Deciding whether to grow or to divert energy to stress responses is a major physiological trade-off for plants surviving in fluctuating environments. We show that three leucine-rich repeat receptor kinases (LRR-RKs) act as direct ligand-perceiving receptors for PLANT PEPTIDE CONTAINING SULFATED TYROSINE (PSY)-family peptides and mediate switching between two opposing pathways. By contrast to known LRR-RKs, which activate signaling upon ligand binding, PSY receptors (PSYRs) activate the expression of various genes encoding stress response transcription factors upon depletion of the ligands. Loss of PSYRs results in defects in plant tolerance to both biotic and abiotic stresses. This ligand-deprivation–dependent activation system potentially enables plants to exert tuned regulation of stress responses in the tissues proximal to metabolically dysfunctional damaged sites where ligand production is impaired.

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A photoresist removal method for liquid crystal display manufacturing, using highly concentrated ozone gas and water vapor, has been developed. This method overcomes limitations of conventional ozone processing for resist removal, and obtains a resist removal rate over 1 m/min at substrate temperatures lower than 100°C. In our experiment, ozone gas was bubbled into water, and water vapor concentration in the gas phase was controlled by the water temperature (T w ). The influence of treatment parameters, such as substrate temperature (T s ), water vapor concentration, and residence time ͑͒, on the removal rate has been experimentally examined. The treatments were performed at T s ϭ 25-83°C, T w ϭ 27-92.5°C, ϭ 0.5-2 min, ozone concentration ͓O 3 ͔ 0 ϭ 4.2-10.7 vol % ͑90-230 g/m 3 ͒, gas flow rate 1-12.5 slm, and total pressure 100 kPa. The observed removal rate was 1.4 m/min for a sample with a dry etching treatment at T s ϭ 83°C, T w ϭ 90°C, and ͓O 3 ͔ ϭ 10.7 vol %. It was also shown that the difference between the water and the substrate temperatures, T w Ϫ T s , was a critical parameter for determining the removal rate. The removal rate in this process is more than ten times greater than that of the conventional ozone processing, such as ozone gas ashing and ozonized water treatment. A higher removal rate was realized by optimizing the amount of condensed water with respect to a resist oxidation rate and the diffusion rate of ozone into the resist in the water.Surface cleaning and resist stripping processes in semiconductor and liquid crystal display ͑LCD͒ manufacturing use a large amount of chemicals such as sulfuric acid, hydrogen peroxide, and an amine-based organic solvent. An alternative cleaning process without these chemicals could reduce the cost of chemicals and the amount of water for rinsing the substrate after the chemical treatment. A toxic chemicals-free process also has the benefit of lower environmental impact in the recent trend for stricter regulations for environmental protection.Photoresist plays an important role for constructing electric devices precisely, and must be completely removed after an etching and/or ion implantation process. Although oxygen plasma ashing is widely used for removing a hard-baked and/or an ion-implanted resist, several problems occur, such as a dielectric breakdown by charged particles, 1 or nonuniformity of the treatment for 300 mm wafers. A mixture of an amine-based solvent is also used for resist stripping, especially in LCD factories. This method features higher performance with over 1 m/min and a lower process temperature of about 80°C. However, the removal rate is strongly affected by a baking process, and the surface tends to generate thin film residue, which is difficult to rinse off. 2 Ozone is one of the most powerful oxidants, and it has the potential to realize an ecofriendly and economical process for the resist and/or organic residue removal. A resist removal process using ozone gas had already been investigated. In the ozone gas ashing, it is require...

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A method of removing the photoresist using ozone gas with acetic acid vapor has been developed. Glass substrates ͑size 100 ϫ 100 mm 2 ͒ coated with I-line resist were treated under the conditions of substrate temperature, (T S ) 27-50°C; acetic acid vapor, 2-18 vol %; ozone, 0-9.3 vol % ͑0-200 g/m 3 ͒; total gas flow rate, 2 L/min; and gas pressure, 100 kPa. A previous ozone treatment with oversaturated water vapor or sprayed water overcame the limitation of ozone diffusion into the resist by the control of the water film on the resist. In this study, pure acetic acid vapor has been first applied for the resist removal by ozone in order to improve the oxidation rate of the resist, because acetic acid is an inactive solvent in the ozonization, and the solubility of ozone is much higher than water. It was observed that the resist removal rate increased with acetic acid and ozone concentration, and reached at 6 m/min at T S ϭ 50°C, which was about six times greater than that of the previous ozone treatment. Metal corrosion of molybdenum and aluminum electrodes was found negligible during the ozone treatment with acetic acid vapor. The mechanism of resist removal without the metal corrosion by ozone with acetic acid vapor is also discussed, based on the solubility of ozone in acetic acid and the corrosion current in ozonized solutions.