公开(公告)号：JPH11239296A

公开(公告)日：1999-08-31

申请号：JP31429098

申请日：1998-11-05

Applicant: ST MICROELECTRONICS INC

Inventor： KRAMER ALAN H ,  RAMBALDI ROBERTO ,  TARTAGNI MARCO

IPC: H01L21/66 ,  H04N5/367 ,  H04N5/374 ,  H04N5/335

Abstract: PROBLEM TO BE SOLVED: To speedily and exactly identify a CMOS image array including a pixel provided with a leaky access switch by judging that the selected pixel is provided with the leaky access switch when the output of the pixel is considerably deviated from a scheduled value. SOLUTION: A read line corresponding to a pixel under testing at pressure is reset to a reset voltage and the pixel is held for a time Vtest of a prescribed length. Then, a defect analytic block 24 selects the first pixel to be evaluated. The evaluation includes the determination of an output voltage related to electric charges on that pixel. Typically, this output voltage is converted to a digital signal by an analog/digital converter 18. From this digital value, a logic block 24 determines whether that pixel has real output charges considerably smaller than the scheduled output charges or not. At such a time point, the logic block 24 determines whether than pixel has a leaky access switch or not.

公开(公告)号：JPH11220662A

公开(公告)日：1999-08-10

申请号：JP31416798

申请日：1998-11-05

Applicant: ST MICROELECTRONICS INC

Inventor： GUERRIERI ROBERTO ,  RAMBALDI ROBERTO ,  TARTAGNI MARCO

IPC: H01L27/146 ,  H04N5/363 ,  H04N5/374 ,  H04N5/3745 ,  H04N5/335

Abstract: PROBLEM TO BE SOLVED: To provide a method and device for compensating a kTC noise in the individual pixel of an array for forming a MOS image. SOLUTION: At first, a photo-diode is exposed to a reset voltage, and then a well area is cut from Vdd , and floated so that compensation can be attained. The well is floated so that a kTC charge introduced later (at the end of a reset process) can be re-distributed, and therefore, most of this is stored on a capacitor between the well and a substrate. Afterwards, the well is clamped to the Vdd again, and the noise stored in the capacitor between the well and the substrate is offset. This device is provided with an array constituted of plural pixels, and each pixel is provided with each well. Moreover, access to the power supply source (Vdd ) should be switchable. Therefore, a transistor is provided at the connecting part of each pixel.

公开(公告)号：JPH11252464A

公开(公告)日：1999-09-17

申请号：JP31421198

申请日：1998-11-05

Applicant: ST MICROELECTRONICS INC

Inventor： RAMBALDI ROBERTO ,  TARTAGNI MARCO ,  KRAMER ALAN H

IPC: H01L27/146 ,  H04N5/367 ,  H04N5/374 ,  H04N5/335

Abstract: PROBLEM TO BE SOLVED: To make or correct a defective pixel just after its production and also in its life period by replacing an output of the pixel with an average of outputs of ambient pixels having no defective property and increasing or reducing an output level of the pixel at correction. SOLUTION: An analog signal 16 from separate pixels of an area sensor 12 is outputted via a line 14 and an analog-to digital converter 18 converts it into a digital signal 22. A logical block 24 decides whether or not the pixel has actual output voltage deviated drastically from the output voltage estimated by the pixel from the signal. The block 24 further classifies collapses, and when it determines that the pixel has partially collapsed, it stores that position and the collapsed type in a memory 26. After storing information about the collapsed pixel, it shifts to another pixel in the array and evaluates an output voltages a new current pixel.

公开(公告)号：DE69821442T2

公开(公告)日：2004-12-16

申请号：DE69821442

申请日：1998-10-27

Applicant: ST MICROELECTRONICS INC

Inventor： KRAMER ALAN H ,  RAMBALDI ROBERTO ,  TARTAGNI MARCO

IPC: H01L21/66 ,  H04N5/367 ,  H04N5/374 ,  H04N5/217 ,  H04N3/15

Abstract: Disclosed is a CMOS image sensor that includes circuitry for identifying defective pixels, particularly pixels having leaky access switches. The leaky access switches allow charge to escape from the pixel over a row or column line in a pixel array, thereby corrupting the outputs of an entire row or column of pixels. A disclosed test involves (a) electronically setting a defined charge in a selected pixel of the CMOS imager; (b) reading the output of the selected pixel; and (c) comparing the output of the selected pixel to an expected value based upon the defined charge set in the selected pixels. If the output significantly deviates from the expected value, then the selected pixel is identified as having a leaky access switch. Preferably, a newly fabricated sensor is first tested as described. If such leaky access switch is discovered, the imager is discarded without incurring further manufacturing cost. If, on the other hand, the imager is not found to contain a leaky access switch, it may packaged and then subjected to an optical test.

公开(公告)号：DE69840907D1

公开(公告)日：2009-07-30

申请号：DE69840907

申请日：1998-10-27

Applicant: ST MICROELECTRONICS INC

Inventor： RAMBALDI ROBERTO ,  TARTAGNI MARCO ,  KRAMER ALAN H

IPC: H01L27/146 ,  H04N5/367 ,  H04N5/374

Abstract: Disclosed is a fault tolerant CMOS image sensor that includes circuitry for identifying defective pixels and masking them during image generation. Masking may involve, in one example, replacing the output of a given pixel with an average of the output of surrounding non-faulty pixels. Thus, while image sensors may be fabricated with some number of faulty pixels, the images produced by such sensors will not have undesirable bright or dark spots. The disclosed sensor includes (a) one or more pixels (active or passive) capable of providing outputs indicative of a quantity of radiation to which each of the one or more pixels has been exposed; and (b) one or more circuit elements electrically coupled to the one or more pixels and configured to identify and correct faulty pixels in the CMOS imager. The one more pixels each include a photodiode diffusion formed in a well and a tap to power or ground also formed in the well. The disclosed sensor also identifies pixels that were initially acceptable but later became defective. The newly defective pixels so identified may then be masked to thereby increase the CMOS detector lifetime.

公开(公告)号：DE69821442D1

公开(公告)日：2004-03-11

申请号：DE69821442

申请日：1998-10-27

Applicant: ST MICROELECTRONICS INC

Inventor： KRAMER ALAN H ,  RAMBALDI ROBERTO ,  TARTAGNI MARCO

IPC: H01L21/66 ,  H04N5/367 ,  H04N5/374 ,  H04N5/217 ,  H04N3/15

Abstract: Disclosed is a CMOS image sensor that includes circuitry for identifying defective pixels, particularly pixels having leaky access switches. The leaky access switches allow charge to escape from the pixel over a row or column line in a pixel array, thereby corrupting the outputs of an entire row or column of pixels. A disclosed test involves (a) electronically setting a defined charge in a selected pixel of the CMOS imager; (b) reading the output of the selected pixel; and (c) comparing the output of the selected pixel to an expected value based upon the defined charge set in the selected pixels. If the output significantly deviates from the expected value, then the selected pixel is identified as having a leaky access switch. Preferably, a newly fabricated sensor is first tested as described. If such leaky access switch is discovered, the imager is discarded without incurring further manufacturing cost. If, on the other hand, the imager is not found to contain a leaky access switch, it may packaged and then subjected to an optical test.