Development of endpoint detection using optical transmittance and magnetic permeability based on skin effect in chemical mechanical planarization

Fujita, Takashi; Kitade, Keita

doi:10.1016/j.precisioneng.2019.03.004

Cited by 8 publications

(3 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to resolve the concerns described above, a novel mechanism for end point detection using eddy current was developed by making use of the skin effect. 4,[8][9][10] According to the skin effect use, critical changes can be made in accordance with the copper film thickness. Figure 2 shows magnetic flux change by skin effect.…”

Section: Principles Of the Developed End Point Detection Systemmentioning

confidence: 99%

Verification of Operation Principle on End Point Detection by Skin Effect in Chemical Mechanical Planarization

Fujita

Kitade

2017

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

An original eddy current sensor by making use of skin effect of copper film was developed for end point prediction in CMP (Chemical Mechanical Planarization). The main operation principle is based on detecting a local maximum point of eddy current due to skin effect in the course of film thickness reduction by CMP. This paper focuses on the verification of the operation principle. The verification evaluation using ferrite sheet supported that magnetic field passing through to a copper film is indispensable to operate the end point detection. From the result of both copper film process and tungsten film process, it was apparent that the resonant frequency profile depends on the skin depth of film material. The equivalent circuit model including the plane inductor and copper film indicates that a real part of an impedance of a plane inductor is proportion to the square of mutual inductance corresponding to eddy current induced. The simulation result of the real part of impedance of the plane inductor was a good agreement with actual resonant frequency profile. It was clarified that the operation principle of the end point detection is based on eddy current generation due to skin effect. End point detection technology that detects polishing end is essential for CMP (Chemical Mechanical Polishing) technology to stop polishing accurately without dishing and erosion caused by overpolishing. 1 As conventional methods on end point detection technology, there were some measures by means of motor torque measurement or observation of reflection rate change of light. 2 In particular, end point detection technology by eddy current has been widely used for copper CMP. 3 In the former paper, authors reported that end point detection using eddy current due to skin effect was developed for copper chemical mechanical planarization process. 4 The operation principle was shown with the some simulation results. In addition, the paper shows that resonant frequency profile was reproduced at three times under same experimental condition precisely. It was demonstrated that the end point system is quite sensitive and robust for actual polishing process. 5 The developed end point system has a great advantage on applying to actual end point detection, compared with the conventional end point system. 6,7 The advantages are as follows.(1) It was difficult for the conventional system to detect polishing end point precisely because eddy current fades out at the polishing end point. The developed system can detect the polishing end point easily because a local maximum point of eddy current emerges around skin depth just before cupper film elimination. (2) Under the developed end point system, even if the initial copper film thickness were uneven in the lot, the polishing end point can be detected accurately because the detection point is based on the remaining film thickness which corresponds to skin depth of the film material. (3) The magnetic field generated by developed end point system is feeble and spread out enough to pass through very th...

show abstract

Section: Principles Of the Developed End Point Detection Systemmentioning

confidence: 99%

Verification of Operation Principle on End Point Detection by Skin Effect in Chemical Mechanical Planarization

Fujita

Kitade

2017

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…When the thickness of the copper film is reduced to about 600-1000 nm, the measurement of the electrical conductivity of the copper film becomes relevant, both to control the deposition process and to control the thickness. Currently, there are several methods for monitoring electrical conductivity, including the four-probe method (4PP) [20--22], the optical method [23], and the eddy current method [24]. The 4PP method is a common method for determining the thickness of a copper film in the semiconductor industry, but it requires contact of the probes with the sample surface [25].…”

Section: Introductionmentioning

confidence: 99%

Automated Control Ofthe Thin Films Electricalconductivity by the Eddy Current Method

Malikov

2024

Eurasian phys. tech. j.

View full text Add to dashboard Cite

The article considers the possibility of using the eddy current method of non-destructive testing for the problems of measuring the electrical conductivity of thin metal films. As the object of measurement, we used copper films of various thicknesses obtained by vacuum vapor deposition. A review of current trends in the use of copper films in modern industry and science is presented, and an analysis is made of current methods of non-destructive testing suitable for studying thin copper films. A brief description of the deposition method and the hardware-software complex for measuring the electrical conductivity of the film is presented. A calibration curve is presented, which makes it possible to restore the values of the electrical conductivity of the film from the value of the signal of the eddy current transducer. GaAs samples were selected to construct a calibration curve. The decision is explained by the proximity of the values of the electrical conductivity of this chemical compound to the calculated indicators of the obtained thin films. The results of testing films with different characteristics are presented and the distribution of the electrical conductivity of the films depending on the batch is shown. A series of practical measurements of thin films demonstrated the existence of a relationship between the mass of the initial substance that was subjected to deposition and the characteristics of the resulting films. According to different values of electrical conductivity within the same batch, it was concluded that there is a difference in the quality of deposition of different films.

show abstract

“…When the thickness of Cu film is reduced to about 600-1000 nm, the electrical conductivity measurement of Cu film is essential for both process control deposition and thickness inspection. Presently, it has several methods, including four-point probe (4PP) method [11][12][13], optical method [14], and eddy current method [15]. The 4PP method is a common method for determining the thickness of Cu film in the semiconductor industry, but it requires probes to contact the surface of the sample [16].…”

Section: Introductionmentioning

confidence: 99%

Superminiature Eddy Current Probe for Measuring the Electrical Conductivity of Copper Thin Films

Ишков

Kunitsyn

2022

KEM

View full text Add to dashboard Cite

The article considers the possibility of applying the eddy current method of non-destructive testing for measuring the electrical conductivity of new material - thin metal films. Copper films of various thickness obtained by physical vapour deposition were used as the measurement object. The deposition method and the hardware and software complex for measuring the electrical conductivity of the film were briefly described. A calibration curve that makes it possible to restore the values of the electrical conductivity of the material by the signal value of the eddy current probe was presented. The test results of films with different characteristics were given, and the distribution of the electrical conductivity of the films depending on the batch was shown. Based on different values of the electrical conductivity in a batch, the difference in deposition quality of various films was found.

show abstract

Development of endpoint detection using optical transmittance and magnetic permeability based on skin effect in chemical mechanical planarization

Cited by 8 publications

References 6 publications

Verification of Operation Principle on End Point Detection by Skin Effect in Chemical Mechanical Planarization

Verification of Operation Principle on End Point Detection by Skin Effect in Chemical Mechanical Planarization

Automated Control Ofthe Thin Films Electricalconductivity by the Eddy Current Method

Superminiature Eddy Current Probe for Measuring the Electrical Conductivity of Copper Thin Films

Contact Info

Product

Resources

About