A method is provided for subtractively processing a layer of etchable material formed over an electrically conductive surface region of a workpiece. The workpiece is immersed in a liquid solution, generally but not exclusively a conductive solution, that comprises an etchant for the etchable material, so that etching of the etchable material is initiated. An electric circuit is connected to include a control electrode, a reference electrode, and the electrically conductive surface region of the workpiece. The electric circuit is used to monitor the development process dynamically at each of a plurality of intervals during the etching. The etching is terminated when the electrochemical signal satisfies a criterion indicating that the etching is complete.

A reference electrode includes a metal body, a lead disposed within the metal body, an insulator disposed between the lead and the metal body, the insulator including a ceramic material, and a porous metal chamber coupled to the metal body, the lead extending into the porous metal chamber. The porous metal chamber is configured to maintain an electrolyte solution within the porous metal chamber to establish a redox couple with the lead.

Closed-loop systems and methods for controlling pH. The system includes a working electrode, a counter electrode, a reference electrode, a first ion-sensitive field-effect transistor (ISFET), a second ISFET, and an electronic controller. The working electrode, the counter electrode, the reference electrode, and a first sensing terminal of the first ISFET are immersible in an active solution. A second sensing terminal of the second ISFET is immersible in a reference solution. The electronic controller is configured to apply a first amount of current or voltage to the working electrode and determine a differential voltage between the first ISFET and the second ISFET. The electronic controller is also configured to set a second amount of current or voltage to reduce a difference between the differential voltage and a target voltage. The electronic controller is further configured to apply the second amount of current or voltage to the working electrode.

A measuring electrode for chemical liquid in semiconductor process that measures a chemical liquid used for a semiconductor process comprises a first body having a first internal liquid chamber into which a first internal liquid is filled, and a flow tube for a part or all of which a responsive glass is used and that forms a flow channel where a chemical liquid as being a measuring object flows, wherein the flow tube is so arranged to penetrate the first body and the responsive glass makes contact with the first internal liquid in the first internal liquid chamber.

A solid state electrolyte and method of preparation is provided. The solid state electrolyte includes a plasticized polymer matrix with non-dissolved salt crystals embedded in the polymer matrix and wherein the non-dissolved crystals are suitable for dissolving ions in the plasticized polymer. The method of preparation includes dissolving a plasticizer and a polymer matrix in an organic solvent to obtain a plasticized polymer matrix; and mixing the salt crystals with the plasticized polymer matrix, wherein the weight ratio of salt crystals versus plasticizer and polymer matrix and organic solvent is above saturation concentration such that non-dissolved salt crystals are embedded in the plasticized polymer matrix.

A measuring electrode for chemical liquid in semiconductor process that measures a chemical liquid used for a semiconductor process comprises a first body having a first internal liquid chamber into which a first internal liquid is filled, and a flow tube for a part or all of which a responsive glass is used and that forms a flow channel where a chemical liquid as being a measuring object flows, wherein the flow tube is so arranged to penetrate the first body and the responsive glass makes contact with the first internal liquid in the first internal liquid chamber.

The present invention provides an electrolyte measuring device that makes it possible to detect failure in the device with a high degree of accuracy. The electrolyte measuring device has: an ion-selective electrode to which an ion solution including ions is supplied; a reference electrode; a measurement section to measure a potential difference between the ion-selective electrode and the reference electrode; and a current measurement section to measure an electric current flowing in the reference electrode.

An electrochemical sensor is used in a state of being immersed in water to be inspected for water quality inspection. The electrochemical sensor includes a working electrode, a reference electrode, a first counter electrode, and a second counter electrode. The working electrode, the reference electrode, the first counter electrode, and the second counter electrode are electrically isolated from each other.

The present disclosure relates to an amperometric sensor for measuring free chlorine, which sensor comprises:

an elongate body with a tip, wherein the circumferential surface of the body constitutes a counter electrode;

a reference electrode having a silver/silverchloride electrode surface arranged on the tip of the elongate body; and

a working electrode having a gold electrode surface arranged on the tip of the elongate body wherein the gold electrode surface is composed out of a string of electrically connected, spaced apart surface parts.

The invention is directed to apparatus and methods for delivering multiple reagents to, and monitoring, a plurality of analytical reactions carried out on a large-scale array of electronic sensors under minimal noise conditions. In one aspect, the invention provides method of improving signal-to-noise ratios of output signals from the electronic sensors sensing analytes or reaction byproducts by subtracting an average of output signals measured from neighboring sensors where analyte or reaction byproducts are absent. In other aspects, the invention provides an array of electronic sensors integrated with a microwell array for confining analytes and/or particles for analytical reactions and a method for identifying microwells containing analytes and/or particles by passing a sensor-active reagent over the array and correlating sensor response times to the presence or absence of analytes or particles. Such detection of analyte- or particle-containing microwells may be used as a step in additional noise reduction methods.