TWI313040B - Etching method for forming deep trench. - Google Patents

Description

1313040 索号 92103493 曰 曰 五 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明(Micro E1 ectro Meehan i ca 1 Systems; ME MS) engraving method of structure. 2. Prior Art: Microelectromechanical systems are assembled by micron-scale (A m) components formed in a semiconductor or glass substrate. Common microelectromechanical components such as accelerometers used to sense the acceleration of moving objects. And a gyroscope (gyros cope) for sensing the angular velocity of the rotating object, and a mirror array for reflecting light in the fiber communication. The technology for manufacturing micron-sized microelectromechanical components accumulated in semiconductor or glass substrates uses a large number of common semiconductor device fabrication techniques such as thin film deposition, residual, diffusion or ion implantation doping and plating. . In a microelectromechanical system, a m〇ving part suspended in or tied to a lower substrate and separately electrically movable is used to sense a mobile electronic signal generated by the moving part in the system. Therefore, an appropriate electrical isolation structure should be formed between the different electrodes used in the MEMS and between the electrodes and the moving portion to achieve electrical isolation therebetween to achieve better sensing effect. In U.S. Patent No. 5,663,343, Kevin et al. disclose a single crystal lithography and metallized microelectromechanical process for a low-single single mask, referred to as the SCREAM-1 process, which is first used in this process. Reactive ion etch procedure 'and use gas-gas (Cl2) and tri-carbide (BCl3) anti-0503-921511F1 (N1); TSMC2002-0699; Shawn. ptc page 6 1313040 No. 9210 阽曰 阽曰 五DESCRIPTION OF THE INVENTION (2) The gas should be formed to form a plurality of grooves in the substrate with an aspect ratio of up to 4j:1. A suitable protective layer is then formed in the trenches and the depth of the trenches is further deepened by a reactive ion etching process using chlorine (C12). The single snicon beam of the single crystal germanium layer between the trenches is formed as a part of the constituent elements of the microelectromechanical system by a subsequent etching process. In U.S. Patent No. 5,501,893, Franze et al. disclose an electropolymer etched ruthenium substrate to form a process having a good concave structure in the ruthenium substrate, which is commonly known as the Bosch process, and its method is first. The electric fine step is to engrave the stone eve base, and then borrow the second = for the appropriate time in the subsequent surname step to stop the center of the heart for an appropriate number of times to etch the etch every 2 to 3 microns ("m) The base is formed in the base of the crucible, and has a good non-4-direction etching effect, and has a good non-4-direction etching effect from the place where w 1 is abundance and the corner is a large body. U.S. Patent No. 6071 822 In the patent, the jnh I Bosch process has been slightly improved, and it is further proposed that the case of the above-mentioned germanium substrate is improved to improve the formation of deep trench etch etching to form an undercut, to form a shape and A deep trench with the effect of etching the bottom surface of the trench. x has better non-isotropic deep trenches in the micro-electromechanical process, the second step of the component structure of the partial substrate is used as a suspension or part manufacturing technology to fill in the appropriate isolation material to Can be used as a semiconductor element. However, in actual MEMS, the Φ electrical isolation trench

0503-9215TWF1 (Nl); TSMC2002-0699; Shawn. pt c Page 7 to 10 micron (#m) or more, already semi-conducting # _The depth of this deep trench often needs -.-:_______________________~ϋ土导^ Etching recipe in the process

1313040 Correction; ;c° ^ ^ ^Β〇δεί1 ^ ^ ^ m ^ (^^20" Many, quite time-consuming and repeatable lines between the order and the steps will be more increased: =: degrees C when 'its The process is expected to be. The third is the microelectromechanical process. In view of this, the main θ groove etching method of the present invention is suitable for the microelectromechanical system to provide a deep trench for forming a deep trench with a proper depth. The groove structure is formed in the ruthenium layer for the above purpose, and the present invention comprises the following steps: a method for etching a water trough, providing a substrate having a ruthenium layer on the surface; and partially exposing the ruthenium layer a patterned mask layer, wherein the patterned mask layer is an etched military curtain, and a first etching process is performed and recessed into a non-equal width, wherein the non-face-exposed layer is formed by Forming a first depth; and performing a second residual wide depression from the surface of the ruthenium layer to form a ruthenium layer in the non-equal width depression to form a deep-ordered 'specifically etched one of the ruthenium layers Equal width 夕 m measures 'where the deep trench is two depths. A surface layer of Xi

Briefly, the forming of the deep trench of the present invention comprises: performing a first plasma etching process, in a drop=etching method, the step of forming the germanium layer to form a non-uniform width recess therein, and preparing an etching gas etching_ ~ ________ above non-equal width depression ^

0503 - 9215TWF1 (N1); TSMC2002 - 0699; Shawn. ptc 1313040 曰"! · Case No. 92103493 V. Description of invention (4) = a first depth of the surface of the enamel layer; and a second electro-agglomerating process The gas is etched with an appropriate amount of 'isotropically etched to form a deep trench. The deep trench is a recess of substantially equal width within the layer and a surface from the surface of the layer Second deep production.蚀刻 The etching method of the present invention is suitably applied to a deep trench process having a depth of 丨〇 micron 1 " m) or more using a substrate such as a broken substrate (S 0 丨) on a general insulating layer. The etching process described above is carried out in a preferred etching environment as follows: 〇 First etching procedure (a): The pressure of the surname is between 4 and 22 mTorr; (b): bias power Between 1〇~log watts (w); and | (c): The etch source power is between 1 〇〇 and 8000 watts (w). (d) Hydrogen bromide (HBr) and carbon tetrafluoride (CFO as the main residual gas, hydrogen bromide (HBr) preferably has a gas flow rate of 〇~20 cubic centimeters per minute (SCCM) and tetrafluorination Carbon (CFO, the gas flow rate is preferably between 1 〇 and 6 () ^ square centimeters per minute (SCCM). Second etching procedure: the engraving pressure is between 5 and 20 mTorr; the bias power is between 1〇〇~280 watts (W); and etching source power between 50 0~1 20 watts (W) with hydrogen bromide (HBr), sulfur hexafluoride (SF6) and oxygen (〇2) as main residues Engraving gas, wherein hydrogen bromide (HBr) preferably has a gas flow rate of 1 〇 5 〇 cubic centimeters per minute (SCCM), and sulfur hexafluoride (SFe) preferably has a gas flow rate of 50 to 200 cubic centimeters per per minute. The minute (SCCM) and oxygen (〇2) gas flow rate is between 50 and 100 cubic centimeters per minute (SCCM). 0503-9215TWFl (Nl); TSMC2002-0699; Shawn.ptc Page 9 1313040 Heart ----- ---- 92103493 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Non-equal width depression, Further, the unequal width of the unequal recess is etched to the pre-ice by a second etching process to obtain a deep trench formed by a recess formed substantially in the sap layer. The deep trench formed by the etching method of the present invention has a flat inner surface and a good contour, and the angle between the sidewall and the bottom surface of the trench can be substantially 9 degrees. Fourth Embodiment: In this embodiment, The description of "isotropic" or "irerometric" describes the relative comparison between the different etching steps, such as the first etching step and the second etching step, and is not intended to limit the difference in etching rate in the direction of the etching step. The etching rates in the different directions must be absolutely equal. The method of forming the deep trenches of the present invention will be described as follows with reference to Figs. 1 to 6. First, a surface is provided as shown in Fig. 1. The substrate having the germanium layer is, for example, a substrate or a substrate (s〇I) having an antimony layer on the insulating layer, and the germanium substrate 10 is used for explanation. Then a patterned layer is formed on the germanium substrate 1 , the curtain 12 and part of the dew The substrate 10 is made of a photoresist or a dielectric layer. Preferably, the dielectric layer material is selected from the group consisting of cerium oxide, tantalum nitride or a composite formed by the two materials. Then, a first etching process 14 is applied and the patterned mask layer 12 is used as an etching mask to etch the exposed portion of the substrate. Please refer to FIG. 2, by the first etching described above. Preface 4

1313040 ^----- Case No. 92Ί034阽, invention description (6) η 曰 Correct the first depth of the soil surface 18, and listen to the narrow depression, the whistle ^ 匕 first / wood degree 18 - width by width Up to 2 〇 ^ and in the first etching process 18 simultaneously formed a character 厣 20 on the surface of the non-equal width depression 16 . The role of the layer, jl a Xu A into ^ then have ~ this first etching procedure 18 〃 thickness through a few angstroms to tens of angstroms. —= This first etching process 18 is preferably an electro-agglomerating process: a preferred plasma etching process (HDP etching pr〇cess). The preferred conditions of the month are as follows: The etching pressure is between 4 and 22 mTorr. (mTorr); bias power is between 1〇~l〇〇E(w); etching source power is between 100~8〇〇W (W); hydrogen bromide (HBr) and carbon tetrafluoride (CM is The main etching gas, hydrogen bromide (HBr), the gas flow rate is preferably 〇~2〇 cubic centimeters per minute (SCCM), while the carbon tetrafluoride (eh), the gas flow rate is preferably between 1〇~6〇3 Centimeters per minute (SCCM). For example, here (a (b) (c) (d)

Referring to FIG. 3, a second etching process 2 2 is then performed, and the previously patterned mask layer 12 is used as an etching mask to further etch the non-equal width recess 16 in the germanium substrate, first etching and removing. After the polymer layer 20 on the surface of the recess 16 is not equal in width, the underlying substrate 1 material is subsequently etched.

Notably, the second etching process 2 2 is preferably a plasma etching process, such as a high-density plasma etching process (HDP etching process), which forms a reactive plasma that is isotropically Ly) etching to remove the 〇 substrate 1 下 portion of the non-equal width recess 16 , the preferred characterization conditions of the present invention are as follows: (a): the residual pressure is between 5 and 20 milliTorr (mTorr); (b): bias power between 100 and 280 watts (W);

0503-92l5TWF1(N1);TSMC2002_0699;SIwwn.Ptc Page 11 Picture 92〗 n:u(10)_年月日日 Revision_ V. Invention description (7) "" ' ' (C): Etching source power is between 500~1 200 watts (W); U): Hydrogen bromide (HBr), sulfur hexafluoride and oxygen as the main etching gas. Among them, hydrogen bromide (HBr) has a gas flow rate of preferably 丨〇~5 〇^ Square centimeters per minute (SCCM), sulfur hexafluoride (SF6) preferably has a gas flow rate of 50 to 200 cubic centimeters per minute (SCCM) and oxygen (〇2) with a gas flow of 50 to 1 cubic centimeter. Centimeters per minute (SCCM). > Next, referring to FIG. 4, etching the underlying substrate 1 portion under the non-uniform width recess 16 by the second etching process 2 2 can form a deep trench 28 in the germanium substrate 1 , and the deep trench 28 is a second depth 24 from the surface of the substrate 1 , and the deep trench 28 is formed by a recess having a substantially equal width, and a polymer layer 26 is simultaneously formed in the deep trench 28 in the second etching process 22 . On the surface, it also has the effect of terminating this second etching process 22, and its thickness is often between several angstroms and tens of angstroms. By the etching method of the above two etching procedure steps of the present invention, a deep trench 28 having a final depth (ie, a second depth 24) as shown in FIG. 4 can be formed, which is generally deep in the microelectromechanical process. Up to 2 microns (" m) or more. The deep trench formed by the etching method of the present invention "has a depth of 20 to 200 micrometers (" m), preferably 2 〇 to 1 〇〇 micron (# its aspect ratio can be up to 1 〇: 1 to 10 〇: 1. Before forming the deep trenches 28 in the present invention, the unequal width recess 16 formed in the 矽 substrate 1 首先 by the first etching process 14 is firstly spaced from the first depth of the 矽 substrate surface 10 18, which is usually 1/3 to 1/2 of the final depth (two depths 24) of the deep trenches 28. The deep trenches formed by the deep trench etching method of the present invention have flat surfaces (side walls and bottom surfaces) and are round Good corridor (the width of the groove is roughly 9

0503 -9215TWF1 (N1) ;TSMC2002-0699; Shawn. pt c Page 12 1313040

-- Case No. 921034卯五, invention description (8) Width) 'As shown in Figure 4, the deep trench 28 苴 sidewall (10) can approach 90 degrees (can be = degree) sidewall W and bottom _ inflammatory angle please Referring to Fig. 5K, a perspective view of the stencil/slot 28 of the present invention is utilized. In the micro-electromechanical process library, the above-mentioned etching method can be used to form a plurality of two Γ Γ ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Γ Γ Γ Γ Γ Γ Γ The process is etched and etched to partially suspend or sew it to the bottom of the soil to form a suitable component structure. These processes are already cooked; as is well known to those skilled in the art, the detailed process is not detailed here. ', and, in addition, the etching method of the present invention is also applicable to an integrated circuit (Uytry), suitable for forming isolation trenches 2mi〇U2nCh between isolation elements) and applied to a trench DRAM process to form A common semiconductor process such as a large surface area deep trench capacitor. Refer to Fig. 6 for a clear view of the formation of a deep trench in the present invention. In the first and second processes of the present invention, the same plasma plasma etching process can be performed by the same as in Fig. 6. The plasma source etching system (achieved by dec〇upled source. In (4) System 1 () (), the reaction chamber system is composed of a canopy 102 and a chamber wall (chamber w^l 1 ) 104 formed of a conductive material. The outer top of the canopy 丨〇 2 is connected to a plurality of coils 1 〇 8 connected to the first RF power generator (RF 〇 〇 〇 ce , , , , , , , , , , , , , , , The cavity wall 104 includes an anode pedestal, a second RF power generator 112 coupled to the anode pedestal 11, a vacuum pump 114, and a throttling.

Throttle valve 126. The etched substrate, for example, a substrate Π6, is adsorbed on the anode pedestal 丨1〇 by an electrostatic chuck (not shown), and is supported by a helium source 128 and a rear helium duct 118. In order to provide a proper flow of gas to the stone substrate 116 and the anode base. In the etching process of the invention, the reaction gas (such as hydrogen bromide, carbon tetrafluoride, oxygen, sulfur hexafluoride, chlorine, etc.) is passed through the gas inlet 120 located on both sides of the chamber wall 104. Into the reaction chamber and form a mixture 122 of reactive gases, and provide a suitable source of power and a second RF power generator 11 2 by the first RF power generator 1〇6. Providing a 'plasma guidance' formed by a suitable bias power, the vacuum pump 114 and the throttle valve 26 maintain a proper degree of vacuum in the reaction chamber (such as the aforementioned reaction conditions) This etch process is then performed on the ruthenium substrate 116 to form deep trenches within the ruthenium substrate 丨16. The etching method for forming a deep trench of the present invention has the following features and advantages:

1. The characterization method of the present invention is suitable for use in a substrate such as a substrate (s〇I) which is etched on a general ruthenium substrate or a common insulating layer to form a deep trench having an ice of 10 μm or more in the shi shi base. The groove is suitable for the semiconductor component process and the micro-electromechanical process, and can be directly applied to the conventional semiconductor device process, and can be appropriately adjusted according to the foregoing reaction conditions. The etching effect of the present invention, the etching effect thereof It can form deep trenches with a depth of 2 〇~2 〇〇 microns, and its aspect ratio can reach 丨0:丨~丨〇〇: J. 2. The etching process of the present invention is a two-step etching method, first by forming a non-equal width/depression of a predetermined depth in the crucible layer by a surname program. By the second etching

Page 14 1313040 Case No. 92103493 V. Invention Description (ίο) Ridge Day _ Correction of the 矽 layer in the same width depression to obtain - a deep groove formed by a general width equal width depression. The steps are simple 'there is no need to repeat the process cycle to form deeper trenches as in the Bosch process of U.S. Patent Nos. 5,591,893 and 6,017,822, and to provide another formation different from U.S. Patent 5,663,343. The remaining method of deep trenches. 3. The surname of the invention is flat and well contoured, and the groove side is 90 degrees, which is in accordance with the requirements of the semiconductor component process. The deep trench formed by the method has an angle between the inner surface of the trench and the bottom surface of the trench, which can be substantially exposed to the trench structure of the microelectromechanical process as described above. However, the present invention is not intended to be used without departing from the spirit of the invention. The protection will prevail. While the present invention has been described in its preferred embodiments, the scope of the invention is intended to be

1313040 Case No. 92103493 Λ_R. 修正 Correction Brief Description of the Drawings FIGS. 1 to 4 are a series of cross-sectional views for explaining an etching method for forming deep trenches in a preferred embodiment of the present invention. Fig. 5 is a perspective view for explaining a three-dimensional structure in which a deep trench formed by the etching method of the present invention is applied to a microelectromechanical process. Figure 6 is a cross-sectional view showing the coupled plasma source system (d e c 〇 u p 1 e d p 1 a s m a s u r c e etching system) used in the etching method of the present invention. Related symbols: 12~ mask layer; 1 6~ non-uniform width depression; 20, 26~ polymer layer 24 to second depth; 2 8 a~ side wall; 30~ corner; 1 0, 11 6~矽 substrate; 4 ~ first etching procedure; 1 8 ~ first depth; 2 2 ~ second etching procedure; 2 8 ~ deep trench; 28b ~ bottom surface; cavity wall electrostatic adsorption pedestal 1 0 0~ coupling plasma source etching system 1 0 2 ~ canopy; 104 1 0 6 ~ first RF power generator I 0 8 'coil; 110 118 ~ helium gas duct; 1 2 2 ~ gas mixture 1 2 6 ~ throttle valve; II 2 ~ second RF power supply Generator 11 4 ~ vacuum pumping; 1 2 0 ~ gas inlet; 124 ~ plasma; 1 2 8 ~ helium source.

0503 -9215TWF1 (N1) ;TSMC2002-0699; Shawn. pt c第16页

Claims (1)

1313040 _ Case No. 92103493 VI. Patent application scope υ 今 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成 形成The enamel layer is partially exposed on the enamel layer; a first engraving process is performed and the mask layer patterned by the above is a silver engraved mask, and the slat layer is exposed by silver to form a non-equal width depression. Wherein the non-equal width depression is a first depth from the surface of the crucible layer; and performing a second etching process to etch the crucible layer in the non-equal width depression to form a deep trench, wherein the deep trench is located One of the crucible layers is substantially equal in width and has a second depth from the surface of the crucible layer. 2. The etching method for forming a deep trench as described in claim 1, wherein the deep trench has an aspect ratio of 1 0 : 1 to 1 0 0 : 1. 3. The method of forming a deep trench according to claim 1, wherein the first depth is 1/2 to 1/3 of the second depth. 4. The method of forming a deep trench, as described in claim 3, wherein the second depth is between 20 and 200 microns. 5. The method of forming a deep trench according to claim 3, wherein the second depth is between 20 and 1.0 micrometers. 6. The method of forming a deep trench, as described in claim 1, wherein the non-equal width recess is a wide to narrow recess. 7. The method of forming a deep trench according to claim 1, wherein the surface having the base layer is a stone substrate or a substrate (SOI) on the insulating layer. 8. The etching method for forming deep trenches as described in claim 1 of the patent application scope 0503-9215TWF2(Nl);shawnchang.ptc Page 17 1313040 The method wherein the mask layer is a photoresist layer or a dielectric layer.曰 Correction 9. The etching method of forming a deep trench according to claim 1, wherein the material of the dielectric layer is selected from the group consisting of cerium oxide and tantalum nitride. - ???, 10 · The method of forming a deep trench as described in the scope of claim ii, wherein the first etching process is a first plasma etching process, and the second etching process is a second Plasma etching procedure. Μ弟, 11. The method of forming a deep trench etch as described in claim 10, wherein the first plasma etching process is performed under the following reaction conditions: (a) · The etching pressure is between 4~22 mTorr (mT〇rr); (b): bias power between 10 and 100 watts (W); and (c): source power between 1 〇〇 and 8 watts (W) . 1 2. The method for forming a deep trench surface according to claim 10, wherein the first plasma etching process is performed under the following reaction conditions: (a): hydrogen bromide (η β r ), the gas flow rate is between 0 and 20 cubic meters (SCCM); and the mother (b): carbon tetrafluoride (cf), the gas flow rate is between 1 〇 6 6 cubic meters per minute (SCCM). A-point / 1 3 · The method of forming a deep trench surface as described in the first paragraph of the patent application scope, wherein the second plasma etching procedure is performed under the following reaction conditions: x (a): button engraving The pressure is between 5 and 2 Torr (mTorr); 1313040 Case No. 92103493 Rev. 6 Scope of application for patent (b): bias power between 1 〇〇 and 280 watts (W); and (c) : # 刻源 power between 5 〇〇 丨 〇 2 〇 〇瓦 (w). Line 1 4. The method for forming a deep trench surface as described in claim 10 of the patent application, wherein the plasma etching process is performed under the following reaction conditions, and the gas flow rate is between 1 〇 and 50. Cubic centimeters / (a): desert hydrogen (HBr) per minute (SCCM); (b): sulfur hexafluoride (sfb) with a gas flow of 50 to 20 cubic centimeters per minute (SCCM); (c): Oxygen (〇2) with a gas flow rate of 50 to 1 〇〇 cubic centimeter per minute (SCCM). 1 5. The etching method for forming a deep trench as described in the scope of the patent application, wherein the first plasma and the second electrical etching process are performed by high-density plasma etching . Page 19 0503 -9215TWF2( N1); shawnchang. pt c B13040 ^ 曰_修正-----plug number 921f); UQ3____ four 'Chinese hair> The present invention relates to a forming step: providing - surface having 矽: etching The method comprises the following two parts on the above-mentioned stone layer and partially exposed; i: the mask of the case and the mask layer patterned by the above is the first etching process surface-first depth; The wide depression is located in the above-mentioned non-equal width depression of the Shixi layer. The structure is as follows::::: The second deep household is silver-engraved. Generally, the width of the wide depression is one from the surface of the stone layer. (1) The representative figure of this case is: Figure 3 (1). The symbol of the representative figure of the representative figure in this case is simple: 1 〇~矽 base; 12~ hood Curtain layer; 16~ non-equal width depression; 7. English abstract (invention name: Etching method for forming deep trench.) An etching method for forming a deep trench includes the following steps: providing a substrate with a silicon layer on the surface; forming a patterned mask layer on the silicon layer and exposing part of the silicon layer; performing a first etching process and using the patterned Mask layer as an etching mask to etch the exposed silicon layer and forming a first 0503-9215TWF1 (N1); TSMC2002 - 0699; Shawn. ptc Page 3 1313040 " _ Case No. 921034 Ship Correction a IV. Abstract of Chinese Invention (Invention Name: Formation Turn ^^ 1 8~ First Depth 2 0~ Polymer Having a second etching process to the surface of the silicon layer; performing a second etching process to the etch the silicon Layer in the first recess isotropical ly and forming a deep trench, the deep trench is composed of a recess with substantially even width in the silicon layer. 0503-9215TWFl(Nl);TSMC2002-0699;Shawn.ptc Page 4