A connection detection device for semiconductor pipes and a detection method thereof

Abstract

The application discloses a kind of connecting detection device for semiconductor pipeline and its detection method, including detection terminal, connecting cap, reflecting cap and controller.Detection terminal is blown at the same time, with pressure difference sensor collection blowing steady-state pressure value, with ultraviolet light along pipe wall total reflection transmission to reflecting cap reflection return, controller only when double condition meets standard simultaneously determines pipeline blowing qualified.The application is replaced with double parameter quantization detection instead of artificial sense of touch ear, whole process is without pipe contact, without consumable generation, suitable for clean workshop semiconductor pipeline secondary distribution engineering;Effectively solve the inherent defects of single pressure or flow judgment;Double-end independent detection is equivalent to twice verification to the same pipeline, any one end detection exception can be intercepted, reduce the risk of missed detection.

Description

Technical Field

[0001] This invention relates to the field of automated equipment technology for secondary assembly construction of semiconductor equipment, specifically a connection detection device for semiconductor pipelines. Background Technology

[0002] Before installation, each special process gas pipeline in a semiconductor wafer fab must be individually purged with gas to identify its identity and confirm its status. The current industry standard procedure is as follows: the two ends of the pipeline are located on different floors. At one end, an operator connects to a nitrogen pressure cylinder and purges gas, while at the other end, an operator judges the airflow characteristics by touch and hearing to identify the pipeline's circuit. After purging, a label is affixed to the pipe opening, marking the circuit number for subsequent installation verification. However, this existing method has certain problems: firstly, pipeline identification relies entirely on manual qualitative judgment. Different operators may have inconsistent perceptions of airflow characteristics based on touch and hearing, and even the same operator may make different judgments under different circumstances. In the secondary distribution engineering of large wafer fabs, thousands of pipes often need to be processed one by one. The reliability of manual identification is difficult to guarantee. Once the pipe identification is wrong, it will lead to major production accidents such as incorrect pipe connection and gas mixing. Secondly, air blowing identification can only determine the pipe identification and cannot simultaneously confirm whether the pipe itself is intact. Defects such as micro-leakage, partial blockage, and scratches on the inner wall of the pipe cannot be detected by blowing air before installation. Once a defective pipe enters the installation process, subsequent quality problems such as unstable gas supply, process gas turbulence, and particulate contamination will directly impact the production yield. Summary of the Invention

[0003] The purpose of this invention is to provide a connection detection device and method for semiconductor pipelines to solve the problems existing in the background art.

[0004] The technical solution of this invention is implemented as follows: A connection detection device for semiconductor pipelines includes a quick connector, a pressure regulating valve, a connecting pipe, and a connector. The quick connector passes through the end face of the housing and is connected to the connecting pipe inside the housing. The pressure regulating valve, filter, and tee are sequentially connected inside the housing through the connecting pipe. The pressure regulating valve, filter, and tee all pass through the top of the housing. The connector passes through the other end face of the housing and is connected to the tee through the connecting pipe. A sealing plate is installed on the top of the tee, and a differential pressure sensor is installed at the bottom of the sealing plate and inside the tee. Four ultraviolet LEDs are evenly distributed on the end face of the connector. The housing, quick connector, connecting pipe, pressure regulating valve, filter, tee, sealing plate, differential pressure sensor, connector, and ultraviolet LEDs together form a detection terminal. A controller is also embedded inside the housing of the detection terminal. A switch, indicator light, and buzzer are installed on the controller through the housing. The connector of the detection terminal is connected to a connector cap. The top of the connector cap has a vent hole A that connects to the connector. The inner wall of the connector cap has an annular sealing boss A at its root. A sealing ring A is attached to the surface of the annular sealing boss A. The inner wall of the connector cap has an annular elastic clamp A. The top of the connector cap and the area around the vent hole A are integrated with a photosensitive receiver. A contact point is installed in the middle of the inner side of the vent hole A and connected to the photosensitive receiver cable. The other end of the connecting cap is connected to the pipe to be tested, and the other end of the pipe is connected to the reflective cap. The top of the reflective cap has a vent hole B, and the root of the inner wall of the reflective cap has an annular sealing boss B. The surface of the annular sealing boss B is covered with a sealing ring B. The reflective cap has an annular elastic clamp B, and an annular reflective mirror is embedded in the top of the reflective cap and around the vent hole B. The controller is connected to the differential pressure sensor and the ultraviolet LED via a cable; the controller is connected to the photosensitive receiver via a contact contact. The pipeline is deemed to be qualified only when the steady-state pressure value falls within the preset qualified threshold range and the light signal reception intensity reaches the qualified threshold. When qualified, the indicator light is green and the buzzer sounds a short beep; when unqualified, the indicator light is red and the buzzer sounds an intermittent alarm.

[0005] Preferably, the ultraviolet light emitted by the ultraviolet LED enters the end face of the pipe opening at an incident angle of 82°~88° and is transmitted axially along the pipe wall in a total internal reflection manner.

[0006] Preferably, the connecting cap and the reflective cap are made of antistatic polytetrafluoroethylene, and the sealing ring A of the connecting cap and the sealing ring B of the reflective cap are perfluoroether sealing rings.

[0007] Preferably, the preset qualified threshold range is the set pressure value ±6.7%, and the qualified threshold for optical signal receiving intensity is greater than or equal to 20% of the ultraviolet LED emitted light power.

[0008] The detection method of the detection device includes: (1) Install a connecting cap on the pipe opening and push it until the pipe opening end face contacts the annular sealing boss A. The annular elastic clamp A automatically grips the outer wall of the pipe to achieve an airtight seal at the pipe opening end face. Put the reflective cap on the other end of the pipe and push it until the pipe opening end face contacts the annular sealing boss B. The annular elastic clamp B automatically grips the outer wall of the pipe. (2) Insert the test terminal connector into the vent hole A at the top of the connector cap, connect the contact contacts, establish a signal link between the photosensitive receiver and the controller, connect the test terminal quick connector to the external air source, open the external air source valve, press the switch button of the controller, and enter the test program: the differential pressure sensor continuously collects 100 pressure data points and takes the average value as the steady-state pressure value of the blowing air; at the same time, the ultraviolet LED is lit, and the ultraviolet light is incident at an angle of 82°~88° into the end face of the pipe opening, and is axially transmitted along the pipe wall in a total reflection manner to the other end of the pipe opening to the reflector cap. After being reflected by the annular reflector surface of the reflector cap, it returns and is received by the photosensitive receiver of the connector cap. The blowing air is discharged through the pipe from the central vent hole B of the reflector cap. (3) When the steady-state pressure value falls within the preset qualified threshold range and the light signal receiving intensity reaches the qualified threshold, the pipeline is judged to be qualified. At this time, the indicator light is green and the buzzer sounds a short time. When the pressure value is lower than the lower limit, it indicates pipeline leakage. When the pressure value is higher than the upper limit, it indicates pipeline blockage. When the light signal attenuation exceeds the standard, it indicates damage to the inner wall of the pipeline or obstruction by foreign objects. The pipeline is judged to be unqualified. When it is unqualified, the indicator light is red and the buzzer alarms intermittently. (4) Both ends of the pipeline are tested independently, and the test results of both ends are independently verified. After the test of one end is completed, the connecting cap and reflector cap are removed and retrieved. After the test of one end is completed, the test terminal is moved to the other end of the pipeline, the connecting cap is put on, and the reflector cap is put on the original end of the pipeline. The same test operation is performed. After both ends are tested and qualified, the pipeline can enter the installation process. If either end is tested and qualified, the cause must be investigated and the test must be repeated.

[0009] The beneficial effects of this invention are as follows: This invention replaces manual touch and hearing with differential pressure sensors and ultraviolet waveguide detection. It simultaneously detects leaks and blockages based on steady-state pressure values: a pressure below the lower limit triggers a leak alarm, and a pressure above the upper limit triggers a blockage alarm. The ultraviolet waveguide transmission detects the integrity of the pipe wall structure: inner wall damage, detachment of the mirror-polished layer, and excessive light attenuation due to foreign object obstruction. The two signals are independent and complementary; a single parameter's compliance does not trigger a pass judgment, effectively solving the inherent defects of relying solely on pressure or flow rate. Dual-end independent detection is equivalent to verifying the same pipeline twice; an anomaly detected at either end can be intercepted, reducing the risk of missed detections.

[0010] The connector cap and reflector cap of this invention are both externally snapped end-face sealing structures, which do not extend into the inner diameter of the pipe or come into contact with the area through which the high-purity medium flows inside the pipe, thus eliminating the risk of particulate matter precipitation and pipe wall scratches from the source. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of the present invention.

[0012] Figure 2 This is a schematic diagram of the connecting cap of the present invention.

[0013] Figure 3 This is a schematic diagram of the structure of the reflector cap of the present invention.

[0014] In the diagram, 1-detection terminal, 101-shell, 102-quick connector, 103-connecting pipe, 104-pressure regulating valve, 105-filter, 106-te-way, 107-sealing plate, 108-differential pressure sensor, 109-connector, 110-ultraviolet LED, 2-connecting cap, 201-vent A, 202-annular sealing boss A, 203-sealing ring A, 204-annular elastic clamp A, 205-photosensitive receiver, 206-contact contact, 3-reflector cap, 301-vent B, 302-annular sealing boss B, 303-sealing ring B, 304-annular elastic clamp B, 305-annular reflector, 4-controller, 401-switch, 402-indicator light, 403-buzzer, 100-pipeline. Detailed Implementation

[0015] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0016] like Figure 1-3 As shown, a connection detection device for semiconductor pipelines includes a quick connector 102, a pressure regulating valve 104, a connecting pipe 103, and a connector 109. The quick connector 102 passes through the end face of the housing 101. The quick connector 102 is connected to the connecting pipe 103 inside the housing 101. The pressure regulating valve 104, filter 105, and tee 106 are sequentially connected to the connecting pipe 103 inside the housing 101. The pressure regulating valve 104, filter 105, and tee 106 all pass through the top of the housing 101. The connector 109 passes through the other end face of the housing 101 and is connected to the tee 106 via the connecting pipe 103. The top of the tee 106... A sealing plate 107 is installed, and a differential pressure sensor 108 is installed at the bottom of the sealing plate 107 and inside the tee 106. Four ultraviolet LEDs 110 are evenly distributed on the end face of the connector 109. The housing 101, quick connector 102, connecting pipe 103, pressure regulating valve 104, filter 105, tee 106, sealing plate 107, differential pressure sensor 108, connector 109 and ultraviolet LEDs 110 together form a detection terminal 1. A controller 4 is also embedded inside the housing 101 of the detection terminal 1. A switch 401, an indicator light 402 and a buzzer 403 are installed on the controller 4 through the housing 101. The connector 109 of the detection terminal 1 is connected to a connector cap 2. The top of the connector cap 2 has a vent hole A201 that is connected to the connector 109. The inner wall of the connector cap 2 has an annular sealing boss A202 at the root. The surface of the annular sealing boss A202 is covered with a sealing ring A203. The inner wall of the connector cap 2 has an annular elastic clamp A204. The top of the connector cap 2 and the area around the vent hole A201 are integrated with a photosensitive receiver 205. A contact contact 206 is installed in the middle of the inner side of the vent hole A201 and is connected to the photosensitive receiver 205 by a cable. The other end of the connecting cap 2 is connected to the pipe 100 to be tested, and the other end of the pipe 100 is connected to the reflective cap 3. The top of the reflective cap 3 is provided with a vent hole B301. The root of the inner wall of the reflective cap 301 is provided with an annular sealing boss B302. The surface of the annular sealing boss B302 is covered with a sealing ring B303. The reflective cap is provided with an annular elastic clamp B304. An annular reflective mirror 305 is embedded in the top of the reflective cap 3 and around the vent hole B301. The controller 4 is connected to the differential pressure sensor 108 and the ultraviolet LED 110 via a cable; the controller 4 is connected to the photosensitive receiver 205 via a contact contact 206. The air blowing in the pipeline 100 is deemed qualified only when the steady-state pressure value falls within the preset qualified threshold range and the light signal reception intensity reaches the qualified threshold. When qualified, the indicator light 402 is green and the buzzer 403 sounds a short beep; when unqualified, the indicator light 402 is red and the buzzer 403 sounds an intermittent alarm.

[0017] The detection method of the detection device includes: (1) Install the connecting cap 2 on the pipe opening of pipe 100 and push it until the end face of pipe opening of pipe 100 contacts the annular sealing boss A202. The annular elastic clamp A204 automatically clamps the outer wall of the pipe to achieve an airtight seal at the pipe opening end. Install the reflective cap 3 on the other end of pipe 100 and push it until the end face of pipe opening of pipe 100 contacts the annular sealing boss B302. The annular elastic clamp B304 automatically clamps the outer wall of the pipe. (2) The connector 109 of the detection terminal 1 is inserted into the vent hole A201 on the top of the connecting cap 2, the contact contact 206 is connected, and a signal link is established between the photosensitive receiver 205 and the controller 4. The quick connector 102 of the detection terminal 1 is connected to the external air source, the external air source valve is opened, and the switch 401 button of the controller 4 is pressed to enter the detection program: the differential pressure sensor 108 continuously collects 100 pressure data points and takes the average value as the blowing steady-state pressure value; at the same time, the ultraviolet LED 110 is lit, and the ultraviolet light is incident at an angle of 82°~88° into the end face of the pipe 100, and is axially transmitted along the pipe wall in a total reflection manner to the other end of the pipe 100 to the reflector cap 3. After being reflected by the annular reflector surface 305 of the reflector cap 3, it returns and is received by the photosensitive receiver 205 of the connecting cap 2. The blowing gas is discharged through the pipe 100 from the central vent hole B301 of the reflector cap 3. (3) When the steady-state pressure value falls within the preset qualified threshold range and the light signal receiving intensity reaches the qualified threshold, the air blowing of pipe 100 is deemed qualified. At this time, the indicator light 402 is green and the buzzer 403 sounds a short time. When the pressure value is lower than the lower limit, it indicates that pipe 100 is leaking. When the pressure value is higher than the upper limit, it indicates that pipe 100 is blocked. When the light signal attenuation exceeds the standard, it indicates that the inner wall of pipe 100 is damaged or blocked by foreign objects. The air blowing of pipe 100 is deemed unqualified. When it is unqualified, the indicator light 402 is red and the buzzer 403 alarms intermittently. (4) Both ends of the pipeline 100 are tested independently, and the test results of both ends are verified independently. After the test of one end is completed, the connecting cap 2 and the reflective cap 3 are removed and retrieved. After the test of one end is completed, the test terminal is moved to the other end of the pipeline 100, the connecting cap 2 is put on, and the reflective cap 3 is put on the original end of the pipeline 100. The same test operation is performed. After both ends are tested and qualified, the pipeline 100 can enter the installation process. If either end is tested and qualified, the cause must be investigated and the test must be repeated. Example

[0018] In a cleanroom of a 12-inch wafer fab, the pipeline has been installed but has not yet been connected to the main system and equipment. The gas pipeline is made of stainless steel and has two 90° bends. The total length is 18m and the inner wall thickness Ra≤0.4μm.

[0019] The detection terminal 1 is set to output pressure of 0.3MPa and flow rate of 2L / min. When the switch 401 button is pressed, the differential pressure sensor 108 continuously collects 100 points with an average value of 0.297MPa. The ultraviolet LED 110 is lit, the ultraviolet incident angle is 82°, and the ultraviolet light is transmitted to the reflector cap 3 by total internal reflection along the pipe wall and then reflected back to the photosensitive receiver 205. The received power is 55% of the transmitted power. The controller 4 determines that both conditions are met, the indicator light 402 turns green, and the buzzer 403 sounds a short beep. Both ends of pipe 100 are tested independently, and the test results at both ends are verified independently. After the test at one end is completed, the connecting cap 2 and the reflector cap 3 are removed and retrieved. After the test at one end is completed, the test terminal is moved to the other end of pipe 100, the connecting cap 2 is put on, and the reflector cap 3 is put on the original end of pipe 100. The same test operation is performed as described above. The steady-state pressure value is 0.298MPa, the light receiving power is 53%, both conditions are met, the indicator light 402 is green, and the buzzer 403 sounds a short beep.

[0020] Therefore, it can be determined that this pipeline has passed the 100% inspection. Example

[0021] In a cleanroom of a 12-inch wafer fab, the pipeline has been installed but has not yet been connected to the main system and equipment. The gas pipeline is made of stainless steel and has three 90° bends. The total length is 30m and the inner wall thickness Ra≤0.4μm.

[0022] The detection terminal 1 is set to output pressure of 0.4MPa and flow rate of 2L / min. When the switch 401 button is pressed, the differential pressure sensor 108 continuously collects 100 points with an average value of 0.398MPa. The ultraviolet LED 110 is lit, the ultraviolet incident angle is 85°, and the ultraviolet light is transmitted to the reflector cap 3 by total internal reflection along the pipe wall and then reflected back to the photosensitive receiver 205. The received power is 63% of the transmitted power. The controller 4 determines that both conditions are met, the indicator light 402 turns green, and the buzzer 403 sounds a short beep. Both ends of pipe 100 are tested independently, and the test results at both ends are independently verified. After the test at one end is completed, the connecting cap 2 and the reflector cap 3 are removed and retrieved. After the test at one end is completed, the test terminal is moved to the other end of pipe 100, the connecting cap 2 is put on, and the reflector cap 3 is put on the original end of pipe 100. The same test operation is performed as described above. The steady-state pressure value is 0.397MPa, the light receiving power is 65%, both conditions are met, the indicator light 402 is green, and the buzzer 403 sounds a short beep.

[0023] Therefore, it can be determined that this pipeline has passed the 100% inspection. Example

[0024] In a cleanroom of a 12-inch wafer fab, the pipeline has been installed but has not yet been connected to the main system and equipment. The gas pipeline is made of stainless steel and has four 90° bends, with a total length of 50m and an inner wall Ra≤0.4μm.

[0025] The detection terminal 1 is set to output pressure of 0.5MPa and flow rate of 2L / min. When the switch 401 button is pressed, the differential pressure sensor 108 continuously collects 100 points with an average value of 0.497MPa. The ultraviolet LED 110 is lit, the ultraviolet incident angle is 88°, and the ultraviolet light is transmitted by total internal reflection along the pipe wall to the reflector cap 3 and then reflected back to the photosensitive receiver 205. The received power is 33% of the transmitted power. The controller 4 determines that both conditions are met, the indicator light 402 turns green, and the buzzer 403 sounds a short beep. Both ends of pipe 100 are tested independently, and the test results at both ends are verified independently. After the test at one end is completed, the connecting cap 2 and the reflector cap 3 are removed and retrieved. After the test at one end is completed, the test terminal is moved to the other end of pipe 100, the connecting cap 2 is put on, and the reflector cap 3 is put on the original end of pipe 100. The same test operation is performed as described above. The steady-state pressure value is 0.496MPa, the light receiving power is 31%, both conditions are met, the indicator light 402 is green, and the buzzer 403 sounds a short beep.

[0026] Therefore, it can be determined that this pipeline has passed the 100% inspection.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A connection detection device for semiconductor pipelines, comprising a quick connector, a pressure regulating valve, a connecting pipe, and a connector, characterized in that, The quick connector passes through the end face of the housing. Inside the housing, the quick connector is connected to a connecting pipe. Inside the housing, a pressure regulating valve, a filter, and a tee are sequentially connected via the connecting pipe. The pressure regulating valve, filter, and tee all pass through the top of the housing. The connector passes through the other end face of the housing and is connected to the tee via the connecting pipe. A sealing plate is installed on the top of the tee. A differential pressure sensor is installed at the bottom of the sealing plate and on the inside of the tee. Ultraviolet LEDs are evenly distributed around the end face of the connector. The housing, quick connector, connecting pipe, pressure regulating valve, filter, tee, sealing plate, differential pressure sensor, connector, and ultraviolet LEDs together constitute a detection terminal. Inside the housing of the detection terminal, a controller is also embedded. A switch, indicator light, and buzzer are installed on the controller through the housing. The connector of the detection terminal is connected to a connector cap. The top of the connector cap has a vent hole A that connects to the connector. The inner wall of the connector cap has an annular sealing boss A at its root. A sealing ring A is attached to the surface of the annular sealing boss A. The inner wall of the connector cap has an annular elastic clamp A. The top of the connector cap and the area around the vent hole A are integrated with a photosensitive receiver. A contact point is installed in the middle of the inner side of the vent hole A and connected to the photosensitive receiver cable. The other end of the connecting cap is connected to the pipe to be tested, and the other end of the pipe is connected to the reflective cap. The top of the reflective cap has a vent hole B, and the root of the inner wall of the reflective cap has an annular sealing boss B. The surface of the annular sealing boss B is covered with a sealing ring B. The reflective cap has an annular elastic clamp B, and an annular reflective mirror is embedded in the top of the reflective cap and around the vent hole B. The controller is connected to the differential pressure sensor and the ultraviolet LED via a cable; the controller is connected to the photosensitive receiver via a contact contact. The pipeline is deemed to be qualified only when the steady-state pressure value falls within the preset qualified threshold range and the light signal reception intensity reaches the qualified threshold. When qualified, the indicator light is green and the buzzer sounds a short beep; when unqualified, the indicator light is red and the buzzer sounds an intermittent alarm.

2. The connection detection device for semiconductor pipelines according to claim 1, characterized in that, The ultraviolet LEDs are four in number and are evenly distributed around the end face of the connector.

3. The connection detection device for semiconductor pipelines according to claim 1, characterized in that, The ultraviolet light emitted by the ultraviolet LED enters the end face of the pipe opening at an incident angle of 82°~88° and is transmitted axially along the pipe wall by total internal reflection.

4. The connection detection device for semiconductor channels according to claim 1, characterized in that, The connecting cap and the reflector cap are made of antistatic polytetrafluoroethylene, and the sealing ring A of the connecting cap and the sealing ring B of the reflector cap are perfluoroether sealing rings.

5. The connection detection device for semiconductor pipelines according to claim 1, characterized in that, The preset qualified threshold range is set pressure value ±6.7%, and the qualified threshold for optical signal receiving intensity is greater than or equal to 20% of the ultraviolet LED emitted light power.

6. A connection detection method for semiconductor channels, characterized in that, The connection detection device according to any one of claims 1 to 5 includes the following steps: (1) Install a connecting cap on the pipe opening and push it until the pipe opening end face contacts the annular sealing boss A. The annular elastic clamp A automatically grips the outer wall of the pipe to achieve an airtight seal at the pipe opening end face. Put the reflective cap on the other end of the pipe and push it until the pipe opening end face contacts the annular sealing boss B. The annular elastic clamp B automatically grips the outer wall of the pipe. (2) Insert the test terminal connector into the vent hole A at the top of the connector cap, connect the contact contacts, establish a signal link between the photosensitive receiver and the controller, connect the test terminal quick connector to the external air source, open the external air source valve, press the switch button of the controller, and enter the test program: the differential pressure sensor continuously collects 100 pressure data points and takes the average value as the steady-state pressure value of the blowing air; at the same time, the ultraviolet LED is lit, and the ultraviolet light is incident at an angle of 82°~88° into the end face of the pipe opening, and is axially transmitted along the pipe wall in a total reflection manner to the other end of the pipe opening to the reflector cap. After being reflected by the annular reflector surface of the reflector cap, it returns and is received by the photosensitive receiver of the connector cap. The blowing air is discharged through the pipe from the central vent hole B of the reflector cap. (3) When the steady-state pressure value falls within the preset qualified threshold range and the light signal receiving intensity reaches the qualified threshold, the pipeline is judged to be qualified. At this time, the indicator light is green and the buzzer sounds a short time. When the pressure value is lower than the lower limit, it indicates pipeline leakage. When the pressure value is higher than the upper limit, it indicates pipeline blockage. When the light signal attenuation exceeds the standard, it indicates damage to the inner wall of the pipeline or obstruction by foreign objects. The pipeline is judged to be unqualified. When it is unqualified, the indicator light is red and the buzzer alarms intermittently. (4) Both ends of the pipeline are tested independently, and the test results of both ends are independently verified. After the test of one end is completed, the connecting cap and reflector cap are removed and retrieved. After the test of one end is completed, the test terminal is moved to the other end of the pipeline, the connecting cap is put on, and the reflector cap is put on the original end of the pipeline. The same test operation is performed. After both ends are tested and qualified, the pipeline can enter the installation process. If either end is tested and qualified, the cause must be investigated and the test must be repeated.

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