Application of soft landing to the process control of chemical mechanical polishing

Chiu, Jian-Bin; Yu, Cheng‐Ching; Shen, Shing Chuan

doi:10.1016/s0167-9317(02)01024-9

Cited by 12 publications

(6 citation statements)

References 10 publications

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“…A uniform pressure distribution is beneficial for reduction in dishing [26]. In addition, dishing can be reduced through gentle contacts of pad through Y 2 O 3 NS to wafer, which is similar to soft landing in abrasive free polishing [30][31][32]. The CMP conducted using the Y 2 O 3 slurry obtained little dishing.…”

Section: Resultsmentioning

confidence: 99%

Y2O3 nanosheets as slurry abrasives for chemical-mechanical planarization of copper

Chen

Zhao

et al. 2013

Friction

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Continued reduction in feature dimension in integrated circuits demands high degree of flatness after chemical mechanical polishing. Here we report using new yttrium oxide (Y 2 O 3 ) nanosheets as slurry abrasives for chemical-mechanical planarization (CMP) of copper. Results showed that the global planarization was improved by 30% using a slurry containing Y 2 O 3 nanosheets in comparison with a standard industrial slurry. During CMP, the two-dimensional square shaped Y 2 O 3 nanosheet is believed to induce the low friction, the better rheological performance, and the laminar flow leading to the decrease in the within-wafer-non-uniformity, surface roughness, as well as dishing. The application of the two-dimensional nanosheets as abrasive in CMP would increase the manufacturing yield of integrated circuits.

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Section: Resultsmentioning

confidence: 99%

Y2O3 nanosheets as slurry abrasives for chemical-mechanical planarization of copper

Chen

Zhao

et al. 2013

Friction

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“…In recent years, CMP has become an important technology because there exists the requirement of global wafer planarity for multilevel interconnect devices in integrated circuit fabrication. CMP also gives the advantages of defect reduction, wide windows for etching and lithography, and yield improvement. − Despite recent advances in CMP, some manufacturing concerns associated with successful implementation of CMP remain to be overcome. − In theory, CMP can achieve global planarity, but the problem of within wafer nonuniformity (WIWNU) still remains as one of the major operation concerns. WIWNU indicates the variation in the surface thickness across the wafer radial position, especially on the edge.…”

Section: Nonsquare Cmp Examplementioning

confidence: 99%

“…[16][17][18] Despite recent advances in CMP, some manufacturing concerns associated with successful implementation of CMP remain to be overcome. [16][17][18][19][20][21][22][23] In theory, CMP can achieve global planarity, but the problem of within wafer nonuniformity (WIWNU) still remains as one of the major operation concerns. WI-WNU indicates the variation in the surface thickness across the wafer radial position, especially on the edge.…”

Section: Multizone Cmpmentioning

confidence: 99%

Batch Sequencing for Run-to-Run Control: Application to Chemical Mechanical Polishing

Chen¹,

Su²,

Shiu³

et al. 2005

Ind. Eng. Chem. Res.

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This work compliments and extends the capability of the run-to-run (R2R) control by sequencing the incomings such that improved control performance can be achieved. Unlike chemical or mechanical systems, this is important for semiconductor manufacturing processes because some prior information about the incoming wafers is generally available. First, the limitation of a R2R control type of feedback system is explained. The frequency domain explanation is as follows: a negative feedback system is effective rejecting a low-frequency type of disturbance. From the feedback property, then the answer to the feed sequencing problem becomes clear: arrange the feed (which we are capable of doing) in such a way that it gives a low-frequency characteristic. Furthermore, a scalar load strength indicator is derived, and an engineering approach is taken to sort the incomings effectively. Two policies, from thin to thick (in terms of prethickness, policy L2R) and from thick to thin (policy R2L), are proposed, and they are shown to provide a better control performance over the conventional random feed policy (R). The feed sequencing problems are tested for systems with different dimensions, e.g., single input single output, single input multiple output, and multiple input multiple output systems, which include the model of an experimental chemical mechanical polishing process, and the results show that an improved control performance can be obtained simply by arranging the feeds.

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“…Under the situation, the strength of material on the silicon wafer decreases and the traditional CMP technique would give rise to damages to the Cu interconnects because of the high downforce from the polishing chuck. To overcome the problem, two-step stress free polishing (SFP) technology has been studied in recent years [4], [5]. For the first step, the traditional CMP process is applied to remove a large portion of the Cu film on the silicon wafer till the thickness of Cu film is reduced to about 200 nm ∼ 300 nm.…”

Section: Introductionmentioning

confidence: 99%

Noncontact Thickness Measurement of Cu Film on Silicon Wafer Using Magnetic Resonance Coupling for Stress Free Polishing Application

Wang

Yang

et al. 2019

IEEE Access

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A novel noncontact measurement method based on double-coil sensor is proposed for determining the thickness of copper (Cu) film on the silicon wafer in the process of stress free polishing (SFP). The double-coil sensor consists of two identical coaxial eddy current coils and corresponding auxiliary circuits, where the two coils are excited with the same sinusoidal signal and interact through the magnetic resonance coupling. The induced currents are produced in the Cu film through the electromagnetic coupling between double coils. The interaction equivalent circuit model of Cu film and two coils of double-coil sensor is discussed and the coil design and its lumped parameter extraction are analyzed. The linear relationship between the inductance difference of two coils and lift-off distance change (LODC) is formed and analyzed. By simulating the Cu film with different thicknesses sandwiched between two coils, the distribution and intensity of the magnetic field are presented. The slope of the relationship line between the inductance difference and the LODC is termed as SOR. Dependent on the LODC, the relationship between SOR and thickness of Cu film is extracted. Finally, the double-coil sensor is fabricated and the experiment is implemented. Different specimens with the thickness ranges from 100 to 500 nm are prepared and measured, where the measured maximum relative error is 4.7% and standard errors are between 2 and 13 nm. The experimental results demonstrate that the proposed measurement method is feasible and can confirm the thickness of Cu film on the silicon wafer. It is not only insensitive to the LODC but also can measure the thickness of less than 1 µm for Cu film on the silicon wafer.INDEX TERMS Double-coil sensor, magnetic resonance coupling, Cu film on the silicon wafer, stress free polishing, equivalent circuit model.

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Application of soft landing to the process control of chemical mechanical polishing

Cited by 12 publications

References 10 publications

Y2O3 nanosheets as slurry abrasives for chemical-mechanical planarization of copper

Y2O3 nanosheets as slurry abrasives for chemical-mechanical planarization of copper

Batch Sequencing for Run-to-Run Control: Application to Chemical Mechanical Polishing

Noncontact Thickness Measurement of Cu Film on Silicon Wafer Using Magnetic Resonance Coupling for Stress Free Polishing Application

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