TW200834685A - Method of cleaning wafer after etching process - Google Patents

Abstract

A method of cleaning a wafer after an etching process is provided. A substrate having an etching stop layer, a dielectric layer, a patterned metal hard mask sequentially formed thereon is provided. Using the patterned metal hard mask, an opening is defined in the dielectric layer. The opening exposes a portion of the etching stop layer. A dry etching process is performed in the environment of helium to remove the etching stop layer exposed by the opening. A dry cleaning process is performed on the wafer surface using a mixture of nitrogen and hydrogen as the reactive gases. A wet cleaning process is performed on the wafer surface using a cleaning solution containing a trace amount of hydrofluoric acid.

Description

200834685 UMCD-2005-0528 18213twfdoc/n IX. Description of the Invention: [Technical Field] The present invention relates to a method for cleaning a wafer, and more particularly to a method for cleaning a wafer after the engraving. [Prior Art] Metal inlay recording is a kind of ingenious shouting of metal interconnects into insulation

i green scorpion surgery. The dielectric layer towel on the substrate is in accordance with the pattern of the desired metal line and the position of the contact window, and the dielectric layer is formed to form the groove and the contact window is opened by π. Then, a layer of metal is deposited on the substrate to form a gold wire and a via window when the eight filled trenches and the vias are closed. = Knowing the way of double metal inlay, (4) The method of forming a via window and then forming a metal wire without the typical method of forming the overlay error and the process deviation (Pr〇cess Deviati〇n) The problem is that the reliability of the component is increased and the process capability is improved. Therefore, after the component is highly integrated, double metal inlaid red has gradually become a technology used in the semiconductor industry. However, in the process of etching the dielectric layer to form the trench and the contact opening, a mask layer of a metal such as titanium nitride is often used as an etching mask, and the etching gas contains a cxF "b compound. During the etching process, a long carbon chain polymer is formed, and the long carbon chain polymer itself is a polymer formed by a long carbon chain polymer and a metal ion, other reaction gas or photoresist material which is struck by the plasma. Will deposit on the surface of the wafer. In addition, after the end of the money, the residual fluorine will adhere to the surface of the wafer and react with metal ions in the metal mask to form a fluoride metal such as titanium fluoride. These polymers and fluorinated Gold 200834685 UMCD-2005^0528 182l3twf.doc/n The genus "the money will adversely affect the electrical properties of the components, thereby reducing the efficiency of 70 pieces", so these polymers must be removed and fluorinated after etching There is a method for removing these polymers in the metal/technical technology, which is a three-stage cleaning method for the wet-dry-wet cleaning process. The first wet cleaning process is Used to gather these together The composition softens and separates from the surface of the wafer. The subsequent dry cleaning process is to miniaturize the polymer.

Finally, a second wet cleaning process is performed to remove the remaining polymer. However, in the wet cleaning process performed, the cleaning solution used is an inspectability test, which causes damage to the exposed metal layer in the substrate. On the one hand, the removal method of the above polymer has poor ability to remove the metal fluoride formed on the wafer, so the gasification metal will still be on the wafer after the polymer removal process. Up, and the component has a bad influence. ° In addition, the above-mentioned polymer removal method is a three-stage cleaning process, and the process steps are complicated, which limits the productivity. SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a cleaning method for rounding after a remnant engraving, which can be effectively removed and formed on a wafer surface and a metal fluoride. Qiaochengkou

This issue (4) is again - the purpose is to provide - the secret wafer method to avoid the residue of polymer and fluoride metal to the component H

A bad influence' and thus improve the performance of the component. I 6 200834685 um^-^005-0528 18213twf. doc/n The invention proposes that the cleaning of the wafer after etching = the second is formed sequentially - the termination layer, the dielectric = the metal hard mask layer defines the dielectric II * Take out some of the money and finish it.

Body, the body of the wafer surface as a reaction gas, a small amount of hydrofluoric acid cleaning, dry cleaning process. Next, to include the process. For the (4) surface, a wet-cleaning method is well-known in the embodiment, and the back crystal is 100~500sccm on the side. The flow rate of helium in the dry etching process is the reverse round cleaning method of the dry etching process according to the embodiment. According to the present invention, after the etching, the crystal gas is, for example, gas-containing gas according to the present invention. - Tuyi

In the circular cleaning method, as described in the human embodiment, after the etching, the crystals c4F8, c5f8, and chf3 ^ f gas, for example, * are selected from the group consisting of CF4, peach 'sucking, L according to the present invention 3, or two (inclusive) The above mixed gas. In the round cleaning method, as described in the preferred embodiment, the flow rate of the crystal after the etching described above. The flow rate of hydrogen gas in the dry cleaning process is larger than that of nitrogen. According to the round cleaning method of the present invention, as described in the preferred embodiment, the flow rate of the crystal according to the present invention after the above etching is 400 to 1200 sccm. In the preferred embodiment, in the above-described etching method, the flow rate of nitrogen gas is 2 〇〇 6 〇〇 sccm. According to a preferred embodiment of the present invention, in the above-described etching method for etching a crystal, the cleaning solution is, for example, an acidic solution or an alkaline solution. According to a preferred embodiment of the present invention, in the above-described etching method for etching a crystal, the acidic solution is, for example, an organic acid solution, an inorganic acid solution or a mixed solution of an organic acid solution and a mineral acid solution. . According to a preferred embodiment of the present invention, after the etching

In the round cleaning method, the inorganic acidic solution is, for example, one selected from the group consisting of a sulfuric acid solution, a hydrochloric acid solution, a phosphoric acid solution, and a nitric acid solution, or a mixed solution of two or more. According to a preferred embodiment of the present invention, in the above-described etching method for etching a crystal, the alkaline solution is, for example, an amine-containing solution. . According to a preferred embodiment of the present invention, in the above-described method of cleaning the wafer, the dry cleaning process is carried out in the form of in-situ (four) (four) after the dry etching process. . According to the preferred embodiment of the present invention, in the above-described method of wafer cleaning, the material of the patterned metal mask layer is, for example, titanium nitride, nitrogen, group or group. . In accordance with a preferred embodiment of the present invention, the h-washing method of the wafer having the back side is comprised of a trench and a connection. The invention proposes a cleaning method for a post-mortem wafer, firstly providing a dielectric layer and a patterned metal hard mask layer sequentially formed on the substrate, and the metal hard mask layer of the case is defined. An opening in the electrical layer. Next, a dry cleaning process is performed on the surface of the wafer by using a mixed gas of a rat gas and a hydrogen gas as 200828685 υινι^-^005-052δ 18213twf.doc/n. Then, a wet cleaning process is performed on the surface of the wafer with a cleaning solution containing a trace amount of hydrofluoric acid. Since the cleaning method of the post-etched wafer proposed by the present invention cleans the surface of the wafer by using a cleaning solution containing nitrous acid fluoride, the polymer and the metal fluoride formed on the surface of the wafer can be effectively removed. Therefore, residues such as polymers and metal fluorides can be prevented from adversely affecting the electrical properties of the components, thereby improving the performance of the components. Further, in the wet cleaning process performed, when the etching liquid used is an acidic cleaning solution, the cleaning solution can be prevented from causing damage to the metal layer in the substrate exposed by the opening. In addition, the cleaning method of the etched wafer proposed by the present invention is a two-stage cleaning method for performing a dry _/thermal cleaning process, which can effectively shorten the manufacturing process and increase the productivity. The above and other objects, features and advantages of the present invention will become more <RTIgt; [Embodiment] FIG. 1A to FIG. 1B are cross-sectional views showing a cleaning process of an etched wafer according to an embodiment of the present invention. First, referring to Fig. 1A, a substrate 1 is provided, and a substrate 1 is, for example, a metal layer 1〇1 for use as a wire or an electrode. An etch stop layer 1 〇 2, a dielectric layer 1 〇 4 and a patterned metal hard mask layer 1G6 are sequentially formed on the substrate 1 , and a patterned metal hard mask layer ( 10 ) is defined in the dielectric layer 104 . The open ship, and the opening 1〇8 exposes part of the surname to end 9 200834685 UMCD-2005-0528 18213twf.doc/n layer 102. The substrate 100 is, for example, a chopped substrate. The material of the engraving stop layer is, for example, niobium carbide, tantalum nitride, and other suitable materials. The material of the dielectric layer 104 is, for example, a low dielectric constant material such as fluorinated amorphous carbon, carb〇n d〇ped 〇xide,

Parylene AF4, PAE or Cyclotene. The material of the patterned metal hard mask layer 106 is, for example, a material such as titanium nitride, tantalum nitride, titanium or a button. The opening 108 is composed of, for example, a ditch 108a and a contact opening 1 rib, but the present invention is not recorded. In addition, an oxide layer UG may be formed between the dielectric layer and the patterned metal hard mask layer 106. The material of the oxide layer ιι is, for example, oxygen (tetra) formed by using tetraethoxy Wei (TEOS) as a reaction gas. The method for forming the side-stop layer, the dielectric layer, and the patterned hard mask layer 106 and the oxide layer 11G is well known to those skilled in the art, and thus will not be described herein. A dry etching process is carried out in the environment of the 、L, 氦L, to remove the smoke from the π exposed layer, to hide the metal layer bribe. In the dry process, the flow of suffocation = ~ 5 〇 Gseem. The dry material (4) reaction (4) is, for example, an air-containing gas. The body 9 may be a mixed gas selected from the group consisting of ruthenium, ruthenium, station, helium, ruthenium, and chf3, for example, 15 GsL or more. The flow rate of the fluorine-containing gas is in the process of forming the opening 〇8, and the length of the chain polymer is itself or the pure chain polymer and the metal ions and other reaction gases. The formed poly: 1 2 is on the surface of the wafer. In addition, after the end of (iv), the residual gas ^200834685 UMCD-2005-0528 18213twf.d〇c/n is formed on the wafer sheet to form a fluoride metal 114 such as titanium fluoride. , (4) Sub-anti 1〇2^^ Fluorine in the chamber, because: can be two:: carrier gas (, (4) take away, but, Bu Gan c 乂 reduce the residual fluorine will adhere to the wafer After the fluorine-free = coffee should be ϋϋ: the side of the process side, f, that is, without destroying the real work. In the dry type of clear women, flow" but the flow of hydrogen and gas is two Two ^ 2 =: r domain · ~ gallbladder ~ __ perimeter = row one with miscellaneous 4 hydrofluorin_cleaning dissolved on the surface of the wafer into the liquid. Acid process. Cleaning solution such as acidic solution or test solution == = is a mixed solution of an organic acid solution, a mineral acid solution or an organic acid sulfuric acid machine. The inorganic mixed solution is, for example, selected from the group consisting of: species =, bribe solution, mixed solution and two solutions thereof - or a mixed solution of the above The test solution is, for example, an amine-containing solution. The value liquid, 'although the acidic solution or the test solution can be used as a cleaning solution; the alkaline solution is destroyed under the metal layer ι〇ι located in the substrate 100, It is preferred to use an acidic solution as the cleaning solution.

Referring to Fig. 2, 200834685 UMCD-2005-0528 18213twf.doc/n, the acid content of the sprayed surface is taken, so that the metal fluoride 114 can be removed in addition to the water 112. In this way, after the engraving process, it is possible to avoid the contour of the residue on the wafer, such as the composition of the residue, such as the poly-KiA rat metal 114, and the etched wafer proposed by the present invention. Cleaning

The two-stage cleaning method of the Hit-type wet cleaning process can be used to increase the production capacity. Photograph of the side back surface profile of the θ opposite side stop layer ^ Tulin invented the photo of the back end surface of the side stop layer. The etching process of the etch-stop layer of your white dog's mouth = no gas is passed in. After the can, the residual gas is deposited on the surface and reacts with the metal of the metal hard mask to form a gasification genus. . Therefore, the 2W 2 towel clearly sees the projection of the surface formed by the fluorinated metal. Referring to FIG. 3, in the etching of the etching stop layer of the present invention, the helium gas is taken as a carrier gas to carry away the reaction chamber (10). Fluorine = 3 = on the surface of the wafer, which can reduce or even avoid fluorine. Reacts with metal ions in the metal mask layer to form a metal fluoride. Therefore, it can be clearly seen from Fig. 3 that the surface profile is very flat, and almost no projections formed by the vaporized metal are generated. In summary, the present invention has at least the following advantages: ^ The cleaning method of the etched wafer proposed by the present invention is to clean the surface of the wafer by using a cleaning solution containing hydrofluoric acid, which can effectively remove the shape 12 200834685 Umcu-z005-0528 18213twf.doc/n Polymer and fluorinated metal formed on the surface of the wafer. 2. The cleaning method of the wafer after the money is invented by the present invention can prevent the residue of the polymer and the metal fluoride from adversely affecting the electrical properties of the component, thereby improving the performance of the component. 3. In the cleaning method of the wafer after the remnant of the present invention, when the etching solution used in the wet cleaning process is an acidic cleaning solution, the cleaning solution can be prevented from causing the metal in the substrate exposed by the opening. damage.

4. The cleaning method of the etched wafer proposed by the present invention is a two-stage cleaning method of the dry type: wet cleaning process, which can effectively shorten the manufacturing process and improve the production efficiency. Although the present invention has been disclosed in the above preferred embodiments, it is not intended to be used in the present invention, and the present invention may be made in a manner that does not depart from the spirit of the present invention. The protection cost is determined by the definition of the patent application. [Simple description of the diagram] The clearing map of the present invention - the side of the wafer after the actual closing. 2 is a photograph of a side rear surface profile of a conventional etch stop layer. FIG. 3 is a photograph of a front surface porch of the axillary stop layer of the present invention. [Main component symbol description] 1 〇〇: substrate 101: metal layer 13 200834685 UMCD-2005-0528 18213twf.doc/n 102: etch stop layer 104: dielectric layer 106: patterned metal hard mask layer 108: opening 108a · ditch 108b: contact window opening 110: oxide layer 112: Polymer 114 ··Fluorine 14

Claims (1)

200834685 UM (JD-2005-0528 18213twf.doc/n X. Patent application scope: 1. A method for cleaning wafers after etching, comprising: - a human-provided substrate is sequentially formed with a pattern on the bottom of the filament Metal hard mask layer, the patterned gold i hard = layer out of the opening in the dielectric layer, and the opening f = the etch stop layer; Performing a dry etching process in a helium-enriched environment to remove the etch stop layer exposed by the vent; /= nitrogen and a mixed gas as a red gas, and performing a wafer on the wafer a dry cleaning process; and a leak cleaning process on the surface of the wafer with a cleaning solution of 3 micro-hydrofluoric acid. 2. The cleaning λ of the etched wafer as described in the scope of the patent application is 〇〇 于 于 于 于 于 于 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 3. The cleaning of the etched wafer as described in claim 1 wherein the reactive gas of the dry etching process comprises a fluorine-containing gas. 4. If the etched wafer is cleaned as described in item 3 of the patent application, the fluorine-containing gas is selected from the group consisting of CF4, C2F6, C3F8, C4F8, C5F8, CHF3, or two (including a mixed gas on β. 5. The cleaning method of the etched wafer as described in the first application of the patent scope, wherein the flow rate of the hydrogen gas in the dry cleaning process is greater than the flow rate of the nitrogen gas. 6. The cleaning of the wafer after etching according to item 5 of the patent application scope is wherein the flow rate of the hydrogen gas is 400 to 1200 sccm. 7. The cleaning method of the etched wafer described in item 5 of the patent application scope is as follows: 200834685 UMUJ-2005-0528 182l3twtdoc/n method, wherein the flow rate of the rat gas is 200 to 600 sccm. 8. The cleaning method for the etched wafer as described in the first paragraph of the patent application, wherein the 'washing> is an acidic solution or an experimental solution. 9. The method for cleaning a post-etched wafer according to item 8 of the patent application scope, and the medium and k-type liquid is an organic acid solution, a mineral acid solution or a mixture of the organic acid solution and the inorganic acid solution. Solution. 1. The method for cleaning a post-etched wafer according to claim 9, wherein the inorganic acidic solution is one or two selected from the group consisting of a sulfuric acid solution, a hydrochloric acid solution, a phosphoric acid solution, and a nitric acid solution. The above mixed solution 0 U. The method of cleaning an etched wafer according to claim 8, wherein the alkaline solution comprises an amine-containing solution. U. The cleaning of the etched wafer described in the first paragraph of the patent application, wherein the Wei-type cleaning process is carried out in a hiding manner after the dry-type engraving. I3. The method for cleaning an etched wafer as described in claim 1 wherein the patterned metal mask layer is made of titanium nitride, nitride button, chin or coarse. The method of cleaning an etched wafer as described in claim 1, wherein the opening comprises a trench and a contact opening. 15. The method of cleaning an etched wafer as described in claim </ RTI> wherein the opening comprises a trench opening. 16--A method for cleaning a wafer after etching, comprising: providing a substrate on which a dielectric layer has been sequentially formed and a pattern of FIG. 16 200834685 um^u-z005-0528 l8213twf.doc/n a metal hard mask layer, the patterned metal hard mask layer defines an opening in the dielectric layer; and a dry cleaning process is performed on the surface of the wafer by using a gas of gas and hydrogen as a reactive gas; And performing a wet cleaning process on the surface of the wafer with a cleaning solution containing a trace amount of hydrofluoric acid. 17. The method of cleaning an etched wafer as described in claim 16 wherein the flow rate of hydrogen in the dry cleaning process is greater than the flow rate of nitrogen. 18. The method of cleaning an etched wafer according to claim 16, wherein the cleaning solution is an acidic solution or an alkaline solution. 19. The method of cleaning an etched wafer according to claim 18, wherein the acidic solution is an organic acid solution, a mineral acid solution or a mixed solution of the organic acid solution and the inorganic acid solution. 2. The method of cleaning an etched wafer as described in claim 16 of the patent application, wherein the material of the metal mask layer is reduced in size, titanium or button. From the 21st 21st, the main cleaning process of the etched wafer as described in claim 16 of the patent application is in situ in the dry mode: