CN111508858B - EMCCD multiplication region electrode short circuit detection method - Google Patents

Abstract

The invention discloses a method for detecting short circuit of an EMCCD multiplication region electrode, which defines an arc-shaped region at the junction of an EMCCD multiplication region and a horizontal region as a fourth suspicious region, sequentially defines a first suspicious region, a second suspicious region and a third suspicious region along a fourth aluminum wiring, and sequentially judges whether each suspicious region has a short circuit point or not; and dividing unqualified EMCCD devices in the same batch into a plurality of groups, respectively taking one group of devices for each judgment, cutting off the fourth aluminum wiring of the suspicious region to be judged of the group of devices by adopting a local photoetching method, and gradually judging the position of the compressed short-circuit point. According to the method, suspicious areas are divided according to the manufacturing process flow of the EMCCD multiplication area, and the fourth aluminum wiring of the suspicious areas is cut off by adopting a local photoetching method for judgment, so that each suspicious area is detected and judged, the area where a short-circuit point is located is found out, the range where the short-circuit point is located can be further compressed according to needs, and the reason of short circuit is judged, so that improvement is facilitated.

Description

Detection method of electrode short circuit in EMCCD multiplication region

technical field

The invention relates to the field of CCD detection, in particular to a detection method for electrode short circuit in an EMCCD multiplication region.

Background technique

The existing EMCCD (Electron-Multiplying CCD, i.e. electron-multiplying CCD) multiplication region includes primary polysilicon 1, secondary polysilicon and tertiary polysilicon 4, and the secondary polysilicon includes first secondary polysilicon 2 and second secondary polysilicon 3, Its local polysilicon distribution structure is shown in Figure 1. As shown in Figure 2, the primary polysilicon 1 is connected through the first aluminum wiring 5, the first and secondary polysilicon 2 are connected through the second aluminum wiring 6, and the second and secondary polysilicon 3 are connected through the third aluminum wiring 7 , the third polysilicon 4 is connected through the fourth aluminum wiring 8, and the four aluminum wirings are primary metal aluminum. As shown in Figure 3, the second aluminum wiring 6 is externally connected with a second aluminum wiring external line 10, and the fourth aluminum wiring 8 is externally connected with a fourth aluminum wiring external line 12; as shown in Figure 4, in the EMCCD multiplication area The primary metal aluminum light-blocking area 25 is provided in the middle of the primary metal aluminum light-blocking area 25. The primary metal aluminum light-blocking layer 13 made of primary metal aluminum is provided, and the first aluminum wiring 5 is connected with a first aluminum Wiring external connection line 9, the third aluminum wiring 7 is externally connected with the third aluminum wiring external connection line 11; the first secondary metal aluminum light blocking area 26 and the second metal aluminum light blocking area 25 are respectively arranged on both sides of the primary metal aluminum light blocking area 25; The secondary metal aluminum light blocking area 27, the first secondary metal aluminum light blocking area 26 and the second secondary metal aluminum light blocking area 27 are respectively provided with a secondary metal aluminum light blocking layer made of secondary metal aluminum 14; Wherein, one time, two times and three times are used to indicate the sequence of making polysilicon and metal aluminum in the process of making the EMCCD multiplication area, that is, the primary polysilicon 1 represents the first polysilicon made on the EMCCD multiplication area, and the secondary polysilicon Indicates the polysilicon produced for the second time on the EMCCD multiplication area, and the third polysilicon 4 indicates the polysilicon produced for the third time on the EMCCD multiplication area; the primary metal aluminum indicates the metal aluminum first produced on the EMCCD multiplication area, and the secondary metal aluminum indicates Metallic aluminum fabricated for the second time on the EMCCD multiplication region.

When the EMCCD multiplication region is made by the existing technology, there is a common phenomenon of electrode short circuit, and the qualified rate of the finished product is only 8.1%. It is judged that there is a problem in the plate making process.

Table 1

It can be seen from Table 1 that the electrodes of the second and second polysilicon 3 are short-circuited with the electrodes of the third polysilicon 4, and the short-circuit test curve is shown in Figure 5, and the short-circuit resistance is about 26 ohms. From the resistance value, it can be determined that it is caused by metal residue or connection. According to this judgment, the design structure and manufacturing process of the second secondary polysilicon 3 and the tertiary polysilicon 4 were first analyzed, the layer structure of the second secondary polysilicon 3 is shown in Figure 6; the layer structure of the tertiary polysilicon 4 The structure is shown in Figure 7; the electrodes of the first secondary polysilicon 2 and the tertiary polysilicon 4 that are close to each other are normal (not short-circuited), the electrodes of the close primary polysilicon 1 and the second secondary polysilicon 3 are not short-circuited, and the remote The tertiary polysilicon 4 and the second and second polysilicon 3 are indeed short-circuited; because there are many connection pressure points in the primary metal aluminum light blocking area 25, the primary metal aluminum light blocking area 25 is detected by scanning electron microscope (SEM), and no Metal residue or connection can basically determine that the primary metal aluminum light blocking area 25 is normal, but the short circuit location cannot be further effectively analyzed, the short circuit factor cannot be judged, and the cause of the problem cannot be found, so the defects in the plate making process cannot be solved.

Contents of the invention

The technical problem to be solved by the present invention is to provide a detection method for an electrode short circuit in an EMCCD multiplication region capable of determining the short circuit position of an EMCCD electrode.

Technical scheme of the present invention is as follows:

A detection method for an EMCCD multiplication region electrode short circuit, comprising the following steps:

Step S1, define the arc-shaped area at the junction of the EMCCD multiplication area and the horizontal area as the fourth suspicious area, define the side towards the horizontal area in the multiplication area as the front stage, and the side towards the output amplifier as the rear stage, between the output amplifier and the first Between the four suspicious areas, the first suspicious area, the second suspicious area and the third suspicious area are sequentially defined along the fourth aluminum wiring from the rear stage to the front stage; wherein, the first suspicious area is located in the primary metal aluminum light blocking area and the output amplifier between, and close to the primary metal aluminum light blocking area; the second suspicious area and the third suspicious area are both located between the primary metal aluminum light blocking area and the fourth suspicious area, and the second suspicious area is adjacent to the primary metal aluminum light blocking area, The third suspicious area is adjacent to the fourth suspicious area;

Step S2, divide the unqualified EMCCD devices of the same batch into multiple groups, and cut off the fourth aluminum wiring in the first suspicious area of one group of unqualified EMCCD devices by local photolithography;

Step S3, measure whether the electrodes of the third polysilicon of the group of devices and the electrodes of the second secondary polysilicon are short-circuited, if short-circuited, determine that the short-circuit point is between the first suspicious area and the horizontal area, and perform step S5; otherwise, determine that the short-circuit point is at between the first suspicious area and the output amplifier, and perform step S4;

Step S4, compressing the area where the short-circuit point is located between the first suspicious area and the output amplifier;

Step S5, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring in the second suspicious area of the group of devices is cut off by local photolithography;

Step S6, measure whether the electrode of the tertiary polysilicon of the group of devices is short-circuited with the electrode of the second secondary polysilicon, if short-circuited, determine that the short-circuit point is between the second suspicious area and the first suspicious area, and perform step S7; otherwise, determine If the short-circuit point is between the second suspicious area and the horizontal area, execute step S8;

Step S7, judging that the fault location is in the primary metal aluminum light blocking area;

Step S8, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring in the third suspicious area of the group of devices is cut off by local photolithography;

Step S9, measure whether the electrodes of the tertiary polysilicon of the group of devices and the electrodes of the second secondary polysilicon are short-circuited, if short-circuited, determine that the short-circuit point is between the third suspicious area and the second suspicious area, and perform step S10; otherwise, determine the short-circuit Click on the fourth suspicious area, and execute step S11;

Step S10, compressing the area where the short-circuit point is located between the second suspicious area and the third suspicious area;

Step S11 , judging the cause of the short circuit in the fourth suspicious area.

Further, in the step S4, compressing the area where the short-circuit point is located between the first suspicious area and the output amplifier includes the following steps:

Step S301, defining a new suspicious area between the first suspicious area and the output amplifier;

Step S302, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring at the newly defined suspicious area of the group of devices is cut off by local photolithography;

Step S303, measure whether the electrode of the polysilicon three times and the electrode of the second secondary polysilicon are short-circuited, if short-circuited, determine that the short-circuit point is between the suspicious area and the previous-level suspicious area, and perform step S306; otherwise, determine that the short-circuit point is between the suspicious area between the suspicious area and the output amplifier, and perform step S304;

Step S304, judging whether it is necessary to further compress the area where the short-circuit point is located, if yes, execute step S305; otherwise, execute step S312;

Step S305, define another suspicious area between the suspicious area and the output amplifier, and return to step S302;

Step S306, judging whether it is necessary to further compress the area where the short-circuit point is located, if yes, execute step S307; otherwise, execute step S312;

Step S307, defining a new suspicious area between the suspicious area and the previous suspicious area;

Step S308, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring at the newly defined suspicious area of the group of devices is cut off by local photolithography;

Step S309, measure whether the electrode of the polysilicon three times and the electrode of the second secondary polysilicon are short-circuited, if short-circuited, determine that the short-circuit point is between the suspicious area and the previous-level suspicious area, and return to step S306; otherwise, determine that the short-circuit point is between between the suspicious area and the subsequent suspicious area, and perform step S310;

Step S310, judging whether it is necessary to further compress the area where the short-circuit point is located, if yes, execute step S311; otherwise, execute step S312;

Step S311, define a new suspicious area between the suspicious area and the subsequent suspicious area; return to step S308;

Step S312, judging the area where the short-circuit point is located.

Further, in the step S10, compressing the area where the short-circuit point is located between the second suspicious area and the third suspicious area includes the following steps:

Define a new suspicious area between the second suspicious area and the third suspicious area; and execute step S308.

Further, in the step S11, judging the cause of the short circuit in the fourth suspicious area includes the following steps:

Another group of unqualified EMCCD devices is taken, and the fourth suspicious area of the group of devices is coated with photoresist, exposed, developed, and the exposed area is checked with an electron microscope, and the next step is performed after confirming that there is no photoresist in the exposed area;

Etching and removing the low-temperature silicon dioxide passivation layer in the suspicious area;

Etching and removing the secondary metal aluminum light-shielding layer in the suspicious area;

Detect whether the short-circuit point in the suspicious area disappears. If it disappears, it is determined that the cause of the short-circuit is that the secondary metal aluminum light-shielding layer in this area is connected to the third aluminum wiring and the fourth aluminum wiring through the lower low-temperature silicon dioxide medium to cause a short circuit.

Further, truncating the fourth aluminum wiring in the suspicious area by local photolithography includes the following steps:

Step S201, apply photoresist on the suspicious area, perform exposure and development, use an electron microscope to check the exposed area, and perform step S202 after confirming that there is no photoresist in the exposed area;

Step S202, etching the low-temperature silicon dioxide passivation layer at the position of the suspicious area;

Step S203, etching the secondary metal aluminum light blocking layer at the position of the suspicious area;

Step S204, etching the low-temperature silicon dioxide dielectric layer at the location of the suspicious area;

Step S205, etching the fourth aluminum wiring at the location of the suspicious area;

Step S206 , using dry etching and wet etching in sequence to remove the photoresist around the suspicious area, and cleaning with an organic solution.

Further, in the step S202 and step S204, the low-temperature silicon dioxide passivation layer and the low-temperature silicon dioxide dielectric layer are etched with carbon tetrafluoride or trifluoromethane.

Further, in the step S203 and step S205, chlorine or boron trichloride is used to etch the secondary metal aluminum light-shielding layer and the fourth aluminum wiring.

Beneficial effect: in the present invention, divides four suspicious areas according to the manufacturing process flow of EMCCD multiplication area, and judge whether there is short-circuit point in each suspicious area successively; Take a group of devices, and use local photolithography to cut off the aluminum wiring connected to polysilicon three times in the suspicious area of the group of devices to be judged, so as to detect and judge each suspicious area, find out the area where the short circuit point is located, and The scope of the short-circuit point can be further compressed as required, and the cause of the short-circuit can be judged, so as to facilitate improvement.

Description of drawings

Fig. 1 is the schematic diagram of the local polysilicon structure of EMCCD multiplication region;

Figure 2 is a schematic diagram of the aluminum wiring structure in the EMCCD multiplication region;

Fig. 3 is a schematic diagram of the external wiring structure of the aluminum wiring in the EMCCD multiplication area;

Fig. 4 is the schematic diagram of the hierarchical outer connection structure of the EMCCD multiplication area;

Fig. 5 is a schematic diagram of the layer structure at the secondary polysilicon place;

Figure 6 is a schematic diagram of the layer structure at the tertiary polysilicon place;

Fig. 7 is the short-circuit test curve figure of the second secondary polysilicon and the tertiary polysilicon of EMCCD multiplication region;

Fig. 8 is a work flow diagram of the present invention;

Fig. 9 is a schematic diagram of the positions of the first suspicious area, the second suspicious area, the third suspicious area and the fourth suspicious area;

Fig. 10 is a flow chart of compressing the area where the short-circuit point is located between the first suspicious area and the output amplifier.

In the figure: 1. Primary polysilicon, 2. First secondary polysilicon, 3. Second secondary polysilicon, 4. Tertiary polysilicon, 5. First aluminum wiring, 6. Second aluminum wiring, 7. Third aluminum wiring, 8. The fourth aluminum wiring, 9. The first aluminum wiring outer connection, 10. The second aluminum wiring outer connection, 11. The third aluminum wiring outer connection, 12. The fourth aluminum wiring outer connection, 13. Once Metal aluminum light blocking layer, 14. secondary metal aluminum light blocking layer, 20. horizontal area, 21. first suspicious area, 22. second suspicious area, 23. third suspicious area, 24. fourth suspicious area, 25 . Primary metal aluminum light blocking area, 26. First secondary metal aluminum light blocking area, 27. Second secondary metal aluminum light blocking area.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, and to make the above-mentioned purposes, features and advantages of the embodiments of the present invention more obvious and understandable, the following describes the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings For further detailed explanation.

In the description of the present invention, unless otherwise specified and limited, it should be noted that the term "connection" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the internal communication of two elements, it can be Directly connected or indirectly connected through an intermediary, those skilled in the art can understand the specific meanings of the above terms according to specific situations.

As shown in Figure 8, an embodiment of the detection method of EMCCD multiplication region electrode short circuit of the present invention comprises the following steps:

Step S1, as shown in Figure 9, define the arc-shaped area at the junction of the EMCCD multiplication area and the horizontal area 20 as the fourth suspicious area 24, define the side towards the horizontal area 20 in the multiplication area as the front stage, and the side towards the output amplifier For the subsequent stage, between the output amplifier and the fourth suspicious area 24, the first suspicious area 21, the second suspicious area 22, and the third suspicious area 23 are sequentially defined along the fourth aluminum wiring 8 from front to rear, and step S2 is performed.

Since no metal residue or connection is found in the detection of the primary metal aluminum light blocking area 25 by the scanning electron microscope, it can basically be judged that the primary metal aluminum light blocking area 25 is normal. Select the first suspicious area 21 in the position of the light blocking area 25; select the second suspicious area 22 at the position close to the primary metal aluminum light blocking area 25 in the second secondary metal aluminum light blocking area 27; The position of the light blocking area 27 near the fourth suspicious area 24 defines the third suspicious area 23; because the length of the first secondary metal aluminum light blocking area 26 and the second secondary metal aluminum light blocking area 27 is longer, for the convenience of marking the second The positions of a suspicious area 21, the second suspicious area 22 and the third suspicious area 23, only the parts at the two ends of the first secondary metal aluminum light blocking area 26 and the second secondary metal aluminum light blocking area 27 are shown in Fig. 9 , the structure of the omitted middle part is the same as that of both ends.

Step S2. Divide the unqualified EMCCD devices of the same batch into multiple groups, cut off the fourth aluminum wiring 8 in the first suspicious area 21 of a group of unqualified EMCCD devices by local photolithography, and perform step S3.

Since the same batch of products adopts the same process, when the failure rate of the finished product is high and the failure phenomenon is the same, it can be considered that the failure point is at the same location; of course, in order to avoid the failure points of individual components being different, a group of components can be reasonably selected When the measurement results of individual devices are inconsistent, the measurement results of most devices shall prevail. For example, if 10 devices are used as a group, when the measurement results of 9 devices are all consistent and only 1 is different, then 9 The measurement results of each device shall prevail. If the proportion of devices with consistent measurement results is relatively small, for example, less than 80%, it is judged that there are multiple fault points, and the method of the present invention is not applicable.

Step S3, measure whether the electrodes of the third polysilicon 4 and the electrodes of the second secondary polysilicon 3 of the group of devices are short-circuited, if short-circuited, determine that the short-circuit point is between the first suspicious area 21 and the horizontal area 20, and perform step S5; otherwise, Determine that the short-circuit point is between the first suspicious area 21 and the output amplifier, and execute step S4;

Step S4, compress the area where the short-circuit point is located between the first suspicious area 21 and the output amplifier; since the area between the first suspicious area 21 and the output amplifier is relatively long, it is not convenient to judge the cause of the short circuit, therefore, it is necessary to further compress the short circuit point in the area.

Step S5, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring 8 in the second suspicious area 22 of the group of devices is cut off by local photolithography, and step S6 is executed;

Step S6, measure whether the electrodes of the third polysilicon 4 of the group of devices and the electrodes of the second secondary polysilicon 3 are short-circuited, and if short-circuited, determine that the short-circuit point is between the second suspicious area 22 and the first suspicious area 21, and perform step S7; Otherwise, it is determined that the short-circuit point is between the second suspicious area 22 and the horizontal area 20, and step S8 is executed;

Step S7. Since the second suspicious area 22 and the first suspicious area 21 are respectively located on both sides of the primary metal aluminum light blocking area 25 and adjacent to the primary metal aluminum light blocking area 25, it is judged that the fault location is in the primary metal aluminum light blocking area. District 25;

Step S8, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring 8 in the third suspicious area 23 of the group of devices is cut off by local photolithography, and step S9 is performed;

Step S9, measuring whether the electrodes of the third polysilicon 4 of the group of devices and the electrodes of the second secondary polysilicon 3 are short-circuited, and if short-circuited, it is determined that the short-circuit point is between the third suspicious area 23 and the second suspicious area 22, and step S10 is performed; Otherwise, it is determined that the short-circuit point is in the fourth suspicious area 24, and step S11 is executed;

Step S10, compressing the area where the short-circuit point is located between the second suspicious area 22 and the third suspicious area 23;

Step S11 , judging the cause of the short circuit in the fourth suspicious area 24 .

As shown in FIG. 10, in the step S4, compressing the area where the short-circuit point is located between the first suspicious area 21 and the output amplifier includes the following steps:

Step S301, define a new suspicious area between the first suspicious area 21 and the output amplifier, and execute step S302; defining a new suspicious area should meet at least one of the following two requirements:

(1) The structure of the suspicious area is likely to cause a short circuit between the third polysilicon 4 and the second and second polysilicon 3;

(2) The suspicious area helps to compress the area where the short-circuit point is located. For example, here, the middle part of the area between the first suspicious area 21 and the output amplifier can be defined as the suspicious area, so that the area where the short-circuit point is located can be reduced by half.

Step S302, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring 8 at the newly defined suspicious area of the group of devices is cut off by local photolithography, and step S303 is executed;

Step S303, measure whether the electrode of the polysilicon 4 and the electrode of the second polysilicon 3 are short-circuited three times, if short-circuited, determine that the short-circuit point is between the suspicious area and the previous-level suspicious area, and perform step S306; otherwise, determine the short-circuit point between the suspicious area and the output amplifier, and perform step S304;

Step S304, judging whether it is necessary to further compress the area where the short-circuit point is located, if yes, execute step S305; otherwise, execute step S312;

The basis for judging whether to further compress the area where the short-circuit point is located is: according to whether the area where the short-circuit point is located is easy to find out the cause of the short-circuit. If the area where the short-circuit point is located is large and it is not easy to find out the cause of the short-circuit, it is necessary to further compress the area where the short-circuit point is located.

Step S305, define a new suspicious area between the suspicious area and the output amplifier, and return to step S302;

Step S306, judging whether it is necessary to further compress the area where the short-circuit point is located, if yes, execute step S307; otherwise, execute step S312;

Step S307, define a new suspicious area between the suspicious area and the previous suspicious area, and execute step S308;

Step S308, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring 8 at the newly defined suspicious area of the group of devices is cut off by local photolithography, and step S309 is executed;

Step S309, measure whether the electrode of the polysilicon 4 and the electrode of the second secondary polysilicon 3 are short-circuited three times, if short-circuited, determine that the short-circuit point is between the suspicious area and the previous-level suspicious area, and return to step S306; otherwise, determine the short-circuit The point is between the suspicious area and the subsequent suspicious area, and step S310 is executed;

Step S310, judging whether it is necessary to further compress the area where the short-circuit point is located, if yes, execute step S311; otherwise, execute step S312;

Step S311, define a new suspicious area between the suspicious area and the subsequent suspicious area; return to step S308;

Step S312, judging the area where the short-circuit point is located.

In the step S10, compressing the area where the short-circuit point is located between the second suspicious area 22 and the third suspicious area 23 includes the following steps:

Define a new suspicious area between the second suspicious area 22 and the third suspicious area 23; and execute step S308.

In the step S11, judging the cause of the short circuit in the fourth suspicious area 24 includes the following steps:

Another group of unqualified EMCCD devices is taken, and the fourth suspicious area 24 of the group of devices is coated with photoresist, exposed, developed, and the exposed area is checked with an electron microscope, and the next step is performed after confirming that there is no photoresist in the exposed area ;

removing the low-temperature silicon dioxide passivation layer above the secondary metal aluminum light-shielding layer 14 in the suspicious area by etching with carbon tetrafluoride or trifluoromethane;

Using chlorine gas or boron trichloride etching to remove the secondary metal aluminum light blocking layer 14 in the suspicious area, inspecting the etched area with an electron microscope, and performing the next step after confirming that there is no secondary metal aluminum residue in the suspicious area;

Detect whether the short-circuit point in the suspicious area disappears. If it disappears, it is determined that the cause of the short-circuit is that the secondary metal aluminum light-shielding layer 14 in this area is connected to the third aluminum wiring 7 and the fourth aluminum wiring 8 through the low-temperature silicon dioxide medium below. cause a short circuit. From a structural point of view, the second secondary polysilicon 3 is superimposed on the polysilicon 1, so the step height is relatively high, and the fourth suspicious area 24 has a relatively high step of the third polysilicon 4 because of its arc-shaped structure; at the edge of the high step There is a problem of poor glue coverage. In the process of manufacturing the EMCCD multiplication region, when the low-temperature silicon dioxide dielectric hole is etched, the low-temperature silicon dioxide dielectric at the edge of the high step is etched, resulting in a short circuit.

Cutting off the fourth aluminum wiring 8 in the suspicious area by local photolithography includes the following steps:

Step S201, apply photoresist at the position of the suspicious area, perform exposure and development, check the exposed area with an electron microscope, and perform step S202 after confirming that there is no photoresist in the exposed area;

Step S202, using carbon tetrafluoride or trifluoromethane to etch the low-temperature silicon dioxide passivation layer at the position of the suspicious area, and then performing step S203; the etching time depends on the thickness and etching rate of the low-temperature silicon dioxide passivation layer Sure;

Step S203, using chlorine gas or boron trichloride to etch the secondary metal aluminum light-blocking layer 14 at the position of the suspicious area, and then inspecting the etched area with an electron microscope, and performing the step after confirming that there is no secondary metal aluminum residue at the position of the suspicious area S204;

Step S204, using carbon tetrafluoride or trifluoromethane to etch the low-temperature silicon dioxide dielectric layer above the fourth aluminum wiring 8 at the position of the suspicious area, and then perform step S205; the etching time depends on the thickness of the low-temperature silicon dioxide dielectric layer and etch rate determination;

Step S205, using chlorine gas or boron trichloride to etch the fourth aluminum wiring 8 at the position of the suspicious area, and then inspecting the etched area with an electron microscope, and performing step S206 after confirming that there is no primary metal aluminum remaining at the position of the suspicious area;

Step S206 , using dry etching and wet etching in sequence to remove the photoresist around the suspicious area, and then cleaning with an organic solution until no photoresist residue is detected by the electron microscope.

The parts not described in the present invention are consistent with the prior art, and will not be repeated here.

The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structures made using the description of the present invention and the contents of the accompanying drawings are directly or indirectly used in other related technical fields, and are equally applicable to the present invention. within the scope of patent protection.

Claims (7)

1. a detection method of EMCCD multiplying region electrode short circuit, is characterized in that, may further comprise the steps: Step S1, define the arc-shaped area at the junction of the EMCCD multiplication area and the horizontal area as the fourth suspicious area, define the side towards the horizontal area in the multiplication area as the front stage, and the side towards the output amplifier as the rear stage, between the output amplifier and the first Between the four suspicious areas, the first suspicious area, the second suspicious area and the third suspicious area are sequentially defined along the fourth aluminum wiring from the rear stage to the front stage; wherein, the first suspicious area is located in the primary metal aluminum light blocking area and the output amplifier between, and close to the primary metal aluminum light blocking area; the second suspicious area and the third suspicious area are both located between the primary metal aluminum light blocking area and the fourth suspicious area, and the second suspicious area is adjacent to the primary metal aluminum light blocking area, The third suspicious area is adjacent to the fourth suspicious area; Step S2, divide the unqualified EMCCD devices of the same batch into multiple groups, and cut off the fourth aluminum wiring in the first suspicious area of one group of unqualified EMCCD devices by local photolithography; Step S3, measure whether the electrodes of the third polysilicon of the group of devices and the electrodes of the second secondary polysilicon are short-circuited, if short-circuited, determine that the short-circuit point is between the first suspicious area and the horizontal area, and perform step S5; otherwise, determine that the short-circuit point is at between the first suspicious area and the output amplifier, and perform step S4; Step S4, compressing the area where the short-circuit point is located between the first suspicious area and the output amplifier; Step S5, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring in the second suspicious area of the group of devices is cut off by local photolithography; Step S6, measure whether the electrode of the tertiary polysilicon of the group of devices is short-circuited with the electrode of the second secondary polysilicon, if short-circuited, determine that the short-circuit point is between the second suspicious area and the first suspicious area, and perform step S7; otherwise, determine If the short-circuit point is between the second suspicious area and the horizontal area, execute step S8; Step S7, judging that the fault location is in the primary metal aluminum light blocking area; Step S8, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring in the third suspicious area of the group of devices is cut off by local photolithography; Step S9, measure whether the electrodes of the tertiary polysilicon of the group of devices and the electrodes of the second secondary polysilicon are short-circuited, if short-circuited, determine that the short-circuit point is between the third suspicious area and the second suspicious area, and perform step S10; otherwise, determine the short-circuit Click on the fourth suspicious area, and execute step S11; Step S10, compressing the area where the short-circuit point is located between the second suspicious area and the third suspicious area; Step S11 , judging the cause of the short circuit in the fourth suspicious area. 2. the detection method of EMCCD multiplication region electrode short circuit according to claim 1, it is characterized in that, in described step S4, between the first suspicious region and output amplifier, compressing the short-circuit point location region comprises the following steps: Step S301, defining a new suspicious area between the first suspicious area and the output amplifier; Step S302, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring at the newly defined suspicious area of the group of devices is cut off by local photolithography; Step S303, measure whether the electrode of the polysilicon three times and the electrode of the second secondary polysilicon are short-circuited, if short-circuited, determine that the short-circuit point is between the suspicious area and the previous-level suspicious area, and perform step S306; otherwise, determine that the short-circuit point is between the suspicious area between the suspicious area and the output amplifier, and perform step S304; Step S304, judging whether it is necessary to further compress the area where the short-circuit point is located, if yes, execute step S305; otherwise, execute step S312; Step S305, define another suspicious area between the suspicious area and the output amplifier, and return to step S302; Step S306, judging whether it is necessary to further compress the area where the short-circuit point is located, if yes, execute step S307; otherwise, execute step S312; Step S307, defining a new suspicious area between the suspicious area and the previous suspicious area; Step S308, another group of unqualified EMCCD devices is taken, and the fourth aluminum wiring at the newly defined suspicious area of the group of devices is cut off by local photolithography; Step S309, measure whether the electrode of the polysilicon three times and the electrode of the second secondary polysilicon are short-circuited, if short-circuited, determine that the short-circuit point is between the suspicious area and the previous-level suspicious area, and return to step S306; otherwise, determine that the short-circuit point is between between the suspicious area and the subsequent suspicious area, and perform step S310; Step S310, judging whether it is necessary to further compress the area where the short-circuit point is located, if yes, execute step S311; otherwise, execute step S312; Step S311, define a new suspicious area between the suspicious area and the subsequent suspicious area; return to step S308; Step S312, judging the area where the short-circuit point is located. 3. the detection method of EMCCD multiplication region electrode short circuit according to claim 2, it is characterized in that, in described step S10, between the second suspicious region and the 3rd suspicious region, compressing the short circuit point location region comprises following step: Define a new suspicious area between the second suspicious area and the third suspicious area; and execute step S308. 4. the detection method of EMCCD multiplication region electrode short circuit according to claim 1, is characterized in that, in described step S11, the short circuit cause of the 4th suspicious region is judged and comprises the following steps: Another group of unqualified EMCCD devices is taken, and the fourth suspicious area of the group of devices is coated with photoresist, exposed, developed, and the exposed area is checked with an electron microscope, and the next step is performed after confirming that there is no photoresist in the exposed area; Etching and removing the low-temperature silicon dioxide passivation layer in the suspicious area; Etching and removing the secondary metal aluminum light-shielding layer in the suspicious area; Detect whether the short-circuit point in the suspicious area disappears. If it disappears, it is determined that the cause of the short-circuit is that the secondary metal aluminum light-shielding layer in this area is connected to the third aluminum wiring and the fourth aluminum wiring through the lower low-temperature silicon dioxide medium to cause a short circuit. 5. according to the detection method of the EMCCD multiplication region electrode short circuit described in any one of claim 1-4, it is characterized in that, adopting local photolithography etching method the 4th aluminum wiring truncation of suspect region comprises the following steps: Step S201, apply photoresist on the suspicious area, perform exposure and development, use an electron microscope to check the exposed area, and perform step S202 after confirming that there is no photoresist in the exposed area; Step S202, etching the low-temperature silicon dioxide passivation layer at the location of the suspicious area; Step S203, etching the secondary metal aluminum light blocking layer at the position of the suspicious area; Step S204, etching the low-temperature silicon dioxide dielectric layer at the location of the suspicious area; Step S205, etching the fourth aluminum wiring at the location of the suspicious area; Step S206 , using dry etching and wet etching in sequence to remove the photoresist around the suspicious area, and cleaning with an organic solution. 6. the detection method of EMCCD multiplication region electrode short circuit according to claim 5, is characterized in that, in described step S202 and step S204, adopt carbon tetrafluoride or trifluoromethane to low temperature silicon dioxide passivation layer and The low temperature silicon dioxide dielectric layer is etched. 7. the detection method of EMCCD multiplication region electrode short circuit according to claim 5, it is characterized in that, in described step S203 and step S205, adopt chlorine or boron trichloride to secondary metal aluminum light-shielding layer and the fourth Aluminum wiring is etched.

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