Patent Application
20210278382
This application claims priority to and the benefit of Taiwan Patent Application No. 109202472 filed on Mar. 5, 2020, which is incorporated by reference herein in its entirety.
This disclosure relates to a measurement apparatus for gas sensor, in particular, to a measurement apparatus of measuring a gas-sensing cell in its wafer form.
To test the function of a gas sensor, the gas sensor has to be operated under an environment having a specific gas with a certain concentration. In general, the testing is performed after the gas sensor is packaged.
However, as realized by the inventor, generally speaking, in the manufacturing process of a semiconductor type gas sensor-(e.g., a micro-electromechanical system (MEMS) type), a piece of wafer may include more than thousands or ten thousands of uncut gas-sensing cells. The uncut gas-sensing cells have to be separated from each other and packaged. The foregoing tests are then applied to each of the packaged gas-sensing cells. As a result, the testing procedure is time-consuming. Moreover, as the defects of the gas-sensing cells cannot be repaired by subsequent cutting and packaging procedures, the subsequent cutting and packaging procedures applied to the defected cells are time consuming and increases the production costs.
In view of this, according to one or some embodiments of the instant disclosure, a measurement apparatus for gas sensor is provided, and the measurement apparatus is adapted to measure gas-sensing cells in their wafer form.
In one embodiment, a measurement apparatus for gas sensor includes a wafer-holding module and a vacuuming module. The wafer-holding module includes a holding carrier configured to hold a wafer. The holding carrier includes an uppermost surface, a bottommost surface, an outermost side surface between the uppermost surface and the bottommost surface, a plurality of grooves, and a plurality of through holes. The wafer includes at least one uncut gas-sensing cell. At least one gas-sensing cell has a cavity located right above at least one of the grooves. The grooves extend downwardly from the uppermost surface and not reaching the bottommost surface. The grooves extend outwardly in a horizontal direction to expose out of the outermost side surface. The vacuuming module couples to the plurality of through holes, and is configured to attach the gas-sensing cell to the holding carrier.
Detailed description of the characteristics and the advantages of the instant disclosure are shown in the following embodiments. The technical content and the implementation of the instant disclosure should be readily apparent to any person skilled in the art from the detailed description, and the purposes and the advantages of the instant disclosure should be readily understood by any person skilled in the art with reference to content, claims, and drawings in the instant disclosure.
The disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus not limitative of the disclosure, wherein:
Embodiments are provided, along with the figures, for facilitating the descriptions of the instant disclosure. It is understood that, a plenty of details are provided for readers to understand the disclosure; however, the inventions of the disclosure are still implementable in the premise that some or all of the details are omitted. In all the figures, same reference numbers designate identical or similar elements. It is worthy to mention that, the figures are provided for illustrative purposes, and are not used to indicate the actual size or number of the element. Moreover, some details may be omitted in the drawings for the sake of clarity for the drawings.
Please refer to
The holding carrier 10 has an uppermost surface 100, a bottommost surface, an outermost side surface 102, at least one groove 104, and at least one through hole 106. The outermost side surface 102 connects the uppermost surface 100 and the bottommost surface. In this embodiment, the profile of the holding carrier 10 is a circle, the uppermost surface 100 is a circular plane, and the outermost side surface 102 surrounds the uppermost surface 100 to form an annular side surface, but embodiments are not limited thereto.
The grooves 104 are located on the uppermost surface 100 and recessed downwardly, and the grooves 104 are extending outwardly and horizontally to the outermost side surface 102 in communication with outside environments. In other words, the grooves 104 are open channels, rather than hermetic ones. The grooves 104 are extending downwardly from the uppermost surface 100 and not reaching the bottommost surface. Moreover, the grooves 104 are arranged to pass through the bottom portions of the gas-sensing cells W1, W2, W3, W4, so that the cavities W10 inside the gas-sensing cells W1, W2, W3, W4 are respectively in communication with the grooves 104. Hence, the cavities W10 inside the gas-sensing cells W1, W2, W3, W4 are in communication with the outside environments. The gas pressure among the cavities W10, the grooves 104, and the outside environment can be balanced. In one embodiment, the grooves 104 are stripe trenches, but embodiments are not limited thereto.
The through holes 106 are located on the uppermost surface 100 of the holding carrier 10 and through the holding carrier 10 but not in communication with outside environment. In one embodiment, the shape of the cross section area of the through hole 106 is circular or rectangular, but embodiments are not limited thereto. The vacuuming module 2 may be in direct or indirect communication with the through holes 106. A negative pressure is generated in the through hole 106 through the vacuuming module 2, so that annular walls W12 of the gas-sensing cells W1, W2, W3, W4 are sucked on the holding carrier 10. In one embodiment, the vacuuming module 2 has a pump and a vacuum pipe assembly, but embodiments are not limited thereto.
Accordingly, when the gas-sensing cells W1, W2, W3, W4 of the wafer W are placed on the holding carrier 10, negative pressures are formed in the through holes 106 due to the suction caused by the vacuuming module 2, and the annular walls W12 of the gas-sensing cells W1, W2, W3, W4 are sucked on the holding carrier 10. Hence, the wafer W can be held on the holding carrier 10. Moreover, the gas pressures within the cavities W10 of the gas-sensing cells W1, W2, W3, W4 and outside the environment can be adjusted to be balanced or close to each other through the grooves 104 in communication the cavity and the outside environment. As a result, the cavities W10 can be immune from becoming hermetic spaces which have different gas pressures from the exterior pressure. The pressure difference can further bring damage(s) and failure(s) to the gas-sensing cells W1, W2, W3, W4. Moreover, a more accurate measurement result can be obtained by testing the gas-sensing cells W1, W2, W3, W4 under a condition of balanced or quasi-balanced pressure.
Furthermore, according to one or some embodiments of the instant disclosure, the measurement apparatus for gas sensor is adapted to perform a wafer-scale measurement to the gas-sensing cells which are not cut and not packaged. Hence, the characteristic parameters and the defect-free rate of the gas-sensing cells may be measured at the wafer stage, and the defective cells can be filtered and do not need to be performed subsequent procedures. Therefore, the overall manufacturing costs can be effectively reduced and the product reliability can be ensured.
In at least one embodiment, a surface area of the holding carrier 10 is greater than that of an object to be measured; for example, the surface diameter of the holding carrier 10 may be, but not limited to, greater than 300 mm. In one embodiment, the arrangement of the through holes 106 and the grooves 104 are staggered on the holding carrier 10. For example, the grooves 104 of the holding carrier 10 may be arranged in a two-dimensional array, and the through holes 106 are arranged at center portions of plural rectangular regions enclosed by the two-dimensional array.
In one embodiment, as shown in
In another embodiment, with reference to
The temperature sensing unit 14 is coupled to the holding carrier 10. The temperature sensing unit 14 is adapted to sense the temperature of the holding carrier 10 to obtain a surface temperature of the uppermost surface 100 and output a corresponding temperature parameter/data. The temperature controlling unit 16 is electrically connected to the heating unit 12 and the temperature sensing unit 14. The temperature controlling unit 16 receives the temperature data measured by the temperature sensing unit 14 and compares the temperature data with a predetermined temperature data. When the surface temperature of the uppermost surface 100 is lower than the predetermined temperature data which is suitable for the operation of the gas-sensing cells W1, W2, W3, W4, the temperature controlling unit 16 outputs a temperature rising signal to the heating unit 12, so that the heating unit 12 provides more heats to the holding carrier 10. Conversely, when the surface temperature of the uppermost surface 100 is greater than the predetermined temperature data which is suitable for the operation of the gas-sensing cells W1, W2, W3, W4, the temperature controlling unit 16 outputs a temperature deceasing signal to the heating unit 12, so that the operation of the heating unit 12 is paused.
Based on the foregoing embodiment, the measurement apparatus for gas sensor has the wafer-holding module 1 integrated with a thermal control device. Hence, the thermal control device heats the wafer W to the operation temperature of the gas-sensing cells W1, W2, W3, W4 for measuring the gas-sensing cells W1, W2, W3, W4, and adjusting the heating temperature by monitoring the temperature of wafer W.
In one embodiment, with reference to
The circuit board 40 has a control circuit 400, a hole 402, and a heat conduction ring 404. The circuit board 400 is electrically connected to the pin structure 44, and the control circuit 400 is adapted to process the electrical signals measured by the pin structure 44. From a top perspective view, the heat conduction ring 404 encloses the hole 402 and is connected to the circuit board 40. The heat conduction ring 404 is adapted to take the heats on the circuit board 40 away from the probe module 4.
The heat conduction ring 404 of the circuit board 40 is electrically insulated and has a good thermal conductivity. For example, the heat conduction ring 404 may be, but not limited to, made of an epoxy resin. In an example, it is understood that the operation temperature of the cells to be measured (e.g., the gas-sensing cells W1, W2, W3, W4) is near to 200 Celsius degrees, and the circuit board 40 of the probe module 4 is a printed circuit board (PCB) which can sustain a temperature not greater than about 150 Celsius degrees. The heats come from the pin structure 44 can be transmitted away from the circuit board 40 by the heat conduction ring 404, so that the circuit board 40 can be protected from being damaged by the high temperature and the probe module 4 can be kept to be operated normally.
In another embodiment, the measurement apparatus for gas sensor can be applied in measuring gases, such as hydrogen (H2), hydrogen sulfide (H2S), ammonia (NH3), ethanol (C2H5OH), and carbon monoxide (CO). The measurement apparatus may be used along with a flow controller to adjust the concentration of the testing gas. The gas inlet channel 42 is in communication with the hole 402, and the gas inlet channel 42 is adapted to allow the testing gas to flow into the measurement apparatus. The testing gas flows toward the holding carrier 10 through the hole 402. After the testing gas reacts with the sensing material on the surfaces of the gas-sensing cells W1, W2, W3, W4, the gas-sensing cells W1, W2, W3, W4 can react with the testing gas and output the characteristic parameters of the testing gas. Accordingly, the characteristic parameters of the measured gas-sensing cells W1, W2, W3, W4 are compared with the reference parameters of a standard sample to determine the quality of the gas-sensing cells W1, W2, W3, W4.
As shown in
Based on the foregoing embodiment, the measurement apparatus for wafer-scale gas sensor can detect several cells at one time. Therefore, a high quality electrical property measurement and quality sorting can be provided, and the measurement efficiency can be improved.
In one embodiment, the probes 440 may be made of a tungsten material, which is suitable for testing the corrosive gas or the wafer W with a high operation temperature. In another embodiment, each of the probes 440 further includes a protection layer, and the protection layer is made of a fluoro material for isolating the corrosive gas.
Based on the above, according to one or some embodiments of the instant disclosure, a measurement apparatus for gas sensor is suitable for measuring the wafer-type gas sensor cells by using the through holes 106 to generate a vacuum suction force to hold the wafer-type gas-sensing cells. The grooves 104 are used to balance the internal gas pressures of the gas-sensing cells and the outside environmental. Hence, the measurement apparatus can get the accurate measurement results. Accordingly, the performance of the gas-sensing cells can be measured at the wafer stage in advance, and the data can be feedback to the research and development engineers. Therefore, the time duration and the cost for research and development can be reduced. Moreover, regarding the production, since the electrical property of the cells can be detected at the wafer stage in advance, the defect cells can be prevented from processing subsequent procedures. Therefore, the overall manufacturing costs can be effectively reduced, making the product more competitive.
While the instant disclosure has been described by the way of example and in terms of the preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 109202472 | Mar 2020 | TW | national |
