ARRAY OBJECTIVE LENS MODULE AND OPTICAL INTERFERENCE MICROSCOPY SYSTEM

An array objective lens module, having an optical axis and including a substrate, multiple lens frames, and multiple objective lens sets is provided. The substrate includes multiple accommodating vias. Each accommodating via includes an internal thread structure. The lens frames are respectively disposed in the accommodating vias. Each lens frame includes an external thread structure. The external thread structure is adapted to the internal thread structure. The objective lens sets are respectively disposed in the lens frames. Each objective lens set includes at least one lens, and a relative position of each frame and the substrate in an extension direction of the optical axis changes according to a relative rotation angle of the corresponding external read structure and internal thread structure.

TECHNICAL FIELD

The disclosure relates to an optical module and a microscopy device, and in particular to an array objective lens module and an optical interference microscopy system.

BACKGROUND

In the future market demand, with the widespread application of advanced packaging chips, High Performance Computing (HPC) chip will gradually become the mainstream of the market. HPC Chips usually need to integrate multiple computing units such as High Bandwidth Memory (HBM) and other chiplets, so it will be integrated into a large chip in size. Traditional detection method will be limited to the detection speed and cannot be used for this detection. Therefore, providing fast and accurate3D shape detection equipment is in strong demand.

Currently, the detection technique of white light interference can reach nanometer-level precision, but the detection speed of known white light interference equipment is very limited. In the solution that uses multiple lens for detection, it always needs multiple additional components to be equipped for scanning, so the construction cost of the whole equipment is quite high. In addition, for implementing simultaneous scanning, the coplanarity of each elements in the multi-lens structure must be consistent to make the white light coherence length less than or equal to 10 μm and meet specification. However, the insufficient processing precision of the existing optical clamping mechanism causes the coplanarity of the lens elements is far greater than 10 μm, so simultaneous scanning cannot be implemented to expand the field of view by using array lens for speeding up online detection.

SUMMARY

The disclosure provides an array objective lens module, which has an optical axis and includes a substrate, multiple lens frames, and multiple objective lens sets. The substrate includes multiple accommodating vias. Each accommodating via includes an internal thread structure. The lens frames are respectively disposed in the accommodating vias. Each lens frame includes an external thread structure. The external thread structure is adapted to the internal thread structure. The objective lens sets are respectively disposed in the lens frames. Each objective lens set includes at least one lens, and a relative position of each lens frame and the substrate in an extension direction of the optical axis changes according to a relative rotation angle of the corresponding external thread structure and internal thread structure.

The disclosure also provides an optical interference microscopy system for imaging a to-be-measured object. The optical interference microscopy system includes a light source module, a second light splitter, an array objective lens module, a lens barrel module, and at least one imaging element. The light source module is used to provide an illumination beam. The second light splitter is disposed on a transmission path of the illumination beam from the light source module and is used to reflect the illumination beam and allow a measuring beam to pass through. The array objective lens module is disposed on the transmission path of the illumination beam from the second light splitter to the to-be-measured object. The array objective lens module has an optical axis and includes a substrate, multiple lens frames, and multiple objective lens sets. The substrate includes multiple accommodating vias. Each accommodating via includes an internal thread structure. The lens frames are respectively disposed in the accommodating vias. Each lens frame includes an external thread structure. The external thread structure is adapted to the internal thread structure. The objective lens sets are respectively disposed in the lens frames. Each objective lens set includes at least one lens. In an extension direction of the optical axis, a relative position of each lens frame and the substrate changes according to a relative angle of the corresponding external thread structure and internal thread structure. The lens barrel module is disposed on a transmission path of the measuring beam from the second light splitter. The lens barrel module includes a lens barrel, an array eyepiece module, and at least one array light barrier module. The at least one array light barrier module is disposed in the lens barrel. The at least one array light barrier module includes multiple light barriers, and optical axes of the light barriers are respectively coaxial with optical axes of the objective lens sets. The array eyepiece module is connected to an end of the lens barrel and is located between the array objective lens module and the at least one array light barrier module. The array eyepiece module includes multiple eyepiece sets, and optical axes of the eyepiece sets are respectively coaxial with the optical axes of the objective lens sets. The at least one imaging element is disposed on the transmission path of the measuring beam from the lens barrel module and is used to generate imaging information according to the measuring beam.

DETAILED DESCRIPTION OF DISCLOSURED EMBODIMENTS

FIG.1is a schematic view of an optical interference microscopy system according to an embodiment of the disclosure. Please refer toFIG.1. The embodiment provides an optical interference microscopy system50for imaging and measuring a to-be-measured object10(for example, a chip package). The optical interference microscopy system50includes a light source module60, a second light splitter70, an array objective lens module100, a lens barrel module80, and at least one imaging element90. The optical interference microscopy system50is, for example, a white light interference microscope, which is a microscope that displays a surface or an internal structure of the to-be-measured object10using the principle of light interference and may be applied to fast and accurate3D measurement.

The light source module60is used to provide an illumination beam L1. Specifically, in the embodiment, the light source module60includes a light emitting element62and a collimation lens set64. The light emitting element62is a white light emitting element and is used to provide the white illumination beam L1, such as an incandescent lamp, a xenon lamp, a high pressure sodium lamp, a fluorescent lamp, a metal halide lamp, a white light emitting diode, or a white organic light emitting diode, but the disclosure is not limited thereto. The collimation lens set64includes, for example, a combination of one or more optical lenses with diopter and is used to collimate the illumination beam L1. In other words, the light source module60is a collimated light source.

The second light splitter70is disposed on a transmission path of the illumination beam L1from the light source module60and is used to reflect the illumination beam L1and allow a measuring beam L2to pass through. The second light splitter70is, for example, a spectroscope. When the illumination beam L1is transmitted to the second light splitter70, the second light splitter70reflects the illumination beam L1and then the illumination beam L1passes through the array objective lens module100to the to-be-measured object10, so that the measuring beam L2with structural information is reflected from the to-be-measured object10.

The lens barrel module80is disposed on a transmission path of the measuring beam L2from the second light splitter70. That is, the second light splitter70is located between the lens barrel module80and the to-be-measured object10. Specifically, in the embodiment, the lens barrel module80includes a lens barrel82, an array eyepiece module84, and at least one array light barrier module86. The lens barrel82has two opposite ends inside and an internal accommodating space. The disclosure does not limit the type and the appearance of the lens barrel82. The array eyepiece module84is connected to an end of the lens barrel82. Specifically, the array eyepiece module84is connected to a side of the lens barrel82facing the second light splitter70. The array eyepiece module84includes multiple eyepiece sets210, and each eyepiece set210includes at least one lens. Optical axes of the eyepiece sets210respectively correspond to optical axes of multiple objective lens sets in the array objective lens module100. For example, in the embodiment, the array eyepiece module84includes four eyepiece sets210arranged in a 2×2 array, and the optical axes of the four eyepiece sets210respectively correspond to optical axes of four objective lens sets in the array objective lens module100.

The at least one array light barrier module86is disposed in the lens barrel82, the at least one array light barrier module86includes multiple light barriers220, and optical axes of the light barriers220respectively correspond to optical axes of multiple objective lens sets130in the array objective lens module100. Specifically, the optical axes of the light barriers220are respectively coaxial with the optical axes of multiple objective lens sets130. The array eyepiece module84is located between the array objective lens module100and the at least one array light barrier module86. The number of the at least one array light barrier module86is multiple, and the array light barrier modules86are spaced apart from one another. For example, in the embodiment, the number of the array light barrier modules86is four, and each array light barrier module86includes four light barriers220arranged in a 2×2 array. The optical axes of the four light barriers220respectively correspond to the optical axes of the four objective lens sets130in the array objective lens module100. Specifically, the optical axes of the four light barriers220are respectively coaxial with the optical axes of the four objective lens sets130. However, in other embodiments, the number of the array light barrier modules86may be designed differently according to a spurious ratio, but the disclosure is not limited thereto. By the design of the lens barrel module80having the array eyepiece module84and the array light barrier module86of the embodiment, the array eyepiece module84can correspond to the array objective lens module100to achieve consistent optical axes, thereby reducing interference signal aberration, and absorbing and suppressing stray light with a via structure of the array light barrier module86to maintain good optical interference signals.

The at least one imaging element90is disposed on the transmission path of the measuring beam L2from the lens barrel module80and is used to generate imaging information according to the measuring beam L2. The imaging element90is, for example, a photosensitive element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor transistor (CMOS). In the embodiment, the number of the imaging element90is single. However, in other embodiments, the number of the imaging element90may be multiple, and the number thereof is, for example, equal to the number of the objective lens sets130of the array objective lens modules100, but the disclosure is not limited thereto.

FIG.2is a schematic top view of an array objective lens module according to an embodiment of the disclosure.FIG.3Ais a schematic cross-sectional view along a line A-A′ of the array objective lens module ofFIG.2. Please refer toFIG.1toFIG.3A.FIG.2andFIG.3Ashow partial structures. The array objective lens module100is disposed on the transmission path of the illumination beam L1from the second light splitter70and is used to transmit the illumination beam L1to the to-be-measured object10to generate the measuring beam L2. The array objective lens module100includes a substrate110, multiple lens frames120, and the objective lens sets130. The substrate110includes multiple accommodating vias112, and each accommodating via112includes an internal thread structure B1. In the embodiment, the substrate100also includes a calibration via114located at the center of symmetry among the accommodating vias112and used to allow a calibration beam to pass through. The calibration beam, such as a laser beam, is transmitted from the imaging element90toward the array objective lens module100, and then focus calibration is performed by reflection imaging of the calibration beam reflected by a reflector in the array objective lens module100.

The lens frames120are respectively disposed in the accommodating vias112. Each lens frame120includes an external thread structure B2adapted to the internal thread structure B1. In other words, each lens frame120is adapted to move on the substrate110in an extension direction D3of an optical axis by the thread structures. In the embodiment, each lens frame120includes at least one adjustment hole122respectively located around the objective lens sets130and used to respectively adjust the relative positions of the lens frames120and the substrate110on the substrate110.

The objective lens sets130are respectively disposed in the lens frames120, and each objective lens set130includes at least one lens132. The array objective lens module130has the optical axis, and in the extension direction D3of the optical axis, the relative position of each lens frame120and the substrate110changes according to a relative angle of the corresponding external thread structure B2and internal thread structure B1. In other words, in the embodiment, by adjusting the rotation angle of the lens frame120, the position of each lens frame120on the substrate110may be adjusted to adjust focal plane positions of the objective lens sets130, so as to effectively improve the coplanarity. According to the design of the embodiment, a maximum distance difference between respective focal planes of the objective lens sets130may reach a precision of less than 10 μm, which has better coplanarity and good optical effects. In the embodiment, the number of the lens132of each objective lens set130is one. However, in other embodiments, the number of lenses of each objective lens set may also be greater than one. For example,FIG.3Bshows an array objective lens module100A according to another embodiment. In the embodiment, the number of the lenses132of each objective lens set130A is two, but not limited to two, and each objective lens set may also be formed by combining more than two lenses. In addition, in the embodiment, the lens frames120and the objective lens sets130are arranged in an array in a direction perpendicular to the extension direction D3of the optical axis. Specifically, in the embodiment, the number of the lens frames120and the objective lens sets130in a first direction D1is equal to the number in a second direction D2. The first direction D1and the second direction D2are both perpendicular to the extension direction D3of the optical axis, and the first direction D1is perpendicular to the second direction D2. For example, in the embodiment, the number of the lens frames120and the objective lens sets130is, for example, four, and the lens frames120and the objective lens sets130are arranged in a 2×2 array. In other words, the number of the objective lens sets130in the array objective lens module100, the number of the eyepiece sets210in the array eyepiece module84, and the number of the light barriers in each array light barrier module86are the same as each other.

FIG.4is a schematic cross-sectional view of a part of the optical interference microscopy system ofFIG.1. Please refer toFIG.4. In the embodiment, the array objective lens module100also includes a first light splitter140and a reflector150. The first light splitter140is disposed on the transmission path of the illumination beam L1from the objective lens sets130. The illumination beam L1includes a first beam L11and a second beam L12. The first light splitter140is used to reflect the first beam L11and allow the second beam L12to pass through to be transmitted to the to-be-measured object10. The reflector150is disposed between the first light splitter140and the substrate110, and is used to reflect the first beam L11from the first light splitter140to the first light splitter140, and a part of the first beam L11forms the measuring beam L2with a part of the second beam L12. Specifically, in the embodiment, the reflector150includes a light transmitting member152and multiple reflection patterns154formed on the light transmitting member152. Positions of the reflection patterns154respectively correspond to positions of the objective lens sets130. Specifically, the reflection patterns154are respectively located on the optical axes of the objective lens sets130. For example, the reflection patterns154may be respectively formed on specific positions of the light transmitting member152using a reflective material and with a yellow light photolithography process. Therefore, compared with traditional non-array lens modules, the embodiment does not need to additionally configure a reflective mirror. On the other hand, the first light splitter140includes a light splitting surface C, and a distance E1from the light splitting surface C to the reflector150is equal to a distance E2from the light splitting surface C to the to-be-measured object10. When this condition is met, the light L12reflected by the object will interfere with the reference light L11. The light splitting surface C may be formed by coating.

In other words, the illumination beam L1forms the first beam L11and the second beam L12by the light splitting effect of the first light splitter140, wherein the first beam L11is reflected by the light splitting surface C of the first light splitter140to reach the reflection patterns154of the reflector150and be reflected, and then reach the light splitting surface C of the first light splitter140again. At this time, a part of the first beam L11is reflected by the light splitting surface C. By an optical path of the same length, the second beam L12is reflected back to the light splitting surface C of the first light splitter140by the to-be-measured object10, so that a part of the transmitted second beam L12interferes with the part of the first beam L11reflected by the light splitting surface C to generate the measuring beam L2.

In summary, in the array objective lens module and the optical interference microscopy system of the disclosure, the array objective lens module includes the substrate, the lens frames, and the objective lens sets. The lens frames are respectively disposed in the accommodating vias of the substrate, and the objective lens sets are respectively disposed in the lens frames. Each accommodating via includes the internal thread structure, each lens frame includes the external thread structure, and the external thread structure is adapted to the internal thread structure. The array objective lens module has the optical axis, and the relative position of each lens frame and the substrate in the extension direction of the optical axis changes according to the relative angle of the corresponding external thread structure and internal thread structure. In this way, the position of each lens frame on the substrate can be adjusted by the rotation angle of each lens frame, thereby respectively adjusting the focal plane positions of the objective lens sets.