TW383458B - Manufacturing method for barrier layer of contact - Google Patents

Abstract

A kind of manufacturing method for contact window barrier layer includes the following steps : providing a substrate with an insulation layer on the substrate and the insulation layer with a contact, forming a titanium layer on the surface of insulation layer and perimeter and bottom of contact; then, forming a first titanium nitride layer on the surface of titanium layer; applying annealing process on titanium layer and first titanium nitride layer; then, forming a second titanium nitride layer on the surface of first titanium nitride layer.

Description

Printed by the Staff Consumer Cooperative of the Central Bureau of Standards, Ministry of Economic Affairs

File: 1591 TWF.DOC / Arthur / 004 ^ 7 ~ B7 V. Description of the Invention (/) The present invention relates to a method for manufacturing a barrier layer for a contact window, and particularly relates to a contact window using titanium and titanium nitride. Manufacturing method of barrier layer. In the Ultra Large Scale Integration (ULSI) process, titanium and titanium nitride (Ti / TiN) are often used as barrier layers for contact windows of metal connections. To improve the contact resistance of the metal interconnect. Please refer to FIG. 1 to FIG. 5, which show a method for manufacturing a conventional contact window barrier layer. In FIG. 1, a metal-oxide-semiconductor (MOS) device is provided on the substrate 10. The metal-oxide-semiconductor (MOS) device includes a smell electrode 12 and source / drain regions 14 on both sides. The gate 12 has a spacer 16 at its periphery, and the source / drain region 14 generally has a lightly doped drain (LDD) structure to prevent short channel effects, while the field oxide layer 18 is used to isolate adjacent MOS element. In order to improve the sheet resistance of source / drain 14, gate 12, a "seif_aligned silicide" process is often used, and at source / drain 14, gate A sanded titanium layer 20 (TiSi2) is formed on 12. Next, referring to FIG. 2, an insulating layer 22 is formed on the substrate 10, and a contact window 24 is formed over the source / drain region 14 where a metal line is to be formed by a lithographic etching method. Referring to FIGS. 3 and 4, a titanium layer 26 (Ti) and a titanium nitride layer 28 (TiN) are sequentially formed on the insulating layer 22. In order to reduce the contact resistance, tempering is performed after the titanium layer 26 and the titanium nitride layer 28 are formed. In order to reduce the thermal budget to maintain the shallow junction, it is conventional to use a rapid thermal process (RTP) for tempering. Please refer to Figure 5, deposit a tungsten layer on the titanium nitride layer 28, and then borrow 3 paper sizes to apply the Chinese National Standard (CNS) A4 specification (210X297 mm) (Please read the precautions on the back before filling this page ) 丨 Λ 衣. ≫ 1Τ Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs

File: 159 1TWF.DOC / Arthur / 004 A7 B7 V. Description of the invention ()) The tungsten plug 30 as shown in the figure is formed by an etch back method. However, the RTP treatment often causes the titanium nitride layer 28 to crack, especially when the titanium nitride layer 28 is formed by collimator sputtering, and the crack is particularly severe. These cracks not only cause the contact resistance to increase, but also cause stringer during tungsten etchback, which affects subsequent processes. Please refer to Figure 6, which is a microscopic view of the conventional contact window barrier layer after tungsten etchback. Among them, the titanium nitride layer is formed by collimating tube sputtering technology. It can be clearly seen in the figure that the part pointed by the arrow is tungsten residue caused by cracks. The conventional method to improve the cracking of the titanium nitride layer 28 is as follows: After depositing the titanium nitride layer 26 (as shown in FIG. 3), first perform a rapid heating process, pass nitrogen (] ^ 2) or ammonia (NH3), and then deposit nitrogen Of titanium layer 28. Although this method prevents cracking of the titanium nitride layer 28, it causes other problems. First, in the rapid heating process, the nitriding reaction of the titanium layer 26 to the process gas and the silicidation reaction of the bottom layer of the contact window have mutual effects. Due to the lack of protection of the titanium nitride layer 28, the titanium silicide layer will be too thin. And the titanium silicide layer is not in good contact with the silicon layer, increasing the contact resistance. Second, in the rapid heating process, titanium oxynitride will be formed on the surface of the titanium layer 26, increasing the contact resistance. It can be seen that the conventional method cannot effectively improve the contact resistance. Therefore, the main object of the present invention is to provide a method for manufacturing a contact window barrier layer. By the method of the present invention, not only the problem of cracking the titanium nitride layer can be solved, but also the contact resistance can be reduced. To achieve the above and other objects of the present invention, a method for manufacturing a contact window barrier layer includes the following steps: providing a substrate, an insulating layer on the substrate, and an insulating layer having a contact window. A titanium layer is formed on the surface of the insulating layer and the periphery and bottom of the contact window. Next, a first titanium nitride layer is formed on the titanium. 4 This paper is in accordance with Chinese national standards (CNS> A4 size (210X297 mm). (Please read the precautions on the back before filling in this page).

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File: 1 59 1TWF.DOC / Arthur / O04 A7 B7 V. Description of the invention (ii) The surface of the layer. Tempering the titanium layer and the first titanium nitride layer. Then, a second titanium nitride layer is formed on the surface of the first titanium nitride layer. According to a preferred embodiment of the present invention, the first titanium nitride layer has a relatively thin thickness, which can reduce the thermal stress in the rapid heating process and avoid cracking. And it can protect the titanium layer, make its silicidation reaction complete, and isolate impurities. The stacked second titanium nitride layer can ensure a good connection with the tungsten layer in the future, and through appropriate control, the thickness of the final Ti / TiN layer can be made thinner than conventional, and the degree of accumulation can be improved. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is described below in conjunction with the accompanying drawings to make a detailed description as follows: < A brief description of the drawings:. FIG. 1 to FIG. 5 illustrate a method for manufacturing a conventional contact window barrier layer. Figure 6 is a microscopic view of the conventional contact window barrier layer after tungsten etchback. 7 to 12 illustrate a method for manufacturing a contact window barrier layer according to a preferred embodiment of the present invention. Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling this page). Figure 13 is a microscopic view of tungsten etchback during the manufacture of the contact window barrier layer according to the present invention. Figure 14 shows a comparison table of the contact resistance between the present invention and the conventional contact window barrier layer. Embodiments Please refer to FIG. 7 to FIG. 12, which illustrate a method for manufacturing a contact window barrier layer according to a preferred embodiment of the present invention. First please refer to Section 7 5 This paper size applies Chinese National Standard (CNS) A4 specification (210X297 mm)-File: 159ITWF.DOC / Arthur / 0〇4 A7-__; ____ B7__ 5. Description of the invention () • Figure A metal oxide semiconductor device is provided on the substrate 40 and includes a gate electrode 42 and source / drain regions 44 on both sides. The gate 42 has a spacer 46 on the periphery, and the source / drain region 44 generally has a lightly doped drain structure to prevent short channel effects, while the field oxide layer 48 is used to isolate adjacent MOS devices. In order to improve the chip resistance of source / drain 44 and gate 42, a "self-aligned gold

I. "Silicon" process is often used, and a titanium silicide layer 50 (TiSi2) is formed on the source / drain 44 and the gate 42, respectively. Next, referring to FIG. 8, a substrate 40 is formed on the substrate 40. An insulating layer 52 is formed on the insulating layer 52 and the contact window by using a lithographic etching method over the source / drain region 44 where the metal wiring is to be formed. Please refer to FIGS. 9 and 10. A titanium layer 56 (Ti) and a first nitride layer 58 (TiN) are sequentially formed at the bottom and the periphery. Among them, the method for forming the titanium layer 56 is, for example, using a magnetron DC sputtering method, Its thickness is about 150 ~ 1000A. The method for forming the first titanium nitride layer 58 is, for example, depositing on the titanium layer 56 by reactive sputtering, and the thickness is about 100 ~ 600A. The thickness of a titanium nitride layer 58 is about 100 to 45 Å, and the thickness of the first titanium nitride layer 58 without a collimated tube is about 250 to 600 A. The purpose of adding a collimation tube is to Improve the step coverage of titanium nitride so that it evenly covers the titanium layer 56. Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (Please Read the precautions on the back before filling this page) Then, perform a rapid heating process to temper the titanium layer 56 and the first titanium nitride layer 58. The process gas is nitrogen or ammonia. Please refer to section 11 In the figure, a second titanium nitride layer 60 is formed by stacking on the surface of the first titanium nitride layer 58. The method for forming the second titanium nitride layer 60 may be sputtering (including a collimated tube and a non-collimated tube), Or chemical vapor deposition (CVD), and its thickness can be determined according to need. @ 为 6 This paper size is applicable to China National Standard (CNS) A4 specification (210X297 mmΊ)

File :! 59 1TWF.DOC / Arthur / O04 A7 B7 Printed by the employee consumer cooperative in the ministry 5. Description of the invention (Ya) 100 ~ 300A 〇 Please refer to Figure 12 to deposit a metal layer on the second titanium nitride layer 60 For example, tungsten, and then by etch back, remove part of the metal layer to expose the upper surface of the second titanium nitride layer, leaving the metal layer filled in the contact window. Plug 62. In summary, the titanium nitride layer in the present invention is formed by stacking the first titanium nitride layer 58 and the second titanium nitride layer 60. The first titanium nitride layer has a relatively thin thickness (the thickness of the conventional titanium nitride layer sputtered by the collimated tube is about 600A, and the thickness of the titanium nitride layer without the collimated tube sputter is about 800A) Therefore, in the rapid heating process, its thermal stress is low, which can prevent the occurrence of cracking. Please refer to FIG. 13, which shows a microscopic view of the contact window barrier layer according to the present invention after the tungsten plug is etched back. It can be seen from the figure that there is no tungsten residue, that is, the titanium nitride layer has no cracks. . However, the first titanium nitride layer has a protective effect on the titanium layer underneath, which can prevent impurities such as titanium oxynitride from being generated on the titanium layer, and make the titanium layer completely react with silicon during the tempering process, ensuring a good Contact resistance. The second titanium nitride layer is used to improve the adhesion between the titanium layer and a metal plug (such as a tungsten plug) and reduce the ohmic resistance. Please refer to FIG. I4. It can be seen from the table that the contact window barrier layer according to the present invention can obtain a lower contact resistance and improve the quality of the metal connection process. In addition, since the second titanium nitride layer can be formed by any of the conventional deposition techniques, its thickness can be very thin. Relatively speaking, the combined thickness of the first and second titanium nitride layers is easier to control than the conventional one. The thickness is low, so the degree of accumulation can be increased. Although the present invention has been disclosed as above with a preferred embodiment, and it is used. The paper size is applicable to Chinese national standards (CNS > A4 specification (210X297)) (Please read the precautions on the back before filling this page)

File: 1 59 lTWF.DOC / Arth-iir / 004 A7-B7 V. Description of the Invention (b) To limit the present invention, anyone skilled in the art can make some changes without departing from the spirit and scope of the present invention. Changes and retouching, so the protection scope of the present invention shall be determined by the scope of the appended patent application. (Please read the notes on the back before filling out this page) Order Printed by the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs This paper size applies to China National Standard (CNS) A4 (210X297 mm)

Claims (1)

ABCD File: 1_59 1TWF.DOC / Arthur / O04 6. Scope of Patent Application 1. A method for manufacturing a contact window barrier layer includes the following steps: A substrate is provided, the substrate has an insulating layer, and the insulating layer has A contact window; forming a titanium layer on the surface of the insulating layer and the periphery and bottom of the contact window; forming a first titanium nitride layer on the surface of the titanium layer; tempering the titanium layer and the first titanium nitride layer And forming a second titanium nitride layer on the surface of the first titanium nitride layer. 2. The manufacturing method as described in item l · of the scope of patent application, wherein the tempering process includes a rapid heating process. 3. The manufacturing method according to item 1 of the scope of patent application, wherein the method for forming the titanium layer includes magnetron DC sputtering. 4. The manufacturing method according to item 1 of the scope of patent application, wherein the thickness of the titanium layer is about 15.0 to 1000A. 5. The manufacturing method according to item 1 of the scope of patent application, wherein the method for forming the first titanium nitride layer includes reactive sputtering. 6. The manufacturing method according to item 1 of the scope of patent application, wherein the thickness of the first titanium nitride layer is about 100A to 600A. 7. The manufacturing method according to item 1 of the scope of patent application, wherein the thickness of the second titanium nitride layer is about 100A to 300A. 8. The manufacturing method according to item 1 of the scope of patent application, further comprising the following steps: forming a metal layer on the surface of the second titanium nitride layer and filling the contact window; and etching back the metal layer to expose The second titanium nitride 9 above the insulation layer This paper size is in accordance with Chinese National Standard (CNS) A4 specification (210X297 mm) (Please read the precautions on the back before filling this page) 丨 installed. * 1T, Ministry of Economic Affairs File: I 591TWF.DOC / Arthur / 004 ABCD patent application surface printed by the Central Bureau of Consumers Cooperative, the metal layer remaining in the contact window forms a plug. 9. The manufacturing method according to item 8 of the scope of patent application, wherein the metal layer includes tungsten. (Please read the precautions on the back before filling out this page.) 'Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs. This paper is sized for the Chinese National Standard (CNS) A4 (210X297 mm).