjacent components. The trench isolation at least includes forming a trench or a cavity in the substrate, and then filling an insulating material, such as silicon dioxide. Trench isolation areas can generally be divided into three types: shallow trench isolation (ditch depth of about one micron), medium depth trench isolation (ditch depth of about one to three microns), and deep trench isolation (ditch depth of about Three microns). A conventional method for forming an isolation trench is shown in the first to fifth figures below. Referring to the first figure, the semiconductor wafer 10 includes a substrate 12, and an oxide layer 14, a nitride layer 16, and a patterned photoresist layer 18 are sequentially formed on the substrate 12. The material used for the substrate 12 contains at least polycrystalline silicon, and is usually lightly doped with a dopant that promotes conductivity. The substrate 12 includes an upper surface 15 which is oxidized

V. Description of the invention (2) —- ^ The layer 1 4 is shaped on the upper surface 5 and the material of this oxide layer includes oxide stone and then the nitride layer 16 is formed to cover the oxide layer 14 The material of the nitrided layer is nitride stone. Referring to the second figure, the patterned photoresist layer 8 is used as a mask in the etching process. The patterned photoresist layer 丨 8 defines a hole area. In the etching process, part of the nitride layer 16, part of the oxide layer 1 4, and-part of the substrate 12 are removed. An opening 20 is formed. In addition, this etching process is divided into three etching processes, namely the etching process of the nitride layer 16, the oxide layer 丨 4, and the substrate 1 2. The focus is on the required depth in the substrate 丨 2 to form the opening. φ port 20, for example, the opening 20 is used as a shallow trench. This etching process is mainly to make the depth of the opening 20 less than or equal to one micron. Referring to the second figure, an insulating substance is formed on the nitride layer 16 and within the opening 20, and then a part of the insulating substance and the nitride layer are sequentially removed. Here, the insulator is different from the nitride layer 16 in that when the nitride layer 16 is completely removed, the insulator at the opening 20 position is not removed. This insulating substance becomes an insulating plug 30 on the substrate 12, and this insulating plug 30 can be used as a trench.

Known parameter, the fourth figure, the oxide layer 14 is removed. The oxide layer can be removed by a wet etching method using hydrogen fluoride. As shown in the figure, the etching process will also remove some of the insulation plugs, 30. Unlike the nitride layer 16 and the conventional insulating materials such as nitrides or oxides, the edge of the plug 30 is lower than the substrate 12 and the upper surface 15 during the etching process. A gap 43 is generated between the insulating plug 30 and the lower surface 5.

Page 5 511225 V. Description of the invention (3) More specifically, the insulating plug 30 includes a peripheral wall 44 in which a portion 42 extends below the upper surface 15 and a portion 44 is higher than the upper surface 15. The portion 42 includes a lower section 45 and an upper section 4 6 ′, where the lower section 45 is adjacent to the substrate ② and the high section 4 6 is separated from the substrate 12 by the p'house 4 3. Referring to the fifth figure, an additional insulating layer 5 is grown on the upper surface 5, for example, by a thermal oxidation method. A polycrystalline silicon layer 52 is then formed on the additional insulating layer 5 丨. The spar stone slab layer 5 2 can be finally formed into the word line, which includes the transistor region immediately adjacent to the insulating plug 30, and then the insulating plug system can be used as a trench isolation region. When the time drops, the element generates voltage. Send the pieces that are in the shape of the starting process, and the elements will follow the body, hinder Jingjing, and the electricity will be adjacent to 3, and then 4 will be built, and the backlash will be the most interlaced. On the 40% non-gap interval, until now 'there are some methods to uncover the gap 4 3, such as US Patent No. 6, 0 9 3, 6 52. As shown in the sixth figure, one of the methods for reducing the gap 43 is to lower the surface of the substrate 2 to the first new upper surface 61 before forming an additional insulating layer, etc. The first new upper surface 61 is lower than The upper surface 1 5 'so the gap 4 3 will disappear. As shown in the seventh figure, another method of reducing the gap 4 3 is to remove a part of the insulating plug 3 0 on the substrate 12, and after the gap 4 3 is formed, make the remaining insulating plug 30 completely with the bottom. The substrate 12 is opposite, and the upper section 46 adjacent to the substrate 12 is also removed, so that the substrate 12 becomes the upper surface 15 and becomes the second upper surface 71.

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V. Description of the Invention (4) In summary, the methods used to reduce the gap 4 3 are accompanied by the sign ^ ^ ', so it is necessary to develop a more complete method to reduce the gap 4 3. —, 5-3 Object and Summary of the Invention: The object of the present invention at least includes the disadvantage of forming an insulation trench without a gap & born between the substrate and the insulation trench. The object of the present invention further includes preventing the formation of a gap in the formation of the trenches # 日 寺 Overall, a method of the present invention includes at least the following basic steps. First, an insulating plug is formed in an opening of a substrate, wherein the insulating plug has a surface with an outermost surface extending on a nearest surface of the substrate. Then ‘remove a part of the insulation plug in a horizontal direction until the remaining insulation plug is only inside the substrate. Another method of the present invention comprises at least the following steps. First, a masking layer is formed to cover the substrate, and the masking layer includes exposing a part of the bottom = opening. Next, the exposed portion of the substrate is removed to form an opening extending into the I substrate. Then the 'formation-insulating material's opening in the substrate is plugged with a π edge. After that, perform a removal ^ ± f, remove the mask layer and a Qiu on the same day, and exit the upper surface of the substrate and expose the Zhi, Ba, and the edge plugs to make more than just exposure. Sergeant,

Page 7 511225 V. Description of the invention (5) Only the insulation plug remaining in the substrate. 5-4 Detailed description of the invention: The semiconductor design of the present invention can be widely applied to many semiconductor designs, and can be made of many different semiconductor materials. When the present invention is described by a preferred embodiment, Those skilled in the art should recognize that many steps can be changed, materials and impurities can be replaced, and these general replacements undoubtedly do not depart from the spirit and scope of the present invention. Between them, and the system is less gap. The gap channel does not reduce the gap between the channels. The gap between the gaps is not changed. When it is repaired, it is formed but it will be less shaped. When the shape of the channel is not reduced, the method of making gaps is not necessary. Yuxingou Guan is free from the same ditch, and the new ditch is avoided. The pair is Chengdu, the shape of the needle is changed, and the tone is emphasized by Yu Fangdangxiu. It must be clearly understood that the necessary steps must be in place and the production must be made. The law still breaks. First of all, the difficult point of the first shape is that there are technical difficulties, gaps, but no way

A preferred embodiment of the present invention relates to a method for forming an insulating trench. Referring to the eighth figure, the method includes at least two basic steps. First, as shown in block 81, an insulating plug is formed in an opening in a substrate, wherein the insulating plug has an outermost surface extending on a nearest surface of the substrate.

厶 z: > V. The description of the invention (6) must be followed by the 'as shown in block 82' after removing it in a horizontal direction, including the edge plug until the remaining insulation plug is only at the bottom. The inner pi 7 ditch of the material was formed. After the removal procedure is completed, the surface of the insulation insert is immediately adjacent to the substrate. The plug part is naturally covered. In addition, the cover layer is formed on the substrate. Then fill the opening with the most side wall of the substrate in the open part. In addition, it usually contains a part of the insulation direction and the insulating plug can be put on, and this cover forms an opening. The near surface of the insulating material is in the mouth and immediately adjacent to the insulation The procedure using a chemical machine containing a wet I-embedded plug before plugging is formed in the following steps. First, the mask layer is formed by an oxide layer and a mouth in the mask layer and the substrate, and is formed on the mask layer and the outermost surface of the substrate, and the substrate is insulated. During the removal process, the mask layer can be removed first. The mechanical grinding process removes a part of the process. The nearest surface is then processed on the substrate or the bottom to form a stack of nitride layers with an insulating substance in the mouth. The other edge plug is an insulating plug that removes the horizontal insulating material, and repairs the scratches in the removed material. Obviously, this method uses advanced performance methods, mechanical grinding procedures, and removes some substances to make the substrate A part of the insulating plug can be directly removed. Especially chemical machines

In another embodiment of the present invention, the figures of the drawings and the tenth figure are similarly numbered, and the differences are shown in the ninth and tenth figures. In the ninth, as shown in the prior art, the first to seventh figures are shown or used with an additional symbol "a".

511225 5. Description of the invention (7) New number. Referring to the ninth figure, this figure is a step following the third figure of the conventional technology, in which a part of the insulating plug 3a is located in the substrate 12a. Although the procedure shown in the figure is similar to the fourth figure, there is a significant difference. In the ninth and third figures, the insulating plug 30 is located in the substrate 12 and the substrate 12 and the gap 4 3 will exist between the substrate 12 and the remaining insulating plug 30. However, the insulating plug 3 0 a is located only in the substrate 12 a and there is no gap between the substrate 12 a and the remaining insulating plug 30 a. However, it is worth noting that the upper surface 15 a is independent of the upper surface 15. Further referring to the tenth figure, after the additional insulating layer 5 1 a and the polycrystalline silicon layer 5 2 a are sequentially formed on the upper surface 15 a, no parasitic element is generated because there is no gap. In this method, a part of the insulating plugs 30 and the oxide layer 14 are removed at the same time by a planarization process. A better effect is to use a chemical mechanical polishing process, which can remove different substances at the same time without etching. The question of selectivity is the source of the gap 4 3 in conventional methods. On the other hand, the conventional method uses an etching technique to remove the oxide layer 14, especially a wet etching process, and then the etching selectivity of the oxide layer 14 and the insulating plug 30 causes a gap 43. However, in this embodiment, the oxide layer 14 and part of the insulating plugs 30 are simultaneously removed by other methods, and then the etching selectivity of the oxide layer 14 and the insulating plugs 30 will not cause the gap 43 to be generated. Since the planarization process will inevitably generate some scratches on the upper surface 15a, this embodiment further includes a step of arbitrarily selecting the upper surface 15a to repair all the scratches by a wet etching process.

Page 10 511225 V. Description of the invention (8) Further, in the practical application of this embodiment, the thickness range of the oxide layer 14 is approximately 100 to 50 angstroms, and the thickness range of the nitride layer 16 is approximately It is 1 0 0 0 to 3 0 0 0 Angstroms. In addition, the material of the insulating layer is silicon dioxide, the nitride layer 16 is removed by a chemical mechanical polishing process, and the removal process is a chemical mechanical polishing process. Finally, compared with other conventional technologies, as shown in Figures 6 and 7, the advantages of the present invention include at least the substrate that does not need to be removed, and the structure is formed in the substrate. For example, the doped regions will not be damaged. , And also does not need to use two p steps to remove the oxide layer and part of the insulating plug. The above are merely preferred embodiments of the present invention, and are not intended to limit the scope of patent application for the present invention; all other equivalent changes or modifications made without departing from the spirit disclosed by the present invention shall be included in the following Within the scope of patent application.

511225 Brief description of the drawings The first to fifth drawings are successive cross-sectional schematic diagrams of a method for generally forming an insulation trench. Figures 6 and 7 are schematic cross-sectional views of two methods of usually reducing the gap between adjacent insulating trenches. The eighth diagram is a flowchart of an embodiment of the present invention. The ninth and tenth figures are schematic sectional views of another embodiment of the present invention. Symbols of the main parts ... 1 0 semiconductor wafer 12 substrate 1 4 oxide layer 1 5 upper surface of the substrate 1 6 nitride layer 18 patterned photoresist layer 2 0 opening 3 0 insulating plug 4 1 Side wall 4 2 Insulating plug lower side wall 4 3 Gap 44 Insulating plug upper side wall

Page 12 511225 Brief description of the diagram 4 5 Lower section of the lower part of the side wall of the insulating plug 4 6 Upper section of the lower part of the side wall of the insulating plug 5 1 Additional insulating layer 6 1 Polycrystalline silicon layer 7 1 The second upper surface of the substrate 81 Block 8 2 Block 1 2 a Substrate 1 5 a Upper surface 3 0 a Insulating plug 0 5 1 a Additional insulating layer 52a Polycrystalline silicon layer

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Claims (1)

Called 225 m. ': 1 · A method of forming an insulating trench and a substrate At least a person forms a masking layer to cover the substrate, the mask screen 2 contains: part of an opening of the substrate; ㈢ you include an exposed one Remove the substrate of the 4 storm road parts to form a smelling material; extend into the bottom to form the opening / plug of an insulating substance in the substrate; and form an insulating plug-in-second division procedure to keep on the same day π Buding, the hot plug to remove the plug is not only to expose the top of the substrate, two copies of the insulation, substrate: residual "the insulation plug, in which the removal process: two =: province The insulating plug includes at least one peripheral side wall adjacent to the substrate. 2. The method according to item 丨 of the patent application, wherein the above-mentioned mask layer is formed by stacking an oxide layer and a nitride layer. 3 · The method according to item 1 of the patent application, wherein the above-mentioned insulating substance is simultaneously formed on the inside of the opening and the masking layer. 4 · = The method according to item 1 of the patent application, further includes performing the removal. Remove the insulating material from the masking layer before the procedure. Scope of the methods, Paragraph 1, wherein said line of the mask layer removed to a chemical mechanical polishing process. Page 14 511225 No. 89124590 6. Scope of patent application. For the method of applying for the target range of the patent application, the removal procedure described in i.10, L ^ T, a chemical mechanical polishing procedure, and a method of forming an isolation include at least: Material, forming an oxide layer on the substrate; and the substrate to form a nitride layer on the oxide layer; transferring a pattern to the nitride layer, an opening of the oxide layer extending through the substrate; forming a An insulating layer is formed in the opening to form an insulating plug to remove the nitride layer; and a 'two-row-migration procedure to simultaneously remove a portion of the oxide layer spear, the insulating plug f is in a horizontal direction until the residual The insulating plug is located only inside the substrate, and the insulating plug remaining after the removal process is completed includes at least one peripheral sidewall immediately adjacent to the substrate. The above-mentioned substrate is a silicon semiconductor substrate according to the method in the seventh item of the patent application scope. 9. The method according to item 7 of the scope of patent application, wherein the thickness of the above-mentioned oxide layer ranges from about 1000 to 5000 angstroms. The method according to item 7 of the scope of patent application, wherein the thickness of the nitrided sound is in the range of about 1000 to 300 angstroms. 9 89124590 VI. The method of applying for a patent for more than one month ^ 2 The method of item 7 of the scope of patent application, such as the above-mentioned insulating layer is the nitrided layer described in 13. The method of item 7 of the scope of patent application Method, wherein the above is a chemical mechanical polishing procedure. Removal procedures are as follows: 4. According to the method of claim 7 in the scope of patent application, after completing the _ @ ^ a on the side substrate and the remaining insulating plug in order, an oxide layer and a gate electrode. After removing the program, it becomes a gate Page 16