CN1731565A - Etching method for 0.18 micrometre contact hole - Google Patents
Etching method for 0.18 micrometre contact hole Download PDFInfo
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- CN1731565A CN1731565A CN 200410053419 CN200410053419A CN1731565A CN 1731565 A CN1731565 A CN 1731565A CN 200410053419 CN200410053419 CN 200410053419 CN 200410053419 A CN200410053419 A CN 200410053419A CN 1731565 A CN1731565 A CN 1731565A
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Abstract
The invention discloses a method for etching 0.18-micrometer contact holes. The method comprises the steps of: etching nitrogen silicon oxide on the top; mainly etching the topping oxide film with high etching selection ratio (oxide film/nitrogen silicon oxide) to ensure holes stay on the nitrogen silicon oxide; exploiting mixture gas of nitrogen and oxygen to remove reaction product on the bottom of holes; etching lower nitrogen silicon oxide to make holes stay on the metal silicides on the bottom. The invention has the advantage of preventing the sidewall of active region from damaging during etching by exploiting high etching selecting ratio.
Description
Technical field
The present invention relates to a kind of microelectronics manufacture technical field, especially relate to a kind of lithographic method that is used for 0.18 micron contact hole.
Background technology
Along with the development of semiconductor fabrication, live width is more and more littler, and the diameter of oxide-film contact hole also reduces.Contact hole is the passage that connects preceding road transistor unit and road, back metal wiring, should connect transistorized grid, be connected to source-drain electrode (grid and source-drain electrode have the difference in height of grid) again, its etching result's quality directly has influence on the yield of characteristics of transistor and product.
For 0.18 micron technology, the characteristic size of contact hole and etching requirement, and common problem points is in the etching:
1, the structure of oxidation film layer is Substrate (Gate Poly)/SiON/BPSG/TEOSoxide/SiON/PR from bottom to up, and the diameter in hole is 0.22 micron, and the height in hole is generally about 1 micron, and its depth-width ratio is about 4: 1, as shown in Figure 1.
2, require contact hole finally can be parked in the cobalt silicide rete on grid and the active area (surplus of cobalt silicide is greater than 100 dusts).When the etching condition of exploitation contact hole; consider that film-forming machine growth thickness of oxidation film changes and the silicon chip inner evenness; also have etching machine engraving erosion rate variations and silicon chip inner evenness, can add certain over etching time usually to prevent that etching is not enough and cause circuit obstructed.But when etching was excessive, contact hole was carved silicide and is worn, and will cause that the resistance of contact hole becomes big, even cause element leakage.
Because when undersized designs; for save area, improve integrated level, designed Boardless Contact (edge of edge, hole and shallow trench isolation regions STI joins); in actual production; often have the exposure position skew, when the over etching of hole, the edge of wearing the shallow trench isolation regions active area can be carved in the hole; be carved into the ion implanted junction that leak in the source; knot is caused damage, cause electric leakage, as shown in Figure 2.
Summary of the invention
The objective of the invention is to the above-mentioned deficiency at prior art, it is good to propose a kind of etching effect, can prevent to owe the lithographic method of etching and over etching.
Above-mentioned purpose of the present invention is achieved through the following technical solutions: the first step, the top silicon oxynitride is carried out etching;
Second step, the upper strata oxide-film is carried out main etching, adopt high etch rate to select ratio, thereby guarantee that the hole is parked on the silicon oxynitride; In the 3rd step, use nitrogen and oxygen mixed gas to remove reaction product;
The 4th step, adopt high etch rate to select lower floor's silicon oxynitride to be carried out main etching than (silicon oxynitride/oxide-film), guarantee that the hole is parked on the underlying metal silicide.
When the first step is carried out etching to the top silicon oxynitride, select top and the bottom electrode spacing 18-22mm, chamber pressure 55-65 millitorr, top power 900-1100 watt, bottom power 900-1100 watt, argon gas l80-220sccm, fluoroform 15-25sccm, oxygen 12-20sccm, the 10-25 holder of backside helium pressure middle part, backside helium pressure edge 5-15 holder; When the first step is carried out etching to the top silicon oxynitride, select top and the bottom electrode spacing 20mm, chamber pressure 60 millitorrs, 1000 watts of top power, 1000 watts of bottom power, argon gas 200sccm, fluoroform 20sccm, oxygen 15sccm, 15 holders of backside helium pressure middle part, edge 5 holders; When in second step upper strata oxide-film being carried out main etching, use octafluoroization five carbon gases to add that suitable oxygen proportion obtains high etch rate and selects ratio, described high etch rate selects ratio greater than 15; When the upper strata oxide-film being carried out etching in second step, select top and the bottom electrode spacing 18-22mm, chamber pressure 45-55 millitorr, top power 1800-2200 watt, bottom power 1000-1400 watt, octafluoroization five carbon 9-12sccm, argon gas 600-800sccm, oxygen 10-15sccm, the 5-15 holder of backside helium pressure middle part, backside helium pressure edge 10-25 holder; When the upper strata oxide-film being carried out etching, select top and the bottom electrode spacing 20mm, chamber pressure 50 millitorrs, 2000 watts of top power in second step, 1200 watts of bottom power, octafluoroization five carbon (C5F8) 12sccm, argon gas 750sccm, oxygen 15sccm, 5 holders of backside helium pressure middle part, edge 15 holders; When removing reaction product in the 3rd step, select top and the bottom electrode spacing 18-22mm, chamber pressure 20-30 millitorr, top power 400-600 watt, bottom power 150-250 watt, argon gas 180-220sccm, oxygen 8-15sccm, the 5-15 holder of backside helium pressure middle part, backside helium pressure edge 10-25 holder; When removing reaction product, select top and the bottom electrode spacing 20mm, chamber pressure 25 millitorrs, 500 watts of top power, 200 watts of bottom power, argon gas 200sccm, oxygen 10sccm, 5 holders of backside helium pressure middle part, edge 15 holders in the 3rd step; When in the 4th step lower-layer oxide film being carried out main etching, described high etch rate selects ratio greater than 5; When lower-layer oxide film being carried out main etching in the 4th step, select top and the bottom electrode spacing 18-22mm, chamber pressure 35-45 millitorr, top power 900-1100 watt, bottom power 150-250 watt, argon gas 180-220sccm, fluoroform 12-20sccm, oxygen 12-20sccm, the 10-25 holder of backside helium pressure middle part, backside helium pressure edge 5-15 holder; When lower-layer oxide film being carried out main etching, select top and the bottom electrode spacing 20mm, chamber pressure 40 millitorrs, 1000 watts of top power in the 4th step, 200 watts of bottom power, argon gas 200sccm, fluoroform 15sccm, oxygen 15sccm, 15 holders of backside helium pressure middle part, edge 5 holders.
Compare with prior art, the present invention has following beneficial effect:
1, when second goes on foot the oxide-film main etching, because oxide-film is selected even add 50% over etching, also can guarantee that the hole is parked on the silicon oxynitride than (greater than 15) to the high etch rate of silicon oxynitride;
2, when the 4th goes on foot the oxide-film main etching,, do not damage the active area sidewall because the high etch rate of oxide-film is selected can be parked on the oxide-film for the part that is displaced to because of the photoetching process deviation of the alignment on the STI than (greater than 5).
Description of drawings
The structural representation of etch layer when Fig. 1 is contact hole etching;
Fig. 2 is the structural representation of the contact hole of prior art institute etching;
When Fig. 3 is the present invention second step oxide-film main etching, because the two-forty of silicon oxynitride is selected ratio, make the hole be parked in structural representation on this rete;
When Fig. 4 is the present invention the 3rd step etching, then be carved into bell-mouthed bad shape because of the loss of photoresist at the contact hole top open part if oxygen concentration is too high;
When Fig. 5 is the present invention's the 4th step etching,, the hole is parked on this rete, is unlikely to damage the structural representation of active area sidewall because the two-forty of silica is selected ratio.
Wherein, 1 is contact hole; 2 is device active region; 3 is the sti oxide layer; 4 is silicon oxynitride.
Embodiment
Below in conjunction with drawings and Examples the present invention is further described.
Because the etching of contact hole will be carved SiON/TEOS oxide/BPSG/SiON (as shown in Figure 1) from top to bottom successively, so, use corresponding etching condition at the film of different materials.
The first step: the etching of top layer silicon oxynitride.If this tunic is not carved clean (residual silicon oxynitride is arranged), will have influence on the etching of oxide-film, the perforate Halfway Stopping takes place.
Major parameter: top and the bottom electrode spacing 18-22mm, preferred 20mm; Chamber pressure 55-65 millitorr, preferred 60 millitorrs; Top power 900-1100 watt, preferred 1000 watts; Bottom power 900-1100 watt, preferred 1000 watts; Argon gas 180-220sccm, preferred 200sccm; Fluoroform 15-25sccm, preferred 20sccm; Oxygen 12-20sccm, preferred 15sccm; The 10-25 holder of backside helium pressure middle part, preferred 15 holders; Backside helium pressure edge 5-15 holder, preferred 5 holders.
Second step: the main etching of oxide-film (comprising TEOS OXIDE and BPSG).Consider the Thickness Variation and the interior inhomogeneities of face of oxide-film deposit, and inhomogeneities in dry etching rate variation and the face, append 50% over etching, can guarantee that each contact hole is all opened in the silicon chip face.Require the hole to be parked on the bottom buffer layer silicon oxynitride,,, can cause when next step etching, beneath silicide is carved worn, produce electric leakage if can not be parked on the silicon oxynitride if the etching deficiency can cause perforate bad by this step etching.So requiring this step oxide-film selects than high (greater than 15) the etch rate of silicon oxynitride, the major parameter here is octafluoroization five carbon (C5F8), cooperate corresponding oxygen, reaction produces hydrocarbon (C-H) compound, be attached to the sidewall in hole, the vertical etching of retaining hole obtains high etching selection ratio.Because silicon oxynitride is had low etch rate,, can guarantee that also silicon oxynitride layer can not worn by quarter even increase etch period.Argon gas under the traction of lower electrode, vertically bombards the silicon chip rete that is etched because atomic mass is big, can prevent that perforate is bad.As shown in Figure 3.
Major parameter: top and the bottom electrode spacing 18-22mm, preferred 20mm; Chamber pressure 45-55 millitorr, preferred 50 millitorrs; Top power 1800-2200 watt, preferred 2000 watts; Bottom power 1000-1400 watt, preferred 1200 watts; Octafluoroization five carbon 9-12sccm, preferred 12sccm; Argon gas 600-800sccm, preferred 750sccm; Oxygen 10-15sccm, preferred 15sccm; The 5-15 holder of backside helium pressure middle part, preferred 5 holders; Backside helium pressure edge 10-25 holder, preferred 15 holders.
In the 3rd step, reaction product is removed at the bottom of the hole.Because (because high selectivity condition) produces a large amount of reaction products when the previous step etching, need remove these products with the oxygen ashing reaction.Add the argon-dilution oxygen proportion, prevent that oxygen concentration is too high, can fall a part of photoresist (making the warpage of the top open part photoresist in hole) by reactive ion etching, cause that the hole is carved into the horn mouth sample when next step etching, as shown in Figure 4.
Major parameter: top and the bottom electrode spacing 18-22mm, preferred 20mm; Chamber pressure 20-30 millitorr, preferred 25 millitorrs; Top power 400-600 watt, preferred 500 watts; Bottom power 150-250 watt, preferred 200 watts; Argon gas 180-220sccm, preferred 200sccm; Oxygen 8-15sccm, preferred 10sccm; The 5-15 holder of backside helium pressure middle part, preferred 5 holders; Backside helium pressure edge 10-25 holder, preferred 15 holders.
The 4th step: the etching of bottom silicon oxynitride.Adjust the ratio of fluoroform and oxygen, add argon-dilution, obtain the condition of higher silicon oxynitride, remove silicon oxynitride, the hole is parked in lower floor's silicide the etching selection ratio of oxide-film.Because high etch rate is selected ratio,, cause electric leakage even when the hole exposure takes place just to move,, can not injure the sidewall of STI because the etch rate low to oxide-film can be parked in the oxide layer of STI the hole.The bottom power in this step only is set at 200W, and the main etching step of comparing oxide-film is very soft etching, and is little to the damage of lower membrane (metal silicide), can greatly improve substrate leakage.As shown in Figure 5.
Major parameter: top and the bottom electrode spacing 18-22mm, preferred 20mm; Chamber pressure 35-45 millitorr, preferred 40 millitorrs; Top power 900-1100 watt, preferred 1000 watts; Bottom power 150-250 watt, preferred 200 watts; Argon gas 180-220sccm, preferred 200sccm; Fluoroform 12-20sccm, preferred 15sccm; Oxygen 12-20sccm, preferred 15sccm; The 10-25 holder of backside helium pressure middle part, preferred 15 holders; Backside helium pressure edge 5-15 holder, preferred 5 holders.
Claims (11)
1, a kind of lithographic method that is used for 0.18 micron contact hole is characterized in that:
The first step is carried out etching to the top silicon oxynitride;
Second step, the upper strata oxide-film is carried out main etching, adopt high etch rate to select ratio, thereby guarantee that the hole is parked on the silicon oxynitride;
In the 3rd step, use nitrogen and oxygen mixed gas to remove reaction product at the bottom of the hole;
The 4th step, adopt high etch rate to select comparison lower floor silicon oxynitride to carry out main etching, guarantee that the hole is parked on the underlying metal silicide.
2, the lithographic method that is used for 0.18 micron contact hole according to claim 1, it is characterized in that: when the first step is carried out etching to the top silicon oxynitride, select top and the bottom electrode spacing 18-22mm, chamber pressure 55-65 millitorr, top power 900-1100 watt, bottom power 900-1100 watt, argon gas 180-220sccm, fluoroform 15-25sccm, oxygen 12-20sccm, the 10-25 holder of backside helium pressure middle part, backside helium pressure edge 5-15 holder.
3, the lithographic method that is used for 0.18 micron contact hole according to claim 2, it is characterized in that: when the first step is carried out etching to the top silicon oxynitride, select top and the bottom electrode spacing 20mm, chamber pressure 60 millitorrs, 1000 watts of top power, 1000 watts of bottom power, argon gas 200sccm, fluoroform 20sccm, oxygen 15sccm, 15 holders of backside helium pressure middle part, edge 5 holders.
4, the lithographic method that is used for 0.18 micron contact hole according to claim 1, it is characterized in that: when the upper strata oxide-film being carried out main etching in second step, use octafluoroization five carbon gases to add that suitable oxygen proportion obtains high etch rate and selects ratio, described high etch rate selects ratio greater than 15.
5, the lithographic method that is used for 0.18 micron contact hole according to claim 4, it is characterized in that: when the upper strata oxide-film being carried out etching in second step, select top and the bottom electrode spacing 18-22mm, chamber pressure 45-55 millitorr, top power 1800-2200 watt, bottom power 1000-1400 watt, octafluoroization five carbon 9-12sccm, argon gas 600-800sccm, oxygen 10-15sccm, the 5-15 holder of backside helium pressure middle part, backside helium pressure edge 10-25 holder.
6, the lithographic method that is used for 0.18 micron contact hole according to claim 5, it is characterized in that: when the upper strata oxide-film being carried out etching in second step, select top and the bottom electrode spacing 20mm, chamber pressure 50 millitorrs, 2000 watts of top power, 1200 watts of bottom power, octafluoroization five carbon (C5F8) 12sccm, argon gas 750sccm, oxygen 15sccm, 5 holders of backside helium pressure middle part, edge 15 holders.
7, the lithographic method that is used for 0.18 micron contact hole according to claim 1, it is characterized in that: when removing reaction product in the 3rd step, select top and the bottom electrode spacing 18-22mm, chamber pressure 20-30 millitorr, top power 400-600 watt, bottom power 150-250 watt, argon gas 180-220sccm, oxygen 8-15sccm, the 5-15 holder of backside helium pressure middle part, backside helium pressure edge 10-25 holder.
8, the lithographic method that is used for 0.18 micron contact hole according to claim 7, it is characterized in that: at the bottom of removing the hole in the 3rd step during reaction product, select top and the bottom electrode spacing 20mm, chamber pressure 25 millitorrs, 500 watts of top power, 200 watts of bottom power, argon gas 200sccm, oxygen 10sccm, 5 holders of backside helium pressure middle part, edge 15 holders.
9, the lithographic method that is used for 0.18 micron contact hole according to claim 1 is characterized in that: when in the 4th step lower-layer oxide film being carried out main etching, described high etch rate selects ratio greater than 5.
10, the lithographic method that is used for 0.18 micron contact hole according to claim 9, it is characterized in that: when lower-layer oxide film being carried out main etching in the 4th step, select top and the bottom electrode spacing 18-22mm, chamber pressure 35-45 millitorr, top power 900-1100 watt, bottom power 150-250 watt, argon gas 180-220sccm, fluoroform 12-20sccm, oxygen 12-20sccm, the 10-25 holder of backside helium pressure middle part, backside helium pressure edge 5-15 holder.
11, the lithographic method that is used for 0.18 micron contact hole according to claim 10, it is characterized in that: when lower-layer oxide film being carried out main etching in the 4th step, select top and the bottom electrode spacing 20mm, chamber pressure 40 millitorrs, 1000 watts of top power, 200 watts of bottom power, argon gas 200sccm, fluoroform 15sccm, oxygen 15sccm, 15 holders of backside helium pressure middle part, edge 5 holders.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB200410053419XA CN100388437C (en) | 2004-08-04 | 2004-08-04 | Etching method for 0.18 micrometre contact hole |
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| Application Number | Priority Date | Filing Date | Title |
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| CNB200410053419XA CN100388437C (en) | 2004-08-04 | 2004-08-04 | Etching method for 0.18 micrometre contact hole |
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| CN100388437C CN100388437C (en) | 2008-05-14 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102403218A (en) * | 2010-09-09 | 2012-04-04 | 上海华虹Nec电子有限公司 | Etching method for contact holes |
| CN106960787A (en) * | 2017-03-30 | 2017-07-18 | 中国科学院微电子研究所 | Damage-free dry over-etching preparation method of Schottky junction |
| CN112582263A (en) * | 2019-09-30 | 2021-03-30 | 扬州扬杰电子科技股份有限公司 | Improvement method for punctiform residues |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6228761B1 (en) * | 1999-10-14 | 2001-05-08 | Advanced Micro Devices, Inc. | Method of forming a local interconnect with improved etch selectivity of silicon dioxide/silicide |
| US6436841B1 (en) * | 2001-09-10 | 2002-08-20 | Taiwan Semiconductor Manufacturing Company | Selectivity oxide-to-oxynitride etch process using a fluorine containing gas, an inert gas and a weak oxidant |
-
2004
- 2004-08-04 CN CNB200410053419XA patent/CN100388437C/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102403218A (en) * | 2010-09-09 | 2012-04-04 | 上海华虹Nec电子有限公司 | Etching method for contact holes |
| CN102403218B (en) * | 2010-09-09 | 2013-07-24 | 上海华虹Nec电子有限公司 | Etching method for contact holes |
| CN106960787A (en) * | 2017-03-30 | 2017-07-18 | 中国科学院微电子研究所 | Damage-free dry over-etching preparation method of Schottky junction |
| CN106960787B (en) * | 2017-03-30 | 2020-06-19 | 中国科学院微电子研究所 | Damage-free dry over-etching preparation method of Schottky junction |
| CN112582263A (en) * | 2019-09-30 | 2021-03-30 | 扬州扬杰电子科技股份有限公司 | Improvement method for punctiform residues |
| CN112582263B (en) * | 2019-09-30 | 2024-04-26 | 扬州扬杰电子科技股份有限公司 | Punctiform residue improvement method |
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Effective date of registration: 20171225 Address after: 201203 Shanghai city Zuchongzhi road Pudong New Area Zhangjiang hi tech Park No. 1399 Patentee after: Shanghai Huahong Grace Semiconductor Manufacturing Corp. Address before: No. 1188, Chuan Qiao Road, Pudong, Shanghai Patentee before: Shanghai Hua Hong NEC Electronics Co.,Ltd. |
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Granted publication date: 20080514 Termination date: 20210804 |