Multilayer film is as the manufacture method of the strain source leakage CMOS of hard mask and anti-reflecting layer
Technical field
The present invention relates to have CMOS (Complementary Metal Oxide Semiconductor) (the Complementary Metal Oxide Semiconductor of strain source-drain, CMOS) manufacture method, particularly relate to multilayer film as anti-reflecting layer and the hard mask of polysilicon gate, the manufacture method of removed strain source leakage CMOS after forming strain source-drain.
Background technology
Comprise the formation of gate pattern in the ic manufacturing process, it adopts polysilicon as gate conductive structure usually.In its processing procedure, polysilicon layer is deposited on the substrate, and it is that monocrystalline silicon forms through different process processes such as ion injection, gate oxides.The polysilicon of deposit forms gate pattern through photoetching and etching then.For forming gate pattern, as hard mask, plasma chemical vapor deposition grown silicon oxide, silicon oxynitride or nitride and silicon oxynitride etc. are used for the photoresist design transfer to poly-silicon pattern.This silicon oxynitride also can be used as the anti-reflecting layer of photoetching simultaneously.Because the photoresist that the lip-deep hydrogen of silicon oxynitride (SiON) film waves on key and its top reacts, this reaction causes the photoresist pattern development incomplete.Usually, go up oxidation film on silicon oxynitride (SiON) film top, with contacting of isolated silicon oxynitride and photoresist with plasma-reinforced chemical vapor deposition one deck 100~300A.For the application of selective epitaxial growth strained silicon, need carry out silicon dent by reactive ion beam etching (RIBE) at active region and etch into below the surface, the hard mask of polysilicon also needs as silicon dent etching and epitaxially grown hard mask.Hard mask needs to remove after epitaxial growth, and at this moment the inter polysilicon interlayer forms.Wet method is removed silicon oxynitride hard mask need use hot phosphoric acid, and hot phosphoric acid also can corrode nitride spacer layer when removing silicon oxynitride hard mask.Carry out processing procedure control to remove silicon oxynitride hard mask and to keep wall not to be etched very difficult.
Summary of the invention
The manufacture method that the purpose of this invention is to provide strain source leakage CMOS, multi-layer film structure particularly is provided, as the anti-reflecting layer of photoresist photoetching in the strain source leakage CMOS manufacturing process and as being the hard mask of hard mask of polysilicon and silicon dent etching, grow at this silicon dent etching place SiGe or silicon carbon layer are used for the formation of strained silicon.
One aspect of the present invention, multilayer film comprises the steps: as the manufacture method of the strain source leakage CMOS of hard mask and anti-reflecting layer
A. on silicon substrate, form P, N well, shallow isolating trough, on silicon substrate, form gate oxide level, polysilicon layer, multilayer film, photoresist layer then successively, this multilayer film comprises Si oxide and silicon nitrogen oxide, the anti-reflecting layer of this multilayer film during as photoetching and the hard mask during the silicon dent etching.
B. photoetching, etching form the polysilicon gate conductive structure;
C. form the polysilicon gate wall;
D. be the polysilicon gate of mask protection PMOS with multilayer film and wall,, the etching that caves in leaked in the PMOS source with photoresist protection nmos area territory;
E. remove photoresist;
F. being the polysilicon of mask protection PMOS with multilayer film and wall, is mask protection nmos area territory with multilayer film and wall, and depression etch areas epitaxial growth SiGe is leaked in the PMOS source;
G. remove multilayer film as hard mask;
H. carry out other successive process.
Another aspect of the present invention, multilayer film comprises the steps: as the manufacture method of the strain source leakage CMOS of hard mask and anti-reflecting layer
A. form P, N well, form gate oxide level, polysilicon layer, multilayer film, photoresist layer on the silicon substrate of shallow isolating trough successively, this multilayer film comprises Si oxide and silicon nitrogen oxide, the anti-reflecting layer of this multilayer film during as photoetching and the hard mask during the silicon dent etching.
B. photoetching, etching form the polysilicon gate conductive structure;
C. form the polysilicon gate wall;
D. be the polysilicon gate of mask protection NMOS with multilayer film and wall,, the etching that caves in leaked in the NMOS source with photoresist protection PMOS zone;
E. remove photoresist;
F. being the polysilicon gate of mask protection NMOS with multilayer film and wall, is mask protection PMOS zone with multilayer film and wall, and depression etch areas epitaxial growth silicon-carbon is leaked in the NMOS source;
G. remove multilayer film as hard mask;
H. carry out other successive process;
According to the present invention, multilayer film can also at first leak the epitaxial growth of formation SiGe as the manufacture method of the strain source leakage CMOS of hard mask and anti-reflecting layer in the PMOS source, leaks in the NMOS source then to form the silicon-carbon epitaxial growth.
According to the present invention, multilayer film can also at first leak the epitaxial growth of formation silicon-carbon as the manufacture method of the strain source leakage CMOS of hard mask and anti-reflecting layer in the NMOS source, leaks in the PMOS source then to form the SiGe epitaxial growth.
The multilayer film that polysilicon top layer of the present invention forms comprises trilamellar membrane, ground floor silicon oxide layer, second layer silicon oxynitride layer and the 3rd layer of silicon oxide layer.These films can be by chemical vapor deposition (Chemical Vapor Deposition, CVD) or other deposition technology, as plasma-reinforced chemical vapor deposition (Plasma Enhanced Chemical Vapor Deposition, PECVD) and spin coating methods such as (Spin-on) and forming.The thickness of the ground floor silicon oxide layer of employing PECVD deposit is such as being 50~400A.Silicon oxynitride layer can be controlled in processing procedure, as adopting PECVD, so that the thickness of the refractive index n of this silicon oxynitride film, dielectric constant k and film, is used in the reflection of light amount minimum of photoengraving pattern.The thickness of silicon oxynitride is 100~400A.The 3rd layer of silicon oxide film also can adopt PECVD to form, and the thickness of this oxide skin(coating) is 50~250A.Wherein the 3rd layer of silicon oxide film can prevent the reaction between silicon oxynitride and the photoresist, because this reaction can cause forming the residue that can not remove in lithography development process.
Advantage of the present invention is owing to adopt trilamellar membrane to be used for the formation of poly-silicon pattern, by technology controlling and process, to make the multilayer film of formation have suitable refractive index and dielectric constant, thereby have the lower reflectivity that satisfies the photoetching requirement.
Another advantage of the present invention is, because wet etching with the hydrofluoric acid base, the wall that Si oxide is contained silicon nitride has high selectivity, therefore keep as silicon dent etching and epitaxial growth SiGe or silicon-carbon the time as first tunic in the trilamellar membrane of hard mask, silicon oxide layer is removed easily, and can not produce obvious erosion to wall.
Description of drawings
Fig. 1 is the structural representation of the multilayer film of one embodiment of the present of invention and polysilicon, photoresist layer.
Fig. 2 is the analog result schematic diagram of refractive index, dielectric constant and the reflectivity of multilayer film of the present invention, and wherein abscissa is the dielectric constant k of nitrogen oxide, and ordinate is the refractive index n of nitrogen oxide, the reflectivity that the regions of different colours representative is different.
Fig. 3 be form on the silicon substrate after forming P, N well and shallow isolating trough gate oxide, polysilicon, multilayer film, and photoresist after schematic cross-section.
Fig. 4 is the schematic cross-section after photoetching, etching form the photoresist pattern.
Fig. 5 is the schematic cross-section after design transfer arrives the hard mask of multilayer film.
Fig. 6 is polysilicon and oxide skin(coating) etching, with the schematic cross-section of design transfer behind polysilicon and the oxide skin(coating).
Fig. 7 is the schematic cross-section of multilayer film after by an eating away part in polysilicon and the oxide etching process.
Fig. 8 be after forming the gate spacer layer multilayer film further by the schematic cross-section after the eating away part.
Fig. 9 is one embodiment of the present of invention, the schematic cross-section behind the photoresist pattern in formation protection nmos area territory.
Figure 10 is one embodiment of the present of invention, serves as the protection polysilicon gate with the hard mask of multilayer film of polysilicon and wall, the source of PMOS is leaked the schematic cross-section that carries out after the silicon dent etching.
Figure 11 is one embodiment of the present of invention, the schematic cross-section after silicon dent etch areas epitaxial growth SiGe is leaked in the PMOS source.
Figure 12 is one embodiment of the present of invention, the schematic cross-section behind the hard mask of removal multilayer film.
Description of reference numerals
02 polysilicon gate oxide skin(coating) illuvium
03 polysilicon illuvium
The first tunic illuvium of 04 multilayer film
The second tunic illuvium of 05 multilayer film
The trilamellar membrane illuvium of 06 multilayer film
07 photoresist coating
10 silicon substrates
11N well 12PMOS gate oxide
The 13PMOS polysilicon gate
The hard mask of ground floor multilayer film on the 14PMOS polysilicon gate
The hard mask of second layer multilayer film on the 15PMOS polysilicon gate
The hard mask of the 3rd layer multi-layer film on the 16PMOS polysilicon gate
Photoresist protective layer on the 17PMOS polysilicon gate
18PMOS polysilicon gate wall
Depression etching on leak in the 19PMOS source
Epitaxial growth germanium-silicon layer on leak in the 191PMOS source
20 shallow isolating trough
The 21P well
The 22NOMS gate oxide
The 23NMOS polysilicon gate
The hard mask of ground floor multilayer film on the 24NMOS polysilicon gate
The hard mask of second layer multilayer film on the 25NMOS polysilicon gate
The hard mask of the 3rd layer multi-layer film on the 26NMOS polysilicon gate
Photoresist protective layer on the 27NMOS polysilicon gate
28NMOS polysilicon gate wall
The photoresist in 30 protection nmos area territories
Embodiment
Below in conjunction with drawings and Examples the manufacture method of multilayer film as the strain source leakage CMOS of hard mask and anti-reflecting layer is described in more detail.
Embodiment 1
According to one embodiment of present invention, multilayer film comprises the steps: as the manufacture method of the strain source leakage CMOS of hard mask and anti-reflecting layer
A) on P type silicon substrate 10, form N well 11, P well 21, shallow isolating trough 20; On silicon substrate 10, at first adopt the plasma-reinforced chemical vapor deposition method to form polysilicon oxide layer 02, polysilicon layer 03 then, the ground floor that forms multilayer film is that silicon oxide layer 04, the second layer are that the oxynitride layer 05, the 3rd layer of silicon is silicon oxide layer 06, form photoresist layer 07 then, as shown in Figure 3.Wherein the thickness of ground floor Si oxide is 150A, the thickness of second layer silicon oxynitride is 200A, the thickness of the 3rd layer of Si oxide is 250A, Fig. 1 shows that this multilayer film can have the analog result of low reflectivity to the scanner that adopts the 193nm light source, and the multilayer film of Xing Chenging has refractive index n=1.7+/-0.1 and dielectric constant k=0.7+/-0.2 like this.
Fig. 2 be in refractive index, dielectric constant and the photoresist of trilamellar membrane reflectivity concern simulation drawing, as can see from Figure 2, under the trilamellar membrane of Fig. 1, the reflectivity in the photoresist is 0.8%, meets very much the requirement of photoetching.When so just having avoided owing to photoetching, exposure light reflects to make in photoresist layer and forms the post ripple in the photoresist pattern, loses the control of critical size.Wherein the 3rd layer of silicon oxide film on the second layer silicon oxynitride top can completely cut off silicon oxynitride and photoresist, prevent to produce reaction between silicon oxynitride and the photoresist, avoided the reaction of silicon oxynitride and photoresist to make photoresist developing not exclusively form the residue that to remove.
B) carry out photoetching, etching and form the photoresist pattern 17,27 that requires, as shown in Figure 4, etching adopts common process, as reactive ion beam etching (RIBE) (reactive ion etch, RIE).
Further adopt the reactive ion beam etching (RIBE) multilayer film, the photoresist design transfer to multilayer film, is removed photoresist 17,27, on PMOS, form the pattern of trilamellar membrane 14,15,16, on NMOS, form trilamellar membrane pattern 24,25,26, as shown in Figure 5.Reactive ion beam etching (RIBE) adopts as carbon tetrafluoride (CF4) or three fluorocarbonss (CF3).
Again polysilicon layer 03 and oxide skin(coating) 02 are carried out reactive ion beam etching (RIBE), design transfer to polysilicon, is formed the polysilicon gate conductive structure, polysilicon gate 13,23, grid oxic horizon 12,22, as shown in Figure 6.Etch chemistries is main etching agent as adopting hydrogen bromide (HBr) or chlorine (Cl2).
Because multilayer film is impaired in above reactive ion beam etching (RIBE) several times, trilamellar membrane is by partial etching, and wherein the 3rd layer of silicon oxide layer 16 lost, and therefore, through the processing procedure of front, it is two- layer 14,24 and 15,25 that multilayer film stays, as shown in Figure 7.
C) form the nitride spacer layer 18,28 of polysilicon gate then, as shown in Figure 8.Be that (the process ion beam eat-backs with wet etching and forms for Low Press Chemical Vapor Deposition, LPCVD) silicon nitride by low-pressure chemical vapor phase deposition.
D) in the etch back process of wall, two membranes also can be lost a part, therefore only stays ground floor silicon oxide film 14 and 24.
At first form the photoresist pattern 30 in protection nmos area territory in the nmos area territory; ground floor silicon oxide layer 14 and wall 18 with multilayer film is mask protection PMOS zone polysilicon gate then; with the reactive ion beam etching (RIBE) method etching that caves in is leaked in the PMOS source; form depression etch areas 19, as shown in Figure 9.
E) remove photoresist, as shown in figure 10.
F) with reserved first layer film 14 and wall 18 be the polysilicon gate 13 of the hard mask protection of autoregistration PMOS; with reserved first layer film 24 and wall 28 is the polysilicon gate 23 of the hard mask protection of autoregistration NMOS; silicon dent etch areas 19 epitaxial growth SiGes at PMOS; form epitaxial growth SiGe zone 191, as shown in figure 11.
G) adopt wet etching to remove the oxide skin(coating) 14 and 24 of the hard mask of conduct, PMOS epitaxial growing strain source is leaked and has just been formed like this.This material is SiGex (the x scope is 0.1 to 0.3).Remove multilayer film 14 and 24, as shown in figure 12 as hard mask.Owing to adopt hydrofluoric acid base wet processing, this technology is Si oxide for the ground floor 14 and 24 of the multilayer film that stays, have higher selectivity than silicon nitride spacers 18 and 28, therefore get rid of easily, and can not produce obvious erosion wall 18 and 28 as 14 and 24 of hard mask.
H) carry out other successive process, comprise ion implantation doping, form metal silicide, metal interconnected etc.
Embodiment 2
Multilayer film is as the manufacture method of the CMOS with strain source-drain NMOS of hard mask and anti-reflecting layer.
Wherein a~the c in the making step is identical with embodiment 1.Other steps are as follows:
D) in the etch back process of wall, two membranes also can be lost a part, therefore only stays ground floor Si oxide 14 and 24.
At first form the photoresist pattern in protection PMOS zone in the PMOS zone; ground floor silicon oxide layer 24 and wall 28 with multilayer film is mask protection nmos area territory polysilicon gate then; with the reactive ion beam etching (RIBE) method etching that caves in is leaked in the NMOS source, form the depression etch areas.
E) remove photoresist.
F) with multilayer film and wall polysilicon gate, silicon dent zone epitaxial growth silicon-carbon is leaked in the source of NMOS as hard mask protection NMOS and PMOS.
G and h step are with embodiment 1.
Embodiment 3
Multilayer film is as the manufacture method of the CMOS with strain source-drain PMOS and strain source-drain NMOS of hard mask and anti-reflecting layer.
Wherein a~the c in the making step is identical with embodiment 1.Other steps are as follows:
D~f) is in the etch back process of wall, and two membranes also can be lost a part, therefore only stays ground floor Si oxide 14 and 24.
At first form the photoresist pattern in protection nmos area territory in the nmos area territory; ground floor silicon oxide layer and wall with multilayer film is mask protection PMOS zone polysilicon gate then; with the reactive ion beam etching (RIBE) method etching that caves in is leaked in the PMOS source, form the depression etch areas.Remove photoresist layer.Multilayer film and wall leak silicon dent zone epitaxial growth SiGe as the polysilicon gate of hard mask protection PMOS and NMOS in the PMOS source.
Form the photoresist pattern in protection PMOS zone in the PMOS zone; ground floor silicon oxide layer and wall with multilayer film is mask protection nmos area territory polysilicon gate then; with the reactive ion beam etching (RIBE) method etching that caves in is leaked in the NMOS source; form the depression etch areas of NMOS; remove photoresist; multilayer film and wall leak silicon dent zone epitaxial growth silicon-carbon as the polysilicon gate of hard mask protection NMOS and PMOS in the NMOS source.
G and h step are with embodiment 1.
Embodiment 4
Multilayer film is as the manufacture method of the CMOS with strain source-drain PMOS and strain source-drain NMOS of hard mask and anti-reflecting layer.
Wherein a~the c in the making step is identical with embodiment 1.Other steps are as follows:
D~f) is in the etch back process of wall, and two membranes also can be lost a part, therefore only stays ground floor Si oxide 14 and 24.
At first form the photoresist pattern in protection PMOS zone in the PMOS zone; ground floor silicon oxide layer and wall with multilayer film is mask protection nmos area territory polysilicon gate then; with the reactive ion beam etching (RIBE) method etching that caves in is leaked in the NMOS source; form the depression etch areas of NMOS; remove photoresist; multilayer film and wall leak silicon dent zone epitaxial growth silicon-carbon as the polysilicon gate of hard mask protection NMOS and PMOS in the NMOS source.
Form the photoresist pattern in protection nmos area territory in the nmos area territory; ground floor silicon oxide layer and wall with multilayer film is mask protection PMOS zone polysilicon gate then; with the reactive ion beam etching (RIBE) method etching that caves in is leaked in the PMOS source, form the depression etch areas.Remove photoresist layer.Multilayer film and wall leak silicon dent zone epitaxial growth SiGe as the polysilicon gate of hard mask protection PMOS and NMOS in the PMOS source.
G and h step are with embodiment 1.
In above technological process, the two kinds of material of second and third layer in the trilamellar membrane are consumed by various ion beam etchings and wet method removal process.Final Si oxide is removed after the epitaxial growth of the SiGe of finishing the source leakage or silicon-carbon.Because hydrofluoric acid base wet etching has high selectivity to oxide with respect to the silicon nitride comprising wall, therefore the trilamellar membrane that keeps is that the ground floor silicon oxide layer is easy to be removed, and can not produce obvious erosion to wall.