Arabidopsis thaliana CYCLIC NUCLEOTIDE-GATED CHANNEL2 mediates extracellular ATP signal transduction in root epidermis.

Funder: Agence Nationale de la Recherche; Id: http://dx.doi.org/10.13039/501100001665Funder: Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada; Id: http://dx.doi.org/10.13039/501100002790Damage can be signalled by extracellular ATP (eATP) using plasma membrane (PM) receptors to effect cytosolic free calcium ion ([Ca2+ ]cyt ) increase as a second messenger. The downstream PM Ca2+ channels remain enigmatic. Here, the Arabidopsis thaliana Ca2+ channel subunit CYCLIC NUCLEOTIDE-GATED CHANNEL2 (CNGC2) was identified as a critical component linking eATP receptors to downstream [Ca2+ ]cyt signalling in roots. Extracellular ATP-induced changes in single epidermal cell PM voltage and conductance were measured electrophysiologically, changes in root [Ca2+ ]cyt were measured with aequorin, and root transcriptional changes were determined by quantitative real-time PCR. Two cngc2 loss-of-function mutants were used: cngc2-3 and defence not death1 (which expresses cytosolic aequorin). Extracellular ATP-induced transient depolarization of Arabidopsis root elongation zone epidermal PM voltage was Ca2+ dependent, requiring CNGC2 but not CNGC4 (its channel co-subunit in immunity signalling). Activation of PM Ca2+ influx currents also required CNGC2. The eATP-induced [Ca2+ ]cyt increase and transcriptional response in cngc2 roots were significantly impaired. CYCLIC NUCLEOTIDE-GATED CHANNEL2 is required for eATP-induced epidermal Ca2+ influx, causing depolarization leading to [Ca2+ ]cyt increase and damage-related transcriptional response

Spatial origin of the extracellular ATP-induced cytosolic calcium signature in Arabidopsis thaliana roots: wave formation and variation with phosphate nutrition.

Extracellular ATP (eATP) increases cytosolic free calcium ([Ca2+ ]cyt ) as a specific second messenger 'signature' through the plasma membrane DORN1/P2K1 receptor. Previous studies revealed a biphasic signature in Arabidopsis thaliana roots that is altered by inorganic phosphate (Pi) deprivation. The relationship between the two phases of the signature and possible wave formation have been tested as a function of Pi nutrition. The bioluminescent aequorin and intensiometric GCaMP3 reporters were used to resolve the spatial origin of the eATP [Ca2+ ]cyt signature in Arabidopsis root tips. Application of eATP only to the root apex allowed [Ca2+ ]cyt wave resolution without the confounding effects of eATP delivery by superfusion. The first apical millimetre of the root generates the first [Ca2+ ]cyt increase by eATP, regardless of nutritional status. The second increase occurs sub-apically in the root hair zone, has some autonomy and is significantly reduced in Pi-starved roots. A significant component of the Pi-replete signature does not require DORN1/P2K1, but Pi-starved roots appear to have an absolute requirement for that receptor. Application of eATP specifically to the root apex provides evidence for cell-to-cell propagation of a [Ca2+ ]cyt wave that diminishes sub-apically. The apex maintains a robust [Ca2+ ]cyt increase (even under Pi starvation) that is the basis of a propagative wave, with implications for the ability of the root's eATP signalling systems to signal systemically. Partial autonomy of the sub-apical region may be relevant to the perception of eATP from microbes. eATP-induced [Ca2+ ]cyt increase may not have always have an obligate requirement for DORN1/P2K1

100 nm half–pitch double exposure KrF lithography using binary masks

In this paper we investigate the process margin for the 100nm half - pitch double exposure KrF lithography using binary masks for different illumination settings. The application of Double Exposure Lithography (DEL) would enlarge the capability of 248 nm exposure technique to smaller pitch e.g. for the integration of dedicated layers into 0.13 μm BiCMOS with critical dimension (CD) requirements exceeding the standard 248 nm lithography specification. The DEL was carried out with a KrF Scanner (Nikon S207D, NALens = 0.82) for a critical dimension (CD) of 100nm half pitch. The chemical amplified positive resists SL4800 or UV2000 (Rohm & Haas) with a thickness of 325nm were coated on a 70 nm AR10L (Rohm & Haas) bottom anti-reflective coating (BARC). With a single exposure and using binary masks it is not possible to resolve 100nm lines with a pitch of 200 nm, due to the refraction and the resolution limit. First we investigated the effect of focus variation. It is shown that the focus difference of 1st and 2nd exposure is one critical parameter of the DEL. This requires a good focus repeatability of the scanner. The depth of focus (DOF) of 360 nm with the coherence parameter σ = 0.4 was achieved for DEL with SL4800 resist. The influence of the better resist resolution of UV2000 on the process window will be shown (DOF = 460 nm). If we change the focus of one of the exposures the CD and DOF performance of spaces is reduced with simultaneous line position changing. Second we investigated the effect of different illumination shapes and settings. The results for conventional illumination with different values for σ and annular illumination with σinner = 0.57 and σouter = 0.85 will be shown. In summary, the results show that DEL has the potential to be a practical lithography enhancement method for device fabrication using high NA KrF tool generation

Optical proximity correction for 0.13 m SiGe:C BiCMOS

We present results for a rule based optical proximity (RB-OPC) and a model based optical proximity correction (MB-OPC) for 0.13 m SiGe:C BiCMOS technology. The technology provides integrated high performance heterojunction bipolar transistors (HBTs) with cut-off frequencies up to 300 GHz. This requires an optical proximity correction of critical, layers with an excellent mask quality. This paper provides results of the MB-OPC and RB-OPC using the Mentor Calibre software in comparison to uncorrected structures (NO-OPC). We show RB- and MB-OPC methods for the shallow trench and gate layer, and the RB-OPC for the emitter window-, contact- and metal layers. We will discuss the impact of the RB- and MB-OPC rules on the process margin and yield in the 0.13 m SiGe:C BiCMOS technology, based on CD-SEM data obtained from the evaluation of the RB- and MB-OPC corrected SRAM cells

Optical proximity correction for 0.13 um SiGe:C BiCMOS

We present results for a rule based optical proximity (RB-OPC) and a model based optical proximity correction (MB-OPC) for 0.13 μm SiGe:C BiCMOS technology. The technology provides integrated high performance heterojunction bipolar transistors (HBTs) with cut-off frequencies up to 300 GHz. This requires an optical proximity correction of critical layers with an excellent mask quality. This paper provides results of the MB-OPC and RB-OPC using the Mentor Calibre software in comparison to uncorrected structures (NO-OPC). We show RB- and MB-OPC methods for the shallow trench and gate layer, and the RB-OPC for the emitter window-, contact- and metal layers. We will discuss the impact of the RB- and MB-OPC rules on the process margin and yield in the 0.13 μm SiGe:C BiCMOS technology, based on CD-SEM data obtained from the evaluation of the RB- and MB-OPC corrected SRAM cells

Double exposure technology for KrF lithography

The application of Double Exposure Lithography (DEL) would enlarge the capability of 248 nm exposure technique to smaller pitch. We will use the DEL for the integration of critical layers for dedicated applications requiring resolution enhancement into 0.13 μm BiCMOS technology. In this paper we present the overlay precision and the focus difference of 1st and 2nd exposure as critical parameters of the DEL for k1 ≤ 0.3 lithography (100 nm half pitch) with binary masks (BIM). The realization of excellent overlay (OVL) accuracy is a main key of double exposure and double patterning techniques. We show the DEL requires primarily a good mask registration, when the wafer stays in the scanner for both exposures without alignment between 1st and 2nd exposure. The exposure tool overlay error is more a practical limit for double patterning lithography (DPL). Hence we prefer the DEL for the resolution enhancement, especially if we use the KrF high NA lithography tool for 130 nm generation. Experimental and simulated results show that the critical dimension uniformity (CDU) depends strongly on the overlay precision. The DEL results show CDU is not only affected by the OVL but also by an optical proximity effect of 1st and 2nd exposure and the mask registration. The CD uniformity of DEL demands a low focus difference between 1st and 2nd exposure and therefore requires a good focus repeatability of the exposure tool. The Depth of Focus (DOF) of 490 nm at stable CD of lines was achieved for DEL. If we change the focus of one of the exposures the CD-focus performance of spaces was reduced with simultaneous line position changing. CDU vs. focus difference between 1st and 2nd exposure demands a focus repeatability <100 nm for the exposure tool. Summary, the results show DEL has the potential to be a practical lithography enhancement method for device fabrication using high NA KrF tool generation