CN101906638B

CN101906638B - Surface cleaning method of polished silicon substrate material

Info

Publication number: CN101906638B
Application number: CN2010102314556A
Authority: CN
Inventors: 刘玉岭; 孙鸣; 杨金波; 何彦刚
Original assignee: Hebei University of Technology
Current assignee: Hebei University of Technology
Priority date: 2010-07-21
Filing date: 2010-07-21
Publication date: 2012-09-19
Anticipated expiration: 2030-07-21
Also published as: CN101906638A

Abstract

The invention relates to a surface cleaning method of a polished silicon substrate material, which is characterized by comprising the following concrete steps of: taking 0.5-5 parts of nonionic surfactant, 0.1-5 parts of FA/OII type chelating agent, 0.1-5 parts of FA/O II type compound corrosion inhibitor and the balance of deionized water in parts by weight, and uniformly stirring to prepare a water-soluble surface cleaning solution with the pH value of 6.5-7.6; carrying out polishing cleaning on a silicon substrate material subjected to alkaline chemical-mechanical polishing by using the cleaning solution obtained in the step 1 under the conditions of less than 4000Pa of low pressure and 400-5000ml/minute of large flow, wherein the polishing cleaning time is at least 30 seconds-3 minutes, so that the surface of the silicon substrate material is clean. The invention has the advantages that low-pressure large-flow cleaning is carried out on the silicon substrate material by immediately using the cleaning solution after the polishing process in a CMP (Chemical-Mechanical Polishing) working procedure, and a clean and perfect polished surface can be obtained.

Description

Surface cleaning method of polished silicon substrate material

Technical field

The invention belongs to the cleaning technique of semiconductor material, relate in particular to the surface cleaning method of polished silicon substrate material behind a kind of CMP.

Background technology

Crystalline silicon is a grey black, belongs to atomic crystal, firmly metalluster is arranged, and semiconductor property is arranged.The chemical property of silicon is more active, at high temperature can with multiple element chemical combination such as oxygen, water insoluble, nitric acid and hydrochloric acid are dissolved in hydrofluoric acid and alkali lye.Silicon single crystal is a kind of important semiconductor material, is used to make high power transistor, RF, solar cell etc.

Silicon substrate is present the most general a kind of substrate material, as substrate material plane of crystal has been proposed the ultra clean requirement of ultra-smooth.Research shows that the quality of device depends on the surface working of substrate to a great extent.Develop rapidly along with integrated circuit technique; Unicircuit is to the increase day by day of silicon substrate material demand; In order to satisfy the demand of unicircuit development; The chemically machinery polished of silicon substrate (Chemical-Mechanical Polishing is called for short CMP) technology and throwing post-processing technology become major issue anxious to be solved.Surface of polished clean technology as one of process for treating surface is even more important.After silicon substrate polishes production in batches at present; Silicon substrate wafer surface energy height very easily adsorbs and causes surface tear, residual polishing fluid skewness and the little nodularization of tension force Da Yi in the abrasive grain cleaning process and continue the chemical corrosion surface of silicon and cause surface of silicon non-uniform corrosion and absorption corrosion diagram to occur around the abrasive grain and surperficial consistence is relatively poor, stain heavy metal ion very easily is converted into atomic state and causes phenomenons such as surface of silicon heavy metal contamination with surface of silicon Siliciumatom formation alloy, thereby causes the raising of cost in the following process and the reduction of device yield.

Summary of the invention

The present invention is in order to overcome deficiency of the prior art; A kind of simple and easy to do, pollution-free, clean surface cleaning method of polished silicon substrate material is provided, has solved the high absorption abrasive grain that is prone to of silicon substrate material polishing back silicon substrate wafer surface energy and caused surface tear, residual polishing fluid surface tension Da Yi bead continuation and silicon substrate top layer that chemical reaction takes place to cause the silicon substrate non-uniform corrosion, stain heavy metal ion and be converted into the problem that atom and surface of silicon Siliciumatom formation alloy cause silicon substrate heavy metal contamination.

The present invention realizes that through following technical scheme a kind of surface cleaning method of polished silicon substrate material is characterized in that: concrete steps are following for realizing above-mentioned purpose,

(1) preparation scavenging solution: count by weight (part)

Non-ionics 0.5-5, FA/OII type sequestrant 0.1-5, the compound stopping agent 0.1-5 of FA/O II type, deionized water surplus are prepared into p H value and are the water-soluble surface cleaning liquid of 6.5-7.6 after stirring;

(2) silicon substrate material after using the scavenging solution that obtains in the step (1) to alkaline chemical mechanical polishing carries out polished and cleaned under the big flow condition of the low pressure below the 4000Pa, 400-5000ml/min; At least 30 seconds polished and cleaned time-3 minute is so that the silicon substrate material surface cleaning.

Beneficial effect: use scavenging solution that silicon substrate material is carried out low pressure, big flow cleaning behind the glossing in the CMP operation immediately, can obtain cleaning, perfect glazed surface.The first, adopt low pressure, big flow liquid throwing water to clean no retardation time, can effectively optimize, reduce the surface of silicon roughness, can fast the residual polishing fluid of skewness and the abrasive grain of surface of silicon absorption be washed away and avoid the particle scuffing rapidly again; The second, add the surface tension that nonionogenic tenside can reduce the residual polishing fluid of surface of silicon rapidly in the scavenging solution, avoid the corrosion diagram of abrasive grain unsymmetrical corrosion generation on every side; The 3rd, the compound stopping agent of selecting for use can be preferentially adsorbed on surface of silicon and form the unit molecule passive film after polishing, stops the polishing fluid of surperficial uneven distribution to continue and surface of silicon generation chemical reaction, improves the perfection of surface of polished; The 4th; For preventing that heavy metal ion from combining to form alloy and polluting surface of silicon with the surface of silicon Siliciumatom; Add FA/OII type sequestrant in the scavenging solution, can preferentially generate polymer complex compound stable, soluble in water, break away from from surface of silicon with the surface of silicon heavy metal ion.Adopt this method for cleaning surface, can obtain cleaning, perfect great surface quality silicon substrate glazed surface.

Embodiment

Below in conjunction with preferred embodiment, to details are as follows according to embodiment provided by the invention:

A kind of surface cleaning method of polished silicon substrate material, concrete steps are following,

(1) preparation scavenging solution: count by weight (part)

(2) silicon substrate material after using the scavenging solution that obtains in the step (1) to alkaline chemical mechanical polishing carries out polished and cleaned under the big flow condition of the low pressure below the 4000Pa, 400-5000ml/min; At least 30 seconds polished and cleaned time-3 minute is so that the silicon substrate material surface cleaning.Said nonionic agent is FA/O tensio-active agent, O _∏-7 ((C ₁₀H ₂₁-C ₆H ₄-O-CH ₂CH ₂O) ₇-H), O _∏-10 ((C ₁₀H ₂₁-C ₆H ₄-O-CH ₂CH ₂O) ₁₀-H), O-20 (C _12-18H _25-37-C ₆H ₄-O-CH ₂CH ₂O) ₇₀-H), JFC one or more;

Said FA/O II type sequestrant is Jingling Microelectric Material Co., Ltd., Tianjin commercially available prod, for YD 30 four (tetrahydroxyethyl-ethylene diamine), can be abbreviated as NH ₂RNH ₂Its structural formula is:

The compound stopping agent of said FA/O II type is Jingling Microelectric Material Co., Ltd., Tianjin commercially available prod; The comparable single phenylpropyl alcohol triazole effect of compound stopping agent effect improves 3 times; Mixture for urotropine (vulkacit H) and phenylpropyl alcohol triazole (benzotriazole)

Wherein said urotropine molecular formula is C ₆H ₁₂N ₄, structural formula does

Said phenylpropyl alcohol triazole molecular formula is C ₆H ₅N ₃, structural formula does

Embodiment one

(1) preparation scavenging solution: count by weight (part)

More than 18M Ω, add FA/O tensio-active agent 50g, FA/OII type sequestrant 75g, the compound stopping agent 75g of FA/O II type among the ultrapure deionized water 2300g respectively, stir while adding evenly, be prepared into the 2500g scavenging solution; The silicon substrate material of the scavenging solution that utilization prepares after to alkaline chemical mechanical polishing carries out polished and cleaned under the big flow condition of the low pressure below the 3000Pa, 4000ml/min, polished and cleaned time 2min is so that the silicon substrate material surface cleaning.Surface of silicon after the cleaning does not have corrosion diagram, surface roughness Ra=0.3nm (10 μ mx10 μ m).

Embodiment two

(1) preparation scavenging solution: count by weight (part)

More than 18M Ω, add FA/O tensio-active agent 50g, FA/OII type sequestrant 10g, the compound stopping agent 20g of FA/O II type among the ultrapure deionized water 2200g respectively, stir while adding evenly, be prepared into the 3000g scavenging solution; The silicon substrate material of the scavenging solution that utilization prepares after to alkaline chemical mechanical polishing carries out polished and cleaned under the big flow condition of the low pressure below the 1000Pa, 5000ml/min, polished and cleaned time 1min is so that the silicon substrate material surface cleaning.Surface of silicon after the cleaning does not have corrosion diagram, surface roughness Ra=0.2nm (10 μ mx10 μ m).

Adopt acting as of technology: there are problems such as energy height, big, the residual polishing fluid skewness of surface tension, contamination metals ion in the silicon substrate wafer surface behind the silicon substrate material alkaline polishing.After alkaline polishing is just accomplished; At once with the method that contains non-ionics, sequestrant, compound stopping agent water throwing scavenging solution employing low pressure, big flow water throwing; Can residual polishing fluid be washed away; Can reduce simultaneously surface tension rapidly, form the unit molecule passive film, also can make metals ion form soluble inner complex, thereby reach clean, perfect glazed surface.

The above only is preferred embodiment of the present invention, is not structure of the present invention is done any pro forma restriction.Every foundation technical spirit of the present invention all still belongs in the scope of technical scheme of the present invention any simple modification, equivalent variations and modification that above embodiment did.

Claims

1. surface cleaning method of polished silicon substrate material, it is characterized in that: concrete steps are following,

(1) preparation scavenging solution: count by weight

The mixture 0.1-5 of nonionic agent 0.5-5, sequestrant YD 30 four (tetrahydroxyethyl-ethylene diamine) 0.1-5, compound stopping agent urotropine (vulkacit H) and phenylpropyl alcohol triazole (benzotriazole); The deionized water surplus, being prepared into the pH value after stirring is 6.5-7.6 water-soluble surface cleaning liquids; Said nonionic agent is FA/O tensio-active agent, O _П-7 ((C _1OH ₂₁-C ₆H ₄-O-CH ₂CH ₂O) ₇-H), O _П-10 ((C _1OH ₂₁-C ₆H ₄-O-CH ₂CH ₂O) ₁₀-H), O-20 (C _12-18H _25-37-C ₆H ₄-O-CH ₂CH ₂O) ₇₀-H), JFC one or more;