Double Comb-type Antenna Research Articles

Study of Internal Linear Inductively Coupled Plasma Source for Ultra Large-Scale Flat Panel Display Processing

An internal-type linear inductive antenna, which is referred to as “double comb-type antenna”, was used as a large-area inductively coupled plasma (ICP) source with a substrate area of 2,300 mm × 2,000 mm. The characteristics of the ICP source were investigated for potential applications to flat panel display (FPD) processing. The source showed higher power transfer efficiency at higher RF power and higher operating pressures. The power transfer efficiency was approximately 88.1% at 9 kW of RF power and a pressure of 20 mTorr Ar. This source showed increasing plasma density and improved plasma uniformity with increasing RF power at a given operating pressure. A plasma density >1.5 × 1011/cm3 and a plasma uniformity of approximately 11% was obtained at 9 kW of RF power and 15 mTor Ar using this internal ICP source, which is applicable to FPD processing.

Uniformity of internal linear-type inductively coupled plasma source for flat panel display processing

The variation in plasma uniformity over an extremely large size inductively coupled plasma (ICP) source of 2750×2350mm2 was examined. An internal linear-type antenna called “double comb-type antenna” was used as the ICP source. A plasma density of ∼1.4×1011∕cm3 could be obtained at 5mTorr Ar by applying 10kW rf power to the source at a frequency of 13.56MHz. An increase in rf power from 1to10kW improved the plasma uniformity over a substrate area of 2300×2000mm2 from 18.1% to 11.4%. The improvement in uniformity of the internal ICP source was attributed to the increase in plasma density near the wall.

Plasma Characteristics and Antenna Electrical Characteristics of an Internal Linear Inductively Coupled Plasma Source with a Multi-Polar Magnetic Field

The development of a large-area plasma source with high density plasmas is desired for a variety of plasma processes from microelectronics fabrication to flat panel display device fabrication. In this study, a novel internal-type linear inductive antenna referred to as “double comb-type antenna” was used for a large-area plasma source with the substrate area of 880 mm × 660 mm and the effect of plasma confinement by applying multi-polar magnetic field was investigated. High density plasmas on the order of 3.2 × 1011 cm−3 which is 50% higher than that obtained for the source without the magnetic field could be obtained at the pressure of 15 mTorr Ar and at the inductive power of 5,000 W with good plasma stability. The plasma uniformity <3% could be also obtained within the substrate area. When SiO2 film was etched using the double comb-type antenna, the average etch rate of about 2,100 A/min could be obtained with the etch uniformity of 5.4% on the substrate area using 15 mTorr SF6, 5,000 W of rf power, and −34 V of dc-bias voltage. The higher plasma density with an excellent uniformity and a lower rf antenna voltage obtained by the application of the magnetic field are related to the electron confinement in a direction normal to the antenna line.

Characteristics of Inductive Coupled Plasma with Internal Linear Antenna Using Multi-Polar Magnetic Field for FPD Processing

An internal linear inductive antenna referred to as “double comb-type antenna” was used for a large-area plasma source with the substrate area of 880mm × 660mm and the effects of multi-polar magnetic field applied by inserting permanent magnets parallel to the linear internal antennas on the plasma characteristics were investigated. By applying the multi-polar magnetic field, high density plasmas on the order of 3.2 × 1011-3 which is 50% higher than that obtained for the source without multi-polar magnetic field could be obtained at the RF power of 5000W. Also stable impedance matching with a low Q-factor of the plasma system could be obtained. The application of the multi-polar magnetic field not only increased the plasma density but also improved the plasma uniformity (less than 3%) within the 880mm × 660mm processing area.

Effect of dual frequency on the plasma characteristics in an internal linear inductively coupled plasma source

An internal-type linear inductive antenna, referred to as a “double comb-type antenna,” was used as a large area plasma source with a substrate size of 880×660mm2 (fourth generation glass size). The effects of the dual frequency (2 and 13.56MHz) radio frequency (rf) power to the antenna as well as the power ratio on the plasma characteristics were investigated. High-density plasma on the order of 1.7×1011cm−3 could be obtained with a dual frequency power of 5kW (13.56MHz) and 1kW (2MHz) at a pressure of 15mTorr Ar. This plasma density was lower than that obtained for the double comb-type antenna using a single frequency alone (5kW, 13.56MHz). However, the use of the dual frequency with a rf power ratio of approximately 1(2MHz):5(13.56MHz) showed better plasma uniformity than that obtained using the single frequency. Plasma uniformity of 6.1% could be obtained over the substrate area. Simulations using FL2L code confirmed the improvement in the plasma uniformity using the dual frequency to the double comb-type antenna.

Plasma and antenna characteristics of a linearly extended inductively coupled plasma system using multi-polar magnetic field

A novel internal-type linear inductive antenna, referred to as a “double comb-type antenna”, was used as a large-area plasma source with a substrate area of 880 mm × 660 mm. This study investigated the effect of a multi-polar magnetic field on plasma confinement. High density plasma in the order of 3.2 × 10 11 cm − 3 , which is 50% higher than that obtained for a source without a magnetic field, with good plasma stability was obtained at a pressure of 15 mTorr Ar and an RF power of 5000 W. Plasma uniformity < 3% within the substrate area was also obtained.

Effective plasma confinement by applying multipolar magnetic fields in an internal linear inductively coupled plasma system

A novel internal-type linear inductive antenna referred to as “double comb-type antenna” was used for a large-area plasma source with the substrate area of 880mm×660mm and the effect of plasma confinement by applying multi-polar magnetic field was investigated. High-density plasmas on the order of 3.18×1011cm−3, which is 50% higher than that obtained for the source without the magnetic field, could be obtained at the pressure of 15mTorr Ar and at the inductive power of 5000W with good plasma stability. The plasma uniformity less than 3% could also be obtained within the substrate area. When SiO2 film was etched using the double comb-type antenna, the average etch rate of about 2100Å∕min could be obtained with the etch uniformity of 5.4% on the substrate area using 15mTorr SF6, 5000W of rf power, and −34V of dc bias voltage.

Low impedance antenna arrangement of internal linear ICP source for large area FPD processing

In this study, two different types of internal linear antennas were compared and their characteristics were investigated for a large area ICPs applied to FPD processing. The measured plasma density for the double comb-type antenna was higher than 2 × 10 11/cm 3 and the etch rates of photoresist and SiO 2 at 5000 W rf power, − 60 V of dc-bias voltage, and 15 mTorr SF 6 were about 3000 Å/min and 1500 Å/min. The etch non-uniformity of the photoresist within the substrate was about 7% at 5000 W of rf power.

Plasma and impedance characteristics of internal linear antennas for flat panel display applications

The trend towards large area substrates motivated by flat panel display industries has accelerated the development of the large size plasma sources. In this study, two types of linear internal-type inductively coupled plasma source enabling the production of large area high density plasma, that is, a serpentine-type and a double comb-type were investigated and their characteristics of plasma and impedance were compared. The use of the double comb-type antenna showed higher root-mean-square current, higher plasma density, and lower antenna resistance compared to that of the serpentine-type antenna as the rf power increased from 600 to 5000 W. By the application of 5000 W of rf power with 2 Pa Ar, a high plasma density of 2.2 × 10 11/cm 3 with the plasma uniformity of 8% for the size of 880 × 680 mm could be obtained for the double comb-type antenna. The improved characteristics of the double comb-type antenna compared with the serpentine-type antenna appear to be from the higher inductive coupling and less standing wave effect compared to the serpentine-type antenna.