CN101587853A

CN101587853A - Metal valley manufacture method

Info

Publication number: CN101587853A
Application number: CNA2008100376809A
Authority: CN
Inventors: 周鸣; 尹晓明
Original assignee: Semiconductor Manufacturing International Shanghai Corp
Current assignee: Semiconductor Manufacturing International Shanghai Corp
Priority date: 2008-05-20
Filing date: 2008-05-20
Publication date: 2009-11-25
Anticipated expiration: 2028-05-20
Also published as: CN101587853B

Abstract

The invention provides a metal valley manufacture method. The manufacture of a metal valley is based on the manufacture of a silicon substrate with a prefabricated via hole; and the silicon substrate is provided with a bottom retainer layer and a middle retainer layer. The metal valley manufacture method comprises the following steps: a, filling a bottom antireflection film higher than a standard height in a via hole of the silicon substrate; b, coating light blockage on the silicon substrate and etching media above the middle retainer layer of the silicon substrate uncoated by the light blockage; and c, further etching and removing residual media on the middle retainer layer. The bottom antireflection film higher than the standard height is filled in the via hole, and the c step for removing the residual media is added in the metal valley manufacture method so that the metal valley manufacture method can effectively improve the quality stability of the manufactured metal valley, solve the problems of the high height control requirement of the bottom antireflection film in the via hole as well as a fence-type silicon substrate and facial angles existing in a traditional metal valley manufacture method and avoid tedious monitoring and adjusting work.

Description

A kind of manufacture method of metal valley

Technical field

The present invention relates to the making field of semiconductor chip metal connecting line, relate in particular to the manufacture method of metal valley on the silicon base with intermediate barrier layers.

Background technology

See also the underlying structure of making metal valley as shown in Figure 1 in advance, silicon base 1 has intermediate barrier layers 21 and bottom barrier 22.Be manufactured with via hole 7 on the silicon base 1, silicon base 1 surface that is not manufactured with via hole 7 has hard mask layer 3, and before metal valley was made in etching, coating photoresistance 4 on silica-based 1.The manufacture craft flow process of traditional fabrication metal valley sees also Fig. 2.At first on underlying structure shown in Figure 1, make via hole 7 (Via); In via hole 7, fill bottom anti-reflective film 50 (Bottom Anti-Reflective Coating:Barc) then; And then the Barc50 that fills is returned quarter, the Barc50 of retention criteria height h0 in via hole 7; Coating photoresistance 4 on the hard mask layer 3 of the silicon base 1 of not making metallic channel is prepared disposable master and is etched away medium on the intermediate barrier layers 21 of uncoated photoresistance, the i.e. above silicon base part of part hard mask layer and intermediate barrier layers; Final etch forms metal valley 8.The Barc of retention criteria height is used for protection intermediate barrier layers 21 and the silicon base part of intermediate barrier below 21 when disposable main etching forms metal valley 8 in via hole 7.In the via hole 7 the calibrated altitude h0 of Barc50 normally outline exceed the position of intermediate barrier layers 21 in silicon base 1, mainly be that intermediate barrier layers 21 is not damaged when guaranteeing main etching, and the silicon base of intermediate barrier layers 21 below partly be not damaged.When the height of Barc is higher than calibrated altitude h0 in being retained in via hole 7, main etching is difficult to remove the silicon base part on the intermediate barrier layers 21 of Barc50 sidewall, thereby makes that finally producing metal valley exists unnecessary fence type silicon medium (fence issue); When the height of Barc was lower than calibrated altitude in being retained in via hole 7, medium was crossed the problem that face angle (facet) appears in poly-injury near main etching intermediate barrier layers 21 or intermediate barrier layers 21 occur later easily.

Therefore, along with manufacture of semiconductor constantly trends towards the more development of small-feature-size, the making of metal valley is more responsive to the height that is retained in Barc50 in the via hole 7, Barc50 is higher or lower than calibrated altitude h0, all can cause the final metal valley of making undesirable: to occur fence type silicon medium in the metal valley 8 or face angle problem occurs.Like this, just need check repeatedly, making link be monitored repeatedly and adjusted, with the quality of the metal valley that guarantees to make according to check result to making metal valley.

Summary of the invention

The object of the present invention is to provide a kind of manufacture method of metal valley, be prone to the unnecessary fence type silicon base and the problem at face angle in the metal valley made from the manufacture method that solves the conventional metals groove.

Be the arrival above-mentioned purpose, the manufacture method of metal valley of the present invention, the making of this metal valley is based on the silicon base of making via hole in advance and makes, and silicon base has bottom barrier and intermediate barrier layers.The making of this metal valley may further comprise the steps: a, fill the bottom anti-reflective film of overgauge height in the via hole of this silicon base; B, on silicon base coating photoresistance, the medium that the silicon base intermediate barrier layers of etching uncoated photoresistance is above; Residual medium on the intermediate barrier layers is removed in c, further etching.Wherein, the silicon base surface portion of not making via hole has one deck hard mask layer.The etching of step b is carried out in two steps: main etching and etching excessively, the main above part medium of the unprotected intermediate barrier layers of described bottom anti-reflective film that etches away; Cross the above part medium of intermediate barrier layers that etches away described bottom anti-reflective film protection.The etching gas that main etching is adopted is carbon tetrafluoride and oxygen, and the etching gas of crossing the etching employing is octafluorocyclobutane, oxygen and carbon monoxide.Wherein, can remove photoresistance on the silicon base before the over etching.And the calibrated altitude of bottom anti-reflective film is the height of the bottom anti-reflective film of protection intermediate barrier layers and the following medium of intermediate barrier layers.The etching gas that the further etching of step c is adopted is octafluorocyclobutane and oxygen.

Compare with the manufacture method of existing metal valley, the manufacture method of metal valley of the present invention by keep the Barc that is higher than calibrated altitude in via hole, is divided main etching and is crossed medium on the etching removal intermediate barrier layers, and further residual medium is removed in etching.Therefore, the present invention passes through to reduce the making requirement of Barc height in the via hole, can effectively solve in the traditional fabrication method highly to cause occurring in the metal valley unnecessary fence type silicon base problem or face angle problem because of Barc in the via hole.

Description of drawings

Below in conjunction with the drawings and specific embodiments the manufacture method of metal valley of the present invention is made further specific description in detail.

Fig. 1 is a underlying structure schematic diagram of making metal valley.

Fig. 2 is based on the traditional fabrication method schematic diagram of the underlying structure metal valley of Fig. 1.

Fig. 3 returns in the method for manufacturing of the present invention to carve the bottom anti-reflective film schematic diagram that keeps.

Fig. 4 is a main etching schematic diagram among the metal valley manufacture step b of the present invention.

Fig. 5 crosses the etching schematic diagram among the metal valley manufacture step b of the present invention.

Fig. 6 is metal valley manufacture step c of the present invention and steps d schematic diagram.

Fig. 7 is a method for manufacturing schematic diagram of the present invention.

Embodiment

The manufacture method of metal valley of the present invention, the making of this metal valley are based on the silicon base of making via hole in advance and make.This silicon base has bottom barrier and intermediate barrier layers, and the making of this metal valley may further comprise the steps: a, fill the bottom anti-reflective film of overgauge height in the via hole of this silicon base; B, on silicon base coating photoresistance, the medium that the silicon base intermediate barrier layers of etching uncoated photoresistance is above; Residual medium on the intermediate barrier layers is removed in c, further etching.The surface portion of not making via hole in silicon base has one deck hard mask layer.See also Fig. 3, in the silicon base via hole, fill the Barc schematic diagram of overgauge height, earlier all filled Barc50 on the surface of via hole 7 and hard mask layer 3, return quarter then, make the Barc50 height h1 that is filled in the via hole 7 be higher than the h0 of calibrated altitude Barc50, contrast can be consulted the calibrated altitude h0 of Barc50 in the via hole 7 shown in Figure 2.

See also Fig. 4 and step b shown in Figure 5, coating photoresistance 4 on silicon base, promptly are coated on the hard mask layer 3 on silicon base surface the medium of silicon base intermediate barrier layers more than 21 of etching uncoated photoresistance 4.The etching of step b is finished in two steps: main etching and etching excessively, see also main etching shown in Figure 4, and the master etches away the part medium of the unprotected intermediate barrier layers of Barc50 more than 21, has promptly removed the part hard mask layer and the part silicon base on silicon base 1 surface.The etching gas that main etching is adopted is carbon tetrafluoride and oxygen, and main etched selectivity is relatively poor, the part hard mask layer that is not covered by photoresistance that can effectively etch away, and the part silicon base under this part hard mask layer.See also the etching of crossing shown in Figure 5, cross the part medium of intermediate barrier layers more than 21 that etches away the Barc50 protection, i.e. the part silicon base.Before carrying out etching, can remove photoresistance 4 on the hard mask layer 3, improve overetched uniformity.The etching gas of crossing the etching employing is an octafluorocyclobutane, oxygen and carbon monoxide, main relatively etching, cross etching and have good etching selectivity, cross etching process and can not damage intermediate barrier layers 21, therefore was adopting the quarter main relatively etching reliability can be higher near the etching of the part silicon base of intermediate barrier layers, also easier enforcement.Because the height h1 of the Barc50 that keeps in the via hole 7 in step a is higher than calibrated altitude h0, therefore, after crossing etching, the silicon base part of intermediate barrier layers close Barc50 side more than 21 can appear, and it is not etched promptly to be similar to the fence type silicon base.For addressing this problem, see also Fig. 6, execution in step c, further residual medium on the intermediate barrier layers 21 is removed in etching.But execution in step d after further etching is finished: remove the Barc50 in the via hole 7, form metallic channel 8.Further the etching gas of etching employing is octafluorocyclobutane and oxygen, can effectively remove silicon base residual on the intermediate barrier layers 21.

The flow chart of the manufacture method of metal valley of the present invention sees also Fig. 7, by in the via hole of silicon base, keeping the Barc that is higher than calibrated altitude, the making that can solve the conventional metals groove has so also reduced the control requirement to Barc height in the via hole because of Barc in the via hole highly controls the damage of the inaccurate intermediate barrier layers that causes or the damage of via hole and metallic channel junction silicon base part.By in etching, adopting main etching and crossing etch uniformity and the etched reliability that etching has improved metallic channel, effectively avoid the medium that need keep is caused damage.Adopt further etching to remove because of being higher than the fence type silicon base that calibrated altitude Barc causes in the via hole.The manufacture method of metal valley of the present invention can improve the metal valley quality of stability of making effectively, avoid conventional metals groove manufacturing method problem, the problem includes: because of fence type silicon base or face angle problem, occur thereby further avoid making the instable problem of metal valley quality, save the link that monitoring repeatedly loaded down with trivial details in the conventional metals groove manufacturing process is adjusted.

Claims

1, a kind of manufacture method of metal valley, the making of described metal valley is based on the silicon base of making via hole in advance and makes, described silicon base has bottom barrier and intermediate barrier layers, it is characterized in that it may further comprise the steps: a, in the via hole of described silicon base, fill the bottom anti-reflective film of overgauge height; B, on described silicon base coating photoresistance, the medium that the silicon base intermediate barrier layers of etching uncoated photoresistance is above; Residual medium on the intermediate barrier layers is removed in c, further etching.

2, the manufacture method of metal valley as claimed in claim 1 is characterized in that, the surface portion that described silicon base is not made via hole has one deck hard mask layer.

3, the manufacture method of metal valley as claimed in claim 1 is characterized in that, the etching of described step b is carried out in two steps: main etching and etching excessively, the main above part medium of the unprotected intermediate barrier layers of described bottom anti-reflective film that etches away; Cross the above part medium of intermediate barrier layers that etches away described bottom anti-reflective film protection.

4, the manufacture method of metal valley as claimed in claim 3 is characterized in that, the etching gas that described main etching is adopted is carbon tetrafluoride and oxygen.

5, the manufacture method of metal valley as claimed in claim 3 is characterized in that, the described etching gas of crossing the etching employing is octafluorocyclobutane, oxygen and carbon monoxide.

6, the manufacture method of metal valley as claimed in claim 3 is characterized in that, can remove photoresistance on the described silicon base before the described over etching.

7, the manufacture method of metal valley as claimed in claim 1 is characterized in that, the calibrated altitude of described bottom anti-reflective film is the height of the bottom anti-reflective film of protection intermediate barrier layers and the following medium of intermediate barrier layers.

8, the manufacture method of metal valley as claimed in claim 1 is characterized in that, the etching gas that the further etching of described step c is adopted is octafluorocyclobutane and oxygen.

9, the manufacture method of metal valley as claimed in claim 1 is characterized in that, described method also comprises steps d: remove the bottom anti-reflective film.