Test structure and test method

Abstract

The present application relates to the technical field of semiconductor, and provides a test structure and a test method. By forming a test structure in a local area of a wafer or a chip to be accepted, the performance and characteristic parameters of a measured optical device are evaluated by inputting an optical signal to the test structure and testing the output optical signal or electrical signal processed by the measured optical device, so as to complete the acceptance test of the wafer.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically, to test structures and test methods. Background Technology

[0002] In the process of photonic semiconductor manufacturing, failure to inspect the wafers produced upstream will lead to a decrease in the yield of photonic semiconductor products and generate a lot of wasted effort and human and material resources.

[0003] Existing technologies typically involve visual inspection of wafers, which is insufficient to detect internal defects and manufacturing process deviations. Therefore, this technical field lacks an effective method for accepting newly arrived wafers. Summary of the Invention

[0004] This invention provides a test structure and test method that can be used for wafer acceptance testing.

[0005] On one hand, embodiments of the present invention provide a test structure formed in a designated area of ​​a wafer or chip, comprising:

[0006] An input optical coupler is used to couple the input optical signal into the test structure;

[0007] An output optical coupler is used to output the output optical signal of the test structure;

[0008] A first optical device under test is connected between the input optical coupler and the output optical coupler, wherein the input optical signal is input to the first optical device under test via the input optical coupler, and the optical signal output by the first optical device under test is output via the output optical coupler;

[0009] First photoelectric converter;

[0010] A second optical device under test is connected between the input optical coupler and the first photoelectric converter, wherein the input optical signal is input to the second optical device under test via the input optical coupler, and the optical signal output by the second optical device under test is converted into an electrical signal by the first photoelectric converter; and

[0011] A first electrical contact is electrically connected to the first photoelectric converter, wherein an electrical signal from the first photoelectric converter is output to the outside via the first electrical contact.

[0012] In some embodiments, the first optical device under test and the second optical device under test are selected from beam splitters and optical modulators.

[0013] In some embodiments, the first and second optical devices under test are selected from MMI (Multi-mode Inferometer), directional couplers, Y-type beam splitters, polarization beam splitters, and polarization rotators.

[0014] In some embodiments, the test structure further includes a third optical device under test and a second electrical contact, wherein the third optical device under test includes a second photoelectric converter; wherein the second photoelectric converter is connected to the input optical coupler and the second electrical contact, and the electrical signal output by the second photoelectric converter is output to the outside via the second electrical contact.

[0015] In some embodiments, the first optical device under test includes an optical modulator, and the test structure further includes a third electrical contact for inputting an electrical signal to the optical modulator.

[0016] In some embodiments, the first optical device under test, the second optical device under test, and the third optical device are connected to the input optical coupler via one or more beam splitters.

[0017] In some embodiments, the test structure includes a beam splitter that distributes the input optical signal to the first optical device under test and the second optical device under test.

[0018] In some embodiments, the test structure includes an alignment optical coupler for aligning the test structure with an external fiber optic array.

[0019] In some embodiments, the input optical coupler, the output optical coupler, and the alignment optical coupler respectively include a vertical coupler or a horizontal coupler.

[0020] On the other hand, embodiments of the present invention provide a testing method wherein the test structure described in any of the above embodiments is formed on the wafer to be inspected, the testing method comprising:

[0021] Test light signals are input to the first and second optical devices under test via the input optical coupler in the test structure.

[0022] The optical signal output by the first optical device under test is output via the output optical coupler in the test structure;

[0023] The optical signal output by the second optical device under test is converted into an electrical signal by the first photoelectric converter in the test structure, and the electrical signal is output to the external conductive line through the first electrical contact in the test structure.

[0024] Furthermore, embodiments of the present invention also provide a test structure formed in a designated area of ​​a wafer or chip, comprising:

[0025] An input optical coupler is used to couple the input optical signal into the test structure;

[0026] An output optical coupler is used to output the output optical signal of the test structure;

[0027] A first optical device under test is connected between the input optical coupler and the output optical coupler, wherein the input optical signal is input to the first optical device under test via the input optical coupler, and the optical signal output by the first optical device under test is output via the output optical coupler;

[0028] The third optical device under test includes a second photoelectric converter;

[0029] Second electrical contact;

[0030] The second photoelectric converter is connected to the input optocoupler and the second electrical contact, and the electrical signal output by the second photoelectric converter is output to the outside via the second electrical contact.

[0031] Furthermore, embodiments of the present invention also provide a test structure formed in a designated area of ​​a wafer or chip, comprising:

[0032] At least one input optical coupler is provided for coupling at least one input optical signal into the test structure, wherein the at least one input optical coupler includes a first input optical coupler.

[0033] Multiple output optical couplers are used to output multiple output optical signals of the test structure;

[0034] A plurality of optical devices under test are connected between the at least one input optical coupler and the plurality of output optical couplers, wherein the at least one input optical signal is input to the plurality of optical devices under test via the at least one input optical coupler, and the optical signals output by the plurality of optical devices under test are output via the plurality of output optical couplers.

[0035] According to various embodiments of the present invention, by forming a test structure in a local area of ​​a wafer to be accepted, and by testing its performance or characteristic parameters, it is possible to reflect whether the wafer's manufacturing process or the optical devices corresponding to the optical devices under test in the chips (or dies) manufactured by the wafer are functioning properly. By inputting an optical signal into the test structure and testing the optical or electrical signals processed and output by the optical devices under test, the performance and characteristic parameters of the optical devices under test are evaluated, thereby completing the wafer acceptance test. Specifically, by measuring the characteristic parameters of the relevant devices under test in the test structure on the wafer, it is determined whether there are any abnormalities in the fabrication of the relevant devices, thereby determining whether the wafer's process is abnormal, thus achieving the purpose of rapid and effective wafer acceptance. In addition, the test structure is also applicable to the rapid acceptance of chips.

[0036] Various aspects, features, advantages, etc., of the embodiments of the present invention will be specifically described below in conjunction with the accompanying drawings. These aspects, features, advantages, etc., will become clearer from the following detailed description in conjunction with the accompanying drawings. Attached Figure Description

[0037] Figure 1 This is a schematic diagram showing a wafer having a test structure according to an embodiment of the present invention.

[0038] Figure 2 This is a block diagram illustrating a test structure according to a first embodiment of the present invention.

[0039] Figure 3 This is a block diagram illustrating a test structure according to a second embodiment of the present invention.

[0040] Figure 4 This is a block diagram illustrating a test structure according to a third embodiment of the present invention.

[0041] Figure 5 This is a block diagram illustrating a test structure according to an exemplary embodiment of the present invention.

[0042] Figure 6 This is a schematic diagram illustrating an exemplary application scenario of a test structure according to an embodiment of the present invention. Detailed Implementation

[0043] In the following description, exemplary embodiments will be described in more detail with reference to the accompanying drawings. However, the invention may be embodied in various different forms and should not be construed as limited to the embodiments shown herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and comprehensive, and will fully convey to those skilled in the art various aspects and features of the invention. Therefore, processes, elements, and techniques not necessary for those skilled in the art to fully understand the various aspects and features of the invention may not be described. Unless otherwise stated, similar reference numerals denote similar elements throughout the drawings and textual description, and therefore their description may not be repeated. Furthermore, features or aspects within each exemplary embodiment should generally be considered as other similar features or aspects that may be used in other exemplary embodiments.

[0044] Certain terms may be used in the following description for informational purposes only and are not intended to be limiting. For example, terms such as “top,” “bottom,” “upper,” “lower,” “above,” and “below” may be used to refer to orientation in the accompanying drawings, which are referenced. Terms such as “front,” “back,” “rear,” “side,” “outer,” and “inner” may be used to describe the orientation and / or position of parts of a component within a consistent but arbitrary frame of reference, which can be clearly understood by referring to the text describing the component in question and the associated drawings. Such terms may include words specifically mentioned above, their derivatives, and words with similar meanings. Similarly, unless the context clearly indicates otherwise, the terms “first,” “second,” and other such denotative numerical terms do not imply order or sequence.

[0045] It should be understood that when an element or feature is referred to as "on another element or layer," "connected to," or "attached to" another element or layer, it may be directly on, connected to, or attached to the other element or feature, or there may be one or more intermediate elements or features. Furthermore, it should be understood that when an element or feature is referred to as "between" two elements or features, it may be the only element or feature between the two elements or features, or there may be one or more intermediate elements or features.

[0046] The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the invention. As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” and “having” as used herein specify the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of…” modify the entire list of elements when preceding it, rather than individual elements of the list.

[0047] As used herein, the terms “substantially,” “about,” and similar terms are used as approximations rather than as terms of degree, and are intended to take into account the inherent variations in measured or calculated values ​​that will be recognized by those skilled in the art. Furthermore, the use of “may” in describing embodiments of the invention refers to “one or more embodiments of the invention.” As used herein, the terms “use,” “being used,” and “being utilized” can be considered synonymous with the terms “utilize,” “being utilized,” and “being exploited,” respectively.

[0048] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that, unless expressly defined herein, terms (such as those defined in common dictionaries) should be interpreted as having the same meaning as they have in the relevant field and / or the context of this specification, and should not be interpreted in an idealized or overly formal sense.

[0049] like Figure 1 As shown, this embodiment of the invention forms a test structure 200 in a local area (defined area) of the wafer 100 to be accepted. By inputting an optical signal into the test structure 200 and testing the optical or electrical signals output by the optical device under test (DUT) within the test structure 200, the performance and characteristic parameters of the DUT are evaluated, thereby completing the acceptance test of the wafer 100. Specifically, by measuring the characteristic parameters of the relevant DUTs in the test structure 200 on the wafer 100, it is determined whether there are any abnormalities in the fabrication of the relevant devices, thereby determining whether the wafer 100's process is abnormal, thus achieving the purpose of rapid and effective wafer acceptance. In some embodiments, the wafer 100 may include multiple chips, and the test structure 200 may be formed in a local area of ​​each chip on the wafer.

[0050] The test structure 200 will be described in detail below in the form of an implementation method.

[0051] [First Implementation Method]

[0052] Figure 2 A test structure according to a first embodiment of the present invention is shown. For example... Figure 2 As shown, the test structure 200 includes at least alignment optical couplers 211A and 211B, input optical couplers 212A and 212B, output optical coupler 213, a first optical device under test 221, a second optical device 222, a photoelectric converter 231, and an electrical contact 241. The first optical device under test 221 is connected between the input optical coupler 212A and the output optical coupler 213, the second optical device under test 222 is connected between the input optical coupler 212B and the photoelectric converter 231, and the photoelectric converter 231 is electrically connected to the electrical contact 241.

[0053] In this embodiment, alignment optical couplers 211A and 211B are used to align the test structure 200 with an external fiber optic array, which is connected to external testing equipment. In some embodiments, the external testing equipment includes a multi-channel power meter, a tunable laser, a coupled power meter, a coupled laser, a control computer, etc. In some embodiments, the optical signal from the coupled laser is transmitted to alignment optical coupler 211A via the external fiber optic array, then to alignment optical coupler 211B via the internal waveguide of the test structure 200, and then output via alignment optical coupler 211B. It then passes through the external fiber optic array and is transmitted to the coupled power meter. The alignment of the test structure 200 with the external fiber optic array is determined by the intensity of the optical signal measured by the coupled power meter.

[0054] Once the test structure 200 is aligned and connected to the external fiber array via the alignment optical couplers 211A and 211B, the input optical couplers 212A and 212B and the output optical coupler 213 are respectively connected to the input fiber and the output fiber of the external fiber array.

[0055] After the test begins, the input optical signal (i.e., the test optical signal) from the light source (e.g., a tunable laser) is transmitted to the input optical coupler 212A via the input optical fiber of the external fiber array. The input optical coupler 212A inputs the input optical signal to the first optical device under test 221. The first optical device under test 221 processes the input optical signal and generates an output optical signal. The output optical signal is output to the output optical fiber of the external fiber array via the output optical coupler 213, and then transmitted to external related test equipment, such as a power meter, via the output optical signal to process the output optical signal to test the performance, characteristic parameters, etc. of the first optical device under test 221. An input optical signal (i.e., a test optical signal) from another light source is transmitted to an input optical coupler 212B via an input optical fiber of an external fiber array. The input optical coupler 212B inputs the input optical signal to a second optical device under test (DUT) 222. The second DUT 222 processes the input optical signal and outputs an optical signal. This output optical signal is converted into an electrical signal by a photoelectric converter 231. The electrical signal is then output to the outside via an electrical contact 241, for example, via an external conductive line to relevant testing equipment, so that the performance and characteristic parameters of the second DUT 222 can be obtained by processing the electrical signal. In an optional embodiment, the optical signals input to the input optical couplers 212A and 212B can originate from the same light source. For example, the optical signal emitted from the same light source is split into two paths by a splitter and enters the input optical couplers 212A and 212B respectively.

[0056] In some embodiments, the performance or characteristic parameters of the first optical device under test 221 and the second optical device under test 222 are highly sensitive to the wafer manufacturing process, or they are the same as at least one optical device in the chip (or die) manufactured by the wafer. In some embodiments, the first optical device under test 221 is selected from beam splitters, optical modulators, MMIs, directional couplers, Y-type beam splitters, polarization beam splitters, and polarization rotators.

[0057] In some embodiments, the second optical device under test 222 includes one or more of a 5:95 beam splitter and a 10:90 beam splitter.

[0058] In some embodiments, where the first optical device under test 221 includes an optical modulator, the test structure 200 further includes additional electrical contacts (not shown) for inputting electrical signals to the optical modulator.

[0059] In some embodiments, the electrical contacts in the test structure 200 for electrical connection include electrodes, solder pads, etc. In some embodiments, the electrical contacts in the test structure 200 for electrical connection can be connected to an external probe card to facilitate engagement and electrical connection with the probe tip of an external cable.

[0060] In some embodiments, each optical coupler of the test structure 200 includes a vertical coupler or a horizontal coupler.

[0061] In some embodiments, the test structure 200 may include a plurality of first optical devices under test (DUTs) and / or a plurality of second optical devices under test (DUTs). In some embodiments, the plurality of first DUTs and / or the plurality of second DUTs may be connected to an input optical coupler via one or more beam splitters. Compared to having separate input optical couplers for each DUT, the use of beam splitters reduces the number of input optical couplers, and consequently reduces the number of optical fibers and light sources, thereby reducing test costs.

[0062] exist Figure 2 In the first embodiment shown, the optical and electrical signals output by the test structure 200 are processed to obtain the performance and parameters of the relevant optical device under test, thereby enabling the evaluation of the performance and process of the corresponding wafer for wafer acceptance.

[0063] [Second Implementation Method]

[0064] Figure 3 A test structure according to a second embodiment of the present invention is shown. For example... Figure 3 As shown, the test structure 200 includes at least alignment optical couplers 211A and 211B, an input optical coupler 212, an output optical coupler 213, a first optical device under test 221, a second optical device under test 222, a photoelectric converter 231, an electrical contact 241, and a beam splitter 251. The input end of the beam splitter 251 is connected to the input optical coupler 212, splitting one optical path through the input optical coupler 212 into two output paths. One output end (one path) of the beam splitter 251 is connected to the first optical device under test 221, and the other output end (the other path) is connected to the second optical device under test 222. Figure 3 As shown, the first optical device under test 221 is connected between one output terminal of the beam splitter 251 and the output optical coupler 213, and the second optical device under test 222 is connected between the other output terminal of the beam splitter 251 and the photoelectric converter 231. The photoelectric converter 231 is electrically connected to the electrical contact 241. The beam splitter 251 can split the input optical signal into multiple paths, thereby distributing the input optical signal to the first optical device under test 221 and the second optical device under test 222. For example, the number of optical path branches can be selected according to the number of optical devices under test; for example, the beam splitter 251 can split the light into 2, 3, 6, or more paths. The beam splitter 251 can be a Y-type waveguide, a directional coupler, a multimode interferometer, etc.

[0065] In this embodiment, alignment optical couplers 211A and 211B are used to align the test structure 200 with an external fiber optic array, which is connected to external test-related equipment. Once the test structure 200 is aligned and connected to the external fiber optic array via alignment optical couplers 211A and 211B, input optical coupler 212 and output optical coupler 213 are connected to the input and output optical fibers of the external fiber optic array, respectively.

[0066] After the test begins, the input optical signal (i.e., the test optical signal) from the light source (e.g., a tunable laser) is transmitted to the input optical coupler 212 via the input optical fiber of the external fiber array. The input optical coupler 212 inputs the input optical signal to the beam splitter 251, which splits the input optical signal into two paths and transmits them to the first optical device under test 221 and the second optical device under test 222, respectively.

[0067] The first optical device under test 221 processes the input optical signal and generates an output optical signal. The output optical signal is output to the output optical fiber of the external optical fiber array via the output optical coupler 213, and then transmitted to the external related test equipment, such as a power meter, via the output optical fiber to process the output optical signal to test the performance and parameters of the first optical device under test 221.

[0068] The second optical device under test 222 processes the input optical signal and outputs an optical signal. The output optical signal is converted into an electrical signal by a photoelectric converter 231. The electrical signal is output to the outside via an electrical contact 241, for example, via an external conductive line to a relevant test device, so that the performance and parameters of the second optical device under test 222 can be obtained by processing the electrical signal.

[0069] By testing the performance and parameters of the first optical device under test 221 and the second optical device under test 222, the performance and process of the corresponding wafers can be evaluated, thereby eliminating wafers that do not meet the performance and process standards. This avoids unnecessary processing of these substandard wafers in subsequent steps.

[0070] [Third Implementation Method]

[0071] Figure 4 A test structure according to a third embodiment of the present invention is shown. For example... Figure 4As shown, the test structure 200 includes at least alignment optical couplers 211A and 211B, input optical coupler 212, output optical coupler 213, a first optical device under test 221, a second optical device under test 222, a third optical device under test 223, a photoelectric converter 231, electrical contacts 241 and 242, and beam splitters 251 and 252. In this embodiment, the beam splitters 251 and 252 split the single optical path via the input optical coupler 212 into three optical paths for output, and the first optical device under test 221, the second optical device under test 222, and the third optical device under test 223 are respectively located on the three optical paths. Specifically, the input terminal of beam splitter 251 is connected to input optical coupler 212, one output terminal is connected to the first optical device under test 221, and the other output terminal is connected to the input terminal of beam splitter 252; one output terminal of beam splitter 252 is connected to the second optical device under test 222, and the other output terminal is connected to the third optical device under test 223. For example... Figure 4 As shown, the first optical device under test 221 is connected between one output terminal of the beam splitter 251 and the output optical coupler 213; the second optical device under test 222 is connected between one output terminal of the beam splitter 252 and the photoelectric converter 231, the photoelectric converter 231 being electrically connected to the electrical contact 241; and the third optical device under test 223 is connected between the other output terminal of the beam splitter 252 and the electrical contact 242. In some embodiments, the third optical device 223 includes a photoelectric converter such as a photodetector, thereby enabling the measurement of the characteristics of the photoelectric converter itself.

[0072] In this embodiment, alignment optical couplers 211A and 211B are used to align the test structure 200 with an external fiber optic array, which is connected to external test-related equipment. Once the test structure 200 is aligned and connected to the external fiber optic array via alignment optical couplers 211A and 211B, input optical coupler 212 and output optical coupler 213 are connected to the input and output optical fibers of the external fiber optic array, respectively.

[0073] After the test begins, the input optical signal (i.e., the test optical signal) from the light source (e.g., a tunable laser) is transmitted to the input optical coupler 212 via the input optical fiber of the external fiber array. The input optical coupler 212 inputs the input optical signal to the beam splitter 251. The beam splitter 251 splits the input optical signal into two paths and transmits them to the first optical device under test 221 and the beam splitter 252, respectively. The beam splitter 252 further splits the input optical signal into two paths and transmits them to the second optical device under test 222 and the third optical device under test 223, respectively.

[0074] The first optical device under test 221 processes the input optical signal and generates an output optical signal. The output optical signal is output to the output optical fiber of the external optical fiber array via the output optical coupler 213, and then transmitted to the external related test equipment, such as a power meter, via the output optical fiber to process the output optical signal to test the performance and parameters of the first optical device under test 221.

[0075] The second optical device under test 222 processes the input optical signal and outputs an optical signal. The output optical signal is converted into an electrical signal by a photoelectric converter 231. The electrical signal is output to the outside via an electrical contact 241, for example, via an external conductive line to a relevant test device, so that the performance and parameters of the second optical device under test 222 can be obtained by processing the electrical signal.

[0076] The third optical device under test 223 converts the input optical signal into an electrical signal, which is then output to the outside via the electrical contact 242, for example, via an external conductive line to a relevant test device, so that the performance and parameters of the third optical device under test 223 can be obtained by processing the electrical signal.

[0077] By testing the performance and parameters of the first optical device under test 221, the second optical device under test 222, and the third optical device under test 223, the performance and process of the corresponding wafers can be evaluated, thus eliminating wafers that do not meet the performance and process standards. This avoids unnecessary processing of these substandard wafers in subsequent steps.

[0078] In an optional implementation, the test structure 200 may omit the beam splitters 251 and 252, and instead provide an input optical coupler for each optical device under test.

[0079] In an optional embodiment, the test structure 200 may include one or more first optical devices under test 221, one or more second optical devices under test 222, and one or more third optical devices under test 223. When multiple optical devices under test are present, multiple beam splitters or multiple input optical couplers may be correspondingly provided, as well as multiple output optical couplers, photoelectric converters, electrical contacts, etc.

[0080] In an optional embodiment, the electrical contacts of the test structure 200 for electrical connection can be configured to connect to an external probe card.

[0081] 【Exemplary Implementation】

[0082] Figure 5A test structure according to an exemplary embodiment of the present invention is shown. Those skilled in the art should understand that this description is an exemplary embodiment of the invention, and the invention is not limited thereto. It should be understood that various equivalent transformations and modifications made by those skilled in the art based on this embodiment should fall within the scope of the invention.

[0083] In an exemplary implementation, such as Figure 5 As shown, the test structure includes eight optical couplers (i.e., optical couplers 5011 to 5018). Optical couplers 5011 and 5018 serve as alignment couplers to align the test structure with an external fiber optic array, and their performance can be simultaneously evaluated to verify the coupling performance of the test structure. Optical coupler 5012 serves as an input coupler to couple optical signals into the test structure, and optical couplers 5013 to 5017 serve as output couplers to output optical signals from the test structure.

[0084] In an exemplary embodiment, the test structure further includes multiple beam splitters, polarization beam splitters, waveguides, a waveguide under test, an optical modulator, and multiple photodetectors. The beam splitters 5101 to 5107 are cascaded to split the single optical path via the optical coupler 5012 into eight optical paths. For ease of explanation, in... Figure 5 The text is divided into sections marked with dashed lines from A to H.

[0085] In optical path A, beam splitter 5108 further divides the optical path into two branches. One branch is equipped with 50:50 beam splitters 5112 and 5113. These two branches are combined into one through beam splitter 5110 and connected to optical coupler 5013, which serves as the output. In this embodiment, 50:50 beam splitters 5112 and 5113 serve as the optical devices under test. During testing, the optical signal is input via optical coupler 5012, and then enters 50:50 optical splitters 5112 and 5113 via splitters 5101, 5102, 5104, and 5108. After passing through 50:50 optical splitters 5112 and 5113, the optical signal reaches optical coupler 5013 via splitter 5110 and is coupled into an external fiber optic array. The optical signal is then transmitted to relevant testing equipment via the external fiber optic array for testing to verify whether the performance of 50:50 optical splitters 5112 and 5113 meets the requirements.

[0086] In the B-path, beam splitter 5109 further divides the optical path into two branches. One branch is equipped with a polarization beam splitter 5114. These two branches are combined into one via beam splitter 5111 and connected to an optical coupler 5014, which serves as the output. In this embodiment, polarization beam splitter 5114 serves as the optical device under test. Two diagonally opposite branches of polarization beam splitter 5114 are connected to beam splitter 5109 and beam splitter 5111, respectively, while the other diagonally opposite branches are connected to optical waveguide terminators. These waveguide terminators are used to absorb the optical signals at the corresponding ports, preventing interference with the test. During testing, the optical signal is input via optical coupler 5012 and then enters polarization beam splitter 5114 via beam splitters 5101, 5102, 5104, and 5109. The optical signal then passes through polarization beam splitter 5114 and reaches optical coupler 5014 via beam splitter 5111. It is then coupled into an external fiber array by optical coupler 5014. The optical signal is transmitted to relevant testing equipment via the external fiber array for testing to verify whether the performance of polarization beam splitter 5114 meets the requirements.

[0087] Optical paths C and D are used for waveguide loss testing. No optical components are placed on the waveguide of optical path C, while the waveguide under test (DUT) 5200 is placed on optical path D. During testing, the optical signal is input via optical coupler 5012 and then enters the C-path waveguide and D-path waveguide (DUT) 5200 via beam splitters 5101, 5102, and 5105, respectively. The optical signal from optical path C is coupled into an external fiber array via optical coupler 5015 and transmitted to relevant testing equipment for testing to verify whether the waveguide loss of optical path C meets the requirements. The optical signal from optical path D (DUT) 5200 is coupled into the external fiber array via optical coupler 5016 and transmitted to relevant testing equipment for testing to assess the loss of waveguide 5200. In some embodiments, the length of waveguide 5200 is at least 0.5 mm, for example, 1 mm, 1.5 mm, or 2 mm, but is not limited to this.

[0088] In the E-path, the optical modulator 5300 serves as the optical device under test. One end is connected to a branch of the beam splitter 5106, and the other end is connected to the optical coupler 5017. Furthermore, the optical modulator 5300 is connected to electrical contacts to receive external electrical signals during testing and modulate the data carried by these signals into the optical signal. During testing, the optical signal is input via the optical coupler 5012 and then enters the optical modulator 5300 via beam splitters 5101, 5103, and 5106. The optical modulator 5300 modulates the optical signal according to the input external electrical signal. The modulated optical signal is coupled into an external fiber optic array via the optical coupler 5017. This modulated signal is then transmitted via the external fiber optic array to relevant testing equipment for processing to verify whether the performance of the optical modulator 5300 meets the requirements.

[0089] In the F-path, photodetector 5401 serves as the optical device under test, connected to another branch of beam splitter 5106. Simultaneously, the output of photodetector 5401 is connected to an electrical contact (not shown). During testing, the optical signal is input via optocoupler 5012 and then enters photodetector 5401 via beam splitters 5101, 5103, and 5106. Photodetector 5401 converts the optical signal into an electrical signal, which is transmitted to relevant testing equipment via the electrical contact (not shown) for processing to verify whether the performance of photodetector 5401 meets the requirements.

[0090] In the G-path, the 5:95 beam splitter 5501 serves as the optical device under test. Its input is connected to one branch of the beam splitter 5107, and its two outputs are connected to photodetectors 5402 and 5403, respectively. During testing, the optical signal is input via the optical coupler 5012 and then enters the 5:95 beam splitter 5501 via beam splitters 5101, 5103, and 5107. The 5:95 beam splitter 5501 splits the signal into two paths, which are then transmitted to photodetectors 5402 and 5403, respectively. The photodetectors 5402 and 5403 convert the received optical signals into electrical signals, which are then transmitted to relevant testing equipment via electrical contacts (not shown) for processing. For example, the splitting ratio is determined by the value of the photocurrent to verify whether the performance of the 5:95 beam splitter 5501 meets the requirements.

[0091] In the H-path, the 10:90 beam splitter 5502 serves as the optical device under test. Its input is connected to another branch of the beam splitter 5107, and its two outputs are connected to photodetectors 5404 and 5405, respectively. During testing, the optical signal is input via the optical coupler 5012 and then enters the 10:90 beam splitter 5502 via beam splitters 5101, 5103, and 5107. The 10:90 beam splitter 5502 splits the signal into two paths, which are then transmitted to photodetectors 5404 and 5405, respectively. The photodetectors 5404 and 5405 convert the received optical signals into electrical signals, which are then transmitted to relevant testing equipment via electrical contacts (not shown) for processing. For example, the splitting ratio is determined by the value of the photocurrent to verify whether the performance of the 10:90 beam splitter 5502 meets the requirements.

[0092] In some embodiments, one or more of the optical couplers 5011 to 5018 may be vertical couplers and horizontal couplers.

[0093] In some embodiments, the electrical contacts of the optical modulator 5300 and photodetectors 5401 to 5405 can be connected to an external probe card (8 pins).

[0094] In some embodiments, the optical coupler 50111 and optical coupler 5018 can be used to assist in alignment coupling and to verify the optical coupling performance of the test structure.

[0095] Although this exemplary embodiment uses 8 optical couplers and an 8-channel fiber array, the present invention is not limited thereto, and fiber arrays with more channels and corresponding optical couplers can be used.

[0096] In an exemplary embodiment, by measuring the parameters of the relevant devices under test in the acceptance structure on the entire wafer, it is determined whether there are any abnormalities in the fabrication of the relevant devices, thereby determining whether the wafer process is abnormal, and thus achieving the purpose of wafer acceptance.

[0097] [Exemplary Application Scenarios]

[0098] Figure 6 An exemplary application scenario of the test structure according to an embodiment of the present invention is shown. For example... Figure 6 As shown, a wafer with test structure 3 is mounted on a wafer-level test platform 8. The test structure 3 is the test structure described in any of the above embodiments of the present invention. The optical signal from the coupled laser 1 is transmitted through the fiber array 2 into the test structure 3 of the wafer, and the optical signal output from the test structure 3 is received by the coupling power meter 4, thereby achieving coupling alignment and simultaneously verifying the performance of the optical coupler on the wafer.

[0099] After the test structure 3 is coupled and aligned with the fiber array 2, the control computer 6 controls the tunable laser 5 to emit an optical signal. The optical signal is input into the test structure 3 through the fiber array. Each optical device under test in the test structure 3 processes the optical signal and outputs an optical signal or an electrical signal. The optical signal output from the test structure 3 is transmitted to the multi-channel power meter 7 via the fiber array 2 to complete the relevant tests. The electrical signal output from the test structure 3 is transmitted to the relevant testing equipment via a probe card (not shown) and corresponding circuit cables to complete the relevant tests.

[0100] After the current wafer test is completed, the control computer 6 sends a signal to the wafer-level test platform 8 to begin testing the next wafer. This allows for rapid acceptance testing of newly arrived wafers.

[0101] As can be seen from the above embodiments of the present invention, the testing method of the embodiments of the present invention includes at least:

[0102] The test structure is aligned with an external fiber optic array using an alignment optical coupler, and each optical coupler on the test structure is connected to the external fiber optic array.

[0103] Test light signals are input to the first and second optical devices under test via the input optical coupler in the test structure.

[0104] The optical signal output by the first optical device under test is output to the external fiber array via the output optical coupler in the test structure, and the output optical signal is transmitted to the first test device via the external fiber array to complete the test of the first optical device under test.

[0105] The optical signal output by the second optical device under test is converted into an electrical signal by the first photoelectric converter in the test structure. The electrical signal is output to the external conductive line through the first electrical contact in the test structure and transmitted to the second test device through the external conductive line to complete the test of the second optical device under test.

[0106] In some embodiments, the first optical device under test is selected from beam splitters, optical modulators, MMIs, directional couplers, Y-type beam splitters, polarization beam splitters, and polarization rotators; and / or, the second optical device under test is selected from beam splitters, optical modulators, MMIs, directional couplers, Y-type beam splitters, polarization beam splitters, and polarization rotators.

[0107] In some embodiments, the testing method further includes: transmitting an input optical coupler to a third optical device under test, the third optical device under test including a second photoelectric converter; the electrical signal output by the second photoelectric converter is transmitted to another external conductive line via a second electrical contact in the testing structure, and transmitted to a third testing device via the other external conductive line to complete the testing of the third optical device under test.

[0108] In some embodiments, the testing method further includes verifying the performance of the optical coupler on the wafer by aligning the optical coupler.

[0109] Those skilled in the art should understand that the above-disclosed embodiments are merely implementations of the present invention and should not be construed as limiting the scope of the patent protection claimed in this invention. Equivalent variations made according to the embodiments of the present invention are still within the scope of the claims of the present invention.

Claims

1. A test structure, characterized in that, The test structure is formed in a designated area on a wafer or chip and includes: An input optical coupler is used to couple the input optical signal into the test structure; An output optical coupler is used to output the output optical signal of the test structure; A first optical device under test is connected between the input optical coupler and the output optical coupler, wherein the input optical signal is input to the first optical device under test via the input optical coupler, and the optical signal output by the first optical device under test is output via the output optical coupler; First photoelectric converter; A second optical device under test is connected between the input optical coupler and the first photoelectric converter, wherein the input optical signal is input to the second optical device under test via the input optical coupler, and the optical signal output by the second optical device under test is converted into an electrical signal by the first photoelectric converter; and A first electrical contact is electrically connected to the first photoelectric converter, wherein an electrical signal from the first photoelectric converter is output to the outside via the first electrical contact.

2. The test structure according to claim 1, characterized in that, The first optical device under test and the second optical device under test are selected from beam splitters and optical modulators.

3. The test structure according to claim 1, characterized in that, The first optical device under test and the second optical device under test are selected from MMI, directional coupler, Y-type beam splitter, polarization beam splitter, and polarization rotator.

4. The test structure according to claim 1, characterized in that, The test structure also includes a third optical device under test and a second electrical contact, wherein the third optical device under test includes a second photoelectric converter; The second photoelectric converter is connected to the input optocoupler and the second electrical contact, and the electrical signal output by the second photoelectric converter is output to the outside via the second electrical contact.

5. The test structure according to claim 4, characterized in that, The first optical device under test, the second optical device under test, and the third optical device are connected to the input optical coupler via one or more beam splitters.

6. The test structure according to claim 1, characterized in that, The first optical device under test includes an optical modulator, and the test structure further includes a third electrical contact for inputting an electrical signal to the optical modulator.

7. The test structure according to claim 1, wherein the test structure includes a beam splitter, the beam splitter distributing the input optical signal to the first optical device under test and the second optical device under test.

8. The test structure according to claim 1, wherein the test structure includes an alignment optical coupler for aligning the test structure with an external fiber array.

9. The test structure according to claim 1, characterized in that, The input optical coupler, output optical coupler, and alignment optical coupler respectively include a vertical coupler or a horizontal coupler.

10. A testing method, characterized in that, The accepted wafer has a test structure as described in any one of claims 1 to 9 formed on it, and the test method includes: Test light signals are input to the first and second optical devices under test via the input optical coupler in the test structure. The optical signal output by the first optical device under test is output via the output optical coupler in the test structure; The optical signal output by the second optical device under test is converted into an electrical signal by the first photoelectric converter in the test structure, and the electrical signal is output to the external conductive line through the first electrical contact in the test structure.

11. A test structure, characterized in that, The test structure is formed in a designated area on a wafer or chip and includes: An input optical coupler is used to couple the input optical signal into the test structure; An output optical coupler is used to output the output optical signal of the test structure; A first optical device under test is connected between the input optical coupler and the output optical coupler, wherein the input optical signal is input to the first optical device under test via the input optical coupler, and the optical signal output by the first optical device under test is output via the output optical coupler; The third optical device under test includes a second photoelectric converter; Second electrical contact; The second photoelectric converter is connected to the input optocoupler and the second electrical contact, and the electrical signal output by the second photoelectric converter is output to the outside via the second electrical contact.

12. A test structure, characterized in that, The test structure is formed in a designated area on a wafer or chip and includes: At least one input optical coupler is provided for coupling at least one input optical signal into the test structure, wherein the at least one input optical coupler includes a first input optical coupler. Multiple output optical couplers are used to output multiple output optical signals of the test structure; A plurality of optical devices under test are connected between the at least one input optical coupler and the plurality of output optical couplers, wherein the at least one input optical signal is input to the plurality of optical devices under test via the at least one input optical coupler, and the optical signals output by the plurality of optical devices under test are output via the plurality of output optical couplers.

13. A wafer comprising the test structure as described in any one of claims 1-9, 11 and 12.

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