CN1917169A - Method for forming barrier layer on copper metal without use of electrodeposition - Google Patents
Method for forming barrier layer on copper metal without use of electrodeposition Download PDFInfo
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- CN1917169A CN1917169A CN 200510092413 CN200510092413A CN1917169A CN 1917169 A CN1917169 A CN 1917169A CN 200510092413 CN200510092413 CN 200510092413 CN 200510092413 A CN200510092413 A CN 200510092413A CN 1917169 A CN1917169 A CN 1917169A
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- substrate
- electroless plating
- cap rock
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- metallic barrier
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Abstract
The method for forming metal barrier cover layer on substrate without electro deposition includes steps: first, carrying out procedure for forming copper conducting wire on substrate with upper surface of the wire being exposed out; carrying out pre-cleaning procedure for the exposed upper surface; carrying out activating treatment by using activation solution of surface contact on the said exposed upper surface; carrying out annealing procedure in situ for the exposed upper surface in environment of containing steam of ethanol and carrier gas at temperature lower than 400 deg.C; depositing selected metal barrier cover layer on the said exposed upper surface in not plating mode.
Description
Technical field
The present invention relates to field of semiconductor technology, relate in particular to a kind of with electroless plating (electroless plating) mode through the reduction copper metallic face plate the method that contains the cobalt barrier layer as CoWP or CoWB etc.
Background technology
The copper plain conductor replaces the main material specification that traditional aluminum metal becomes metal interconnecting gradually in present integrated circuit component manufacturing, this is because the copper metal has lower advantages such as resistivity.At present, existing people propose with the electroless plating mode on copper conductor in addition deposition as CoWP etc. contain cobalt barrier layer or resistance barrier cap rock, by this wherein, and utilize tungsten composition among the CoWP obviously to improve the copper resistance to hinder characteristic with the complete coating of copper conductor.This barrier layer generally is optionally to be deposited on the exposed copper plain conductor surface of just having finished polishing.
The method that this barrier layer optionally is deposited on the copper plain conductor surface that exposes normally adopts electroless plating techniques, it comprises the metal ion in the electroless plating solution with chemical mode reduction and be deposited on conductive surface, and does not need to provide from the external world any electric current in the coating process.In practical application, this electroless plating techniques can be utilized immersion electroless plating system or utilize spray-type electroless plating system to finish.If carry out with immersion electroless plating system, the band metallized surfaces need be immersed in the electrolytic solution, and if carry out with spray-type electroless plating system, then is the surface that electrolytic solution is sprayed at thing to be plated.
Aforesaid cobalt barrier layer or the resistance barrier cap rock of containing is being formed in the electroless plating mode in the process on the copper metal, the copper metal in environment easily the characteristic of oxidation promptly become very key and problem demanding prompt solution.Be different from the oxidation of other metals, the copper metal at low temperatures (as below 200 ℃) be oxidized to Cu easily
2O and CuO, and can not form the self-protection layer and avoid by further oxidation.Unfortunately, the aforementioned electroless plating that contains cobalt barrier layer or resistance barrier cap rock is very responsive for the cleanliness factor on copper plain conductor surface.Even exist the cupric oxide of a little still can cause aforementioned selectivity and the technology yield that contains the electroless plating of cobalt barrier layer or resistance barrier cap rock to reduce on the copper conductor surface.
In existing skill, be that wafer is delivered to the wet-cleaned station with the mode of lip-deep cupric oxide of copper conductor or pollutant removal, wafer is immersed in the chemical solution with dissolved oxygen copper or pollutant.Yet, its shortcoming of such practice is in the existing skill wafer is immersed in to differ in the chemical solution fully to remove cupric oxide or pollutant clean surely, in addition, usually wafer is after cleaning is finished at the wet-cleaned station, not necessarily can carry out electroless plating at once, and have one period stand-by period (Q-time), at this moment, the copper conductor surface can produce new cupric oxide, and influences follow-up electroless plating.
Summary of the invention
Main purpose of the present invention plates the method that contains the cobalt barrier layer as CoWP or CoWB etc. in the electroless plating mode at the copper metallic face through reduction providing a kind of, to solve the problem of existing skill.
According to a preferred embodiment of the invention, the present invention discloses and a kind ofly forms the method for metallic barrier cap rock with electroless plating on substrate, may further comprise the steps:
Carry out a copper conductor technology on this substrate, to form at least one copper conductor on this substrate, it has the upper surface that comes out;
This upper surface that comes out to this copper conductor carries out prerinse technology;
To carry out contact one activated solution in surface through this upper surface that comes out of this copper conductor of this prerinse technology, and carry out an activation processing;
This upper surface that comes out of this copper conductor is lower than below 400 ℃ and contains in the environment of an alcohol vapour and at least one carrier gas in temperature carry out an in-situ annealing technology; And
Optionally this metallic barrier cap rock is deposited on this upper surface that comes out of this copper conductor in the electroless plating mode.
In order to make those skilled in the art can further understand feature of the present invention and technology contents, see also following about detailed description of the present invention and accompanying drawing.Yet accompanying drawing is only for reference and aid illustration usefulness, is not to be used for the present invention is limited.
Description of drawings
What Fig. 1 to Fig. 4 illustrated is the generalized section of copper plain conductor technology;
What Fig. 5 illustrated is the method flow diagram of the preferred embodiment of the present invention;
What Fig. 6 illustrated is in order to implement the annealing/reduction apparatus schematic diagram of conductive layer surface in the alcohol vapour environment in the preferred embodiment of the present invention.
The main element symbol description
10 substrates, 12 insulating barriers
14 lead irrigation canals and ditches, 16 layings
18 electric conducting materials, 60 annealing/reduction apparatuss
62 quartz reaction cabins, 64 heaters
66 gas feeds, 68 gas vents
70 alcohol,diluted steam supply systems, 72 bubble flasks
73 carrier gas sources of supply, 74 flow controllers
76 flow controllers, 80 wafers
721 air inlets
722 gas outlets, 723 containers
Embodiment
See also Fig. 1 to Fig. 4, what it illustrated is the generalized section of copper plain conductor technology.According to a preferred embodiment of the invention, the method that forms the copper conductor of semiconductor element is to deposit on substrate 10 earlier as insulating barriers such as advanced low-k materials 12, in insulating barrier 12, etch lead irrigation canals and ditches 14 then, then on lead irrigation canals and ditches 14 bottoms and sidewall, form layings 16 such as Ta/TaN, and then lead irrigation canals and ditches 14 are filled up as electric conducting materials such as copper 18, at last, utilize chemico-mechanical polishing to remove lead irrigation canals and ditches 14 outer additional layings 16 and electric conducting material 18, form the lead in the embedding insulating barrier 12 and obtain smooth surface from insulating barrier 12 surfaces.
Aforesaid advanced low-k materials can be organic advanced low-k materials, as SiLK etc., perhaps inorganic advanced low-k materials, as HSQ etc., and not limit be the material of porousness or imporosity, and in addition, the preferred embodiments of the present invention are not specially limited at specific advanced low-k materials, aforesaid insulating barrier also can be by general dielectric material, constitutes as silicon dioxide or FSG.
As previously mentioned, when being very easy to oxidation under atmospheric environment, the copper metal exposed forms cupric oxide.Therefore, after finishing CMP (Chemical Mechanical Polishing) process and forming copper conductor, need carry out prerinse technology again, to remove such as pollutants such as oxide and high molecular residue, be the activating process that carries out the copper conductor surface with that, normally utilize to contain palladium (palladium) metal of etc.ing and do and replace plated film (displacementplating).Before transferring to the electroless deposition that next reaction cabin contains cobalt barrier layer or resistance barrier cap rock, wafer passes through treatment steps such as the cleaning of multiprogramming and activation usually, in the transfer process of wafer, the copper conductor surface that exposes on the wafer just may contact atmosphere and be oxidized, therefore, the time of staying of copper conductor surface in atmosphere that control cleaning is good promptly seems very crucial.
See also Fig. 5, what it illustrated is the method flow diagram of the preferred embodiment of the present invention.As shown in Figure 5, the inventive method is after the CMP (Chemical Mechanical Polishing) process in finishing aforementioned copper conductor technology (step 51), carry out the prerinse (step 52) on wafer and copper conductor surface immediately, then, optionally carry out copper conductor surface activating process (step 53), then, carry out in-situ annealing (in-situ anneal) under the environment of alcohol vapour and handle containing, copper conductor surface reduction (step 54) with previous overactivation, with the copper conductor surface contact electrolytic solution that has soon just reduced, carry out the so-called electroless deposition process (step 55) that contains cobalt barrier layer or resistance barrier cap rock, next, carry out the back cleaning (step 56) of wafer, carry out the technology that is spin-dried for of wafer at last, wafer drying (step 57).
In aforesaid prerinse, just in the step 52, cleaning solution can be sprinkled upon wafer surface, usually can utilize the pH value to be less than or equal to 4, for example the acid solution of pH value between 1.5 to 3 cleans, this cleaning solution can include chelating agent (chelator) or complexing agent (complexing agent), for example carboxylic acid (carboxylic acid) or as citrate (citrate), oxalates (oxalic acid), glycine carboxylates (carboxylate) such as (glycine).For example, aforesaid cleaning solution can include the citric acid of concentration 0.05M to 0.5M and the pyrovinic acid (methanesulfonicacid) of the about 0.25M of concentration.
At aforesaid copper conductor surface activating process, just in the step 53, its objective is before deposition contains cobalt barrier layer or resistance barrier cap rock, form the initiation layer (initiation layer) that contains just like palladium, platinum, ruthenium (ruthenium), osmium (osmium), rhodium (rhodium) or iridium catalytic metals such as (iridium) by the displacement coating process on the copper conductor surface of coming out earlier.Aforesaid displacement coating process typically uses diluted palladium hydrochloric acid solution, for example palladium bichloride (palladium chloride), palladium nitrate (palladium nitrate) or palladium sulfate (palladium sulfate) etc.For instance, the activated solution preparation method who uses in this displacement coating process can be with the palladium nitrate (Pd (NO of about 1 ml concn as l0wt%
3)
2) add the nitric acid of concentration 10%, add deionized water to 1 liter again.In another example, activated solution can contain the palladium bichloride of the 120ppm that has an appointment and the hydrochloric acid of capacity, makes its pH value approximately between 1.5 to 3.Usually wafer to be activated at room temperature is immersed in the aforementioned activated solution about about 30 seconds.
In the aforesaid electroless deposition process that contains cobalt barrier layer or resistance barrier cap rock, just in the step 55, employed plating bath is formed can comprise that concentration is approximately between the cobalt source metal of 5mM to about 20mM, concentration is approximately between the tungsten source metal of 0.1mM to about 5mM, concentration is approximately between the hypophosphites (hypophosphite) of 5mM to about 50mM, concentration is approximately between the borane reduction agent (borane reductant) of 5mM to about 50mM, concentration is approximately between the citrate of 60mM to about 200mM, concentration is approximately between the alkanolamine (alkanolamine) of 50mM to about 150mM, concentration is approximately between the boric acid of 1mM to about 20mM, concentration is about the interface activating agent of 50ppm, and the pH value adjusts agent, and the pH value of plating bath is maintained between about 7 to 10.In addition, aforesaid plating bath also can comprise the stabilizer (stabilizer) of about 100ppm.
See also Fig. 6, what it illustrated is in order to implement the annealing/reduction apparatus schematic diagram of conductive layer surface in the alcohol vapour environment in the preferred embodiment of the present invention.As shown in Figure 6, annealing/reduction apparatus 60 comprises quartz reaction cabin 62, heater 64 and alcohol,diluted steam supply system 70, and wherein heater 64 can be OTS heater or heating plate.Be placed in the quartz reaction cabin 62 through the wafer 80 after prerinse or the activation processing.Quartz reaction cabin 62 is connected to gas feed 66 that is connected to alcohol,diluted steam supply system 70 and the gas vent 68 that is connected to discharge pipe line.
Aforesaid alcohol,diluted steam supply system 70 comprises a bubble flask (bubbler) 72, is used to provide alcohol vapour, and carrier gas source of supply 73, is used to provide carrier gas such as nitrogen or helium.Bubble flask 72 is connected to air inlet 721 and gas outlet 722, has then taken up ethanol 724 alcohol solutions such as grade in container 723.The temperature suggestion of bubble flask 72 is controlled at 18 ℃, and be blown into the nitrogen flow that froths in the bubble flask 72 via air inlet 721 with flow controller (MFC) 74 control, and, wherein the diluent nitrogen flow control is being about about three times of the nitrogen flow that froths with the nitrogen flow of flow controller 76 control alcohol,diluted steam.
According to a preferred embodiment of the invention, be about 1.25wt.% in the concentration of the alcohol,diluted steam of gas feed 66 ends, and flow is 0.2-0.8slm (standard liter per minute).The heating-up temperature of wafer 80 between 100 ℃ to 400 ℃, is preferably between 150 ℃ to 350 ℃ approximately.Under these conditions, wafer 80 was annealed in the alcohol vapour environment of reproducibility about about 5 minutes.
In addition, aforesaid annealing/reduction apparatus can be integrated with the electroless plating board or be built-in, but also can be independent board kenel.If aforesaid annealing/reduction apparatus and electroless plating board are integrated or are built-in, then aforesaid alcohol vapour annealing steps is to contain the cobalt barrier layer or hindering the electroless plating that hinders cap rock and select to carry out before the deposition, and original position contains the cobalt barrier layer or hinders the electroless plating selection deposition that hinders cap rock immediately then.If aforesaid annealing/reduction apparatus is independent board, then aforesaid alcohol vapour annealing steps can before or after the copper surface active, carry out all can, perhaps also can before pre-wash step, carry out.
The above only is the preferred embodiments of the present invention, and all equalizations of doing according to claim of the present invention change and modify, and all should belong to covering scope of the present invention.
Claims (15)
1. one kind forms the method for a metallic barrier cap rock with electroless plating on substrate, may further comprise the steps:
Carry out a copper conductor technology on this substrate, to form at least one copper conductor on this substrate, it has the upper surface that comes out;
This upper surface that comes out to this copper conductor carries out a prerinse technology;
Make this upper surface that comes out of this copper conductor of this prerinse technology of process contact an activated solution, and carry out an activation processing;
This upper surface that comes out of this copper conductor is lower than below 400 ℃ and contains in the environment of an alcohols steam and at least one carrier gas in temperature carry out an in-situ annealing technology; And
Optionally this metallic barrier cap rock is deposited on this upper surface that comes out of this copper conductor in the electroless plating mode.
2. as claimed in claim 1ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this copper conductor technology may further comprise the steps:
Deposition one dielectric layer on this substrate;
In this dielectric layer, form irrigation canals and ditches;
In these irrigation canals and ditches, form laying;
In these irrigation canals and ditches, fill up the copper metal; And
This copper metal that these irrigation canals and ditches are outer is removed with a CMP (Chemical Mechanical Polishing) process, to form this copper conductor and this upper surface that comes out.
3. as claimed in claim 1ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this prerinse technology is to use the pH value to be less than or equal to acidic cleaning solution about 4.
4. as claimed in claim 1ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this activated solution is drawn together catalytic metal, and it includes palladium, platinum, ruthenium, osmium, rhodium and iridium.
5. as claimed in claim 1ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this alcohols steam is alcohol vapour.
6. as claimed in claim 1ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this alcohols steam produces via a bubble flask.
7. as claimed in claim 1ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this carrier gas comprises nitrogen and helium.
8. as claimed in claim 1ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this in-situ annealing technology is to carry out under the temperature between 150 ℃ to 350 ℃ about about 5 minutes.
9. one kind forms the method for a metallic barrier cap rock with electroless plating on substrate, may further comprise the steps:
Carry out a copper conductor technology on this substrate, to form at least one copper conductor on this substrate, it has the upper surface that comes out;
This upper surface that comes out to this copper conductor carries out a prerinse technology;
This upper surface that comes out of this copper conductor is lower than below 400 ℃ and contains in the environment of an alcohols steam and at least one carrier gas in temperature carry out an in-situ annealing technology; And
Optionally this metallic barrier cap rock is deposited on this upper surface that comes out of this copper conductor in the electroless plating mode.
10. as claimed in claim 9ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this copper conductor technology may further comprise the steps:
Deposition one dielectric layer on this substrate;
In this dielectric layer, form irrigation canals and ditches;
In these irrigation canals and ditches, form laying;
In these irrigation canals and ditches, fill up the copper metal; And
This copper metal that these irrigation canals and ditches are outer is removed with a CMP (Chemical Mechanical Polishing) process, to form this copper conductor and this upper surface that comes out.
11. as claimed in claim 9ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this prerinse technology is to use the pH value to be less than or equal to acidic cleaning solution about 4.
12. as claimed in claim 9ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this alcohols steam is alcohol vapour.
13. as claimed in claim 9ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this alcohols steam is to produce via a bubble flask.
14. as claimed in claim 9ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this carrier gas comprises nitrogen and helium.
15. as claimed in claim 9ly form the method for metallic barrier cap rock with electroless plating on substrate, wherein this in-situ annealing technology is to carry out under the temperature between 150 ℃ to 350 ℃ about about 5 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510092413 CN1917169A (en) | 2005-08-18 | 2005-08-18 | Method for forming barrier layer on copper metal without use of electrodeposition |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510092413 CN1917169A (en) | 2005-08-18 | 2005-08-18 | Method for forming barrier layer on copper metal without use of electrodeposition |
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| CN1917169A true CN1917169A (en) | 2007-02-21 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107635676A (en) * | 2015-05-28 | 2018-01-26 | 麦克德米德股份有限公司 | The preprocess method of electroless plating |
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- 2005-08-18 CN CN 200510092413 patent/CN1917169A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107635676A (en) * | 2015-05-28 | 2018-01-26 | 麦克德米德股份有限公司 | The preprocess method of electroless plating |
| CN107635676B (en) * | 2015-05-28 | 2020-09-18 | 麦克德米德股份有限公司 | Pretreatment method for electroless plating |
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