CN103400762B - The formation method of semiconductor structure - Google Patents
The formation method of semiconductor structure Download PDFInfo
- Publication number
- CN103400762B CN103400762B CN201310376914.3A CN201310376914A CN103400762B CN 103400762 B CN103400762 B CN 103400762B CN 201310376914 A CN201310376914 A CN 201310376914A CN 103400762 B CN103400762 B CN 103400762B
- Authority
- CN
- China
- Prior art keywords
- layer
- power source
- etching
- etched
- radio frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Drying Of Semiconductors (AREA)
- Internal Circuitry In Semiconductor Integrated Circuit Devices (AREA)
Abstract
A formation method for semiconductor structure, comprising: provide substrate, and described substrate surface has layer to be etched; Form mask layer on described surface layer to be etched, described mask layer exposes part surface layer to be etched; With described mask layer for mask, layer to be etchedly plasma etching is carried out to described, at described interior formation opening layer to be etched, the radiofrequency signal that the biased radio frequency power source of described plasma etching exports is pulse signal, the duty ratio of described pulse signal reduces with the increase of etching depth, when biased radio frequency power source is opened, etched portions is layer to be etched and formation etches mouth, and in described etching mouth, there is etch by-products, when biased radio frequency power source is closed, described etch by-products diffuses out described etching mouth.The opening size adopting described plasma etch process to be formed is accurately even, and the etch rate forming described opening is high.
Description
Technical field
The present invention relates to technical field of manufacturing semiconductors, particularly relate to a kind of formation method of semiconductor structure.
Background technology
Along with integrated circuit develops to submicron-scale, the integrated level of device improves constantly, and device size constantly reduces, thus more strict to the requirement of device size accuracy.In ic manufacturing process, conductive plunger is usually used in the electrical interconnection between conductive interconnections layer or between device active region and peripheral circuit, the important function had in device architecture composition.Along with the device dimensions shrink in integrated circuit, integrated level improve, the clear size of opening for the formation of conductive plunger also reduces thereupon, and the corresponding raising of the depth-to-width ratio of described through hole, make the technique of formation through hole receive challenge.
Fig. 1 to Fig. 2 is a kind of cross-sectional view forming the process of through hole.
Please refer to Fig. 1, provide Semiconductor substrate 100, described semiconductor substrate surface has dielectric layer 101, and the material of described dielectric layer 101 is silica or silicon nitride; Form mask layer 102 on described dielectric layer 101 surface, described mask layer 102 has the mask open (sign) on expose portion dielectric layer 101 surface.Dielectric layer 101 shown in Fig. 1 is silica, and mask layer 102 comprises amorphous carbon layer (a-C) and is positioned at the photoresist layer on amorphous carbon layer surface.
Please refer to Fig. 2, with described mask layer 102 for mask, using plasma etching technics etches described dielectric layer 101, till the surface of exposing semiconductor substrate 100, in dielectric layer 101, forms through hole 104.
In described plasma etch process, radiofrequency signal is adopted to make process gas form plasma, and utilize radiofrequency signal to form bias voltage on a semiconductor substrate 100, described plasma is bombarded towards the direction of Semiconductor substrate 100, etching technics is carried out to described dielectric layer 101.Wherein, the radiofrequency signal for the formation of plasma is generally lasting radiofrequency signal, and the radiofrequency signal for the formation of bias voltage is lasting radiofrequency signal or the radiofrequency signal of pulsed.When the radiofrequency signal forming bias voltage is lasting radiofrequency signal, the plasma of etching gas knows from experience etch media layer 101 constantly.When the radiofrequency signal forming bias voltage is the radiofrequency signal of pulsed, described plasma knows from experience the step of alternately carrying out etching and deposited polymer, is conducive to the through hole forming high-aspect-ratio (AR, AspectRatio).
But the clear size of opening adopting existing plasma etch process to be formed is uneven, causes the conductive plunger pattern that is formed in described through hole bad, easily cause the conductive plunger generation bridge joint in adjacent through-holes, or the problem such as conductive plunger open circuit.
The related data of more formation methods about through hole please refer to the U.S. patent documents that the patent No. is US7547636B2.
Summary of the invention
The problem that the present invention solves is to provide a kind of formation method of semiconductor structure, and the opening size that using plasma etching technics is formed is accurately even, and the etch rate forming opening is higher.
For solving the problem, the invention provides a kind of formation method of semiconductor structure, comprising: provide substrate, described substrate surface has layer to be etched, form mask layer on described surface layer to be etched, described mask layer exposes part surface layer to be etched, with described mask layer for mask, described mask material is agraphitic carbon, layer to be etchedly plasma etching is carried out to described, at described interior formation opening layer to be etched, the depth-to-width ratio of described opening is greater than 10:1, the radiofrequency signal that the biased radio frequency power source of described plasma etching exports is pulse signal, the duty ratio of described pulse signal reduces with the increase of etching depth, when biased radio frequency power source is opened, etched portions is layer to be etched and formation etches mouth, and in described etching mouth, there is etch by-products, when biased radio frequency power source is closed, described etch by-products diffuses out described etching mouth.
Optionally, described plasma etch process comprises: in first time period, etches described layer to be etched, forms the first sub-opening, and the pulse signal that biased radio frequency power source exports has the first duty ratio; Within the second time period, etch described first sub-open bottom, form the second sub-opening, the pulse signal that biased radio frequency power source exports has the second duty ratio, and described second duty ratio is less than the first duty ratio; Within the 3rd time period, etch described second sub-open bottom, form described opening, the pulse signal that biased radio frequency power source exports has the 3rd duty ratio, and described 3rd duty ratio is less than the second duty ratio.
Optionally, described first duty ratio is 90% ~ 70%, and described first time period accounts for and forms 30% ~ 50% of described opening total time; Described second duty ratio is 70% ~ 50%, and described second time period accounts for and forms 20% ~ 40% of described opening total time; Described 3rd duty ratio is 50% ~ 30%, and described 3rd time period accounts for and forms 15% ~ 30% of described opening total time.
Optionally, described layer to be etched be single layer structure, and material layer to be etched is the one in silicon oxide layer, silicon nitride layer, silicon oxynitride layer, silicon carbide layer or fire sand layer.
Optionally, described layer to be etched be sandwich construction, and described layer to be etched be silicon oxide layer and the alternatively distributed multilayer lamination structure of silicon nitride layer.
Optionally, described silicon oxide layer and the alternatively distributed number of times of silicon nitride layer are more than or equal to 8 times.
Optionally, the material of described mask layer is amorphous carbon layer.
Optionally, the gas that described plasma etching adopts comprises C
4f
8, C
4f
6, CHF
3, CH
2f
2, one or more in CO.
Optionally, the radiofrequency signal that the plasma rf power source of described plasma etching exports is continuous signal, and the power of described plasma rf power source is 200 watts ~ 3000 watts, and the natural frequency of described plasma rf power source is greater than 13 megahertzes.
Optionally, the radiofrequency signal that the plasma rf power source of described plasma etching exports is pulse signal, the frequency of the pulse signal that described plasma rf power source exports is identical with the frequency of the pulse signal that biased radio frequency power source exports, the pulse frequency of described plasma rf power source is 200 hertz ~ 5000 hertz, the power of described plasma rf power source is 200 watts ~ 3000 watts, and the natural frequency of described plasma rf power source is greater than 13 megahertzes.
Optionally, the pulse frequency of biased radio frequency power source is 200 hertz ~ 5000 hertz, and the power of described biased radio frequency power source is 3000 watts ~ 7000 watts, and the natural frequency of described biased radio frequency power source is less than 13 megahertzes.
Optionally, the pressure of described plasma etching is 15 millitorr ~ 60 millitorrs.
Optionally, described opening is through hole or groove.
Optionally, described substrate and layer to be etched between also there is etching barrier layer, to the described plasma etching that carries out layer to be etched till exposing described etching barrier layer, the material of described etching barrier layer is silicon nitride.
Optionally, also comprise: form bottom layer anti-reflection layer on described mask layer surface; At the photoresist layer on described bottom layer anti-reflection layer surface, described photoresist layer exposes the correspondence position of described opening.
Compared with prior art, technical scheme of the present invention has the following advantages:
When biased radio frequency power source is closed, the bias voltage that substrate is formed reduces, the energy of plasma basad direction bombardment reduces, described plasma is made not easily to enter in etching mouth, and the reactivity of plasma in etching mouth reduces, make the also corresponding minimizing of formed accessory substance, then the diffusivity of described accessory substance is stronger, described accessory substance can be escaped outside etching mouth, thus reduce described accessory substance and adhere to accumulation at random on mask layer surface and etching mouth sidewall surfaces, formed opening size can be made accurately homogeneous.And, because the energy of plasma basad direction bombardment reduces, therefore etch rate reduces, and can ensure that the impact that the sidewall of described mask layer and lower surface are etched is lower, then the size of mask layer not easily changes, and is conducive to making formed opening size accurate.Secondly; when biased radio frequency power source is opened; the energy of plasma basad direction bombardment improves; plasma can enter bottom etching mouth and etch; and the reactivity of plasma in etching mouth improves, while etching is layer to be etched, polymeric layer can be formed to protect in the sidewall surfaces of etching mouth and mask layer surface.Therefore, the opening size formed is accurately homogeneous.
In addition, for plasma etch process, the pulse signal duty ratio that biased radio frequency power source exports is less, and the time that time shorter, the biased radio frequency power source that namely biased radio frequency power source is closed is opened is longer, then etch rate is faster.When the duty ratio of pulse signal reduces with the increase of etching depth, namely along with the increase of etching depth, the time that biased radio frequency power source is closed increases gradually, and the time that biased radio frequency power source is opened reduces gradually; When etching the mouth degree of depth and being less, the time that biased radio frequency power source is opened is more, can ensure, when ensureing accessory substance escape diffusion, to make etch rate higher, thus ensures that the average etching rate forming described opening is higher; When etching the mouth degree of depth and being larger, the time that biased radio frequency power source is closed is more, ensures that accessory substance can diffuse out etching mouth completely with this.Therefore, while formed opening size is accurately homogeneous, the etch rate of described plasma etch process is higher.
Further, in first time period, formed the first sub-opening degree of depth is more shallow, and described first duty ratio is 90% ~ 70%, can ensure that the speed etching the sub-opening of formation first is higher.Within the second time period, because the degree of depth of the second sub-opening increases, it is longer that described accessory substance diffuses out the time of etching needed for mouth, and therefore the second duty is 70% ~ 50%, ensure that the speed of the sub-opening of etching second is unlikely to too low simultaneously.Within the 3rd time period, due to opening the degree of depth continue increase, therefore accessory substance diffuse out etching mouth time longer, the 3rd duty ratio is 50% ~ 30%, makes accessory substance have time enough and diffuses out etching mouth.The speed that etching forms described opening is higher, and the opening size simultaneously formed is accurately homogeneous.
Accompanying drawing explanation
Fig. 1 to Fig. 2 is a kind of cross-sectional view forming the process of through hole;
Fig. 3 to Fig. 6 is the schematic diagram of the forming process of the semiconductor structure of the first embodiment of the present invention;
Fig. 7 is in first time period, the sequential chart of the radio-frequency power that plasma rf power source exports and the radio-frequency power that biased radio frequency power source exports;
The cross-sectional view of etching mouth when Fig. 8 is the unlatching of biased radio frequency power source;
The cross-sectional view of etching mouth when Fig. 9 is the closedown of biased radio frequency power source;
Figure 10 is in the second time period, the sequential chart of the radio-frequency power that plasma rf power source exports and the radio-frequency power that biased radio frequency power source exports;
Figure 11 is in the 3rd time period, the sequential chart of the radio-frequency power that plasma rf power source exports and the radio-frequency power that biased radio frequency power source exports;
Figure 12 is the SEM vertical view of the through hole adopting prior art to be formed;
Figure 13 makes the SEM vertical view of the opening that described in employing the present embodiment, method is formed;
Figure 14 is when in plasma atmosphere, oxygen content is different, the radiofrequency signal that biased radio frequency power source exports be pulse signal and non-pulse signal time, the broken line graph of hatch bore diameter and aperture standard variance;
Figure 15 to Figure 16 is the schematic diagram of the forming process of the semiconductor structure of the second embodiment of the present invention.
Embodiment
As stated in the Background Art, the clear size of opening that prior art is formed is uneven, the conductive plunger pattern that is formed in described through hole can be caused bad, cause the problem that the electrical connection properties of described conductive plunger is bad.
Find through research, please continue to refer to Fig. 1 to Fig. 2, when using plasma etching technics etches described dielectric layer 101, in order to form the through hole 104 of high-aspect-ratio in dielectric layer 101, need to introduce high polymer enrichment (polymer-rich) gas in process gas, described high polymer enriched gas comprises C
4f
8, C
4f
6.Described height gathers enriched gas can in etching process, can form polymeric layer as protection at the sidewall of through hole 104 sidewall surfaces and mask layer 102 and top surface.Owing to having the protection of polymeric layer; in described plasma etch process; the power of the radiofrequency signal for the formation of bias voltage can be improved; plasma is improved the bombarding energy of dielectric layer 101; the size that through hole 104 bottom size formed can define with mask layer 105 keeps unified, makes the maintenance surperficial relative to dielectric layer 101 of formed through hole 104 sidewall vertical.But, when processing gas and comprising high poly-enriched gas, carrying out in the process of plasma etching to dielectric layer 101, a large amount of not volatile accessory substance can be produced, described not volatile accessory substance is carbon, one or more large molecules combined in element silicon, fluorine element, oxygen element and nitrogen element or polymer molecule.Along with the reducing of size of device, required through hole 104 size formed also reduces thereupon, accordingly, the depth-to-width ratio of through hole 104 improves, when adopting the formation of existing plasma etch process to have the through hole 104 of high-aspect-ratio, along with the carrying out of etching technics, the degree of depth of through hole 104 increases gradually, the gas exchanges in through hole 104 can be caused more and more slower, the not volatile accessory substance produced by etching is difficult to discharge through hole, described not volatile accessory substance easily attachment is randomly deposited in sidewall and the top surface of mask layer 102, and the sidewall surfaces of through hole 104, the bombardment of plasma counteracts, formed through hole 104 size is caused to reduce, even block through hole 104 top (cloggingeffect), make formed through hole 104 size uneven.
In order to reduce the accessory substance in plasma etching process, a kind of method is by regulating the component of process gas to realize.Concrete, gathered the content of enriched gas by the height reduced in process gas, or improve the content of oxygen in process gas, to reduce the carbon fluorine ratio (C/F) in process gas, thus the formation of not volatile accessory substance can be reduced.But, decrease the content of high poly-enriched gas, or the content of oxygen, correspondingly also can make to be formed at mask layer surface, and the polymeric layer on through-hole side wall surface is thinning, when forming the through hole of high-aspect-ratio, the bombarding energy of plasma to dielectric layer is higher, the protection of described polymeric layer is easily broken in the bombardment of described plasma, enable process gas directly and mask layer or dielectric layer react, while etch media layer, described mask layer sidewall and lower surface also can be etched, the thickness of mask layer is thinned, the size of mask open is extended, namely gas is processed poor for the selectivity of dielectric layer and mask layer, the clear size of opening causing etching to be formed is extended.Therefore, keep the effect of size uniformity of through hole poor by regulating process gas group to assign to, the clear size of opening inaccuracy formed.
In order to solve the problem, the present invention proposes a kind of formation method of semiconductor structure, comprising: provide surface to have substrate layer to be etched; Form mask layer on described surface layer to be etched, described mask layer exposes part surface layer to be etched; With described mask layer for mask, layer to be etchedly plasma etching is carried out to described, at described interior formation opening layer to be etched, the radiofrequency signal that the biased radio frequency power source of described plasma etching exports is pulse signal, the duty ratio of described pulse signal reduces with the increase of etching depth, when biased radio frequency power source is opened, etched portions is layer to be etched and formation etches mouth, and in described etching mouth, there is etch by-products, when biased radio frequency power source is closed, described etch by-products diffuses out described etching mouth.
Wherein, when biased radio frequency power source is closed, the bias voltage that substrate is formed reduces, the energy of plasma basad direction bombardment reduces, described plasma is made not easily to enter in etching mouth, and, the reactivity of plasma in etching mouth reduces, make the also corresponding minimizing of generated accessory substance, therefore, the diffusivity of described accessory substance is comparatively strong, and the accessory substance formed when biased radio frequency power source can be made to open is escaped outside etching mouth, thus reduces described accessory substance and adhere to accumulation immediately on mask layer surface and etching mouth sidewall surfaces; And because the energy of plasma basad direction bombardment reduces, therefore etch rate reduces, can ensure that the impact that the sidewall of described mask layer and lower surface are etched is lower, ensure that the size of mask layer does not change.Secondly; when biased radio frequency power source is opened, the energy of plasma basad direction bombardment improves, and plasma can enter bottom etching mouth and etch; and the reactivity of plasma in etching mouth improves, polymeric layer can be formed in the sidewall surfaces of etching mouth and protect.Therefore, the opening size formed is accurately homogeneous.
In addition, due in plasma etch process, the pulse signal duty ratio (DR, DutyRatio) that biased radio frequency power source exports is less, namely the time that time shorter, the biased radio frequency power source that biased radio frequency power source is closed is opened is longer, then etch rate is faster.When the duty ratio of pulse signal reduces with the increase of etching depth, namely along with the increase of etching depth, the time that biased radio frequency power source is closed increases gradually, and the time that biased radio frequency power source is opened reduces gradually; When etching the mouth degree of depth and being less, the time that biased radio frequency power source is opened is more, can ensure, when ensureing accessory substance escape diffusion, to make etch rate higher, thus ensures that the average etching rate forming described opening is higher; When etching the mouth degree of depth and being larger, the time that biased radio frequency power source is closed is more, ensures that accessory substance can diffuse out etching mouth completely with this.Therefore, while formed opening size is accurately homogeneous, the etch rate of described plasma etch process is higher.
For enabling above-mentioned purpose of the present invention, feature and advantage more become apparent, and are described in detail specific embodiments of the invention below in conjunction with accompanying drawing.
First embodiment
Fig. 3 to Fig. 6 is the schematic diagram of the forming process of the semiconductor structure of the first embodiment of the present invention.
Please refer to Fig. 3, provide substrate 200, described substrate 200 surface has layer to be etched 201; Form mask layer 202 on described 201 surfaces layer to be etched, described mask layer 202 exposes part 201 surfaces layer to be etched.
In the present embodiment, described substrate 200 for comprising Semiconductor substrate, be formed at semiconductor substrate surface or be formed at semiconductor device in Semiconductor substrate, for being electrically connected the conductive structure of described semiconductor device and the insulating barrier for semiconductor device described in electric isolution and conductive structure.Described Semiconductor substrate comprises silicon substrate, silicon-Germanium substrate, silicon carbide substrates, silicon-on-insulator substrate, germanium substrate on insulator, glass substrate or III-V substrate (such as gallium nitride substrate or gallium arsenide substrate etc.).And, substrate 200 surface of the present embodiment exposes the surface of partially conductive structure, thus enable follow-up be formed at layer to be etched in opening expose described conductive structure, then the electric interconnection structure (such as conductive plunger) be formed in opening can be used in the electrical connection of described semiconductor device.
In another embodiment, described substrate is only Semiconductor substrate, and described Semiconductor substrate comprises silicon substrate, silicon-Germanium substrate, silicon carbide substrates, silicon-on-insulator substrate, germanium substrate on insulator, glass substrate or III-V substrate (such as gallium nitride substrate or gallium arsenide substrate etc.).
In the present embodiment, described layer to be etched 201 is single layer structure, and the described material of layer to be etched 201 is the one in silicon oxide layer, silicon nitride layer, silicon oxynitride layer, silicon carbide layer or fire sand layer, the described formation process of layer to be etched 201 is chemical vapor deposition method, follow-up formation electric interconnection structure in described layer to be etched 201, and described layer to be etched 201 for making described electric interconnection structure and other semiconductor device or conductive structure electric isolution.
In one embodiment, between described substrate 200 and layer to be etched 201, also there is etching barrier layer (not shown), the material of described etching barrier layer is different from the material of layer to be etched 201, such as when the material of layer to be etched 201 is silica, the material of described etching barrier layer is silicon nitride, then have Etch selectivity between described layer to be etched 201 and etching barrier layer; Described etching barrier layer defines the stop position of follow-up plasma etch process, follow-uply carries out plasma etching till exposing described etching barrier layer to described layer to be etched 201.
Described mask layer 202 define follow-up required formed opening size, structure and position, described mask layer 202 has Etch selectivity relative to layer to be etched 201, and described mask layer 202 has enough physical strengths, to ensure that the figure of mask layer 202 in follow-up plasma etch process process does not change.In addition, described mask layer 202 surface is also formed with bottom layer anti-reflection layer 211, and at the photoresist layer 212 on described bottom layer anti-reflection layer 211 surface, described photoresist layer 212 exposes the follow-up required correspondence position forming opening.The formation method of described mask layer 202 comprises: after 201 surfaces layer to be etched form mask film, with described photoresist layer 212 for mask, carry out dry etching to mask film and formed, namely formed mask layer 202 figure is determined by described photoresist layer 212.In the present embodiment, the material of described mask layer 202 is amorphous carbon layer.
Prior art in order to form the opening of high-aspect-ratio in layer to be etched 201, need to introduce high polymer enrichment (polymer-rich) gas in the process gas of follow-up plasma etch process, described height gathers enriched gas can form polymeric layer as protection at the sidewall of the sidewall surfaces of opening and mask layer 202 and top surface, but, described height gathers enriched gas while formation polymeric layer, also can produce not volatile accessory substance, described not volatile accessory substance easily attachment is randomly deposited in sidewall and the top surface of mask layer 202, and the sidewall surfaces of opening, the bombardment of plasma counteracts, formed opening size is caused to reduce, described not volatile accessory substance even can block open top.Therefore, the opening size formed with existing plasma etch process is uneven.
After formation mask layer 202, namely can with described mask layer 202 for mask, plasma etching is carried out to described layer to be etched 201, until formation opening, in order to make formed opening size accurately even, the plasma etch process of described opening comprises: with described mask layer 202 for mask, when carrying out plasma etching to described layer to be etched 201, the radiofrequency signal that the biased radio frequency power source of described plasma etching exports is pulse signal, and the duty ratio of described pulse signal reduces with the increase of etching depth, wherein, when biased radio frequency power source is opened, etched portions layer to be etched 201 also forms etching mouth, and in described etching mouth, there is etch by-products, when biased radio frequency power source is closed, described etch by-products diffuses out described etching mouth, repeat described biased radio frequency power source and open and be biased the process that radio frequency power source opens closedown, until formation opening, the depth-to-width ratio of described opening is greater than 10:1.Be specifically described below with reference to accompanying drawing.
Please refer to Fig. 4, in first time period t1, with described mask layer 202 for mask, plasma etching is carried out to described layer to be etched 201, the first sub-opening 203a is formed in described layer to be etched 201, the radiofrequency signal that the biased radio frequency power source of described plasma etching exports is pulse signal, and described pulse signal has the first duty ratio DR1.
Also comprise high poly-enriched substance gas in the process gas of described plasma etching, described height gathers enriched substance gas and comprises C
4f
8, C
4f
6, CHF
3, CH
2f
2, one or more in CO.Because described height gathers containing carbon and fluorine element in enriched substance gas, therefore, it is possible in plasma etch process, react at the etching sidewall surfaces of mouth and the sidewall of mask layer 202 and top surface and form polymeric layer; Described polymeric layer can keep the dimension of picture of mask 202, and can protect the sidewall of the first sub-opening 203a, makes the first formed sub-opening 203a sidewall vertical relative to 201 surfaces layer to be etched.But, when described height gathers enriched substance gas when etching the sidewall surfaces of mouth and mask layer 202 surface reacts, the a large amount of not volatile accessory substance of easy generation, described not volatile accessory substance comprises carbon, element silicon, fluorine element, one or more large molecules combined in oxygen element and nitrogen element or polymer molecule, described accessory substance is easily attached to mask layer 202 randomly, bottom layer anti-reflection layer 211, the sidewall surfaces of photoresist layer 212 and etching mouth, be easy to cause the pattern of the first formed sub-opening 203a to change, follow-up formed opening size is made to be difficult to keep accurately evenly.Therefore, eliminate opening size that described accessory substance makes guarantee be formed accurately all and one of key factor.
Also O is comprised in the process gas of described plasma etch process
2and Ar.Wherein, described O
2can be used in consuming the polymeric layer formed.Therefore, it is possible to pass through O in process gas
2content regulates, and can regulate the thickness of formed polymeric layer, thus realizes the regulation and control to follow-up formed opening sidewalls pattern; Make O in process gas
2content increases, can the thickness of thinning formed polymeric layer; Make O in process gas
2content reduces, and can increase the thickness of formed polymeric layer.Described Ar as carrier gas, for dispersing process gases.In addition, the pressure of described plasma etching is 15 millitorr ~ 60 millitorrs.
In described plasma etch process, using plasma radio frequency power source carries out plasmarized to form plasma to process gas, adopts biased radio-frequency power to make substrate 200 with bias voltage, thus plasma is bombarded to layer to be etched 201.
In the present embodiment, please refer to Fig. 7, the radiofrequency signal that the plasma rf power source of described plasma etching exports is pulse signal (Pulse), the frequency of the pulse signal that described plasma rf power source exports, identical with the frequency of the pulse signal that biased radio frequency power source exports.The pulse frequency of described plasma rf power source is 200 hertz ~ 5000 hertz, the power of described plasma rf power source is 200 watts ~ 3000 watts, the natural frequency of described plasma rf power source is greater than 13 megahertzes, in the present embodiment, the natural frequency of described plasma rf power source is 60 megahertzes.The pulse frequency of described biased radio frequency power source is 200 hertz ~ 5000 hertz, the power of described biased radio frequency power source is 3000 watts ~ 7000 watts, the natural frequency of described biased radio frequency power source is less than 13 megahertzes, in the present embodiment, the natural frequency of described biased radio frequency power source is 2 megahertzes.
In another embodiment, the radiofrequency signal that the plasma rf power source of described plasma etching exports is continuous signal (CW), the power of described plasma rf power source is 200 watts ~ 3000 watts, the natural frequency of described plasma rf power source is greater than 13 megahertzes, such as 60 megahertzes.Meanwhile, the pulse frequency of biased radio frequency power source is 200 hertz ~ 5000 hertz, and the power of described biased radio frequency power source is 3000 watts ~ 7000 watts, and the natural frequency of described biased radio frequency power source is less than 13 megahertzes, such as 2 megahertzes.
The signal exported due to described biased radio frequency power source is pulse signal, when biased radio frequency power source is opened, the bombarding energy of plasma is higher, and reactivity is larger, described plasma can bombard to layer to be etched 201, also forms etching mouth with etched portions layer to be etched 201; Wherein, the plasma of high poly-enriched substance gas can enter in etching mouth and react, and forms polymeric layer in the sidewall surfaces of etching mouth; Meanwhile, after described height gathers enriched substance gas reaction generation polymeric layer, not volatile byproducts accumulation can be formed in etching mouth, and due to plasma constant bombardment, make described accessory substance be compressed on etching mouth inside and not easily discharge.
When biased radio frequency power source is closed, because the bombarding energy of plasma reduces, reactivity reduces, therefore plasma to layer to be etched 201 bombardment reduced capability, described plasma not easily enters etching mouth inside; Therefore, when biased radio frequency power source is closed, not easily form polymeric layer in the sidewall surfaces of etching mouth and mask layer 202, then not easily produce accessory substance; And, when biased radio frequency power source is closed, because plasma is difficult to enter etching mouth inside, make to strengthen in the diffusivity of the accessory substance accumulated in etching mouth when biased radio frequency power source is opened, therefore described accessory substance can spread described etching mouth inside of escaping out, thus inhibit the problem that accessory substance gathers immediately at etching mouth sidewall and mask layer 202 surface, then the pattern of the first formed sub-opening 203a is good, size is accurately even.
In the present embodiment, described first time period t1 accounts for and forms 30% ~ 50% of required opening total time.Because the degree of depth h1 of the formed first sub-opening 203a is more shallow, therefore in the etching process of first time period t1, the accessory substance accumulated in etching mouth is easy to diffuse out described etching mouth, makes the time of described biased radio frequency power source closedown without the need to long.Therefore, in described first time period t1, described first duty ratio DR1 is 90% ~ 70%, and described first duty ratio DR1 is higher, and namely the time of described biased radio frequency power source unlatching is longer, and the time that described biased radio frequency power source is closed is shorter.In first time period t1, can either ensure that accessory substance can diffuse out etching mouth completely, simultaneously guaranteed etch rate when forming the first sub-opening 203a is higher, is conducive to improving the overall etch rate forming required opening.
Concrete, please refer to Fig. 7, Fig. 7 is in first time period t1, the sequential chart of the radio-frequency power that plasma rf power source exports and the radio-frequency power that biased radio frequency power source exports.
The signal that the plasma rf power source of the present embodiment exports also is pulse signal, and the pulse signal frequency that plasma rf power source exports is consistent with the pulse signal frequency that biased radio frequency power source exports; Namely when bias power source is closed, plasma rf power source is in low power state (low), and described low power state is not 0 watt, in case plasma extinguishment; When bias power source is opened, plasma rf power source is in high power state (high).
First time period t1 is 30% ~ 50% of the total time forming follow-up required opening, and in first time period t1, the frequency of the pulse signal of biased radio frequency power source and the first duty ratio DR1 keep constant; And the first duty ratio DR1 of the pulse signal of biased radio frequency power source is 90% ~ 70%.Wherein, in the one-period of the pulse signal of described biased radio frequency power source, the time that described biased radio frequency power source is opened is T1, the time that described biased radio frequency power source is closed is T2, then described first duty ratio DR1=T1/ (T1+T2), from the formula of the first duty ratio DR1, when the first duty ratio DR1 is larger, namely the time that in each cycle, biased radio frequency power source is opened is longer, and the time that biased radio frequency power source is closed is shorter.
Because the degree of depth h1 of the formed through first time period t1 first sub-opening 203a is more shallow, the accessory substance accumulated in etching mouth is made to be easy to diffuse out described etching mouth, therefore within the single cycle of first time period t1, the time of T2 is closed without the need to both long in bias power source, can ensure that the accessory substance accumulated in etching mouth can diffuse out described etching mouth; Simultaneously, within the single cycle of first time period t1, the time that T1 is opened in described bias power source is longer, and namely plasma is longer to bombardment time layer to be etched, make the etch rate in first time period t1 very fast, the average etching rate being conducive to ensureing to be formed follow-up required opening is very fast.
Please refer to Fig. 8, the cross-sectional view of the etching mouth of (T1) when Fig. 8 is the unlatching of biased radio frequency power source.
When bias power source is opened; plasma bombards layer to be etched 201; height wherein gathers enriched substance gas, and to enter etching mouth inner and to react formation polymeric layer in the sidewall surfaces of etching mouth; described polymeric layer can protect the sidewall of described etching mouth and the surface of mask layer 202; ensure that described mask layer 202 can not be thinned; and the figure of described mask layer 202 does not change in etching process, and the sidewall etching mouth can keep vertical with 201 surfaces layer to be etched.When therefore opening in bias power source, the selection and comparison of described plasma etch process is high, can make the size of etching mouth accurately and sidewall is vertical relative to 201 surfaces layer to be etched.The not volatile accessory substance simultaneously produced in etching mouth, and accumulate in due to the constant bombardment of plasma in etching mouth.
Please refer to Fig. 9, the cross-sectional view of the etching mouth of (T2) when Fig. 9 is the closedown of biased radio frequency power source.
When bias power source is closed, the accessory substance that bias power source accumulates in when opening in etching mouth can spread described etching mouth of escaping out, thus described accessory substance can be avoided to be attached to sidewall surfaces and mask layer 202 surface of etching mouth immediately, make the size of follow-up formed opening accurately even.And, due to when described bias power source can be closed, described accessory substance can spread described etching mouth of escaping out, the impact of described accessory substance on follow-up formed opening size pattern and accuracy is eliminated with this, therefore in described plasma etch process, without the need to adjusting the composition of process gas, namely the ratio between high poly-enriched substance G&O can be made to meet technical need, to form the polymeric layer of desired thickness in etching mouth sidewall surfaces and mask layer 202 surface, to ensure that the opening sidewalls formed can be vertical relative to 201 surfaces layer to be etched, make formed opening pattern good.
Please refer to Fig. 5, in the second time period t 2, with described mask layer 202 for mask, to described first sub-opening 203a(as shown in Figure 4) plasma etching is carried out in bottom, form the second sub-opening 203b, the radiofrequency signal that the biased radio frequency power source of described plasma etching exports is pulse signal, and described pulse signal has the second duty ratio DR2, and described second duty ratio DR2 is less than the first duty ratio DR1.
Described second time period accounts for and forms 20% ~ 40% of described opening total time, the etching technics of described second time period t 2 is after first time period t1, the degree of depth h2 of the second therefore formed sub-opening 203b is greater than the degree of depth h1 of the first sub-opening 203a, make in the etching process of the second time period t 2, the difficulty that the accessory substance accumulated in etching mouth diffuses out etching mouth increases, the time that biased radio frequency power source is closed then is needed to increase, therefore described second duty ratio is 70% ~ 50%, described second duty DR2 is less than the first duty ratio DR1, namely within the single cycle, the time scale that biased radio frequency power source is closed improves, to give accessory substance time enough to escape out etching mouth.
Please refer to Figure 10, Figure 10 is in the second time period t 2, the sequential chart of the radio-frequency power that plasma rf power source exports and the radio-frequency power that biased radio frequency power source exports.
Second time period t 2 is 20% ~ 40% of the total time forming follow-up required opening, and in the second time period t 2, the frequency of the pulse signal of biased radio frequency power source and the second duty ratio DR2 keep constant; And the second duty ratio DR2 of the pulse signal of biased radio frequency power source is 70% ~ 50%, is less than the first duty ratio DR1 in first time period t1.Wherein, in the one-period of the pulse signal of described biased radio frequency power source, the time that described biased radio frequency power source is opened is T11, and the time that described biased radio frequency power source is closed is T12, the second duty ratio DR2=T11/ (T11+T12).
Due to through the second time period t 2, the degree of depth h2 of the formed second sub-opening 203b is larger than the degree of depth h1 of the first sub-opening 203a, make in the etching process of the second time period t 2, the difficulty that the accessory substance accumulated in etching mouth diffuses out described etching mouth increases, therefore within the single cycle of the second time period t 2, the time that bias power source is closed needs corresponding increase, ensures that the accessory substance in long-pending etching mouth can diffuse out described etching mouth completely with this; Meanwhile, within the single cycle of the second time period t 2, the time corresponding shortening that described bias power source is opened, the etch rate that the etch rate namely forming the second sub-opening 203b comparatively forms the first sub-opening 203a slows down to some extent.Therefore, the setting of described second duty ratio DR2 needs ensureing that under the prerequisite that accessory substance is escaped completely, the time that bias power source is opened extends as far as possible, ensures that the average etching rate forming follow-up opening is very fast with this; In the present embodiment, described second duty ratio DR2 is 70% ~ 50%, can, while guarantee accessory substance spreads etching mouth of escaping out completely, make the etch rate of the second time period t 2 be in level faster.
Please refer to Fig. 6, in the 3rd time period t 3, with described mask layer 202 for mask, plasma etching is carried out to bottom described second sub-opening 203b, form described opening 203, the radiofrequency signal that the biased radio frequency power source of described plasma etching exports is pulse signal, and described pulse signal has the 3rd duty ratio DR3, and described 3rd duty ratio DR3 is less than the second duty ratio DR2.
Opening 203 degree of depth h3 formed is greater than 1200 nanometers, described opening 203 top is of a size of 35 nanometer ~ 40 nanometers, the depth-to-width ratio of described opening 203 is greater than 10:1, be 10:1 ~ 100:1 in the present embodiment, the degree of depth h3 of described opening 203 is larger, and top dimension is less, therefore formed opening 203 depth-to-width ratio is comparatively large, is conducive to the integrated level improving chip.
Described 3rd time period t 3 accounts for and forms 15% ~ 30% of described opening 203 total time, the etching technics of described 3rd time period t 3 is after the second time period t 2, the degree of depth h3 of the opening 203 formed is larger compared with the degree of depth h2 of the second sub-opening 203b, make in the etching process of the 3rd time period t 3, the accessory substance accumulated in etching mouth more difficultly diffuses out described etching mouth, therefore, in the 3rd time period t 3, the time that biased radio frequency power source is closed is longer, to guarantee that accessory substance has time enough to escape out etching mouth; Described 3rd duty ratio DR3 comparatively the second duty ratio DR2 is larger, and described 3rd duty ratio DR3 is 50% ~ 30%.15% ~ 30% of described opening 203 total time is formed because described 3rd time period t 3 only accounts for, even if therefore described 3rd duty ratio is lower, impact for the average etching rate forming described opening 203 is also limited, and the Mean Speed therefore forming described opening 203 still can keep higher level.
In the present embodiment, three sections are divided into carry out the plasma etch process forming described opening 203, the i.e. etching technics of first time period t1, the etching technics of the second time period t 2 is carried out after described first time period t1, and the etching technics of the 3rd time period t 3 of carrying out after the second time period t 2.Wherein, for the pulse signal of biased radio frequency power source, second duty ratio DR2 of the second time period t 2 is less than the first duty ratio DR1 of first time period t1, 3rd duty ratio DR3 of the 3rd time period t 3 is less than the second duty ratio DR2 of the second time period t 2, namely along with the increase of etching depth, the corresponding reduction of duty ratio of the pulse signal of biased radio frequency power source, the not volatile accessory substance making to result from etching process in etching mouth can have time enough and to escape out etching mouth when biased radio frequency power source is closed, to ensure that the surface of etching mouth sidewall surfaces in etching process and mask layer 202 does not have the attachment immediately of accessory substance, make the size of formed opening 203 accurately even.And, by formed described opening 203 plasma etch process be divided into three sections total time, and the frequency of the pulse signal of biased radio frequency power source in per a period of time and duty ratio all keep constant, can ensure in the accurate uniform situation of the Mean Speed forming described opening 203 opening 203 size that is higher, that formed, the Parameters variation of described plasma etch process is less, then can make the technique relative simplicity of formation opening 203.
In other embodiments, can also according to concrete technology needs, the time of the plasma etch process forming opening is divided into some time section, the quantity of described time period is greater than 3, and in each time period, the flat rate of pulse signal of biased radio frequency power source and duty ratio keep constant, and the duty ratio of the biased radio frequency power source of each time period is less than the duty ratio in previous time period.
It should be noted that, described opening 203 can be through-hole structure or groove structure.The opening 203 that the present embodiment is formed is through-hole structure.
Please refer to Figure 11, Figure 11 is in the 3rd time period t 3, the sequential chart of the radio-frequency power that plasma rf power source exports and the radio-frequency power that biased radio frequency power source exports.
3rd time period t 3 is form described opening 203 total time 15% ~ 30%, and in the 3rd time period t 3, the frequency of the pulse signal of biased radio frequency power source and the 3rd duty ratio DR3 keep constant; And the 3rd duty ratio DR3 of the pulse signal of biased radio frequency power source is 50% ~ 30%, is less than the second duty ratio DR2 in the second time period t 2.Wherein, in the one-period of the pulse signal of described biased radio frequency power source, the time that described biased radio frequency power source is opened is T21, and the time that described biased radio frequency power source is closed is T22, the 3rd duty ratio DR3=T21/ (T21+T22).
Due to through the 3rd time period t 3, to form the degree of depth h3 of opening 203 large compared with the degree of depth h2 of the second sub-opening 203b, make in the etching process of the 3rd time period t 3, the time that diffuses out needed for described etching mouth of accessory substance accumulated in etching mouth is longer, therefore within the single cycle of the 3rd time period t 3, the time that bias power source is closed is longer, ensures that the accessory substance in long-pending etching mouth can diffuse out the etching mouth of described high depth completely with this.In the present embodiment, described 3rd duty ratio DR3 is 50% ~ 30%, etching mouth of escaping out can be spread completely at guarantee accessory substance, and, described 3rd time period t 3 is only and forms 15% ~ 30% of opening 203 total time, it is less that described 3rd time period t 3 accounts for the ratio forming opening 203 total time, even if the etch rate therefore in the 3rd time period t 3 is comparatively slow, the impact for the average etching rate forming opening 203 is also limited.Therefore, the size of the opening 203 formed is accurately even, and the average etching rate forming described opening 203 is higher.
Please refer to Figure 12 and Figure 13, Figure 12 is the SEM vertical view of the through hole adopting prior art to be formed, and Figure 13 makes the SEM vertical view of the opening that described in employing the present embodiment, method is formed.
Formed in the plasma etch process of through hole as shown in figure 12, the radiofrequency signal that biased radio frequency power source exports is continuous signal, the aperture size of visible formed through hole differs, even some through hole is completely plugged, the clear size of opening inaccuracy formed, is unfavorable for the conductive plunger that follow-up forming property is in through-holes stable.
The through hole of Figure 13 adopts the method described in the present embodiment to be formed, the radiofrequency signal that biased radio frequency power source wherein exports is pulse signal, and the duty ratio of described pulse signal reduces with the increase of etching depth, as seen from the figure, the clear size of opening formed is accurately homogeneous, is that the follow-up conductive plunger size be formed in described through hole is accurate, pattern good, stable performance.
Please refer to Figure 14, Figure 14 is when in plasma atmosphere, oxygen content is different, the radiofrequency signal that biased radio frequency power source exports be pulse signal and non-pulse signal time, the broken line graph of through-hole aperture (TCD) and aperture standard variance (TCDnormalizedStDev).
As shown in Figure 14, when the radiofrequency signal that biased radio frequency power source exports is non-pulse signal, through-hole aperture is less, and the radiofrequency signal that biased radio frequency power source exports is when being pulse signal, through-hole aperture is larger, this is due to when the radiofrequency signal that biased radio frequency power source exports is pulse signal, and not volatile accessory substance is not easily attached to sidewall surfaces and mask layer 202 surface of through hole, then formed clear size of opening more meets design standard.
Secondly, when the radiofrequency signal that biased radio frequency power source exports is non-pulse signal, aperture standard variance is larger, and when the radiofrequency signal that biased radio frequency power source exports is pulse signal, aperture standard variance is less, namely, when the radiofrequency signal that biased radio frequency power source exports is pulse signal, the aperture size of the through hole formed is more even.Therefore, the clear size of opening formed with the method for the present embodiment is accurately even.
In the present embodiment, layer to be etched is single layer structure.When biased radio frequency power source is closed, the bias voltage that substrate is formed reduces, the energy of plasma basad direction bombardment reduces, described plasma is made not easily to enter in etching mouth, and the reactivity of plasma in etching mouth reduces, make the also corresponding minimizing of formed accessory substance, then the diffusivity of described accessory substance is stronger, described accessory substance can be escaped outside etching mouth, thus reduce described accessory substance and adhere to accumulation at random on mask layer surface and etching mouth sidewall surfaces, formed opening size can be made accurately homogeneous.And, because the energy of plasma basad direction bombardment reduces, therefore etch rate reduces, and can ensure that the impact that the sidewall of described mask layer and lower surface are etched is lower, then the size of mask layer not easily changes, and is conducive to making formed opening size accurate.Secondly; when biased radio frequency power source is opened; the energy of plasma basad direction bombardment improves; plasma can enter bottom etching mouth and etch; and the reactivity of plasma in etching mouth improves, while etching is layer to be etched, polymeric layer can be formed to protect in the sidewall surfaces of etching mouth and mask layer surface.Therefore, the opening size formed is accurately homogeneous.In addition, for plasma etch process, the pulse signal duty ratio that biased radio frequency power source exports is less, and the time that time shorter, the biased radio frequency power source that namely biased radio frequency power source is closed is opened is longer, then etch rate is faster.When the duty ratio of pulse signal reduces with the increase of etching depth, namely along with the increase of etching depth, the time that biased radio frequency power source is closed increases gradually, and the time that biased radio frequency power source is opened reduces gradually; When etching the mouth degree of depth and being less, the time that biased radio frequency power source is opened is more, can ensure, when ensureing accessory substance escape diffusion, to make etch rate higher, thus ensures that the average etching rate forming described opening is higher; When etching the mouth degree of depth and being larger, the time that biased radio frequency power source is closed is more, ensures that accessory substance can diffuse out etching mouth completely with this.Therefore, while formed opening size is accurately homogeneous, the etch rate of described plasma etch process is higher.
Second embodiment
Figure 15 to Figure 16 is the schematic diagram of the forming process of the semiconductor structure of the second embodiment of the present invention.
Please refer to Figure 15, provide substrate 300, described substrate 300 surface has layer to be etched 301; Form mask layer 302 on described 301 surfaces layer to be etched, described mask layer 302 exposes part 301 surfaces layer to be etched, and described mask layer 302 material is agraphitic carbon.
The structure of described substrate 300 and mask layer 302, material and formation process are identical with described in the first embodiment, do not repeat at this.In addition, in the present embodiment, described mask layer 302 surface is also formed with bottom layer anti-reflection layer 311, and at the photoresist layer 312 on described bottom layer anti-reflection layer 311 surface, described photoresist layer 312 exposes the follow-up required correspondence position forming opening.
Described layer to be etched 301 is sandwich construction, and be specially silicon oxide layer 322 and the alternatively distributed multilayer lamination structure of silicon nitride layer 321, layer to be etched 301 of described multiple-level stack can be applied to VNAND technique, with the flush memory device that forming property is more remarkable.Described silicon oxide layer and the alternatively distributed number of times of silicon nitride layer are more than or equal to 8 times.
Please refer to Figure 16, with described mask layer 302 of stating for mask, plasma etching is carried out to described layer to be etched 301, opening 303 is formed in described layer to be etched 301, the radiofrequency signal that the biased radio frequency power source of described plasma etching exports is pulse signal, the duty ratio of described pulse signal reduces with the increase of etching depth, when biased radio frequency power source is opened, etched portions is layer to be etched and formation etches mouth, and in described etching mouth, there is etch by-products, when biased radio frequency power source is closed, described etch by-products diffuses out described etching mouth, the depth-to-width ratio of described opening 303 is greater than 10:1.
Described plasma etch process and the first embodiment form opening 203(and please refer to Fig. 6) technique identical, and the structure of the opening 303 formed is identical with the structure of the opening 203 of the first embodiment, does not repeat at this.
In the present embodiment, described plasma etch process comprises: in first time period, etch described layer to be etched, form the first sub-opening, the degree of depth of described first sub-opening is h1, the pulse signal that biased radio frequency power source exports has the first duty ratio, and described first duty ratio is 90% ~ 70%, and described first time period accounts for and forms 30% ~ 50% of described opening 303 total time; Within the second time period, etch described first sub-open bottom, form the second sub-opening, the degree of depth of described second sub-opening is h2, the pulse signal that biased radio frequency power source exports has the second duty ratio, described second duty ratio is 70% ~ 50%, and described second duty ratio is less than the first duty ratio, and described second time period accounts for and forms 20% ~ 40% of described opening total time; Within the 3rd time period, etch described second sub-open bottom, form described opening 303, the degree of depth of described opening 303 is h3, the pulse signal that biased radio frequency power source exports has the 3rd duty ratio, described 3rd duty ratio is less than the second duty ratio, and described 3rd duty ratio is 50% ~ 30%, and described 3rd time period accounts for and forms 15% ~ 30% of described opening 303 total time.
In the present embodiment, described layer to be etched be silicon oxide layer and the alternatively distributed multilayer lamination structure of silicon nitride layer, describedly layer to be etchedly can be applied to VNAND technique, to form flush memory device.In the plasma etch process of described interior formation opening layer to be etched, the duty ratio of the pulse signal that biased radio frequency power source exports reduces along with the increase of etching depth, in the single cycle of i.e. described pulse signal, biased radio frequency power source is closed and is increased, make the accessory substance in etching mouth have time enough and spread described etching mouth of escaping out, avoid described accessory substance be attached to etching mouth inner wall surface and mask layer surface and image etching formed opening pattern, therefore formed opening size is accurately homogeneous.And, due to described pulse signal duty ratio from large to small, namely when etching the mouth degree of depth and being more shallow, duty ratio is comparatively large, and etch rate is very fast, and etch the mouth degree of depth darker time, duty is smaller, give accessory substance time enough to spread, therefore when ensureing opening size accuracy, the etch rate forming opening is very fast.
Although the present invention discloses as above, the present invention is not defined in this.Any those skilled in the art, without departing from the spirit and scope of the present invention, all can make various changes or modifications, and therefore protection scope of the present invention should be as the criterion with claim limited range.
Claims (11)
1. a formation method for semiconductor structure, is characterized in that, comprising:
There is provided substrate, described substrate surface has layer to be etched;
Form mask layer on described surface layer to be etched, described mask material is agraphitic carbon, and described mask layer exposes part surface layer to be etched;
With described mask layer for mask, layer to be etchedly plasma etching is carried out to described, at described interior formation opening layer to be etched, the depth-to-width ratio of described opening is greater than 10:1, the radiofrequency signal that the biased radio frequency power source of described plasma etching exports is pulse signal, the duty ratio of described pulse signal reduces with the increase of etching depth, when biased radio frequency power source is opened, etched portions is layer to be etched and formation etches mouth, and in described etching mouth, there is etch by-products, when biased radio frequency power source is closed, described etch by-products diffuses out described etching mouth;
Described plasma etch process comprises: in first time period, etches described layer to be etched, forms the first sub-opening, and the pulse signal that biased radio frequency power source exports has the first duty ratio; Within the second time period, etch described first sub-open bottom, form the second sub-opening, the pulse signal that biased radio frequency power source exports has the second duty ratio, and described second duty ratio is less than the first duty ratio; Within the 3rd time period, etch described second sub-open bottom, form described opening, the pulse signal that biased radio frequency power source exports has the 3rd duty ratio, and described 3rd duty ratio is less than the second duty ratio;
Described first duty ratio is 90% ~ 70%, and described first time period accounts for and forms 30% ~ 50% of described opening total time; Described second duty ratio is 70% ~ 50%, and described second time period accounts for and forms 20% ~ 40% of described opening total time; Described 3rd duty ratio is 50% ~ 30%, and described 3rd time period accounts for and forms 15% ~ 30% of described opening total time.
2. the formation method of semiconductor structure as claimed in claim 1, is characterized in that, described layer to be etched be single layer structure, and material layer to be etched is the one in silicon oxide layer, silicon nitride layer, silicon oxynitride layer, silicon carbide layer or fire sand layer.
3. the formation method of semiconductor structure as claimed in claim 1, is characterized in that, described layer to be etched be sandwich construction, and described layer to be etched be silicon oxide layer and the alternatively distributed multilayer lamination structure of silicon nitride layer.
4. the formation method of semiconductor structure as claimed in claim 3, it is characterized in that, described silicon oxide layer and the alternatively distributed number of times of silicon nitride layer are more than or equal to 8 times.
5. the formation method of semiconductor structure as claimed in claim 1, is characterized in that, the gas that described plasma etching adopts comprises C
4f
8, C
4f
6, CHF
3, CH
2f
2, one or more in CO.
6. the formation method of semiconductor structure as claimed in claim 1, it is characterized in that, the radiofrequency signal that the plasma rf power source of described plasma etching exports is continuous signal, the power of described plasma rf power source is 200 watts ~ 3000 watts, and the natural frequency of described plasma rf power source is greater than 13 megahertzes.
7. the formation method of semiconductor structure as claimed in claim 1, it is characterized in that, the radiofrequency signal that the plasma rf power source of described plasma etching exports is pulse signal, the frequency of the pulse signal that described plasma rf power source exports is identical with the frequency of the pulse signal that biased radio frequency power source exports, the pulse frequency of described plasma rf power source is 200 hertz ~ 5000 hertz, the power of described plasma rf power source is 200 watts ~ 3000 watts, and the natural frequency of described plasma rf power source is greater than 13 megahertzes.
8. the formation method of semiconductor structure as claimed in claim 1, it is characterized in that, the pulse frequency of biased radio frequency power source is 200 hertz ~ 5000 hertz, and the power of described biased radio frequency power source is 3000 watts ~ 7000 watts, and the natural frequency of described biased radio frequency power source is less than 13 megahertzes.
9. the formation method of semiconductor structure as claimed in claim 1, it is characterized in that, the pressure of described plasma etching is 15 millitorr ~ 60 millitorrs.
10. the formation method of semiconductor structure as claimed in claim 1, it is characterized in that, described opening is through hole or groove.
The formation method of 11. semiconductor structures as claimed in claim 1, it is characterized in that, described substrate and layer to be etched between also there is etching barrier layer, to the described plasma etching that carries out layer to be etched till exposing described etching barrier layer, the material of described etching barrier layer is silicon nitride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310376914.3A CN103400762B (en) | 2013-08-26 | 2013-08-26 | The formation method of semiconductor structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310376914.3A CN103400762B (en) | 2013-08-26 | 2013-08-26 | The formation method of semiconductor structure |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103400762A CN103400762A (en) | 2013-11-20 |
| CN103400762B true CN103400762B (en) | 2016-03-02 |
Family
ID=49564362
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310376914.3A Active CN103400762B (en) | 2013-08-26 | 2013-08-26 | The formation method of semiconductor structure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103400762B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104733306B (en) * | 2015-04-17 | 2018-01-26 | 上海华虹宏力半导体制造有限公司 | A kind of semiconductor devices lithographic method |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104681406B (en) * | 2013-11-29 | 2020-03-31 | 中微半导体设备(上海)股份有限公司 | Plasma etching method |
| CN104752331B (en) * | 2013-12-31 | 2018-08-07 | 中微半导体设备(上海)有限公司 | A kind of silicon hole lithographic method |
| CN105084299B (en) * | 2014-05-12 | 2017-02-01 | 中芯国际集成电路制造(上海)有限公司 | Forming method of semiconductor structure |
| CN105185706B (en) * | 2014-05-30 | 2019-01-22 | 中芯国际集成电路制造(上海)有限公司 | The method for removing pseudo- grid |
| CN105655283A (en) * | 2014-11-13 | 2016-06-08 | 北京北方微电子基地设备工艺研究中心有限责任公司 | Isolation etching method for shallow trench with high depth-to-width ratio |
| CN105759356B (en) * | 2014-12-17 | 2019-10-08 | 北京北方华创微电子装备有限公司 | A kind of lithographic method of silica |
| CN106298502B (en) * | 2015-05-18 | 2019-04-09 | 中微半导体设备(上海)股份有限公司 | A method of multilayer material is etched using plasma |
| CN106601609B (en) * | 2016-12-07 | 2019-07-26 | 中国电子科技集团公司第十一研究所 | A kind of low damage mixed type dry etching method of mercury cadmium telluride |
| CN109755108B (en) * | 2017-11-07 | 2021-04-02 | 中芯国际集成电路制造(上海)有限公司 | Method for manufacturing semiconductor device |
| CN110534424B (en) * | 2018-07-31 | 2022-05-27 | 北京北方华创微电子装备有限公司 | Etching method of SiC substrate |
| CN110911344B (en) * | 2018-09-14 | 2023-09-05 | 长鑫存储技术有限公司 | Manufacturing method of semiconductor substrate shallow trench and semiconductor substrate shallow trench structure |
| CN112216702B (en) * | 2020-10-09 | 2022-03-29 | 长江存储科技有限责任公司 | Etching process and 3D NAND manufacturing process |
| CN114772544A (en) * | 2022-03-08 | 2022-07-22 | 苏州子山半导体科技有限公司 | Dry pulse plasma etching photoresist removing method with deep silicon etching and engraving functions |
| CN117936454A (en) * | 2022-10-11 | 2024-04-26 | 长鑫存储技术有限公司 | Method for manufacturing semiconductor structure and semiconductor structure |
| CN116959947B (en) * | 2023-09-21 | 2023-12-08 | 青禾晶元(天津)半导体材料有限公司 | Plasma etching device and method for etching carbon film |
| CN117558624A (en) * | 2023-11-13 | 2024-02-13 | 粤芯半导体技术股份有限公司 | Contact trench forming method and semiconductor device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102737983A (en) * | 2012-07-05 | 2012-10-17 | 中微半导体设备(上海)有限公司 | Method for forming semiconductor structure |
| CN103035470A (en) * | 2012-12-14 | 2013-04-10 | 中微半导体设备(上海)有限公司 | Semiconductor etching device and semiconductor etching method |
-
2013
- 2013-08-26 CN CN201310376914.3A patent/CN103400762B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102737983A (en) * | 2012-07-05 | 2012-10-17 | 中微半导体设备(上海)有限公司 | Method for forming semiconductor structure |
| CN103035470A (en) * | 2012-12-14 | 2013-04-10 | 中微半导体设备(上海)有限公司 | Semiconductor etching device and semiconductor etching method |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104733306B (en) * | 2015-04-17 | 2018-01-26 | 上海华虹宏力半导体制造有限公司 | A kind of semiconductor devices lithographic method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103400762A (en) | 2013-11-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103400762B (en) | The formation method of semiconductor structure | |
| KR101158205B1 (en) | Method of etching a high aspect ratio contact | |
| JP5706946B2 (en) | Plasma etching method and plasma etching apparatus | |
| US7713430B2 (en) | Using positive DC offset of bias RF to neutralize charge build-up of etch features | |
| TW546737B (en) | Method of plasma etching organic antireflective coating | |
| US20110027999A1 (en) | Etch method in the manufacture of an integrated circuit | |
| EP1042796A1 (en) | Improved techniques for etching an oxide layer | |
| JP2000216135A (en) | Etching method | |
| KR20080067970A (en) | Manufacturing method of fin-type field effect transistor | |
| CN108321090B (en) | Semiconductor device and method of forming the same | |
| Oehrlein et al. | Surface science issues in plasma etching | |
| JP2988455B2 (en) | Plasma etching method | |
| Flamm et al. | VLSI Electronics, Microstructure Science, vol. 8 | |
| US6227211B1 (en) | Uniformity improvement of high aspect ratio contact by stop layer | |
| CN106504982B (en) | Substrate etching method | |
| CN110890277B (en) | Preparation method of groove type metal oxide semiconductor Schottky barrier transistor | |
| JPH10144633A (en) | Manufacture of semiconductor device | |
| JP2009259996A (en) | Semiconductor device and method for manufacturing the same | |
| JP2003282535A (en) | Method of manufacturing semiconductor | |
| JP2003229411A (en) | Manufacturing method of thin film transistor | |
| KR20010075177A (en) | Device and method for etching spacers formed upon an integrated circuit gate conductor | |
| JP3326864B2 (en) | Dry etching method | |
| KR100431818B1 (en) | Forming method for self aligned contact of semiconductor device | |
| JP2639402B2 (en) | Oxide layer taper etching method | |
| KR20080072255A (en) | The method for etching insulating layer of semiconductor devices |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 201201 No. 188 Taihua Road, Jinqiao Export Processing Zone, Pudong New Area, Shanghai Patentee after: Medium and Micro Semiconductor Equipment (Shanghai) Co., Ltd. Address before: 201201 No. 188 Taihua Road, Jinqiao Export Processing Zone, Pudong New Area, Shanghai Patentee before: Advanced Micro-Fabrication Equipment (Shanghai) Inc. |