CN101329288B

CN101329288B - Correcting method of boron and phosphorus content measurement in BPSG

Info

Publication number: CN101329288B
Application number: CN2007100423913A
Authority: CN
Inventors: 肖建军; 宋国宁; 张士仁; 杨洪春
Original assignee: Semiconductor Manufacturing International Shanghai Corp
Current assignee: Semiconductor Manufacturing International Shanghai Corp
Priority date: 2007-06-22
Filing date: 2007-06-22
Publication date: 2010-09-15
Anticipated expiration: 2027-06-22
Also published as: CN101329288A

Abstract

The invention discloses a correction method used for the measurement of boron (B) and phosphor (P) content in boron phoshosilicate glass (BPSG) so as to carry out the correction to a measurement instrument which is used for measuring the content of B and P of BPSG such as X-ray fluorometer (XRF), etc. The correction method mainly uses a wet-chemical method to measure the B and P content in the BPSG and compares the B and P content with the results measured by the XRF, thus working out the difference value; the accuracy of the XRF is adjusted by the difference value; the correction method comprises the detailed steps as follows: the B and P consistency of the BPSG film is measured by the XRF; the BPSG film is dissolved in an etching solution; the B and P consistency is measured by element quantitative analysis equipment; furthermore, the B and P consistencies respectively measured by the XRF and the element quantitative analysis equipment form a consistency correction curve used for correcting the XRF; subsequently, the consistency correction curve is used for correcting the XRF; alternatively, the XRF is corrected by XRF standard sheets prepared by the consistency correction curve.

Description

The bearing calibration that boron, phosphorus content are measured among the BPSG

Technical field

The present invention relates to a kind of manufacture of semiconductor, relate in particular to the bearing calibration of B (boron), P (phosphorus) content measurement among a kind of BPSG (Borophosphosilicateglass, boron-phosphorosilicate glass).

Background technology

(Chemical Vapor Deposition, CVD) BPSG in the processing procedure (boron-phosphorosilicate glass) film is a kind of important inter-level dielectric to chemical vapor deposition.In BPSG, B (boron), P (phosphorus) content are to its performance important influence.Stable B concentration determination will effectively improve the insulation effect of upper strata metal and lower floor's silicon layer, and simultaneously accurate and stable P concentration determination with the adsorptive power that effectively improves dissociated ion, prevents the generation because of the free short circuit phenomenon that is produced of ion.

In the CVD processing procedure, after the BPSG film was made on wafer (Wafer) surface, (X-ray fluorescence XRF) measured the composition of BPSG to use x-ray fluorescence analyzer.XRF utilizes the fluorescence of optics or characteristic wave bands to measure, yet owing to use for a long time, can cause the drift of XRF baseline.Do not have standard to proofread and correct if use XRF for a long time, the measuring error of board will exceed the specification of processing procedure so, and person to be measured is not discovered.This quality of production to BPSG will be a very big problem.Therefore need a kind of means that XRF is proofreaied and correct, make it keep enough accuracy.

Summary of the invention

Technical matters to be solved by this invention provides the bearing calibration of boron among a kind of BPSG, phosphorus content measurement, so that 1B, P assay instrument such as BPSG such as XRF are proofreaied and correct.

The present invention is that to solve the problems of the technologies described above the technical scheme that adopts be to utilize wet-chemical (WetChemical) method to measure B, P content among the BPSG, and compare with result that XRF measures, obtain values of disparity, by the accuracy that values of disparity is regulated XRF, concrete steps comprise: boron, the phosphorus concentration of measuring the BPSG film with XRF; Described BPSG Film Fractionation in etching solution, is used its boron of quantitative elementary analysis measuring apparatus, phosphorus concentration; And utilize boron, phosphorus concentration that XRF and quantitative elementary analysis equipment measures respectively to form a concentration correction curve that is used to proofread and correct described XRF.

Like this, can utilize this concentration correction curvature correction XRF, perhaps, come corrected X RF with this standard film then according to this concentration correction curve plotting XRF standard film.

But above-mentioned quantitative elementary analysis equipment using plasma mass spectrometer, and before analysis, utilization can be traced back to the boron of NIST, the standard solution of phosphorus, article on plasma physique spectrometer is proofreaied and correct, and uses these ion mass-spectrometers that the B, the P concentration that are dissolved in the BPSG film in the special etch liquid are measured then.

The above-mentioned bearing calibration that the present invention adopts has higher accuracy, the method is to the correction of XRF, can reduce the correction expense of XRF, reduce and the risk of board baseline wander to occur, thus the frequency of occurrence that has further lowered the process of the making problem that produces because of baseline wander with control cost.

Description of drawings

For above-mentioned purpose of the present invention, feature and advantage can be become apparent, below in conjunction with accompanying drawing the specific embodiment of the present invention is elaborated, wherein:

Fig. 1 is the process flow diagram of an embodiment of bearing calibration of boron among the BPSG of the present invention, phosphorus content measurement.

Fig. 2 is the concentration correction curve map of the bearing calibration that boron, phosphorus content are measured among the BPSG according to the present invention.

Embodiment

See also Fig. 1, one embodiment of the present of invention step is as follows:

It at first is step 11, adopt x-ray fluorescence analyzer (XRF) that boron, the phosphorus concentration of a series of boron-phosphorosilicate glasss (BPSG) film are measured, XRF reflects the concentration that it is measured with signal intensity, according to the baseline of this XRF, obtain also boron, the phosphorus concentration of pairing each the BPSG film of tracer signal intensity.

Next is a step 12, utilizes wet chemical method to measure boron, the phosphorus concentration of BPSG film, is about to the BPSG Film Fractionation in specific etching solution, with its boron of quantitative elementary analysis measuring apparatus, phosphorus concentration.

Quantitative elementary analysis equipment is preferably and adopts ICP/MS (Inductively Coupled PlasmaMass Spectrometer, the inductively coupled plasma mass spectrometer), before this equipment uses, need a series of board optimizations of experience, and can trace back to NIST (National Institute of Standards andTechnology by using, American National Standard technology institute) B, the standard solution of P is proofreaied and correct.For instance, utilize the standard solution of B, P to carry out the linear fit of concentration, obtain following standard feature curve:

B standard feature curve:

Y＝4.085＊10 ³＊+4.326＊10 ³，R ²＝0.9999

P standard feature curve:

Y＝2.157＊10 ³＊+4.331＊10 ⁴，R ²＝0.9998

In above-mentioned two characteristic curvees, X represents the concentration of standard solution, and Y represents the signal intensity that ICP/MS records, R ²It is fitting coefficient, the degree of accuracy of its expression curve, according to above-mentioned curve, by plasma power (Plasma Power) to ICP/MS, (Plasma Distance) the isoparametric adjusting of plasma distance, this equipment is to B, the RSD of the measurement of P (relative error number percent)＜1% so both can guarantee measured B, the absolutely accurate of P, the ability and the frequency of usage of the duplicate measurements of board can be guaranteed again, the correct and rigorous of result can be guaranteed externally to export for a long time.

After ICP/MS proofreaies and correct, but execution in step 12, and it further comprises:

Step 121, the etching solution of the about 100g of adding in container;

Step 122, the wafer that will have the BPSG film is put into etching solution, and it is flooded, and waits for after 20 minutes, and wafer is taken out;

Step 123, with the etching solution constant volume to 100g;

Step 124, (De-ionized water is DIW) with 100 times of solution dilutions to use deionized water; And

Step 125 uses quantitative elementary analysis equipment that solution is carried out quantitative test.

Wherein after step 122 is taken out wafer, can again wafer be put into etching solution,, the BPSG film fully be dissolved by repeatedly submergence washing, and and contrast experiment's resultant error be controlled at 5%.Even the B in crystal column surface silica membrane layer, the P dissolving, the ratio of collection also can be less than 5%.So just can be controlled at the operate miss of the process of operating accurately.

The above results is carried out mathematical statistics, and less than 6%, and the error that XRF requires only needs less than 20% the arithmetic square value of all devices sum of errors operate miss on the number percent level.Therefore above-mentioned wet chemical method not only adopted brand-new experimentation, and the board of control survey and operator's operate miss is less than the board measuring error of XRF.

Moreover, after the measurement result that obtains XRF and ICP/MS respectively, enter step 13, contrast the difference of the two, formation one concentration correction curve as shown in Figure 2, wherein curve a represents the corresponding relation curve of signal intensity (CPS) Yu the concentration of XRF self, signal intensity that curve b (baseline) expression XRF is measured and the accurate B of BPSG, the corresponding relation of P concentration (being the measured concentration of ICP/MS).Utilize this curve can come corrected X RF, promptly the B of ICP/MS, the P measured value is as the reference value of XRF, for the shift point of XRF reading, regulate the characteristic wave signal of XRF and scale-up factor and other correlation parameter of concentration, make the reading value of XRF keep relative stablizing with baseline.

In addition, can be according to above-mentioned concentration correction curve, (step 14), (step 15), as XRF mark sheet (step 16), this mark sheet can use the drift that did not occur concentration in three months in nitrogen environment through the overaging preservation again to define and produce the XRF standard film.The benefit that adopts the mark sheet to proofread and correct is all can proofread and correct XRF in the term of validity of mark sheet.

The above embodiment of the present invention has following beneficial effect at least:

1.Wet the employed reagent of Chemical method is the B with trackability, the P standard solvent has enough public credibility.The method is on existing technological means basis, uses less cost to solve data and sets up and stability problem, has further reduced correction cost and the baseline wander institute generation problem of XRF.Save cost, improved accuracy and efficient.

2. the relative error of the method is little, improves and the perfect technological development and the popularization ability of wet chemical method, and can realize the unit platform of chemical laboratory in the wafer factory and the relevant board coupling of other department.

3. the method can reduce the correction expense of XRF to the correction of XRF, reduce the risk of board baseline wander to occur, thereby the frequency of occurrence that has further lowered the process of the making problem that produces because of baseline wander with control cost.

Above embodiment explanation only is preferred embodiment explanation of the present invention, and those skilled in the art can make the replacement and the modification of other all equivalence according to the above embodiment of the present invention explanation.Yet these all equivalences of doing according to the embodiment of the invention are replaced and are revised, and belong to invention spirit of the present invention and reach by in the claim that claim defined.

Claims

1. the bearing calibration that boron, phosphorus content are measured in the boron-phosphorosilicate glass is characterized in that, comprising:

Measure boron, the phosphorus concentration of bpsg film with x-ray fluorescence analyzer;

Described bpsg film is dissolved in etching solution, with its boron of quantitative elementary analysis measuring apparatus, phosphorus concentration;

The boron, the phosphorus concentration that utilize x-ray fluorescence analyzer and quantitative elementary analysis equipment to measure respectively, formation one is used to proofread and correct the concentration correction curve of described x-ray fluorescence analyzer; And

According to the described x-ray fluorescence analyzer of described concentration correction curvature correction; Perhaps, utilize described x-ray fluorescence analyzer standard film to proofread and correct described x-ray fluorescence analyzer again according to described concentration correction curve plotting x-ray fluorescence analyzer standard film.

2. the bearing calibration of the boron of boron-phosphorosilicate glass as claimed in claim 1, phosphorus content mensuration is characterized in that described quantitative elementary analysis equipment is plasma mass spectrograph.

3. the bearing calibration of the boron of boron-phosphorosilicate glass as claimed in claim 2, phosphorus content mensuration is characterized in that, also comprises utilizing respectively and can trace back to the boron of American National Standard technology institute, the standard solution of phosphorus, and described plasma mass spectrograph is proofreaied and correct.

4. the bearing calibration of the boron of boron-phosphorosilicate glass as claimed in claim 1, phosphorus content mensuration is characterized in that the step that bpsg film is dissolved in etching solution comprises:

1) in a container, puts into a certain amount of etching solution;

2) wafer that will have bpsg film is put into described etching solution, it is flooded, through after a while wafer being taken out;

3) described etching solution is carried out constant volume; And

4) with deionized water described etching solution is diluted.

5. the bearing calibration measured of the boron of boron-phosphorosilicate glass as claimed in claim 4, phosphorus content is characterized in that, in step 2) take out wafer after, put it in the described etching solution, repeatedly execution in step 2 again).

6. the bearing calibration measured of the boron of boron-phosphorosilicate glass as claimed in claim 1, phosphorus content is characterized in that, comprises the standard film preservation of wearing out according to the step of described concentration correction curve plotting x-ray fluorescence analyzer standard film.