Light source device and method for testing image sensor chip

Abstract

The present invention provides a light source device for testing image sensor chips, and a chip testing method using the device. The light source device includes: a box, an LED array disposed on the lower surface of the top of the box, a first light-emitting plate and a second light-emitting plate disposed in sequence from high to low within the box, parallel to the top of the box, a lens disposed at the bottom of the box, the lens configured to optically convert incident light from within the box into parallel light and output it to the outside of the box, so as to provide the light to the image sensor chip to be tested that is located outside the box and faces the lens, an infrared laser is also disposed at the bottom of the box, and a one-way reflective film is disposed on the side of the second light-emitting plate facing away from the bottom of the box, the one-way reflective film configured to reflect infrared light emitted by the infrared laser to the lens, so as to provide the light to the image sensor chip to be tested.

Description

Technical Field

[0001] The present invention relates to the field of CI S chip testing, and in particular to a light source device and method for testing an image sensor chip. Background Art

[0002] CMOS (Complementary Metal Oxide Semiconductor) image sensors are manufactured using CMOS technology. Their operating principle is to use a photodiode at each pixel to convert light into a stable electrical signal using an amplifier and A / D converter circuit. Compared to CCD (Charge Coupled Device) image sensors, CMOS image sensors offer several key advantages: low production cost, fast imaging speed, easier system integration, low power consumption, wide dynamic range, and strong radiation resistance. These advantages have led to the rapid growth of CIS (CMOS Image Sensor) chips. Furthermore, with the rapid development of smartphones, the Internet of Things, biometrics, and life sciences, CIS chips have rapidly become one of the most sought-after products in the semiconductor industry.

[0003] After CIS chips are manufactured, they must be tested before they can be shipped to ensure a high yield. The FT (Final Test) test is a pre-shipment test performed on the packaged chips.

[0004] The traditional light source device used for FT testing of CI S chips can only provide parallel light and cannot test the response delay of CI S chips. Summary of the Invention

[0005] In view of this, the present invention provides a light source device and method for testing an image sensor chip, which can provide parallel light for measuring a CIS chip and can also measure the response delay of the CIS chip.

[0006] The present invention provides a light source device for testing an image sensor chip, comprising: a box, an LED lamp bead array being provided on the top lower surface of the box, a first light averaging plate and a second light averaging plate being provided in the box in descending order and parallel to the top of the box, a lens being provided at the bottom of the box, the lens being used to optically convert incident light from the box into parallel light and output it to the outside of the box so as to provide it to the image sensor chip to be tested that is located outside the box and faces the lens, an infrared laser being further provided at the bottom of the box, a one-way reflection film being provided on the side of the second light averaging plate facing away from the bottom of the box, the one-way reflection film being used to reflect infrared light emitted by the infrared laser to the lens so as to provide it to the image sensor chip to be tested.

[0007] With the above structure, the LED light source can provide stable light, and the first and second light-equalizing plates can transform the light into pseudo-natural light, providing suitable environmental conditions for testing. The box can isolate the interference of external light sources and improve the accuracy of the test. The lens can receive the incident light and convert it into parallel light and provide it to the chip to be tested, so that the chip to be tested can receive light in a controllable manner and be tested. The one-way reflection film can reflect the laser emitted by the infrared laser at the bottom into the lens to which it belongs, thereby testing the chip to be tested.

[0008] As a possible implementation, a reflective film is provided on the bottom upper surface of the box; the reflective film and the one-way reflective film are used to reflect the infrared light emitted by the infrared laser to the lens after at least three reflections.

[0009] By adopting the above possible implementation manner, the reflective film can reflect the infrared laser reflected by the one-way reflective film, thereby increasing the optical path and the light propagation time, facilitating observation and adapting to test instruments of different precisions.

[0010] As a possible implementation, heat dissipation holes are provided on the top of the box.

[0011] By adopting the above possible implementation manner, the heat dissipation holes can discharge the heat generated by the LED light source during operation, so as to prevent excessive heat from causing deformation of the material, deviation of the test data, or damage to the equipment.

[0012] As a possible implementation, the positions of the first light averaging plate and the second light averaging plate are adjustable.

[0013] By adopting the above possible implementation, adjusting the second light-diffusing plate can change the optical path length of the infrared laser to meet different testing requirements. Correspondingly adjusting the first light-diffusing plate can maintain the stability of the pseudo-natural light.

[0014] As a possible implementation, a heating rod is further provided at the bottom of the box.

[0015] With the above possible implementation, the heating rod can heat the chip to be tested to simulate the daily operating temperature of the chip to be tested.

[0016] As a possible implementation, a temperature sensor is further provided at the bottom of the box.

[0017] By adopting the above possible implementation manner, the temperature sensor can sense the real-time temperature of the chip to be tested, control the operation of the heating rod, and keep the chip to be tested at a suitable operating temperature.

[0018] The present invention also provides a method for testing an image sensor chip, comprising: placing the image sensor chip to be tested on the outside of the bottom of the box of the light source device for testing the image sensor chip according to any one of claims 1 to 6, at a position directly opposite the lens; turning on the LED lamp bead array to test the image sensor, turning on the infrared laser, and testing the response delay of the image sensor according to the turning-on time of the infrared laser and the imaging time of the image sensor chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following further illustrates the various technical features of the present application and the relationships between them with reference to the accompanying drawings. The accompanying drawings are exemplary, and some technical features are not shown in actual proportion. In addition, some drawings may omit technical features that are commonly used in the technical field to which the present application belongs and are not essential for understanding and implementing the present application, or additional technical features that are not essential for understanding and implementing the present application may be shown. In other words, the combination of the various technical features shown in the accompanying drawings is not intended to limit the present application. In addition, throughout the present application, the same figure numbers refer to the same content. The specific description of the drawings is as follows:

[0020] Figure 1 A schematic cross-sectional view showing the principles of an embodiment of the present invention;

[0021] Figure 2 is an overall schematic diagram of an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of a box according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the bottom of the box according to an embodiment of the present invention;

[0024] Figure 5 This is a top view of the bottom of the box according to an embodiment of the present invention.

[0025] Explanation of the reference numerals: 100 - housing; 110 - upper housing; 111 - heat dissipation holes; 112 - LED lamp beads; 113 - first light-dissipating plate; 120 - lower housing; 121 - second light-dissipating plate; 122 - fixing structure; 123 - second fixing structure; 124 - one-way reflection film; 200 - housing bottom; 210 - lens; 211 - pressure plate; 212 - chip to be tested; 220 - laser device; 221 - laser light outlet; 230 - heating rod; 240 - temperature sensor; 250 - insert waist. DETAILED DESCRIPTION

[0026] Below, the specific implementation methods of the present application are described in detail with reference to the accompanying drawings.

[0027] Unless otherwise defined, all technical and scientific terms used in this application are the same as those commonly understood by those skilled in the art to which this application belongs. In the event of any inconsistency, the meaning described in the full text of this application or the meaning derived from the content recorded in the full text of this application shall prevail. In addition, the terms used in this description are only for the purpose of describing the embodiments of the present application and are not intended to limit this application.

[0028] like Figure 2 FIG. 1 is a schematic diagram of a light emitting device for implementing FT testing of CIS chips according to a first embodiment of the present invention, which includes a housing 100 and a bottom portion thereof, wherein the housing 100 and the bottom portion thereof are connected by a fixing structure 122 .

[0029] <Box 100>

[0030] like Figure 3 The illustrated housing 100 is a rectangular container. Multiple LED lamp beads 112 are disposed on the upper inner wall of the housing 100, which are used to provide ambient light. A first light-diffusing plate 113 and a second light-diffusing plate 121 are disposed parallel to the upper inner wall. The first light-diffusing plate 113 and the second light-diffusing plate 121 are spaced a certain distance apart, with a cavity between them. The first light-diffusing plate 113 is closer to the LED lamp beads 112, while the second light-diffusing plate 121 is farther away. A one-way reflective film 124 is disposed on the underside of the second light-diffusing plate 121. This one-way reflective film 124 is used to reflect light emitted from the lower inner wall, allowing light emitted by the LED lamp beads 112 to pass through the one-way reflective film 124.

[0031] The upper inner wall, the first light-dispersing plate 113, and the housing 100 together form a closed space. In the closed space, the multiple LED lamp beads 112 arranged on the upper inner wall serve as the test light source, which can avoid interference from external light and maintain a stable light source for the FT test.

[0032] The upper side wall of the housing 100 is provided with heat dissipation holes 111 for dissipating heat from the LED lamp beads 112, so as to keep the device able to operate at a normal operating temperature for a long time. In this embodiment, the temperature is less than or equal to 65 degrees Celsius.

[0033] The housing 100 can be divided into an upper housing 110 and a lower housing 120 with the second light homogenizing plate 121 as a boundary, and the upper housing 110 and the lower housing 120 are connected by a second fixing structure 123 .

[0034] When customizing / assembling the device of this embodiment, the distance between the upper inner wall and the first light diffuser 113, as well as the distance between the first light diffuser 113 and the second light diffuser 121, should be determined. The distance between the second light diffuser 121 and the lower inner wall should then be designed and set based on specific requirements. The design height of the lower housing 120 is the distance between the second light diffuser 121 and the lower inner wall.

[0035] In addition, a reflector can also be provided on the emission side of the infrared laser light source to allow the laser to enter the lens 210 after multiple refractions, thereby extending the optical path, making observation more convenient, and being adaptable to more test instruments.

[0036] In this embodiment, the box body 100 should be made of a light-proof material with a certain degree of high temperature resistance, such as aluminum alloy.

[0037] In this embodiment, the fixed connection structure can be a bolt structure. In addition, other structures, such as a snap-fit ​​structure, can also be used.

[0038] In this embodiment, the first light homogenizing plate 113 and the second light homogenizing plate 121 are made of the same material, which may be PMMA (Polymethyl Methacrylate).

[0039] <Box bottom 200>

[0040] like Figure 4 As shown, the bottom 200 of the box is provided with a laser device 220 , a lens 210 , an insert waist 250 , a chip to be tested 212 , a heating rod 230 and a temperature sensor 240 .

[0041] Lens 210 is covered with a pressure plate 211 to secure it. Below lens 210 is a chip under test 212. A heating rod and temperature sensor are positioned around chip under test 212. An infrared laser emitter is also positioned on the same level as lens 210. All of these devices are mounted on the insert waist 250.

[0042] The heating rod 230 is used to heat the chip under test 212 to an operating temperature, and the temperature sensor 240 is used to detect the temperature of the chip under test 212 to prevent the chip under test 212 from being damaged by excessive temperature.

[0043] In this embodiment, if Figure 5 As shown, four lenses 210, chips under test 212, and four infrared laser emitters are provided. The two infrared laser emitters are integrated into a laser device 220. Each laser device 220 has two laser light outlets 221. Each pair of lenses 210 and chips under test 212 are symmetrically arranged around a laser device 220. Therefore, this embodiment can test four chips simultaneously.

[0044] In this embodiment, the heating rod 230 may be a heating resistor.

[0045] In this embodiment, the infrared laser emitter can be a VCSEL (Vertical-Cavity Surface-Emitting Laser) light source. Preferably, when using a VCSEL light source, heat dissipation holes should be added to the bottom 200 of the box according to actual conditions to ensure the normal operation of the VCSEL light source.

[0046] <Circuit>

[0047] The device provided by the present invention is controlled by a control circuit and driven by a driving circuit. The driving circuit is used to generate a cross-current driving unit, and the control circuit is used to generate a control signal for controlling brightness.

[0048] In this embodiment, a digital programmable power supply can be used to realize the integration of the control circuit and the drive circuit, and a test power supply can be used to simultaneously control and drive the device.

[0049] The term "comprising" used throughout this application should not be interpreted as being restricted to what is listed thereafter; it does not exclude other structural elements or steps.

[0050] It can be understood that those skilled in the art can combine the features mentioned in one or more embodiments mentioned throughout the present application with the features of other embodiments in any appropriate manner to implement the present application.

[0051] Note that the above are only preferred embodiments of the present application and the technical principles employed. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the technical concept of the present application, all of which fall within the scope of protection of the present application.

Claims

1. A light source device for testing an image sensor chip, characterized in that: include: The box body has an LED lamp array on the top lower surface. The box body is provided with a first light emitting plate and a second light emitting plate in order from high to low and parallel to the top of the box body. A lens is provided at the bottom of the box, and is used to optically transform the incident light from the box into parallel light and output it to the outside of the box, so as to provide it to the image sensor chip to be tested facing the lens on the outside of the box. The bottom of the box is also provided with an infrared laser. A one-way reflection film is provided on a side of the second light-averaging plate facing away from the bottom of the box, and the one-way reflection film is used to reflect the infrared light emitted by the infrared laser to the lens to provide it to the image sensor chip to be tested.

2. The device according to claim 1, characterized in that A reflective film is provided on the upper surface of the bottom of the box; the reflective film and the one-way reflective film are used to reflect the infrared light emitted by the infrared laser to the lens after at least three reflections.

3. The device according to claim 1, characterized in that The top of the box is provided with heat dissipation holes.

4. The device according to claim 1, characterized in that The positions of the first light averaging plate and the second light averaging plate are adjustable.

5. The device according to claim 1, characterized in that A heating rod is also provided at the bottom of the box.

6. The device according to claim 5, characterized in that A temperature sensor is also provided at the bottom of the box.

7. A method for testing an image sensor chip, characterized in that: include: Placing the image sensor chip to be tested on the outer side of the bottom of the box of the light source device for testing image sensor chips according to any one of claims 1 to 6, facing the lens; Turn on the LED array to test the image sensor. The infrared laser is turned on, and the response delay of the image sensor is tested according to the turning-on time of the infrared laser and the imaging time of the image sensor chip.

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