Abstract: Disclosed is a method of manufacturing a capacitive micro-machined ultrasonic transducer (CMUT) device comprising a first electrode (112) on a substrate (110) and a second electrode (122) embedded in an electrically insulating membrane, the first electrode and the membrane being separated by a cavity (130) formed by the removal of a sacrificial material (116) in between the first electrode and the membrane, the method comprising forming a membrane portion (22) on the second electrode and a further membrane portion (24) extending from the membrane portion towards the substrate alongside the sacrificial material, wherein the respective thicknesses the membrane portion and the further membrane portion exceed the thickness of the sacrificial material prior to forming said cavity. A CMUT device manufactured in accordance with this method and an apparatus comprising such a CMUT device are also disclosed.

Abstract: CMUT devices are used in many applications e.g. for ultrasound imaging and pressure measurement. These devices operate by sensing a change in capacitance caused by deflection of a membrane (32) comprising one of a pair of electrodes in the device by ultrasound exposure of or pressure applied on, the membrane. The CMUT device may be susceptible to the effects of changing temperature.

Abstract: The present invention relates to a pre-collapsed capacitive micro-machined transducer cell (10) comprising a substrate (12), and a membrane (14) disposed above a total membrane area (Atotal), wherein a cavity (20) is formed between the membrane (14) and the substrate (12), the membrane comprising a hole (15) and an edge portion (14a) surrounding the hole (15). The cell (10) further comprises a stress layer (17) on the membrane (14), the stress layer (17) having a predetermined stress value with respect to the membrane (14), the stress layer (17) being adapted to provide a bending moment on the membrane (14) in a direction towards the substrate (12) such that the edge portion (14a) of the membrane (14) is collapsed to the substrate (12). The present invention further relates to a method of manufacturing such pre-collapsed capacitive micro-machined transducer cell (10).

Abstract: Disclosed is a method of manufacturing a capacitive micro-machined ultrasonic transducer (CMUT) device comprising a first electrode (112) on a substrate (110) and a second electrode (122) embedded in an electrically insulating membrane, the first electrode and the membrane being separated by a cavity (130) formed by the removal of a sacrificial material (116) in between the first electrode and the membrane, the method comprising forming a membrane portion (22) on the second electrode and a further membrane portion (24) extending from the membrane portion towards the substrate alongside the sacrificial material, wherein the respective thicknesses the membrane portion and the further membrane portion exceed the thickness of the sacrificial material prior to forming said cavity. A CMUT device manufactured in accordance with this method and an apparatus comprising such a CMUT device are also disclosed.

Abstract: The present invention relates to a pre-collapsed capacitive micro-machined transducer cell (10) comprising a substrate (12), and a membrane (14) disposed above a total membrane area ((Atotal), wherein a cavity (20) is formed between the membrane (14) and the substrate (12), the membrane (14) comprising a hole (15) and an edge portion (14a) surrounding the hole (15), the edge portion (14a) of the membrane (14) being collapsed to the substrate (12). The cell further comprises a plug (30) arranged in the hole (15) of the membrane (14), the plug (30) being located only in a subarea (Asub) of the total membrane area (Atotal). The present invention further relates to a method of manufacturing such pre-collapsed capacitive micro-machined transducer cell (10).

Abstract: The present invention relates to a pre-collapsed capacitive micro-machined transducer cell (10) comprising a substrate (12), and a membrane (14) disposed above a total membrane area (Atotal), wherein a cavity (20) is formed between the membrane (14) and the substrate (12), the membrane comprising a hole (15) and an edge portion (14a) surrounding the hole (15). The cell (10) further comprises a stress layer (17) on the membrane (14), the stress layer (17) having a predetermined stress value with respect to the membrane (14), the stress layer (17) being adapted to provide a bending moment on the membrane (14) in a direction towards the substrate (12) such that the edge portion (14a) of the membrane (14) is collapsed to the substrate (12). The present invention further relates to a method of manufacturing such pre-collapsed capacitive micro-machined transducer cell (10).

Abstract: The present invention relates to a pre-collapsed capacitive micro-machined transducer cell (10) comprising a substrate (12), and a membrane (14) disposed above a total membrane area ((Atotal), wherein a cavity (20) is formed between the membrane (14) and the substrate (12), the membrane (14) comprising a hole (15) and an edge portion (14a) surrounding the hole (15), the edge portion (14a) of the membrane (14) being collapsed to the substrate (12). The cell further comprises a plug (30) arranged in the hole (15) of the membrane (14), the plug (30) being located only in a subarea (Asub) of the total membrane area (Atotal). The present invention further relates to a method of manufacturing such pre-collapsed capacitive micro-machined transducer cell (10).

Abstract: CMUT devices are used in many applications e.g. for ultrasound imaging and pressure measurement. These devices operate by sensing a change in capacitance caused by deflection of a membrane (32) comprising one of a pair of electrodes in the device by ultrasound exposure of or pressure applied on, the membrane. The CMUT device may be susceptible to the effects of changing temperature.

Abstract: The invention relates to a method of determining a parameter relating to image blur in an imaging system (IS) comprising the step of illuminating an object having a test pattern (MTP) by means of the imaging system (IS), thereby forming an image of the test pattern. The test pattern (MTP) has a size smaller than the resolution of the imaging system (IS), which makes the image of the test pattern independent of illuminator aberrations. The test pattern (MTP) is an isolated pattern, which causes the image to be free of optical proximity effects. The image is blurred due to stochastic fluctuations in the imaging system and/or in the detector detecting the blurred image. The parameter relating to the image blur is determined from a parameter relating to the shape of the blurred image. According to the invention, resist diffusion and/or focus noise may be characterized. In the method of designing a mask, the parameter relating to the image blur due to diffusion in the resist is taken into account.