Optical Element Carrier and Wafer-Level Pressing Method for Optical Microscope

Abstract

This application relates to a wafer-level bonding method for an optical element carrier and an optical microscope. The optical element carrier includes: a tray, several groups of positioning units arranged in rows and columns on the tray, and an air flow channel in air flow communication with a vacuum source. Each positioning unit respectively includes: positioning pins for positioning and aligning optical elements; air holes in communication with the air flow channel for vacuum adsorbing the optical elements on the tray; at least a pair of stoppers, and a pair of stoppers define a slot for placing the optical elements to prevent the optical elements from moving; the tray also has several first alignment marks for cooperating with second alignment marks on the microlens wafer to be aligned, and the first alignment marks are respectively aligned with each row of positioning units. This application can send the microlens wafer and the carrier into a wafer bonder for combination, realizing wafer-level combination of the optical microscope and shortening the time required for wafer bonding.

Description

Technical Field

[0001] The present application relates to the technical field of optoelectronic manufacturing, and in particular to an optical element carrier used in the manufacturing of wafer-level optical products and a wafer-level pressing method for optical microscopes. Background Art

[0002] In the manufacturing of wafer-level optical products, it may be necessary to place optical elements (such as mirrors) on lenses to enhance or change the optical characteristics of the final optical system. Usually, there are many lenses on a wafer, and each lens needs to place an optical element. In the processing of traditional optical microscopes, the finished micro-lens wafer is cut into individual chips (dies), and then bonded and packaged. This means that the following operations need to be performed on each optical element: 1. Dispensing glue; 2. Picking up the optical element; 3. Pressing the optical element into the adhesive; 4. Aligning the optical element accurately with the lens; 5. Curing the adhesive. The current disadvantages are: 1. Each step needs to be completed in sequence, so it takes a long time and has low efficiency; 2. The optical element needs to be automatically recognized by a camera so as to properly detect the correct direction before picking up the optical element. The requirements for the recognition of expensive optical elements (such as gold mirrors) will be very strict. 3. The optical element needs to be automatically picked up by means of vacuum or mechanical clamping, which may contaminate or even damage the element. Summary of the Invention

[0003] The purpose of the present application is to provide a carrier that can fix multiple optical elements simultaneously to improve the bonding efficiency between the optical element and the micro-lens wafer.

[0004] To achieve the above purpose, the present application adopts the following technical solution: An optical element carrier is adapted to the shape and size of a micro-lens wafer to be combined. There are several micro-lens arrays arranged in rows and columns on the micro-lens wafer. The optical element carrier includes: a tray, several groups of positioning units arranged in rows and columns on the tray, and an air flow channel communicated with a vacuum source air flow. Each of the positioning units includes:

[0005] Positioning pins for positioning and aligning optical elements;

[0006] Air holes communicated with the air flow channel for vacuum adsorbing the optical element on the tray;

[0007] At least a pair of stoppers located outside the optical element for preventing the optical element from moving;

[0008] There are also several first alignment marks on the tray for aligning with the second alignment marks on the micro-lens wafer, and the first alignment marks are aligned with the positioning units in each row respectively.

[0009] In one embodiment of the present application, the positioning unit extends along the row direction.

[0010] In one embodiment of the present application, each of the positioning units respectively includes a pair of the positioning pins and a pair of the air holes.

[0011] In one embodiment of the present application, the pair of positioning pins and the pair of the air holes are both located at the bottom of the slot of the card slot.

[0012] In one embodiment of the present application, the air flow channel is buried in the tray.

[0013] In one embodiment of the present application, the air flow channel includes a main air path and several pairs of branch air paths respectively connected to the main air path, and each pair of the branch air paths is respectively communicated with a pair of air holes of each of the positioning units.

[0014] In one embodiment of the present application, several convex portions extending along the row direction are further provided on the tray, and each of the convex portions is arranged at intervals with each of the positioning units in the column direction.

[0015] In one embodiment of the present application, a flat groove is also cut at the edge of the tray, and the flat groove extends along the row direction.

[0016] Another object of the present application is to provide a wafer-level pressing method for an optical micromirror capable of simultaneously fixing multiple optical elements, so as to improve the bonding efficiency between the optical elements and the microlens wafer.

[0017] Another technical solution of the present application is to provide a wafer-level pressing method for an optical micromirror, including the following steps:

[0018] S1), providing the above-mentioned optical element carrier, placing a plurality of optical elements to be pressed one by one above the carrier, aligning the positioning marks on each optical element with the positioning pins on the tray, and ensuring that each of the optical elements is respectively clamped between a pair of the stoppers of each positioning unit, turning on the vacuum to fix the optical elements;

[0019] S2), providing a microlens wafer, on which there are several rows and columns of microlens arrays, and applying glue dots on each of the microlens arrays;

[0020] S3), keeping the microlens wafer on top and the optical element carrier below, aligning the second alignment mark on the microlens wafer with the first alignment mark on the optical element carrier for positioning alignment, and performing pressing;

[0021] S4), performing ultraviolet irradiation curing on the pressed optical element carrier and microlens wafer;

[0022] S5), Cancel the vacuum to separate the optical element carrier from the optical element, obtaining the optically micro-mirrored wafer after pressing.

[0023] This application realizes wafer-level packaging (Wafer Level Packaging) of optical micro-mirrors through the above method, that is, most or all of the packaging test procedures are directly carried out on the wafer, and then singulation is performed to make single components, thus greatly simplifying the complexity of subsequent processing steps and reducing the technical difficulty. Wafer-level packaging has the advantages of smaller packaging size (CSP) and better electrical performance.

[0024] In an embodiment of the present application, the steps S2-5 are carried out in the same press.

[0025] Since these optical elements used for processing optical micro-mirrors are small in size and high in precision, especially some gold mirrors are expensive, in order to reduce the number of pickups and avoid introducing component damage, in an embodiment of the present application, in the step S1, it further includes picking up the optical elements to be pressed and performing optical inspection, and then placing the qualified optical elements above the carrier, and the unqualified optical elements detected are diverted to another recycling tray. Optical inspection refers to the optical inspection of optical elements. The optical inspection device can be set on the manipulator picking up the optical elements, or can be completed by means of a third-party inspection table set beside the manipulator. For example, a non-contact optical 3D sensor moves along the theoretical curve of the workpiece radial direction to complete the scanning and generate three-dimensional data, which can measure geometric features such as the surface shape and thickness of the optical element.

[0026] Through the above technical solution, this application can clamp and fix several optical elements at one time, and at the same time these optical elements are arranged according to the size and position corresponding to the microlens wafer. Therefore, the microlens wafer and the carrier can be sent into the wafer press to realize wafer-wafer bonding. On the one hand, it eliminates the need to bond each optical element separately in the traditional process, improves the packaging processing efficiency, and greatly reduces the time required to fill the wafer with optical elements; on the other hand, this application no longer needs to use an automatic pick-and-place machine, but uses a general wafer press to complete wafer bonding, saving equipment costs. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of an optical element carrier provided by an embodiment of the present application.

[0028] Figure 2 For using Figure 1 Schematic diagram (partial enlargement) of fixing optical elements by the carrier of the shown embodiment.

[0029] Figure 3 is Figure 1 a partial enlarged schematic view of part A in

[0030] Figure 4 is Figure 2 a partial enlarged schematic view of part B in

[0031] Wherein: 100, tray; 11, positioning pin; 12, air hole; 13, stopper; 14, first alignment mark; 15, air flow channel; 151, main air path; 152, branch air path; 16, convex part; 17, flat groove; 20, optical element. Detailed implementation manners

[0032] To describe in detail the technical content, structural features, achieved objectives and effects of the application, the technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. In the following description, for the purpose of explanation, many specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the invention. However, various exemplary embodiments can also be implemented without these specific details or in the case of one or more equivalent arrangements. In addition, various exemplary embodiments can be different, but do not have to be exclusive. For example, without departing from the inventive concept, the specific shapes, structures and characteristics of the exemplary embodiments can be used or implemented in another exemplary embodiment.

[0033] Refer to the attached Figure 1 As shown, the present application is an optical element carrier for bonding a microlens wafer. The microlens wafer has a plurality of microlens arrays arranged in rows and columns. By placing all the optical elements to be bonded on a predetermined carrier and fixing them, and then feeding the microlens wafer and the carrier into a wafer bonder for bonding and curing, the purpose of simplifying the operation steps and reducing the operation difficulty is achieved. The size and shape of the optical element carrier are the same as those of the microlens wafer, and the number and positions of the plurality of optical elements fixed on the optical element carrier need to correspond one by one to the number and positions of the plurality of microlenses on the microlens wafer.

[0034] As described above, the present application can reduce the lamination of the optical element and the microlens wafer to one-step lamination (wafer to wafer), where the "optical element carrier" functions as a wafer, enabling all the optical elements to be bonded simultaneously.

[0035] Please continue to refer to Figure 1 and Figure 2 As shown, the optical element carrier of the present application includes: a tray 100, a plurality of groups of positioning units arranged in rows and columns on the tray 100, and an air flow channel 15 that is in air flow communication with an external vacuum source.

[0036] Among them, the tray 100 is adapted to the shape and size of the microlens wafer to be combined, and a flat groove 17 is also cut on the edge of the tray. The flat groove extends along the row direction and is parallel to the flat groove direction on the microlens wafer. The flat groove 17 on the tray 100 can help the carrier quickly locate and align with the microlens wafer.

[0037] In addition, there are several first alignment marks 14 on the tray 100 for aligning with the second alignment marks on the microlens wafer. Before the microlens wafer is bonded to the optical element, it is necessary to automatically align the first alignment mark and the second alignment mark with the aid of a vision assistance system.

[0038] Figure 1 In the illustrated embodiment, there are 3 columns of positioning units, and each column of positioning units includes multiple rows. Among them, each positioning unit extends along the row direction and correspondingly covers a microlens array on the microlens wafer, and the positioning unit is used to fix the optical element 20.

[0039] Please refer to Figures 3 - 4 As shown, each of the positioning units respectively includes: a pair of positioning pins 11, a pair of air holes 12, and a pair of stoppers 13.

[0040] When placing the optical elements 10 one by one on the carrier, the positioning pins 11 are aligned with the positioning marks on each optical element 20, so as to position and align the optical element 20, and ensure that each of the optical elements 20 is respectively stuck between a pair of stoppers 13 of each positioning unit.

[0041] The air holes 12 are opened on the tray 100 and communicate with the air flow channel 15 for vacuum-sucking and fixing the optical element 20 on the tray 100. An air flow channel 15 is opened inside the tray 100. The air flow channel 15 includes a main air path 151 and several pairs of branch air paths 152 respectively connected to the main air path 151. Each pair of branch air paths 152 communicates with a pair of air holes 12 in the positioning unit. The end of the main air path 151 of the air flow channel is connected to an external vacuum source, and can provide vacuum suction force to the optical elements through several pairs of air holes on the carrier at the same time.

[0042] The stoppers 13 are fixedly arranged on the carrier 100, and a pair of stoppers 13 are symmetric left and right, defining a slot for fixing the optical element 20, and the optical element 20 is placed between the pair of stoppers.

[0043] In an embodiment of the present application, a pair of positioning pins 11 and a pair of air holes 12 are both located at the bottom of the slot, and the air holes 12 are oval or oblong.

[0044] In one embodiment of the present application, a plurality of convex portions 16 extending in the row direction are further provided on the tray 100. The convex portions 16 slightly protrude from the surface of the tray 100, and are used to form a gap between multiple optical elements and increase the unevenness of the tray surface. Each convex portion 16 and each positioning unit are arranged at intervals in the column direction, that is, there is a convex portion 16 between every two adjacent positioning units. In this way, when the optical element 20 is placed on the carrier, it can be adsorbed and fixed by vacuum. After the wafer bonding is completed, the vacuum adsorption force is withdrawn, and the optical element can be easily separated from the carrier.

[0045] The present application also discloses a wafer-level lamination method for manufacturing an optical micro-mirror using the optical element carrier of the present application, which can achieve one-step wafer-to-wafer lamination. Wafer-level packaging is to package the chip when the chip is still on the wafer. Subsequently, overall packaging and testing can be carried out, and finally the wafer is cut into individual chips. The method includes the following steps:

[0046] S1). Provide the optical element carrier, use a robotic hand to pick up the optical elements 20 to be laminated floatingly, and place multiple optical elements one by one above the carrier. Align the positioning marks on each optical element 20 with the positioning pins 11 on the tray 100, adjust the position of the optical element, so that the two ends of the optical element are respectively stuck between a pair of stoppers 13 of each positioning unit to prevent it from shaking. After placing them, start the vacuum source to adsorb and fix all the optical elements on the tray. The multiple optical elements and the carrier form an integral body, which can be regarded as a wafer by us;

[0047] S2). Provide a microlens wafer. The microlens wafer has a plurality of microlens arrays arranged in rows and columns. In a wafer laminator, automatically apply glue (a polymer glue) to the plurality of microlens arrays of the microlens wafer, and the glue can be cured by ultraviolet irradiation;

[0048] S3). Keep the microlens wafer on top and the optical element carrier below. With the aid of a vision assistance system, align the second alignment mark on the microlens wafer with the first alignment mark 14 on the optical element carrier, and then press the microlens wafer and the optical element carrier integrally in the vertical direction to achieve wafer-to-wafer lamination;

[0049] S4). Perform ultraviolet irradiation on the laminated optical element carrier and microlens wafer to cure the polymer glue;

[0050] S5). Turn off the vacuum source to separate the optical element carrier from the optical element, and obtain the laminated optical micro-mirror wafer, and each optical element is adhesively bonded to a microlens array.

[0051] Step S2-5 of the above method can be carried out in the same laminator. Instead of using an automatic pick-and-place machine, a general wafer laminator is adopted to complete wafer bonding, saving equipment costs.

[0052] In addition, since the optical elements used for processing optical micro-mirror wafers are small in size and high in precision, especially some gold mirrors are expensive, in order to reduce the number of pickups and avoid introducing component damage, in step S1, it also includes the step of picking up the optical elements to be laminated and performing optical inspection. Optical inspection refers to using an optical path system to inspect the defects of optical elements. The optical detection device can be set on the manipulator for picking up optical elements, or can be completed by means of a third-party detection station set beside the manipulator. For example, a non-contact optical 3D sensor moves along the theoretical curve in the radial direction of the workpiece to complete scanning and generate three-dimensional data, which can measure geometric features such as the surface shape and thickness of optical elements. The optical elements that pass the inspection will be placed on a carrier for the next steps of alignment and lamination, etc., while the optical elements that fail the inspection will be diverted to a recycling tray and wait for recycling treatment.

[0053] Through the above lamination method, the present application has the following advantages:

[0054] 1. Multiple optical elements can be bonded simultaneously at one time to achieve wafer-level bonding, with high processing efficiency;

[0055] 2. The manufacturing process of the original optical micro-mirror wafer is turned upside down, with the optical element carrier placed as a whole below and the microlens wafer above, avoiding the movement and alignment deviation of optical elements.

[0056] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present application. In addition to the content disclosed in the specification, the present application will have various changes and improvements. The scope of protection required by the present application is defined by the appended claims, the specification and their equivalents.

Claims

1. An optical element carrier adapted to the shape and size of a microlens wafer to be bonded, wherein the microlens wafer has a microlens array arranged in a number of rows and columns, characterized in that, The described optical element carrier includes: a tray, a number of positioning units arranged in rows and columns on the tray, and an air flow channel in air flow communication with a vacuum source. Each of the positioning units respectively includes: Positioning pins for positioning and aligning the optical elements; Air holes communicated with the air flow channel for vacuum adsorbing the optical elements on the tray; At least a pair of stoppers, and the at least a pair of stoppers define a card slot for placing the optical elements to prevent the optical elements from moving; A number of first alignment marks are further provided on the tray for aligning with second alignment marks on the microlens wafer, and the first alignment marks are respectively aligned with the positioning units in each row.

2. The optical element carrier according to claim 1, characterized in that: Each of the positioning units respectively includes a pair of the positioning pins and a pair of the air holes.

3. The optical element carrier according to claim 2, wherein: The pair of positioning pins and the pair of the air holes are both located at the bottom of the card slot.

4. The optical element carrier according to claim 2, characterized in that: The air flow channel is embedded in the tray.

5. The optical element carrier according to claim 4, characterized in that: The air flow channel includes a main air path and a number of pairs of branch air paths respectively connected to the main air path, and each pair of the branch air paths is respectively communicated with a pair of air holes of each of the positioning units.

6. The optical element carrier according to claim 2, wherein: A number of convex portions are further provided on the tray, and each of the convex portions and each of the positioning units are arranged at intervals in the column direction.

7. The optical element carrier according to claim 1, wherein: A flat groove is further cut at the edge of the tray, and the flat groove extends along the row direction.

8. A wafer-level bonding method for an optical microscope, characterized in that, Including the following steps: S1), Provide the optical element carrier as described in any one of claims 1-7, place a plurality of optical elements to be pressed one by one above the carrier, align the positioning marks on each optical element with the positioning pins on the tray, and ensure that each of the optical elements is respectively clamped between a pair of the stoppers of each positioning unit, turn on the vacuum to fix the optical elements; S2), Provide a microlens wafer, and a number of microlens arrays are arranged in rows and columns on the microlens wafer, and glue is applied to each of the microlens arrays; S3), Keep the microlens wafer on top and the optical element carrier below, align the second alignment marks on the microlens wafer with the first alignment marks on the optical element carrier for positioning alignment, and perform pressing; S4), Perform ultraviolet irradiation curing on the pressed optical element carrier and microlens wafer; S5), Cancel the vacuum to separate the optical element carrier from the optical elements, and obtain the pressed optical microlens wafer.

9. The method according to claim 8, wherein: The steps S2-5 are performed in the same pressing machine.

10. The method according to claim 8, wherein: In the step S1, it further includes picking up the optical elements to be pressed and performing optical inspection, and then placing the qualified optical elements above the carrier.

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