TWI304632B - - Google Patents

Description

1304632

FIELD OF THE INVENTION The present invention relates to semiconductor processes, and more particularly to a method of forming a deep uniform shallow trench isolation structure (S TI ). BACKGROUND OF THE INVENTION With the development of semiconductor integrated circuit (Jc) fabrication techniques, the number of p-body components in a wafer has been increasing, and the size of components has been continuously reduced due to an increase in the degree of integration. As the size of the components shrinks, the insulation or isolation structure between the components in the wafer is also reduced, and the manufacturing technology needs to be improved. In the case of the element isolation technology, the conventional partial oxidation process (L〇c〇s) is no longer applicable in the case of miniaturization of the component size, mainly due to the problem of invading the bird's beak structure. Therefore, the shallow trench 1 sol at ι〇η (STI) process has become the most commonly used technology due to its small isolation area and the flatness of the substrate after completion. The use of a sill-based 1C inner wall will result in a sufficiency of a. Next, the flow of the conventional shallow trench isolation structure will be described in Figs. 1A to 1E. Referring to Fig. 1A, an oxide layer 12 and a tantalum nitride layer 14 are sequentially formed on a semiconductor substrate 1 . Referring next to Fig. 1B, a shallow trench 16 is formed on the bottom 10 by a lithography and etching process. Referring to the figure, the ruthenium substrate 1 is subjected to a thermal oxidation reaction to form a lining oxide layer 18 on the shallow trench 16 to remove material damage during etching of the ruthenium substrate. Then refer to the figure 1)). In the space of the shallow trench, the chemical vapor dep〇siti〇n (CVD), the edge of the material (is ο 1 at ο r ) 1 9 Into it, for example, high-density plasma

Page 5 1304632 V. Description of the invention (2) Phase deposition method (hi gh densi. + Shi Xi et al., y plasma CVD, HDP-CVD) will planarize the surface of the oxidization (CMP) 6 in. Finally, the structure is removed by chemical mechanical polishing, as in the case of the first substrate, to form a shallow trench spacer on the semiconductor substrate 10. ° "Insulate the elements on the semiconductor substrate 10 in the above-mentioned conventional radish by dry etching, for example ^ ^ 'the formation of shallow trenches 16 etching step, silane (CFO, three-depleted methane (°c ^ active ions Etching (ME), by removing the pad oxide 12 with t / 3) and argon (Ar) as a reaction gas, several thousand angstroms (A, Lu Shishi layer 14 after 'will be Shi Xi base; i 〇 〇 银 银 银 通常 通常 通常 通常 通常 通常 通常 通常 通常 通常 通常 通常 通常 通常 通常 通常 通常 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银 银The etching machine's ga $low ι $, and the influence of the replacement of the machine, the etched depth of the shallow trench 16 不一致 Ϊ Ϊ ί ί ί ί 结构 结构 结构 结构 结构 结构 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻 蚀刻SUMMARY OF THE INVENTION For the quality control of the integrated circuit, a summary of the invention is provided to solve the problem of controlling the depth of the shallow trench structure. Another method of constructing the depth of the present invention is to fabricate a semiconductor substrate according to the present invention. Steady system uniform control of the following The shallow guide is used for the same deep groove junction suitable for the body base 0503-8385TWF3; daphne.ptc 1304632 WJL·5, the invention description (3) sequentially forms an end point control layer and a layer and defines a groove $ > sacrificial layer Then, the energy layer is formed on the sacrificial layer as 冓=case:;;;=; layer 'such as light", and an opening is formed to expose the semiconductor layer and the end point control layer Continued with an established remainder of 5. After that, the energy sensing sacrificial layer is removed until the semiconductor substrate and the read ratio of the endpoint are approximately equal to the ratio of the thickness of the sacrificial layer; The ratio of the two. The rate of the base of the body / the rhyme of the sacrifice layer of the sacrificial layer: i ί U ί: U advantage lies in the ratio of the rate of sacrificial rate of the thickness of the sacrificial base = When the stratified layer is deposited, it is used as the control of the etch end point. The ratio of the etch rate to the end point control is the same, because the gas is etched on different materials. ^ ^.. B„.. The thickness of the sacrificial layer is etched and the trench is etched deep. - Cheng, proportional relationship 'stable control of the uniformity of the ditch depth. The structure:: further provides a shallow trench isolation to form a pad oxide layer, a pad gas #1 first on the semiconductor substrate sequentially as a mask, (4) a sacrificial layer, an end point layer to form an opening to expose the underside After the semiconductor substrate: j 1 婶 = ^, 'with a predetermined silver engraved gas # engraved the exposed semiconductor substrate '1:, θ until reaching the end control layer to form a trench in the semiconductor substrate, wherein The ratio of the depth of the trench/the thickness of the sacrificial layer is approximately equal to the rate at which the semiconductor substrate is etched/the rate at which the sacrificial layer is engraved _丨FW ΐΚ 1Γ f[> ilJJLUJll UllLUJU .LJ JL UJ Jl JIJIU J... ... " 0503 -8385TWF3;daphne.ptc 1304632 Corrected tea on ^) 1124259, the fifth month, the invention description (4) = the proportion of the person. Then, a layer of inner layer is formed on the inner side of the trench by thermal oxidation, and an insulating material is deposited to fill the trench. Finally, the process is performed to remove the excess endpoint control layer to form a shallow trench isolation junction. Embodiments The method of controlling the etch depth of the shallow trench isolation structure according to the present invention will be described in detail below with reference to FIGS. 2A to 2C. Form - A 22nd: On a semiconductor substrate 2, a mat 22 is formed in a conventional manner. For example, generally, in the formation of a shallow trench isolation structure, a pad oxide layer (pad nitride) is generally formed on the germanium substrate as a pad structure 22 to provide a germanium substrate in the etch. Insulation protection.佼Immediately etching only the garments. Referring now to Figure 2A, on a typical bedding structure 22, the inlet boat forms an end point control layer 24 and a sacrificial layer 26. The endpoint control layer 24 can be controlled by atmospheric pressure or low pressure chemical vapor deposition (l〇w 曰

Pressure chemical vapor deposition (LPCVD) deposits tetraethoxy decane (TEOS) as an oxide layer having a thickness of about 3 〇〇 5 5 Å (a). The sacrificial layer 26 can be deposited by a low pressure chemical vapor deposition method (LpcvD) with dichlorosilane (SiCl2%) and ammonia (NH3) as a reaction material to form a ruthenium nitride layer. The thickness (D1) of the sacrificial layer 26 is used to determine the depth of the trench (D2) to be subsequently formed. The thickness (D1) of the sacrificial layer 26 to be formed is converted according to the etching rate ratio of the sacrificial layer 26 to the germanium substrate 20 in accordance with the etching gas formulation to be used for subsequent trench etching. " In an embodiment, the subsequent trench etching gas formulation is plasma etching of a mixed gas of chlorine gas (Cl2) and gas (02), and the chlorine gas is mixed with oxygen" ________, 0503-8385TWF3; daphne.ptc 8th Page 1304632

^ Column is about 15:1 'and the voltage of the electric beam is 20~40 mTorr, and the plasma source power is about 40 watts. 'Bias power case number 91124259 V. Invention description (5) Etching on nitriding The sacrificial layer 26 and the semiconductor are electrically conductive. Therefore, although it is desired to form a depth of 3 Å, the left LPCVD forms a nitride sacrificial layer 26 of about 1000 Å. Then, after the formation of the sacrificial layer 26, then in the cover = see Figure 2B, in the general lithography process in the photoresist "ditch opening pattern, and as a mask, rhyme engraving its end point control layer 24 The germanium layer structure 22 is formed to form a trench opening. Referring next to FIG. 2C, after the photoresist layer 28 is removed, etching is then performed. As described above, the trench is etched with chlorine gas ”"(4)" and (4) the end point is controlled at the sacrificial layer 26: two: =: the end point control layer 24 is exposed. In an embodiment φ 庋 亥 & & 夕 夕 夕 夕 夕/fine (four) (9) acknowledgment = object = er, which means that the disordered layer has been engraved by the surname. Or, when (3) has been etched into the oxide layer as the endpoint control layer 24: on the heart: Table: CN彳§ The speculation is judged as the end point of the silver engraving. θ 5 Since the plasma etching is based on the etched squid = rate, and the depth of the trench to be formed (10) 3 〇. Essence = thickness of the sacrificial layer 26 (D1) It is ι 0 0 0 angstroms, so the sputum and juice are opened and the sacrificial layer 26 is removed. When the etching gas is removed, the nitrogen step of 1 : 0 0 angstrom is etched to a depth of 30 0 0 Å. 3〇., ” represents the base of the base 2 has been the same as the depth formed by the above-mentioned party

〇5〇3-8385TlVF3;daphne.ptc Page 9 1304632 Amendment 91124^0__^ V. Description of invention (6) Corrosion of sacrificial layer and ruthenium base during trench etching is appropriate, M ^ t匕 can be deposited Comparison::Γ= Control the end of the money engraved in the ditch. The above-mentioned party itii controls the end point, which can be used without the money to mark the depth of the machine; more precisely, the depth of the silver engraving of the ditches can be controlled to reach the ditches, which are further explained by the figures 3A to 3E below. Referring to FIG. 3A, the etch depth method is described to form a shallow trench isolation structure. Referring to FIG. 3A, a pad oxide layer 21 and a pad nitride layer 23 are conventionally formed on the semiconductor germanium substrate 20 as an insulating structure 1. Edge protection. The tantalum oxide layer 21 can be opened by a thermal oxidation method on the tantalum substrate, or by low pressure chemical vapor deposition (1 ow).

Pressure chemical vapor deposition (LPCVD) is deposited as a pad oxide layer having a thickness of about 丨丨〇 (human). The pad nitride layer 23 can be deposited by a low pressure chemical vapor deposition process (LPWD) using a mixture of dichlorosilane and ammonia (NH3) to form a pad nitride layer, preferably having a thickness of 丨6 2 5 . Around. Next, referring to Fig. 3A, on the pad nitride layer 23, an end point control layer 24 and a sacrificial layer 26 are further formed. The end point control layer 24 can deposit tetraethoxy decane (TEOS) as an oxide layer by atmospheric or low pressure chemical vapor deposition (LPCVD), and has a thickness of about It is about 3〇〇~5〇〇(a). The sacrificial layer 26 can be deposited by a low pressure chemical vapor deposition method (LpcvD) with dichlorohydrazine (Si (3123⁄4) and ammonia (NHS) as a reaction material to form a tantalum nitride layer. The thickness of the sacrificial layer 26 (D1), is used to determine the subsequent formation of the ditches 0503-8385TWF3; daphne. ptc page 10 1304632 revised month 曰 _ case number 9124259 five, invention description (7) 沬 degree (D2). According to the subsequent trench etching The etch is used as the ratio of the nitrogen cut layer of the sacrificial layer 26 to the (four) ratio of the 11 base (four), and the thickness (d 1) of the sacrificial layer 26 formed by the different formation. In one embodiment, the subsequent trench etching gas recipe For the gas mixture of chlorine gas (Cl2) and milk gas (〇2), the ratio of chlorine gas is about 15: and the plasma (4) is 20~40 millimeters: the power of the ear pulp source is about 400 watts. The voltage power is about 3 watts. At this time, the tantalum nitride sacrificial layer 26 and the semiconductor germanium substrate 2 are etched. Therefore, when a trench having a depth of about 3 angstroms is formed, it is formed by LPCVD to about 100 angstroms. The nitrided sacrificial layer 26 is formed so that after the sacrificial layer 26 is formed, the sacrificial layer 26 is then covered one by one. 8. Cover the 参见 参见 参见 参见 参见 参见 参见 参见 参见 参见 参见 参见 参见 参见 参见 参见 参见 参见 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般 一般Layer 23 and tantalum oxide layer 21, (4) = see Figure 3C, after removing the photoresist layer 28, then the trench is used. The trench (4) is electrically gas-mixed with I gas: the second control is at the sacrificial layer. In the embodiment, the CO and/or CN signals can be measured to confirm the electric erosion of the water 0, sound. For example, #t, + a 疋 has reached the end point control : 2: The signal indicates that the nitride layer as the sacrificial layer 26 has been etched. Or, the detection of the oxide layer = the upper layer as the end point control layer 24 is judged as the etching end point. Xisheng sacrificial layer 2 6 and Shi Xiji page 11 0503-8385TWF3; daphne.ptc 1304632 rt month 倐 _ ;; 5, invention description (8) a "-- bottom 20 after the rate ' and the formation Ditch depth (D2), the tenth is calculated as the thickness of the tantalum nitride sacrificial layer 26 (D1), so when the thickness 〇1 of the tantalum nitride sacrificial layer 26 When the gas is removed, the trenches 30 of the depth D2 are simultaneously etched on behalf of the germanium substrate 2. Next, referring to Fig. 3D, when the trenches 3 on the germanium substrate 2 are formed, the germanium substrate 20 is introduced. A thermal oxidation process causes the inner wall of the trench 3 to form a liner oxide 32 to remove material damage that may result from the etching process of the germanium substrate. Finally, see Figure 3E, filling the trench 3〇 with insulating material. For example, an insulating oxide is filled into the trench 3 by high density plasma deposition (HDPCVD). The excess oxide or nitride layer outside the trench 30 is continuously removed by etch back or chemical mechanical polishing (CMp) to obtain a planar shallow trench isolation structure 34 to isolate the semiconductor substrate 2 The component on 0. According to the present invention, the sacrificial layer in the above method is not limited to the nitride material, and it is only necessary to select an appropriate material, and has an appropriate etching ratio between the semiconductor substrate and the semiconductor substrate. Further, the above-mentioned end point control layer is not limited to the oxide θ only, and a material different from the sacrificial layer is selected to achieve the effect of the end point control. In light of the above description, the present invention is advantageously limited to the etching time control, and the residual end point of the trench can be calculated by the etching rate ratio of the substrate. Therefore, the left-handed death is 1 touch; the ΪΚ:7 + η士,》

1304632 _ Case No. 91124259_年月曰 修正 Amendment _ V. Description of invention (9) The control of the ditch depth of the shallow ditch isolation structure of the uniform one, effectively control the quality of the semi-guided process. While the present invention has been described above by way of a preferred embodiment, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application attached.

0503-8385TWF3; daphne.ptc Page 13 1304632 _ Case No. 91124259_年月曰 _ _ 简单 简单 简单 简单 简单 简单 简单 简单 简单 简单 简单 简单 为了 为了 为了 为了 为了 为了 为了 为了 为了DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, the same drawing symbols represent the same or similar elements: Brief Description of the Drawings Figures 1A to 1E show a side view of a conventional shallow trench isolation structure manufacturing process. 2A through 2C are diagrams showing a method of controlling the etching depth of a shallow trench isolation structure in accordance with an embodiment of the present invention. Figures 3A through 3E illustrate a process flow for forming a shallow trench isolation structure in accordance with one embodiment of the present invention. DESCRIPTION OF SYMBOLS 10 Semiconductor substrate (矽 base semiconductor 矽 substrate); 12 pad oxide layer (塾 oxide), 14 矽 nitride layer 16 trench (shallow trench), 18 lining oxide layer 19 underlayer (insulating material), 20 Semiconductor substrate (矽 base semiconductor 矽 substrate) · ' 21 pad oxide layer (pad oxide layer) 9 22 塾 layer (塾 layer structure) j 23 pad nitride layer j 24 endpoint control layer, 26 sacrificial layer (tantalum nitride Sacrificial layer) 9

0503 -8385TWF3;daphne.p t c Page 14 1304632

0503-8385TWF3;daphne.ptc第15页

Claims (1)

I3〇4632 ^lS_iU24259 Sixth, the scope of application for patents '· 2 method for controlling the etching depth of the trench, applicable to & includes the following steps: a base layer; sequentially forming an end point control layer on the semiconductor substrate and a sacrificial layer on the sacrificial layer Forming and defining a trench layer, M wood one photoresist # & with a far photoresist layer as a mask, etching the sacrificial layer and the final &> into an opening to expose the semiconductor substrate; ... occupy the control layer to shift In addition to the photoresist layer; and = a predetermined etching gas etches the exposed semiconductor substrate m to reach the endpoint control layer, so that the semiconductor is turned into a ditch; a solid is formed in the base of the holding, the depth of the trench / The thickness of the sacrificial layer is / the ratio of the rate at which the semiconductor substrate is etched/the etch of the sacrificial layer.心平_者2· According to the method of control described in the first paragraph of the patent application, the straight-through A-body towel/Raspberry depth depth cloud/, the middle includes a step: in the formation of the end point control MA ^ formation - A mat is layered on the semiconductor substrate. The method of controlling the depth of the trench as described in the second item of the irf irf patent range, wherein the underlayer further comprises a pad oxide layer of wood formed sequentially on the semiconductor substrate. The mouse fossil layer 4. The method of controlling according to the scope of claim 2 wherein the endpoint control layer comprises an oxide layer.到到到度 degrees 5. Control trench etch depth as described in item 1 of the scope of the patent application 0503-8385TWF3;daphne.ptc Page 16 1304632 Fix The method of forming the sacrificial layer forms a nitride layer by a low pressure chemical oxygen phase, LPCVD. '''Low' mountain milk phase deposition method cover number 9Π242Μ Six, the patent scope of the party 6 Fagan ί If the control of the ditch as described in item 5 depth gas "n, Z, in the 疋 疋 etching gas Etching, the chlorine gas (C1 milk chaos (02) mixed gas reaction to carry out a plasma residue. 2) and the square v艮ί nd surrounding the control of the trench depth depth and the sacrificial layer 第; ::L gas (four) engraved the exposed semiconductor substrate with Chiang: point to the control layer is more involved: production # ^ p detect a co and / or - (3) signal to confirm the electricity f # : No has reached this End point control layer. Water residual engraving ·8 · According to the method of applying for patent if 圚D, where the gas: ^6 item controls the ditch depth of the groove 15... The mixing ratio of the mixed gas is about 9. Patent application No. 8 method 'The electric (four) engraved pressure material has a depth of about 40 watts, and the bias power is the electric power source of the sacrificial layer and the semiconductor substrate ',,, inch' And the plasma etching pair 10. The method according to the first aspect of the patent application is about 1:3, wherein the sacrificial layer is formed Two kilograms of S control trench etch depth of 1/3. The full extent is about the depth of the trench to be formed. 11. According to the method of the patent application scope, the fabrication of the sacrificial layer is completed by trenching The depth of the deep trench is about 300 angstroms. X ”, ', 〇 0 0 angstroms, and the formed 12. 12. According to the scope of the patent application, the depth of the trench is etched. 0503~8385WF3;daphne.ptc 1304632 _Case No. 91124259_Yearly revision ___ Sixth, the method of applying for a patent range] wherein after forming a ditch in the semiconductor substrate, a further includes: forming a inside of the trench by thermal oxidation Lining an oxide layer; depositing an insulating material to fill the trench; and performing a planarization process to remove the excess endpoint control layer to form a shallow trench isolation structure. 1 3 . The method of controlling the etch depth of a trench according to item 12 of the patent application, wherein the insulating material is deposited by high density plasma vapor deposition (HDPCVD). 1 4 · A method for controlling the etching depth of a trench according to claim 12 of the patent application, wherein the flattening is performed to perform a chemical mechanical polishing (CMP) 1304632 Case No. 911242M IV. Summary of Chinese Invention (Name of Invention One is to control the shallow ditch. On the semiconductor substrate sacrificial layer. Then, at the sacrificial layer, the photoresist and the underlayer are patterned to form a final channel, which is approximately equal to the ratio of the etcher. The etch point control is opened, and the upper layer of the semi-channel is isolated as the deep layer of the channel exposed to the gas layer, and the designated representative figure of the case is designated (the name of the invention:) A) The method of the invention of the present invention is as follows: a step, an end point control layer, a mask, a mask having a trench pattern, a sacrificial layer, and a semiconductor substrate underneath. Moving the second semiconductor, the exposed semiconductor is removed from the semiconductor substrate; = the: the thickness of the sacrificial layer forms a ditch (four) engraving; 1304632 0503-8385TWF3;daphne.pt c Page 3