JP2013165471A - Multiphase drive image signal integration element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a CCD driven by eight phase drive and four phase drive, or six phase drive and three phase drive by folding it into a pixel in an accordion type.SOLUTION: When a substantial change of a transfer direction of an electric charge in a CCD transfer path by 180 degrees is defined as "folding", and the CCD transfer path divided by two continuous foldings is defined as "divided transfer path", two wiring lines crossing the transfer direction are provided for one transfer electrode on the individual transfer electrode on each divided transfer path. One of the wiring lines is electrically bonded with the transfer electrode on the transfer path just before each folding. The other one of the wiring lines is electrically bonded with the electrode on the transfer path just after the folding, and the number of transfer electrodes on one divided transfer path is a multiple of K (K is integer of 3 or more).

Description

  Although the signal is weak, it is suitable for high speed imaging with reproducibility. Moreover, it is suitable as an apparatus for high-function mass spectrometry using information on the intensity, arrival position, and arrival time of charged particles.

  A sensor in which each pixel includes a plurality of image signal memory elements that record an image signal generated by the photoelectric conversion unit of the pixel is referred to as a “pixel unit recording type imaging device”.

  In the pixel unit recording type image pickup device, an operation of recording an image signal generated in each pixel at the time of photographing in one of the memory elements of the image signal memory area included in the pixel is simultaneously performed in all the pixels. At this time, one image is captured by the sum of the time required to collect the image signal generated at each pixel at each pixel and the time required to transfer the collected image signal to one of the image signal memory elements included in the pixel. The The time for collecting the generated image signal can be shortened to a minimum of about 1 nanosecond. The time taken to transfer the collected image signals to one of the memories can be shortened to a minimum of a few nanoseconds. Therefore, the sum of these times can be shortened to about 10 nanoseconds.

  For continuous shooting, this process is repeated while sequentially changing the image signal memory elements recorded in each pixel. Therefore, the frame interval can be shortened to about 10 nanoseconds in the pixel unit recording type imaging device. Since the photographing speed is the reciprocal of the frame interval, the photographing speed can be increased to about 100 million frames / second by the photographing apparatus provided with the pixel unit recording type imaging device.

  With this technique, the same number of images as the number of memory elements of the image signal memory included in each pixel can be continuously photographed.

  Of the pixel-unit recording type imaging device, an element including a large number of image signal memories in each pixel is referred to as an “in-pixel recording type imaging device”. The in-pixel recording type image pickup device and the element for recording the image signal generated by each pixel around each pixel are collectively referred to as “pixel peripheral recording type image pickup device”.

  In addition to the pixel peripheral recording type, the pixel unit recording type imaging element includes an “element peripheral recording type” that records the image signal generated by each pixel outside the light receiving surface on the same chip of the imaging element, and signal charge generation In addition, there is a “stacked type” in which another memory chip is bonded under a chip for collecting electric charges. The stacked pixel unit recording type imaging device is also an in-pixel recording type.

  The recording method may be either an analog type or a digital type, but the analog type is advantageous in terms of shooting speed and compactness of the pixel size as much as the digitization of the signal is unnecessary. The digital type is advantageous in terms of signal holding time and ease of post-digital processing of signals.

  As shown in FIG. 1, the inventors of the present invention are connected to a photodiode (in the case of front-side illumination) or a charge collection gate (in the case of back-side illumination) 100 of each pixel, and are shifted by a small angle with respect to the pixel grid. Invented the pixel peripheral recording type image pickup element 102 using a linear CCD 101 extending in the direction (hereinafter referred to as “an oblique linear CCD”) as a memory (see Patent Document 1 and Non-Patent Document 1).

  Non-Patent Document 1 shows an example of an oblique linear CCD pixel peripheral recording type imaging device disclosed in Patent Document 1. With this element, an extremely high speed of 16 million sheets / second was realized. Moreover, since this element is a back-illuminated type (see Patent Document 2), ultra-high sensitivity was achieved at the same time.

  In the CCD, the fact that the charge transfer direction changes substantially 180 degrees is defined as “folding”.

  As shown in FIG. 2, a circular CCD 103 can be made by folding a linear CCD into two and connecting the start and end. This is connected to the photodiode 104, and this combination is formed in one pixel.

  When a circulating CCD is built in each pixel and used as an image signal memory, continuous image signals obtained in a large number of shooting experiments can be added in the CCD memory in each pixel without being read out of the image sensor. Yes (see Patent Document 4).

  Patent Document 3 discloses a technique in which a CCD is folded in two and changed in direction to be a circulation type.

  For example, two circulating CCDs 105 are shown in FIG. One circulating CCD is built in each pixel. Since the example of FIG. 3 is a four-phase drive CCD, the four electrodes 106 form one analog memory 107, and five image signals can be stored in one circulating CCD. Accordingly, five continuous image signals can be recorded in each pixel.

  After taking five consecutive images generated by the photodiode 104 in the first shooting, and then shooting the next five consecutive images without reading out the image signal to the outside of the image sensor, the first shooting is performed. The image signal shot in the second shooting is automatically added to the image signal recorded in the order of shooting.

  By repeating this, if the high-speed phenomenon has strong reproducibility, even if the signal intensity is weak, the S / N ratio is improved by extracting and integrating the signals, and necessary image information is extracted. be able to. Such a sensor is referred to as an “image signal integrating element”.

  In order to increase the number of continuous shots, a long single CCD is folded many times instead of once (hereinafter referred to as “multiple folding CCD”), and the end and the start are joined to form a loop to circulate multiple folding CCD What should I do? Multiple folding CCDs require at least three foldings.

  In order to build a circular multi-folding CCD in a small area of pixels, the electrode structure and the metal wiring structure for sending drive voltage must be as simple as possible.

  There has been a proposal for a long time to make a multi-function CCD in each pixel to make a high-performance CCD. For example, Non-Patent Document 2 discloses an image sensor 108 having a folding CCD shown in FIG. At the same time, other similar pixel structures were presented (documents not shown). However, there is no example in which such a multiple folding CCD is realized. The reason is that with the technical capabilities at the time of the invention, it has a complex pixel structure (electrode structure and wiring structure) like a multi-folding CCD, fits in a small area called a pixel, and realizes a low noise CCD required for an image sensor. Because it was difficult to do.

  Although the structure presented in FIG. 3 is a relatively simple structure, it cannot be folded multiple times. Improvements for further simplification are necessary to achieve practical multiple folding.

  Since there was no CCD multiple folding technology, in order to realize ultrahigh-speed shooting using a practical pixel unit recording type imaging device, the invention of the oblique linear CCD pixel peripheral recording type imaging device of FIG. It was. With this device, since image signals are only transferred linearly on a slightly oblique CCD memory during shooting, ultra-high-speed shooting can be realized with a very simple structure.

  A device was required to read out the signal to the outside of the image sensor. However, in the pixel unit recording type image pickup device, signal readout is performed after photographing, so that it can be read out slowly using a slightly complicated structure.

  On the other hand, the inventors of the present invention have a technique for realizing an “accordion type CCD” in which the upper CCD 119 and the lower CCD 120 are both multi-folded CCDs as shown in FIG. Invented. By becoming an accordion type, it becomes a multiple folding and a circulating multiple folding CCD 602 in which the start and end of the CCD are joined, and it becomes a practical image signal integrating element.

  This folding technique is illustrated in FIG. That is, the inventors have invented a technique for folding a four-phase drive CCD using a set of two layers of polysilicon electrodes 110/111 and 112/113 intersecting each other. (Patent Document 5).

  FIG. 7 shows the metal wiring of the folding CCD having the cross electrode shown in FIG. Four-phase driving requires four types of metal wirings having different driving voltage waveforms, and the metal wiring is also such a simple parallel wiring. The metal wiring and the polysilicon electrode are electrically joined via the contact point 118.

  As described above, when the crossing electrodes are used, the folding CCD can be driven at high speed only by placing the parallel driving voltage sending wirings 114 to 117 made of only one metal layer on each electrode.

  If this technique is used, an accordion-type CCD in which both the upper side 119 and the lower side 120 are folded as shown in FIG. 5 can be easily constructed.

  This will be described. As shown in FIG. 5 and FIG. 6, the horizontal transfer direction is reversed in the facing portion 200 of the folding of the accordion CCD. In the facing part, the upper and lower transfer paths are isolated by a horizontal channel stop 121. Since the polysilicon electrodes intersect across the horizontal channel stop, the transfer direction above and below the horizontal channel stop is automatically reversed. Accordingly, the structure of the folding opposing portion is the same as that of the normal transfer path portion, and the structure for changing the transfer direction by the CCDs above and below the opposing portion is not required.

  If only the lower side 120 of the folding CCD in FIG. 5 is folded and the upper side 119 is connected by a horizontal CCD to form a circulation type without using the accordion type, the shape of the transfer path is apparently simple (not shown). However, in order to drive the horizontal CCD, it is necessary to place four additional drive metal wirings on the horizontal CCD, and the wiring structure is actually more complicated than that of the accordion type.

  Although the folding CCD shown in FIG. 6 is a four-phase driving CCD, the three-phase driving CCD can be folded easily by a crossing electrode (described in Patent Document 5).

  However, this technology also has problems.

  At the intersection of the electrode 111 made of the first layer polysilicon and the electrode 110 made of the second layer polysilicon, the second layer polysilicon is easily left behind during etching. This leftover causes a short circuit between adjacent electrodes made of the second polysilicon. The relationship between the electrodes 113 and 112 is the same.

  In order to prevent this, it is necessary to give a certain margin to the electrode size. The CCD memory size increases by this margin.

  In contrast, the inventors of the present invention further invented a folding technique 123 shown in FIG. 8 (Patent Document 6).

  This technology has become possible with the miniaturization of IC processes. That is, in the CCD, if the space between adjacent electrodes is 0.2 microns or more, a potential groove is formed in the transfer direction, making it difficult to completely transfer charges. On the other hand, if it becomes too narrow, the electric field between the adjacent electrodes becomes high, and the voltage difference between the two electrodes cannot be increased, so that the handling signal capacity is reduced. Therefore, the space between the electrodes is usually set to about 0.1 microns.

  Conventionally, a two-layer polysilicon is used to form an electrode by etching the first polysilicon, and then the surface is oxidized and insulated to a thickness of about 0.1 micron, and the second layer is formed thereon. A polysilicon layer was placed and etched to form a second polysilicon electrode adjacent to the first polysilicon electrode, thereby reducing the space between adjacent electrodes to about 0.1 microns.

  In the latest advanced IC process, it has become possible to create an insulating space by forming a groove of 0.1 μm or less in the polysilicon layer by etching. Patent Document 6 discloses a technique for easily folding a three-phase driving CCD and a four-phase driving CCD using this technique (see FIGS. 8 to 11).

  As shown in FIGS. 8 and 10, the feature of Patent Document 6 is that the electrode 201 made of single-layer polysilicon is Z-shaped. The Z-type electrode is divided into a first phase electrode 204, a second layer electrode 205, a third phase electrode 206, and a fourth phase electrode 207 according to the phase difference of the applied drive voltage waveform.

  The interelectrode space 202 is about 0.1 microns. However, since the electrode shape is Z-shaped, the inter-electrode space has a right-angled bending point 203.

  When the Z-type electrode of FIG. 10 is placed on the silicon substrate on which the channel 209 and the channel stop 208 of FIG. 9 are formed, the circular accordion CCD of FIG. 8 is obtained. When a standard driving voltage waveform for four-phase driving is applied to each electrode, charge is transferred in the transfer direction in the figure.

  In order to give a drive voltage waveform to each electrode, as shown in FIG. 11, parallel first phase 210, second phase 211, and third phase formed of a single layer of metal wiring on the upper and lower sides of the Z-shaped electrode. 212, the drive voltage transmission wiring of the fourth phase 213 may be placed and electrically connected via the contact point 214.

  In the folding facing portion 200 of FIGS. 8 and 5, the charge transfer direction is automatically changed by arranging the Z-type electrode in a channel stop shape just like the other portions.

  This structure is not without its challenges. The bent portion 203 having a narrow space of 0.1 μm in width is likely to be left behind during etching although the probability is low.

  FIG. 8 shows the case of four-phase driving, but the case of three-phase driving can be folded by the same technique.

  The above has described the existing techniques and problems for folding a three-phase, four-phase drive CCD. However, there is no disclosure of a technique for easily folding a CCD many times for a driving method of five phases or more.

  The handling signal capacity of a multi-phase drive CCD having five or more phases is dramatically increased. For example, in a four-phase drive CCD, the signal charge is stored under two electrodes, and a low voltage is applied to the two electrodes on both sides to lower the channel potential, so that the signal between adjacent CCD elements is reduced. Create a barrier to prevent mixing. In 8-phase drive, it is stored under 6 electrodes. Therefore, in the 8-phase drive CCD, the area of the memory CCD is doubled as compared with the case of 4-phase drive, but the handling signal capacity is at least triple. Actually, since the potential becomes a curve due to the electric field fringe effect, the handling signal capacity is about four times. That is, the handling signal capacity per unit length of the CCD is approximately doubled in the 8-phase drive compared to the 4-phase drive.

  For eight-phase drive transfer, eight continuous transfer electrodes can be independently driven. Four-phase driving can be performed by driving two sets of four electrodes. However, in order to use 4-phase driving and 8-phase driving together in a folding CCD, the folding method is limited.

  The relationship between 3-phase driving and 6-phase driving is the same. The handling signal capacity of 6-phase driving is more than five times that of 3-phase driving. If 12-phase driving is used, 3-phase, 4-phase, 6-phase, and 12-phase driving can be performed.

  However, a CCD memory element is longer in proportion to the number of phases in a CCD with five-phase driving or more. Therefore, if the channel width is the same, the size of the CCD memory increases. If this is made in pixels of the same area, the number of CCD elements that can be made is reduced and the number of continuous shots is reduced. Conversely, if the number of continuous shots is the same, the pixel size of the multi-phase drive CCD increases, and the number of pixels decreases for the same light receiving area.

  FIG. 18 shows a configuration 400 of a multi-turn time-of-flight mass spectrometry imaging apparatus (see Non-Patent Document 3).

  The laser beam emitted from the laser 403 irradiates the sample 405. As a result, many types of ions 409 jump out of the sample surface all at once, and are guided to the ion multiple circuit device.

  The features of the ion multiplex circuit 406 will be described. This device dramatically increases the flight distance of ions by multiple rounds. Lighter ions fly faster due to the electric field during multiple laps. The distance between the ion species is extended during the long-distance flight by multiple laps. Therefore, the arrival time difference of ions having different masses to the sensor 411 is increased.

  Conventional sensors of time-of-flight mass spectrometers require time resolution on the order of nanoseconds. However, the multiple rounds enable time resolution with a time resolution of about 100 nanoseconds.

  The recent ion multiplex circuit has another great feature. That is, the position relationship indicating the position from which the individual ions are ejected on the sample surface is preserved even during the orbit.

  Therefore, if the back-illuminated image sensor is used as a sensor, the magnitude of the signal charge can be measured in addition to the arrival position and arrival time of each ion, and from this information, the individual ion species can be detected in the sample. You can also see how much is present at the location.

  The image sensor of 16 million sheets / second disclosed in Non-Patent Document 1 is a back-illuminated type. The time resolution is 100 nanoseconds or less. Therefore, it is suitable as a sensor for a multi-turn time-of-flight mass spectrometry imaging apparatus.

  However, the number of ions generated by one laser irradiation is insufficient to obtain a clear ion distribution image. Moreover, when laser light that is too strong is irradiated, ions are scattered and the estimation accuracy of the original position information is drastically lowered.

  Therefore, ions are generated with the weakest possible laser beam, and this is repeated to obtain an image of the planar distribution of ions. In this case, the signal strength decreases.

  On the other hand, high-speed imaging is necessary to obtain high time resolution. When high-speed shooting is performed using a normal high-speed video camera, readout noise is large. In order to reduce this, it was necessary to increase the S / N ratio by adding images obtained by many ion irradiations.

  This problem can be solved by applying a high-speed imaging device capable of integrating signals within a pixel, that is, an image signal integrating device.

  However, since the image signal integrating element creates a large number of memory elements for each pixel, the number of shots cannot be increased to some extent. This reduces the dynamic range in the time axis direction. In order to increase the dynamic range in the time direction, in order to increase the number of shots, it is necessary to reduce the size of the memory element, the maximum handling signal capacity is reduced, and signal addition cannot be performed many times. Conversely, if the size of the memory element is increased in order to increase the maximum handled signal capacity, the number of memory elements that can be created per pixel decreases, and the dynamic range in the time direction decreases.

Japanese Patent No. 3704052 Japanese Patent No. 4394437 US Patent P4897728 Japanese Patent No. 4265295 JP 211-151797 JP 2011-258906 A

Goji Eto et al .: Back-illuminated imaging device of 16 million pieces / second, Journal of the Institute of Image Information and Television Engineers, March 2011, pages 349-353. M.M. Elloumi, et al: The study of a photoforsite snapshot video, SPIE, Vol. 2513, pp. 259-267, 1994. Michisato Toyoda, Masaru Nishiguchi, Journal of the Mass Spectrometry Society of Japan, Vol. 55, pp. 17-24, 2007.

  An imaging device suitable for a multi-turn time-of-flight mass spectrometry imaging apparatus is provided.

  This element is desired to satisfy the following conditions. Backside illumination structure that generates signal charge by direct ion input, signal integration function within pixel, time resolution of 100 nanoseconds or less, two-dimensional (planar) sensor that can acquire image signals, as many shots as possible, and as large a handling signal capacity as possible.

    The back-illuminated pixel unit image signal recording type imaging device disclosed in Non-Patent Document 1 satisfies the three conditions of “direct ion input”, “time resolution of 100 nanoseconds or less”, and “two-dimensional sensor”.

  The “intra-pixel signal integration function” is also satisfied by the imaging device including the accordion memory CCD in each pixel shown in FIG.

  However, in addition to these problems, it is necessary to solve the problems of “large number of shots” and “large handling signal capacity”. Since the current technology cannot solve both at the same time, development of a technology that can select one according to the purpose is desired.

  By using the cross electrode shown in FIG. 6 (the technique of Patent Document 5) or the Z-type electrode shown in FIG. 10 (the technique of Patent Document 6), the three-phase drive and the four-phase drive CCD are minimized. Can be folded compactly.

  However, a technique for compactly folding a CCD with a driving system of five or more phases to achieve a “large handling signal capacity” has not been disclosed so far.

  With a linear drive CCD, a 6-phase drive CCD can be driven with 3 phases. The 8-phase drive CCD can drive 4 phases. In this way, depending on the shooting purpose and conditions, the drive method can be used differently, such as when increasing the number of CCD memories at the expense of the transfer charge capacity and vice versa. Can do.

However, a method for driving the folded CCD by two or more types of driving methods such as three-phase driving and six-phase driving, or four-phase driving and eight-phase driving has not been disclosed so far.

  Furthermore, the technique of Patent Document 5 (cross electrode) and the technique of Patent Document 6 (Z-type electrode) have manufacturing problems. In the case of using the intersecting electrode, a short circuit is likely to occur due to the etching residue of the upper polysilicon film at the position where the upper and lower polysilicon electrodes intersect.

  When a Z-type electrode is used, the space for separating one layer of the polysilicon electrode has a right-angled bent portion, and although the probability is low, an etching residue tends to occur at this portion.

Means and effects to solve the problem

When a CCD transfer path that is divided by two consecutive folds is defined as a “partition transfer path”, a photoelectric conversion unit that generates a charge by incidence of charged particles or electromagnetic waves, and at least one connected to the photoelectric conversion unit A semiconductor device comprising a two-dimensionally arranged pixel comprising a CCD, wherein the CCD forms a loop in which the start and end are connected, and has at least three folds,
On each transfer electrode on each divided transfer path, at least two lines crossing the transfer direction are provided for each transfer electrode, and one of the lines is a transfer electrode on the transfer path immediately before each folding. The other wire is electrically connected to the electrode on the transfer path immediately after folding, and the number of transfer electrodes on one section transfer path is K (where K is A semiconductor element characterized by being a multiple of 3)
By a driving method of selectively driving the CCD connected to the photoelectric change portion of each pixel of the semiconductor element by K-phase driving or 2K-phase driving,
By recording image signals continuously all at once, ultra-high-speed image signal recording is possible, and by integrating the image signals obtained by multiple trials without reading them out of the device, the signal-to-noise ratio is dramatically improved. Depending on the application, the number of continuous shots can be increased by sacrificing the handling signal capacity by K-phase driving, and the number of continuous shots can be reduced to 1/2 by increasing the handling signal capacity. Provided are an image sensor that can be selected and driven, is compact, and has a high yield rate at the time of manufacturing, and a driving method thereof.

  Furthermore, an imaging apparatus capable of imaging at a high speed and a high S / N ratio is provided by an imaging apparatus including the semiconductor element.

  In addition, a charged particle sorting apparatus including the semiconductor element provides a high-functional mass analyzing means by measuring the arrival position, arrival time, and arrival amount of various charged particles to the semiconductor element.

FIG. 3 is a plan view of an oblique linear CCD pixel peripheral recording type imaging device. It is explanatory drawing of the image signal integration technique by single circulation type CCD. It is a figure which shows the example of the wiring for driving a single circulation 4 phase drive CCD. It is explanatory drawing of the intra-pixel recording type image pick-up element which uses folding CCD as a memory. It is explanatory drawing of an image signal integrating | accumulating element provided with an accordion type (circular multiple folding type) CCD. It is explanatory drawing which shows the folding technique of CCD by a crossing electrode. It is explanatory drawing of the drive voltage sending wiring of folding CCD by a crossing electrode. It is explanatory drawing of the 4-phase drive folding CCD by a Z-type electrode. It is a figure of the channel and channel stop of 4 phase drive folding CCD by a Z-type electrode. It is a Z-type electrode of a four-phase drive folding CCD and its layout. It is explanatory drawing of the metal wiring of the four-phase drive folding CCD by a Z-type electrode. It is a figure of the channel and channel stop of 8-phase drive and 4 phase drive combined folding CCD. It is a figure of the electrode and contact point of 8-phase drive and 4-phase drive combined folding CCD. It is explanatory drawing of the metal wiring of folding CCD combined with 8-phase drive and 4-phase drive. It is a figure which shows the transfer direction of the electrode of a memory part of an image signal integrating | accumulating element which uses folding CCD as a memory for 8-phase drive and 4-phase drive, and a signal. It is a figure which shows the transfer direction of the electrode of the memory part of an image signal integrating | accumulating element which uses a folding CCD as a memory for 6-phase driving and 3-phase driving, a metal wiring, and a signal. It is explanatory drawing which shows the freedom degree and restriction | limiting of the folding method of 8-phase drive 4-phase drive combined use CCD. It is explanatory drawing of a multi-turn time-of-flight mass spectrometry imaging apparatus.

First embodiment

  FIG. 18 shows a configuration 400 of a multi-turn time-of-flight mass spectrometry imaging apparatus that is the first embodiment of this patent.

  This is a kind of sorting apparatus for ions that are charged particles. This apparatus includes an ion sorting unit 401 and a detection unit 402.

  The ion detector 401 includes a high-intensity ultrashort pulse laser 403, an optical system 404, an ion multiplex circuit 406, and an electrostatic ion lens 407.

  The detection unit 402 includes an image sensor 411, a control unit 412, and an external device unit 413.

  The control unit includes an image sensor driving circuit 414, a clock generation circuit 415, an image signal readout circuit 416, a buffer memory 417, and a control computer 418.

  An imaging control software 419 and image signal processing software 420 are incorporated in the control computer.

  The external device includes a monitor 421, an external storage device 423, and a console 422.

  Laser light emitted from the laser irradiates the sample 405. As a result, many types of ions 409 jump out of the sample surface all at once, and are guided to the ion multiple circuit device.

  Until now, sensors that can detect only the arrival time and the arrival position of individual ions have been used as sensors for multi-round time-of-flight mass spectrometers.

  When the image sensor according to the present invention is used as a sensor, information on the magnitude of signal charges can be obtained in addition to the position and time. Therefore, the abundance of how much each ion species is present at which position is also known.

  However, since the time resolution is about 100 nanoseconds, it could not be used in a conventional reflection flight type (only ions reciprocate) mass spectrometer.

  Furthermore, the image sensor according to the present invention can integrate signals within a pixel.

  The effect of the present invention is exhibited by the characteristics of a CCD (hereinafter referred to as “memory CCD”) used as an image signal memory provided in each pixel of the image sensor 411 provided in the detection unit.

  The imaging device according to the present invention is also an imaging device including the accordion type memory CCD shown in FIG. Therefore, description will be made with reference to this figure.

  In the figure, 4 pixels of 2 × 2 are shown, but the image pickup element of the present embodiment is an image pickup device having 240,000 pixels of 400 × 600.

  The memory CCD of FIG. 5 includes 86 CCD memory elements and can capture 86 continuous images.

  The method of acquiring and recording the image signal and integrating the signal charge in the pixel has been described with reference to FIG. 5 in the description of the prior art.

  Therefore, a description will be given below of the CCD according to the present invention, which uses both the multi-fold folding 8-phase drive and the 4-phase drive.

  For the sake of easy understanding, instead of the CCD shown in FIG. 5, a CCD with six foldings shown in FIGS. 12 to 15 will be described as an example. Although simplified, all functions necessary to describe the present invention are included.

  FIG. 12 shows the channel 209 and channel stop 208 of the memory CCD. FIG. 13 shows contact points 500 with polysilicon electrodes (501 to 508) and metal wiring. FIG. 14 shows metal wiring (511 to 518). FIG. 15 shows the signal charge transfer direction.

  The pixel size is 30 μm × 30 μm and the area is 900 square microns. The number of pixels is 400 × 600 pixels. Therefore, the number of pixels is 240,000 pixels, and the light receiving surface size is 12.0 mm × 18.0 mm. Since there are readout circuits and bonding pads in the periphery (not shown), the chip size is 16 mm × 22 mm.

  The length of the polysilicon electrode shown in FIG. 13 is 0.9 microns. The interelectrode space is 0.1 microns. Therefore, the electrode pitch in the transfer direction is 1.0 micron.

  The metal wiring shown in FIG. 14 has a width of 0.3 μm and a space of 0.2 μm. Therefore, the wiring pitch of the metal wires is 0.5 μm. Therefore, two metal wirings are on each electrode in FIG.

  The CCD channel pitch is 1.0 microns, the channel width is 0.8 microns, and the channel stop width is 0.2 microns. Accordingly, the size of one 4-phase drive CCD memory element is 4.0 microns (= 4 × 1.0 microns) × 1 microns, ie, 4.0 square microns. In 8-phase drive, it is 8.0 square microns.

  Therefore, the area of the CCD memory is 688 (= 86 × 8.0) square microns. A charge collection gate, a readout circuit, and the like are built in 212 square microns excluding the CCD memory from the pixel area of 900 square microns. That is, the area of the memory CCD occupying one pixel is 76.4% (= 688/900).

  As shown in FIG. 15, eight electrodes are mounted on one row of CCD transfer paths for 8-phase driving, and four electrodes are mounted on the folded inner transfer path.

  As shown in FIG. 14, two wirings each made of a single metal layer are placed on each electrode in a direction orthogonal to the transfer direction. One of the two contacts the electrode on the transfer path before the folding point, and the other contacts the electrode on the transfer path after folding.

  Since eight-phase driving is used, eight metal wirings that are not electrically joined together form a set and send eight different driving voltage waveforms φ1 to φ8.

  As can be seen from FIG. 13, the electrode shape is a rectangle, and the inter-electrode space 203 has a simple grid with no bent portions. Therefore, etching is easy and the yield rate at the time of manufacture increases.

  The wiring in the light receiving surface is only a set of two parallel wirings, and has an extremely simple structure despite the fact that the folded CCD is driven with 8 or 4 phases.

  The simple electrode structure and wiring structure greatly contribute to the reduction of the pixel size and the improvement of the yield rate during manufacturing.

  The drive voltage waveform for transfer and the like are described in detail in Japanese Patent Application Laid-Open No. 2003-228561 and a technical document relating to CCD, and thus description thereof is omitted.

  As described above, the mass spectrometer of the first embodiment of the present invention can detect the arrival time, position, and intensity information of ions and can perform intra-pixel signal integration. Equipment can be provided.

Second embodiment

  In FIG. 18, the detection unit 402 is separated and a lens (not shown) is attached thereto. This is an ultra-high-speed image signal integration type video camera that captures images with light or the like.

Third embodiment

  FIG. 16 shows a second embodiment of the CCD transfer path according to the present invention. This is an accordion type image signal integrating CCD using both 6-phase driving and 3-phase driving.

  There are six types of electrodes and drive voltage wirings. The CCD is folded in units of three electrodes.

Fourth embodiment

  FIG. 17 conceptually shows a third embodiment of the present invention. This is an example of a combined CCD transfer path of 8-phase driving and 4-phase driving.

  As can be seen from this figure, when four consecutive electrodes are folded as a unit, two types of electrodes having the same phase are always arranged in the horizontal direction. That is, a combination of the first phase and the eighth phase, and the second phase and the seventh phase (hereinafter abbreviated). Therefore, the metal wiring for sending the driving voltage may always be two horizontal wirings per electrode.

  Thereby, not only an accordion type but the shape of a circulation multiple folding CCD can be selected flexibly. For example, a photodiode, a drain, a CMOS type image signal transfer circuit, and the like can be formed in the inside 300 of the circulating CCD shown in FIG. Even in such a case, the CCD can be driven only by providing two horizontal metal wires on each electrode.

Other examples

  Embodiments of the present invention are not limited to the above-described three embodiments.

  Since the technique using both 5-phase driving and 10-phase driving can be easily assumed from the above-described embodiment, the description thereof will be omitted.

  Three or more horizontal metal wires may be placed on one electrode, and the third wire may be used for further enhancement of functionality.

  The electrode may be an existing system such as silicide.

Specific description of features and effects

  The features and effects of the memory CCD of the image sensor according to the present invention can be more specifically understood from the description of the embodiments. Hereinafter, a combination type of 8-phase driving and 4-phase driving will be described as an example.

  It is bent with a CCD transfer path on which four electrodes are mounted as a unit.

  A drive voltage can be sent by only two metal wirings on each electrode.

  These metal lines are parallel.

  The electrode shape is rectangular, the space between the electrodes is a simple grid, and there is no bending point.

  These characteristics produced the following effects.

  Provided is an imaging device having both a very high imaging speed and an in-element image signal integration function.

  Depending on the purpose, 4-phase driving and 8-phase driving can be used together.

  Since it has a simple structure, the combination of 4-phase driving and 8-phase driving can reduce the CCD element, and many memory elements can be created for the same pixel area, so that the number of continuous shots can be increased. When the chip area is the same as the number of shots, the number of pixels can be increased.

  Various phenomena that could not be detected so far can be detected with high performance by an imaging apparatus including an imaging element according to the present invention or a charged particle sorting apparatus.

  However, the size of the CCD is smaller than that in the case of simply making a three-phase drive or a four-phase drive CCD with a circulating multiple folding CCD using the crossing electrode disclosed in Patent Document 5 and the Z-shaped electrode disclosed in Patent Document 6. growing. Therefore, the 8-phase 4-phase (or 6-phase 3-phase) drive combined type according to the present invention or the simple 4-phase (or 3-phase) drive circulating multiple folding CCD may be selected and used according to the application.

  Provided is an imaging device capable of imaging at a high speed and a high S / N ratio even when the signal strength is very weak if the phenomenon is highly reproducible.

  In addition, a high-functional mass analyzing means by measuring the arrival position, arrival time, and arrival amount of ions to the sensor is provided.

100 photodiode (in case of front side illumination) or charge collection gate (in case of back side illumination 101 linear CCD (skew straight CCD)
102 Peripheral recording image sensor 103, 105, 109 Circulating CCD
104 Photodiode 106 Electrode 107 Analog memory 108 Image sensor 109 having multiple folding CCDs 2 × 2 pixel image signal integration elements 110, 111, 112, 113 Two layers of electrodes 114, 115, 116, 117 Only one metal layer Parallel drive voltage transmission wiring 118 made in the above-mentioned manner 118 Contact point 119 Folding CCD upper side 120 Folding CCD lower side 121 Horizontal channel stop 200 Accordion type CCD folding opposing part 201 Z-type electrode 202 made of single layer polysilicon Interspace 203 Right-angled bending point 204 of interelectrode space 204 First phase electrode 205 Second phase electrode 206 Third phase electrode 207 Fourth phase electrode 208 Channel stop 209 Channel 210 First phase drive voltage wiring 211 Second phase drive voltage Voltage wiring 212 Third phase driving voltage wiring 213 Fourth phase driving voltage wiring 214 Contact point 300 Accordion CCD inside 301 Accordion CCD concave portion 400 Multi-turn time-of-flight mass spectrometry imaging device 401 Ion fractionation unit 402 Detection unit 403 High Intensity Ultrashort Pulse Laser 404 Optical System 405 Sample 406 Ion Multiple Circulation Device 407 Electrostatic Ion Lens 408 Laser Light 409 Ion Group 410 Immediately After Injection Ion Group 411 Imaging Device 412 Control Unit 413 External Device Unit 414 Imaging Device Drive Circuit 415 Clock generator 416 Image signal readout circuit 417 Buffer memory 418 Computer 419 Imaging control software 420 Image signal processing software 421 Monitor 422 External storage device 423 Console 5 0 Contact Point 501-508 8-phase driving of the wires 600 charge collection driving the electrodes 511-518 8-phase gate 601 input gate 602 accordion memory CCD
603 First memory CCD element (starting edge)
604 Second memory CCD element 605 86th memory CCD element (terminal)

Claims (3)

When the charge transfer direction of the CCD transfer path is changed substantially by 180 degrees is defined as “folding”, and a CCD transfer path that is divided by two consecutive folds is defined as “partition transfer path”,
A semiconductor device comprising pixels arranged two-dimensionally, each pixel comprising a photoelectric conversion unit that generates a charge upon incidence of charged particles or electromagnetic waves, and at least one CCD connected to the photoelectric conversion unit, The CCD forms a loop in which the start and end are connected, and has at least three folds,
On each transfer electrode on each divided transfer path, at least two lines crossing the transfer direction are provided for each transfer electrode, and one of the lines is a transfer electrode on the transfer path immediately before each folding. The other wiring is electrically connected to the electrode on the transfer path immediately after folding, and the number of transfer electrodes on one sectioned transfer path is K (here K Is a multiple of 3).   2. A driving method for selectively driving a CCD connected to a photoelectric change portion of each pixel of a semiconductor element according to claim 1 by K-phase driving or 2K-phase driving.   An imaging device comprising the semiconductor element according to claim 1 or a charged particle sorting device.

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