CN102157374A - Method for manufacturing trapezoid field oxide layer - Google Patents
Method for manufacturing trapezoid field oxide layer Download PDFInfo
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- CN102157374A CN102157374A CN2011100324295A CN201110032429A CN102157374A CN 102157374 A CN102157374 A CN 102157374A CN 2011100324295 A CN2011100324295 A CN 2011100324295A CN 201110032429 A CN201110032429 A CN 201110032429A CN 102157374 A CN102157374 A CN 102157374A
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- field oxide
- sacrifice layer
- etching
- layer
- trapezoidal
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Abstract
The invention relates to a method for manufacturing a trapezoid field oxide layer, which comprises the following steps of: forming a field oxide layer on the surface of a substrate; forming a sacrificial layer on the upper surface of the field oxide layer; masking and etching the field oxide layer and the sacrificial layer selectively, and defining an active region and a terminal protective region in the field oxide layer and the sacrificial layer; etching part of the sacrificial layer and the field oxide layer in the terminal protective region selectively, wherein the speed of etching the sacrificial layer by using an etching agent in the etching process is higher than that of etching the field oxide layer, so that two side walls of the retained field oxide layer are inclined planes; and removing the residual sacrificial layer. By the method for manufacturing the trapezoid field oxide layer, the breakdown voltage can be improved effectively, and the sizes of devices can be reduced.
Description
Technical field
The present invention relates to process for fabrication of semiconductor device, relate in particular to a kind of manufacture method of trapezoidal field oxide.
Background technology
Figure 1A～Figure 1B is depicted as the flow chart of fabricating yard oxide layer in the process of making power MOS (Metal Oxide Semiconductor) device in the prior art:
Shown in Figure 1A, on lining base 101, form one deck field oxide (field plate) 102, this field oxide 102 is used for isolating device;
Shown in Figure 1B, optionally shelter and the described field oxide 102 of etching definition active area 103 and terminal protection district 104 in described field oxide 102;
The thickness uniformity of the field oxide 102 that in described terminal protection district 104, retains, the upper surface of two sidewalls, the 1021 approximate and described lining bases 101 of the field oxide 102 that promptly retains is vertical;
In order to obtain bigger puncture voltage (break voltage), the necessary long enough of the length H of the above-mentioned field oxide that retains 102, for example, experiment records, corresponding to 742 volts puncture voltage, the length H of the above-mentioned field oxide that retains 102 is 125um, still, long field oxide is unfavorable for improving the integrated level of power MOS (Metal Oxide Semiconductor) device, does not meet the trend of semiconductor device development.
Summary of the invention
The object of the present invention is to provide a kind of manufacture method that can control the trapezoidal field oxide of gradient flexibly, can effectively improve puncture voltage, reduction of device size.
To achieve the above object, the invention provides a kind of manufacture method that can control the trapezoidal field oxide of gradient flexibly, may further comprise the steps: the upper surface at the lining base forms a field oxide; Upper surface at described field oxide forms a sacrifice layer; Optionally shelter and described field oxide of etching and sacrifice layer definition active area and terminal protection district in described field oxide and sacrifice layer; Selective etch falls described sacrifice layer of part and the field oxide in the described terminal protection district, wherein, the speed of the described sacrifice layer of etching agent etching that adopts in the etching process makes two sidewalls of the field oxide that retains be the inclined-plane greater than the speed of the described field oxide of etching; Remove remaining described sacrifice layer.
The manufacture method of above-mentioned trapezoidal field oxide wherein, adopts the upper surface growth field oxide of thermal oxidation process at described lining base.
The manufacture method of above-mentioned trapezoidal field oxide wherein, adopts wet etching method selective etch to fall described sacrifice layer of part and field oxide.
The manufacture method of above-mentioned trapezoidal field oxide, wherein, the material of described sacrifice layer and the selection of etching agent are satisfied Slope=R by the required gradient decision that reaches of described sidewall
Oxide/ R
Sacrificial, wherein, Slope represents the required gradient that reaches of described sidewall, R
OxideThe etch rate of representing described field oxide, R
SacrificialThe etch rate of representing described sacrifice layer.
The manufacture method of above-mentioned trapezoidal field oxide, wherein, described sacrifice layer be without annealing in process phosphorosilicate glass layer, through the phosphorosilicate glass layer of annealing in process, the deposit of using plasma chemical gas-phase deposition enhanced method and without the oxide layer or the unadulterated polysilicon layer of annealing in process.
The manufacture method of above-mentioned trapezoidal field oxide, wherein, described etching agent is 5 parts of NH
4The mixture of F and 1 part of HF (volume ratio), 10 parts of H
2The mixture of O and 1 part of HF (volume ratio), 126 parts of HNO
3With 60 parts of H
2O and 5 parts of NH
4The mixture of F (volume ratio), 25 parts of H
2The mixture of O and 1 part of HF (volume ratio), perhaps 20 parts of H
2O and 1 part of H
2O
2And the mixture (volume ratio) of 1 part of HF.
The manufacture method of the trapezoidal field oxide of the present invention forms a sacrifice layer on field oxide, utilize this sacrifice layer of different etching speed etching and field oxide, thereby make the field oxide that retains in the district that is etched be trapezoidal, trapezoidal field oxide has improved the Electric Field Distribution of field oxide and lining Ji Guijiemianchu, thereby improved the puncture voltage of power device, shorten the length of field oxide, helped reduction of device size, improved the device integrated level;
The manufacture method of the trapezoidal field oxide of the present invention can obtain the trapezoidal field oxide of different gradients by the selection of etching agent and sacrifice layer, can control the gradient of trapezoidal field oxide flexibly.
Description of drawings
The manufacture method of trapezoidal field oxide of the present invention is provided by following embodiment and accompanying drawing.
Figure 1A～Fig. 1 C is the flow chart of field oxide manufacture method in the prior art.
Fig. 2 A～Fig. 2 G is the flow chart of the manufacture method of the trapezoidal field oxide of the present invention.
Fig. 3 is the partial enlarged drawing of frame of broken lines part among Fig. 2 E.
Embodiment
Below with reference to Fig. 2 A～Fig. 3 the manufacture method of trapezoidal field oxide of the present invention is described in further detail.
The manufacture method of trapezoidal field oxide of the present invention may further comprise the steps:
Upper surface at the lining base forms a field oxide;
Upper surface at described field oxide forms a sacrifice layer (sacrificial layer);
Optionally shelter and described field oxide of etching and sacrifice layer definition active area and terminal protection district in described field oxide and sacrifice layer;
Selective etch falls described sacrifice layer of part and the field oxide in the described terminal protection district, wherein, the speed of the described sacrifice layer of etching agent etching that adopts in the etching process makes two sidewalls of the field oxide that retains be the inclined-plane greater than the speed of the described field oxide of etching;
Remove remaining described sacrifice layer.
The manufacture method of trapezoidal field oxide of the present invention is owing to form sacrifice layer on field oxide, therefore can utilize different etching speed etching sacrificial layer and field oxide, make the field oxide under the block reservation that is etched be trapezoidal, experiment shows, trapezoidal field oxide can effectively improve breakdown voltage value, reduction of device size.
Now describe the manufacture method of trapezoidal field oxide of the present invention in detail with a specific embodiment:
Be example still to make power MOS (Metal Oxide Semiconductor) device:
Shown in Fig. 2 A, form a field oxide 202 at the upper surface that serves as a contrast base 201;
For example in the described upper surface thermal oxide growth layer of silicon dioxide that serves as a contrast base 201;
Described field oxide 202 is used for isolating device;
Shown in Fig. 2 B, form a sacrifice layer 203 at the upper surface of described field oxide 202;
Form described sacrifice layer 203 and can adopt the upper surface deposit one deck phosphorosilicate glass PSG of CVD (Chemical Vapor Deposition) method CVD, form phosphorosilicate glass (PSG unannealed) layer without annealing in process at described field oxide 202; Can adopt CVD (Chemical Vapor Deposition) method behind upper surface deposit one deck phosphorosilicate glass of described field oxide 202, make annealing in process, form phosphorosilicate glass (PSG annealed) layer of annealed processing; Can using plasma chemical gas-phase deposition enhanced method PECVD deposit layer of silicon dioxide, form oxide layer without annealing in process; Can also adopt the upper surface deposit one deck polysilicon of low-pressure chemical vapor phase deposition method LPCVD, form unadulterated polysilicon layer at described field oxide 202;
Shown in Fig. 2 C, at the upper surface coating photoresist 204 of described sacrifice layer 203, by definition active area 205 and terminal protection districts 206 in the described photoresist 204 that exposes, is developed in;
Shown in Fig. 2 D, for sheltering, remove described sacrifice layer 203 of part and field oxide 202 with described photoresist 204;
Described sacrifice layer 203 in the described terminal protection district 206 and field oxide 202 have kept under the sheltering of described photoresist 204 time, and described sacrifice layer 203 and field oxide 202 in the described active area 205 are not subjected to sheltering of described photoresist 204, are removed;
Shown in Fig. 2 E, for sheltering, adopt and select to etch away described terminal protection district 206 interior described sacrifice layer 203 of part and field oxide 202 than the etching agent that is not equal to 1 with described photoresist 204;
The described sacrifice layer 203 and the field oxide 202 that for example adopt wet etching method (wet-etch) etching not sheltered by described photoresist 204;
The speed of the described field oxide 202 of speed ratio etching of the described sacrifice layer 203 of its etching of the etching agent that adopts in the etching process is big;
Because described sacrifice layer 203 of etching agent lateral etching and field oxide 202, and the etch rate of described sacrifice layer 203 is bigger than the etch rate of described field oxide 202, therefore, behind one section etch period, the described photoresist 204 of part is etched away, the described sacrifice layer of being sheltered by described photoresist 204 203 is not etched away fully, and the described field oxide of not sheltered by described photoresist 204 202 is not etched away fully, the field oxide that is not etched away forms the slope, two sidewalls 207 that are the described field oxide 202 that retains in the described terminal protection district 206 are the inclined-plane, that is to say that the described field oxide 202 that retains in the described terminal protection district 206 is trapezoidal shape;
See also Fig. 3, if described sidewall 207 is α with the angle of the upper surface of described lining base 201, available tan α represents the gradient Slope of described sidewall 207, the etch rate of the gradient Slope of described sidewall 207 and described sacrifice layer 203 and the etch rate of described field oxide 202 are relevant, Slope=R
Oxide/ R
Sacrificial, wherein, R
OxideThe etch rate of representing described field oxide 202, R
SacrificialThe etch rate of representing described sacrifice layer 203;
The selection of etching agent and sacrifice layer is by the described sidewall 207 required gradient Slope decisions that reach, for example, the described sidewall 207 required gradient Slope that reach are 1/6.8, then etching agent of Xuan Zeing and sacrifice layer should satisfy, the speed of this etching agent etching sacrificial layer is 6.8 times of speed of this etching agent etching field oxide, and table 1 has been enumerated some etching agents, the pairing gradient Slope of sacrifice layer:
Table 1
Trapezoidal field oxide can improve the Electric Field Distribution of field oxide and silicon lining primary surface, thereby improve the puncture voltage of field oxide, experiment shows, obtain 773 volts puncture voltage, the length H ' of trapezoidal field oxide is 65um, be field oxide contraction in length half, this helps the size of reduction of device, improves the integrated level of semiconductor device;
Shown in Fig. 2 F, remove described photoresist 204;
Shown in Fig. 2 G, remove remaining described sacrifice layer 203.
The manufacture method of the trapezoidal field oxide of the present invention can obtain the trapezoidal field oxide of different gradients by the selection of etching agent and sacrifice layer, can control the gradient of trapezoidal field oxide flexibly.
Claims (6)
1. the manufacture method of a trapezoidal field oxide is characterized in that, may further comprise the steps:
Upper surface at the lining base forms a field oxide;
Upper surface at described field oxide forms a sacrifice layer;
Optionally shelter and described field oxide of etching and sacrifice layer definition active area and terminal protection district in described field oxide and sacrifice layer;
Selective etch falls described sacrifice layer of part and the field oxide in the described terminal protection district, wherein, the speed of the described sacrifice layer of etching agent etching that adopts in the etching process makes two sidewalls of the field oxide that retains be the inclined-plane greater than the speed of the described field oxide of etching;
Remove remaining described sacrifice layer.
2. the manufacture method of trapezoidal field oxide as claimed in claim 1 is characterized in that, adopts the upper surface growth field oxide of thermal oxidation process at described lining base.
3. the manufacture method of trapezoidal field oxide as claimed in claim 1 is characterized in that, adopts wet etching method selective etch to fall described sacrifice layer of part and field oxide.
4. the manufacture method of trapezoidal field oxide as claimed in claim 1 is characterized in that, the material of described sacrifice layer and the selection of etching agent are satisfied Slope=R by the required gradient decision that reaches of described sidewall
Oxide/ R
Sacrificial, wherein, Slope represents the required gradient that reaches of described sidewall, R
OxideThe etch rate of representing described field oxide, R
SacrificialThe etch rate of representing described sacrifice layer.
5. the manufacture method of trapezoidal field oxide as claimed in claim 1, it is characterized in that, described sacrifice layer be without annealing in process phosphorosilicate glass layer, through the phosphorosilicate glass layer of annealing in process, the deposit of using plasma chemical gas-phase deposition enhanced method and without the oxide layer or the unadulterated polysilicon layer of annealing in process.
6. the manufacture method of trapezoidal field oxide as claimed in claim 1 is characterized in that, described etching agent is 5 parts of NH
4The mixture of F and 1 part of HF (volume ratio), 10 parts of H
2The mixture of O and 1 part of HF (volume ratio), 126 parts of HNO
3With 60 parts of H
2O and 5 parts of NH
4The mixture of F (volume ratio), 25 parts of H
2The mixture of O and 1 part of HF (volume ratio), perhaps 20 parts of H
2O and 1 part of H
2O
2And the mixture (volume ratio) of 1 part of HF.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100324295A CN102157374A (en) | 2011-01-28 | 2011-01-28 | Method for manufacturing trapezoid field oxide layer |
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|---|---|---|---|
| CN2011100324295A CN102157374A (en) | 2011-01-28 | 2011-01-28 | Method for manufacturing trapezoid field oxide layer |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103594492A (en) * | 2012-08-14 | 2014-02-19 | 中芯国际集成电路制造(上海)有限公司 | A LDMOS transistor and a forming method thereof |
| CN109713035A (en) * | 2018-12-29 | 2019-05-03 | 上海擎茂微电子科技有限公司 | A kind of planar gate bipolar junction transistor and preparation method thereof |
| CN111785640A (en) * | 2020-08-26 | 2020-10-16 | 上海华虹宏力半导体制造有限公司 | Method for adjusting angle of oxide field plate in LDMOS transistor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4676869A (en) * | 1986-09-04 | 1987-06-30 | American Telephone And Telegraph Company At&T Bell Laboratories | Integrated circuits having stepped dielectric regions |
| CN101719468A (en) * | 2009-11-10 | 2010-06-02 | 上海宏力半导体制造有限公司 | Method for manufacturing oxide layer capable of reducing gradient of side wall |
| CN101752208A (en) * | 2008-12-03 | 2010-06-23 | 上海芯能电子科技有限公司 | Semiconductor high-voltage terminal structure and production method thereof |
-
2011
- 2011-01-28 CN CN2011100324295A patent/CN102157374A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4676869A (en) * | 1986-09-04 | 1987-06-30 | American Telephone And Telegraph Company At&T Bell Laboratories | Integrated circuits having stepped dielectric regions |
| CN101752208A (en) * | 2008-12-03 | 2010-06-23 | 上海芯能电子科技有限公司 | Semiconductor high-voltage terminal structure and production method thereof |
| CN101719468A (en) * | 2009-11-10 | 2010-06-02 | 上海宏力半导体制造有限公司 | Method for manufacturing oxide layer capable of reducing gradient of side wall |
Non-Patent Citations (1)
| Title |
|---|
| LAWRENCE KEITH WHITE: "Bilayer Taper Etching of Field Oxides and Passivation Layers", 《JOURNAL OF THE ELECTROCHEMICAL SOCIETY》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103594492A (en) * | 2012-08-14 | 2014-02-19 | 中芯国际集成电路制造(上海)有限公司 | A LDMOS transistor and a forming method thereof |
| CN109713035A (en) * | 2018-12-29 | 2019-05-03 | 上海擎茂微电子科技有限公司 | A kind of planar gate bipolar junction transistor and preparation method thereof |
| CN109713035B (en) * | 2018-12-29 | 2022-02-15 | 上海擎茂微电子科技有限公司 | Planar gate bipolar transistor and manufacturing method thereof |
| CN111785640A (en) * | 2020-08-26 | 2020-10-16 | 上海华虹宏力半导体制造有限公司 | Method for adjusting angle of oxide field plate in LDMOS transistor |
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Owner name: SHANGHAI HUAHONG GRACE SEMICONDUCTOR MANUFACTURING Free format text: FORMER OWNER: HONGLI SEMICONDUCTOR MANUFACTURE CO LTD, SHANGHAI Effective date: 20140505 |
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Application publication date: 20110817 |