Jia Cheng

Investigation on the Development of Knowledge-Based Engineering and its Application in Rapid Design of Process Chamber of IC Equipment

Design capability of process chamber in IC equipment is of great significance for enhancing the core competitiveness of IC industry. The traditional design methodologies adopted by most enterprises are based on experience and the efficiency is not high. As a new intelligent design methodology, Knowledge-based Engineering (KBE) can realize automation of repeat design and complete the product design quickly to meet market demands. In this paper, the background of KBE is discussed systematically and the evolution of different phases of the technology is described. The definitions of KBE given by the relevant institutions from different perspectives are enumerated and the structure framework is shown. KBE is also compared with other design methodologies commonly used. The main technologies of KBE are introduced in detail, and the domestic and overseas application status of KBE is analyzed. In addition, the roles of this methodology in product design are summed up and the future trends are predicted. At the same time, the design demands and tasks of process chamber are confirmed according to the practice of IC equipment. Moreover, current prevalent problems in the field are pointed out, and the basic ideas and the key steps applying KBE to the rapid design of process chamber are put forward.

A novel measuring method of clamping force for electrostatic chuck in semiconductor devices

Electrostatic chucks are one of the core components of semiconductor devices. As a key index of electrostatic chucks, the clamping force must be controlled within a reasonable range. Therefore, it is essential to accurately measure the clamping force. To reduce the negative factors influencing measurement precision and repeatability, this article presents a novel method to measure the clamping force and we elaborate both the principle and the key procedure. A micro-force probe component is introduced to monitor, adjust, and eliminate the gap between the wafer and the electrostatic chuck. The contact force between the ruby probe and the wafer is selected as an important parameter to characterize de-chucking, and we have found that the moment of de-chucking can be exactly judged. Moreover, this article derives the formula calibrating equivalent action area of backside gas pressure under real working conditions, which can effectively connect the backside gas pressure at the moment of de-chucking and the clamping force. The experiments were then performed on a self-designed measuring platform. The de-chucking mechanism is discussed in light of our analysis of the experimental data. Determination criteria for de-chucking point are summed up. It is found that the relationship between de-chucking pressure and applied voltage conforms well to quadratic equation. Meanwhile, the result reveals that actual de-chucking behavior is much more complicated than the description given in the classical empirical formula.

Design space of electrostatic chuck in etching chamber

One of the core semiconductor devices is the electrostatic chuck. It has been widely used in plasma-based and vacuum-based semiconductor processing. The electrostatic chuck plays an important role in adsorbing and cooling/heating wafers, and has technical advantages on non-edge exclusion, high reliability, wafer planarity, particles reduction and so on. This article extracts key design elements from the existing knowledge and techniques of electrostatic chuck by the method proposed by Paul and Beitz, and establishes a design space systematically. The design space is composed of working objects, working principles and working structures. The working objects involve electrostatic chuck components and materials, classifications, and relevant properties; the working principles involve clamping force, residual force, and temperature control; the working structures describe how to compose an electrostatic chuck and to fulfill the overall functions. The systematic design space exhibits the main issues during electrostatic chuck design. The design space will facilitate and inspire designers to improve the design quality and shorten the design time in the conceptual design.

Modeling of Electrostatic Chuck and Simulation of Electrostatic Force

Electrostatic chuck (ESC) is one of the key components in IC manufacturing process, which applies the principle of electrostatic adsorption to clamp the wafer on its surface. In such a system, electrostatic force is considered as one of the most important indicators. The method of modeling and simulation of electrostatic force by COMSOL software is proposed, and the accurateness is validated by comparing the results with those from reference. Then, the simulation of ESC in real manufacturing process is finished using the above method, which focuses on the effects of dielectric materials and voltage on electrostatic force. The research can offer references for the design of ESC, and it has significance to reduce experimental cost and improve the reliability of the equipment.

Experimental Study of SiO2 Sputter Etching Process in 13.56 MHz rf-Biased Inductively Coupled Plasma

Inductively coupled plasma (ICP) has been widely used in semiconductor manufacturing, especially in nanoscale etching and deposition process. It is important to understand the relationship among th...

Prediction of residual clamping force for Coulomb type and Johnsen–Rahbek type of bipolar electrostatic chucks

As a key component in semiconductor manufacturing equipment, electrostatic chuck is conventionally divided into Coulomb type and J–R type depending on the generating mechanism of clamping force. After supply voltage is cut off, residual clamping force usually remains and becomes a serious issue for production efficiency and process reliability. Hence, it is significant to propose a general prediction model and reveal changing laws of residual force with time for both types. This paper establishes an equivalent circuit model for a bipolar electrostatic chuck containing distributed embosses on dielectric layer surface, and deduces a unified form of mathematical expression describing decaying force, which can cover the two types. The obtained equations can also predict steady force in working state. Furthermore, an experimental method for measuring clamping force and de-clamping time is presented. The results indicate relative deviations tend to decrease as voltages rise. It is found that prediction precision for J–R type is lower than that for Coulomb type. Main reasons are explained and relevant mechanisms are discussed. Overall, the calculations coincide with the measurements within an acceptable error range. The comparisons suggest the theoretical model is effective for simulating the characteristics of residual clamping force for both types of electrostatic chucks.

Simulation of Ion Energy Distributions in ICP Reactor with Bias Voltages Using COMSOL

An inductively coupled plasma reactor driven by continuous wave (cw) or pulse source with dc bias is introduced to investigate the plasma parameters and ion energy distributions using COMSOL and compared with experimental results. The results show that with the increase of pressure, the electron density varies from 4.5×1011cm-3 to 16.7×1011cm-3, and electron temperature is in the range of 3.3eV to 3.9eV. For pulsed power, the change of electron temperature is corresponding to the duty cycle of pulse power. With the dc bias, the ion energy peaks shift from 8eV to 19.5eV, and the full width at half maximum (FWHM) of the IEDs varies in the range of 0.5eV to 2.7eV. Finally, application of a synchronous dc bias in the afterglow of pulsed plasma leads to a bi-modal IEDs with a sharper peaks at lower energy during the afterglow and a broader peak at higher energy when the power is on.

Single Photon Counting Discrimination Voltage Software

Because the output signals of photon detectors are scattered under weak light, the single photon counting method uses pulse discrimination technique and digital counting technique to identify and count weak signals. Compared with analog recording technique, the single photon counting technique has the advantages of high signal-to-noise ratio and good anti drift performance. Discrimination voltage is an important part of single photon counting, which will greatly affect the signal to noise ratio (SNR). The selected process of discrimination voltage is very complicated, especially the number of photomultiplier tube spectral analysis system [1], discrimination voltage selection process more time-consuming. This paper presents a software for automatically searching voltage discrimination. The software can automatically measure the discrimination voltage of a plurality of photomultiplier tubes, greatly improve the efficiency and accuracy of screening voltage selection, and verify the effectiveness of the screening voltage software by calculating the signal-to-noise ratio.

Determination of electrostatic force and its characteristics based on phase difference by amplitude modulation atomic force microscopy

Electrostatic force measurement at the micro/nano scale is of great significance in science and engineering. In this paper, a reasonable way of applying voltage is put forward by taking an electrostatic chuck in a real integrated circuit manufacturing process as a sample, applying voltage in the probe and the sample electrode, respectively, and comparing the measurement effect of the probe oscillation phase difference by amplitude modulation atomic force microscopy. Based on the phase difference obtained from the experiment, the quantitative dependence of the absolute magnitude of the electrostatic force on the tip-sample distance and applied voltage is established by means of theoretical analysis and numerical simulation. The results show that the varying characteristics of the electrostatic force with the distance and voltage at the micro/nano scale are similar to those at the macroscopic scale. Electrostatic force gradually decays with increasing distance. Electrostatic force is basically proportional to the square of applied voltage. Meanwhile, the applicable conditions of the above laws are discussed. In addition, a comparison of the results in this paper with the results of the energy dissipation method shows the two are consistent in general. The error decreases with increasing distance, and the effect of voltage on the error is small.

Electron heating enhancement due to plasma series resonance in a capacitively coupled RF discharge: Electrical modeling and comparison to experimental measurements

The electron heating enhancement due to the self-excitation of the plasma series resonance in capacitively coupled plasmas is revisited by a combination of an equivalent circuit model and experiments. To improve the model accuracy, measured voltage waveforms at the powered electrode are used instead of prescribing a sinusoidal voltage supply in series with a bias capacitance. The results calculated from the electrical model are consistent with the experimental measurements performed by a Langmuir probe with verification of a microwave interferometer, at pressures of 0.2 and 0.3 Torr. High harmonics occurring in the discharge currents agree with observations in previous research. The nonlinear plasma series resonance effect is found to have a notable contribution to both ohmic and stochastic heating evaluated by the electron heating efficiencies.