CN101295665A - Horn shaped contact production method - Google Patents

Abstract

A manufacture method for a trumpet-shaped contact includes the following steps of: forming a first insulating layer on a silicon underlay which is formed with an active structure, an isolation and a metal silicide; then forming a second insulating layer; forming a photosensitive resist and forming a contact hole pattern of the photosensitive resist by photoetching and developing; etching the second insulating layer and the first insulating layer to form a contact hole; returning the photosensitive resist; carrying out the etching adopting a gas with high selectivity ratio of the second insulating layer/the first insulating layer on the second insulating layer and the first insulating layer to form a trumpet-shaped contact hole; removing the photosensitive resist; filling and contacting metals as well as flatting; forming a dielectric medium layer between metals and etching a metal wire pattern; filling a first metal and flatting; continuing other manufacture processes. The trumpet-shaped contact manufactured by the method can prevent the dispersing of copper.

Description

A kind of manufacture method of horn-like contact

Technical field

The present invention relates to the metal interconnected technology in the manufacture of semiconductor, particularly relate to the manufacture method of the horn-like contact that prevents the copper diffusion.

Background technology

In the processing procedure of semi-conductive rear end, before forming the copper metal interconnecting wires, need between ground floor copper metal line and contacting metal, form a contact hole, fill the electric connection between conduct of tungsten metal and the metal wire therein.

As Figure 1A～1E is the forming process of the contact hole of prior art.

On the silicon substrate that forms active device 1 and isolation 2 and metal silicide 3, form silicon oxide layer as interlevel dielectric layer 4, silicon oxynitride is as hard mask layer 5, by form photoresist and photoetching, development forms contact hole pattern, be that mask etching silicon oxide layer 4 and silicon oxynitride layer 5 form contact hole then with the photoresist layer, in contact hole, fill the tungsten metal and form tungsten metal level 6.Because the deposition velocity of the top sharp corner of contact hole is bigger than the deposition velocity of sidewall,, so just stays and fill bad hole 61, shown in Figure 1A at the middle part of contact hole so chemical vapour deposition (CVD) tungsten metal is easier of the sealing of top sharp corner.

Planarization tungsten metal level 6, and remove hard mask silicon oxynitride layer 5, just in the contact hole tungsten, form the hole 61 of opening, shown in Figure 1B.

Form inter-metal dielectric layer 7 then, when carrying out the electrochemical effect of the first metal wire etching and cleaning, with making the hole 61 in the tungsten Metal Contact become big, shown among Fig. 1 C 62.

When carrying out copper metal layer 8 depositions, will there be part copper to be filled in the hole 62 of tungsten Metal Contact, as 81 among Fig. 1 D.

In follow-up high annealing processing procedure, copper 81 is easy to spread along active region by the hole in the tungsten Metal Contact, shown in 82 among Fig. 1 E.

Its result is easy to cause problems such as electric leakage, and product percent of pass is descended.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of manufacture method that can prevent the horn-like contact hole of copper diffusion.

The manufacture method of horn-like contact hole of the present invention comprises the steps:

On the silicon substrate that has formed active structure and isolation and metal silicide, form first insulating barrier;

Form second insulating barrier again;

Form photoresist, and photoetching, development form the contact hole pattern of photoresist;

The etching second and first insulating barrier form contact hole;

(Pull back) photoresist of pulling back;

Etching second insulating barrier and first insulating barrier form horn-like contact hole, and described etching adopts the gas that second insulating barrier/the first insulating barrier selectivity ratios is high to carry out etching;

Remove photoresist;

Fill contacting metal, and planarization;

Form inter-metal dielectric layer, and etch metal line pattern;

Fill first metal, and planarization;

Continue other processing procedures.

According to an embodiment of the invention, first insulating barrier with Si oxide as interlevel dielectric layer; Second insulating barrier with silicon oxynitride layer as hard mask.

Described photoresist pull back (pull back) be meant by adopting dry etching etc., the opening of photoresist pattern is increased, but the material layer below the etching photoresist not.

Preferably adopt Ar/O in the present invention ₂Dry etching is pulled back to photoresist, preferred Ar and O ₂Ratio be 10: 1, the preferred photoresist amplitude of pulling back is 0.01～0.05 μ m.

Then, select those that high etching agent of selectivity ratios of etching second insulating barrier and first insulating barrier is carried out etching, make first insulating barrier be etched away lessly and second insulating barrier etches away morely.In the present invention, the etching selection ratio of preferred second insulating barrier and first insulating barrier is 1～5; More preferably the etching selection ratio of second insulating barrier and first insulating barrier is 3～5.

Therefore the etching gas that preferred etching second insulating barrier and first insulating barrier adopt is CHxFy, 0≤x≤4,0＜y≤4 wherein, x+y=4.CHF more preferably ₃Perhaps CF ₄

According to the present invention, the metal of filling in the preferred contact hole is a tungsten.Formed first metal is a copper.

The method according to this invention, the horn-like contact hole of formation are 90～150 degree openings, and promptly the vertical direction with wafer is 45～75 degree, and more preferably 150 spend openings, and promptly the vertical direction with wafer is 75 degree.

Method of the present invention, therefore the contact hole of formation just can not form hole for being horn-like when filling the tungsten metal, can prevent to form the diffusion of the copper of metal wire by contact hole thus.

Description of drawings

Figure 1A～1E is the process schematic diagram that the method for prior art is made contact hole.

Fig. 2 is the electron micrograph of the structure with copper diffusion problem that forms of the method for prior art.

Fig. 3 A～3I is the process schematic diagram that method of the present invention is made horn-like contact hole.

Description of reference numerals

1 active region

2 isolate

3 metal silicides

4 interlayer dielectric silica

5 silicon oxynitride hard mask

6 tungsten metal deposition

61 holes

62 holes that increase

7 inter-metal dielectric layer

8 bronze medal metal deposition

Copper in 81 holes

The copper of 82 diffusions

31 active regions

32 isolate

33 metal silicides

34 interlayer dielectric silica

35 silicon oxynitride hard mask

351 horn-like contact holes

36 photoresist layers

The big opening that 361 photoresists are pulled back and formed

37 tungsten metal deposition

38 inter-metal dielectric layer

39 bronze medals deposition

Embodiment

Below in conjunction with accompanying drawing, introduce the present invention in more detail by embodiment.

Fig. 3 A～3I is the process schematic diagram that method of the present invention is made horn-like contact hole.

At first on silicon substrate, be formed with source region and contact with isolation and metal silicide etc.,, therefore, no longer describe in detail at this because these are routine techniquess.

Be formed with source region 31 with isolate 32 and metal silicide contact on 33 the silicon substrate, use conventional method, as chemical vapour deposition (CVD), silicon oxide layer deposited 34 is as interlevel dielectric layer, the thickness of formation is 0.9 μ m; Use conventional method, as chemical vapour deposition (CVD), deposition silicon oxynitride layer 35 is as hard mask layer, and thickness is 0.08 μ m; Use conventional method again, form SEPR552 photoresist layer 36 as spin-coating method, thickness is 0.7 μ m; By carrying out steps such as photoetching, development successively, DUV248nm light is adopted in photoetching, develops and uses conventional method, as alkaline-based developer tetramethyl aqua ammonia, forms the contact hole pattern of photoresist, as shown in Figure 3A.

Use dry etching method, as O ₂/ CHxFy, its ratio is 1: 3.5, and silicon oxynitride layer 35 and silicon oxide layer 34 are carried out etching, forms contact hole;

Then photoresist is carried out dry etching, use Ar/O ₂, its ratio is 10: 1, this etching is denitrification silicon oxide layer 35 not, and the photoresist pattern sidewalls is pulled back, as the amplitude of pulling back is 0.01～0.05 μ m, shown among Fig. 3 C 361.

Once more silicon oxynitride layer 35 and silicon oxide layer 34 are carried out etching, adopt silicon oxynitride/silica etching selection than high lithographic method, as, under 0～60 ℃ of temperature, use CH ₃F ₄Perhaps CF ₄To be 3～5 to carry out dry etching to silicon oxynitride/silica etching selection ratio, obtain horn-like contact hole 351, shown in Fig. 3 D, wherein, the profile of horn-like contact hole is openings of 90～150 degree.

Remove photoresist with conventional method, shown in Fig. 3 E.

According to conventional method, as adopting chemical gaseous phase depositing process that tungsten is metal filled in horn-like contact hole, because the contact hole top is bigger, therefore have good filling effect, shown in 37 among Fig. 3 F.

Adopt conventional method then, carry out planarization, remove unnecessary tungsten metal level, shown in Fig. 3 G as cmp.

According to conventional method,, on inter-metal dielectric layer 38, etch metal line pattern, shown in Fig. 3 H with dry etching method as exposure, development.

According to conventional method, fill copper metal 39 as chemical gaseous phase depositing process, shown in Fig. 3 I.

Continue other successive process then.

Do not have hole in the contact of the tungsten that obtains like this, therefore do not have copper to be filled in this hole yet, therefore can not produce of the diffusion of the copper of filling, thereby solved the problem that the copper that forms metal wire spreads by contact hole to active region.

More than be the present invention have been carried out comparatively detailed explanation by embodiment, but these embodiment and constitute any limitation of the invention.Under the condition that does not break away from basic design of the present invention, more other equivalent embodiment can also be arranged.Protection scope of the present invention is determined by appending claims.

Claims (14)

1. the manufacture method of a horn-like contact comprises the steps:

On the silicon substrate that has formed active structure, isolation and metal silicide, form first insulating barrier;

Form second insulating barrier again;

Form photoresist layer, and photoetching, development form the contact hole pattern of photoresist;

Etching second insulating barrier and first insulating barrier form contact hole;

The photoresist of pulling back increases the photoresist opening;

Etching first insulating barrier and second insulating barrier form horn-like contact hole, and described etching adopts the gas that second insulating barrier/the first insulating barrier selectivity ratios is high to carry out etching;

Remove photoresist;

Fill contacting metal, and planarization;

Form inter-metal dielectric layer, and etch metal line pattern;

Fill first metal, and planarization;

Continue other processing procedures.

2. method according to claim 1 is characterized in that, described first insulating barrier is the interlevel dielectric layer of Si oxide.

3. method according to claim 1 is characterized in that, described second insulating barrier is a silicon oxynitride layer.

4. method according to claim 1 is characterized in that, it is to adopt Ar/O that described photoresist is pulled back ₂Carry out dry etching, preferably its ratio is 10: 1.

5. method according to claim 4 is characterized in that, the described photoresist amplitude of pulling back is 0.01～0.05 μ m.

6. method according to claim 1 is characterized in that, the selectivity ratios of described etching second insulating barrier and first insulating barrier is 1～5.

7. method according to claim 6 is characterized in that, the selectivity ratios of described etching second insulating barrier and first insulating barrier is 3～5.

8. method according to claim 1 is characterized in that, the etching gas of described etching second insulating barrier and first insulating barrier is CHxFy, wherein, and 0≤x≤4,0＜y≤4, x+y=4.

9. method according to claim 8 is characterized in that, described etching gas is CHF ₃Perhaps CF ₄

10. method according to claim 1 is characterized in that, the metal of filling in the described contact hole is a tungsten,

11. method according to claim 1 is characterized in that, described first metal is a copper.

12. method according to claim 1 is characterized in that, the opening angle of described horn-like contact hole is 90～150 degree, and promptly it is 45～75 to spend with the angle of wafer vertical direction.

13. method according to claim 12 is characterized in that, described horn-like contact hole opening angle is 150 degree, and promptly the angle with the wafer vertical direction is 75 degree.

14. have the semiconductor interconnect line structure of the horn-like contact of making according to any described method in the claim 1～13.

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