TWI445614B - Mold and method of making optical microlens array using the same - Google Patents

Description

Mould and manufacturing method of micro-optical lens array

The present invention relates to the field of manufacturing optical components, and more particularly to a mold for imprinting a micro-optical lens array and a method of fabricating the micro-optical lens array.

With the development of optoelectronic products, micro-optical lenses have become the basic components of the optoelectronic industry because they can produce optical effects in a small area. For example, a backlight panel of a liquid crystal display uses an optical lens array to achieve an effect of uniformizing the backlight. Therefore, the technology of manufacturing micro-optical components by various processes has become a technology that has been developed in various fields.

At present, there are many methods for manufacturing micro-optical lens arrays, wherein the method of embossing a micro-optical lens is generally to apply a molding material on a substrate, such as a ruthenium wafer, and press it with a pre-made micro-optical lens mold. On top of the molding material, a micro-optical lens array is formed on the tantalum wafer after curing. Generally, in the imprint process, there are steps of aligning the mold core with the germanium wafer to improve the accuracy and quality of the product, for example, manufacturing alignment marks on the mold core and the germanium wafer, respectively, and then Just align the alignment marks.

However, since the micro-optical lens mold and the alignment marks located thereon are usually manufactured by ultra-precision processing technology, the line width is about 100 μm, and the mark made on the germanium wafer is lithography. Manufactured, the size can be accurate to 1 micron, so the two marks differ by two orders of magnitude, resulting in a micro-optical lens mode Ren and 矽 wafers cannot be precisely aligned; in addition, when manufacturing micro-optical lenses, it is impossible to predict how large the deviation is. Only after the production is completed, the position deviation during manufacturing can be calculated according to the product distribution on the 矽 wafer, and then This deviation is taken into account in one production to align the mold and the wafer as much as possible. However, this method obviously brings a high defect rate, and the qualification rate of the product is difficult to reach the requirements of mass production.

In view of the above, it is necessary to provide a mold for an imprinted micro-optical lens array and a method of manufacturing the micro-optical lens array.

A method of manufacturing a micro-optical lens array, comprising the steps of: providing a mold core having a first surface having a first mark made by a lithography process and being fabricated by ultra-precision processing Copying the structure and the second mark; measuring an offset of the second mark from the first mark; providing a substrate having a second surface; and forming a third mark on the second surface by using a lithography process, The third mark is located at the second surface at the same position as the first mark at the first surface; the third mark is first aligned with the first mark; and the substrate is moved according to the offset to make the The third mark is aligned with the second mark; a molding material is applied to the area where the replication structure is located or the substrate, and the micro-optical lens array is embossed.

A mold core having a first surface having a first mark made by a lithography process and a cavity and a second mark made by an ultra-precision process.

The manufacturing method of the micro-optical lens array provided by the invention makes two kinds of marks on the surface of the mold core, and the precision of the two kinds of marks is different, so that the alignment marks on the substrate and the two marks can be sequentially aligned to improve For the purpose of alignment accuracy. The surface of the mold provided by the invention has two kinds of marks, and the precision of the two kinds of marks is different, so that the alignment mark on the substrate can be sequentially aligned with the two marks to achieve an improved pair. The purpose of quasi-accuracy.

10‧‧‧Metal plates

12‧‧‧ first surface

21‧‧‧ first mark

14‧‧‧ cavity array

140‧‧‧ cavity

20‧‧‧Men

22‧‧‧second mark

30‧‧‧Substrate

23‧‧‧ third mark

32‧‧‧second surface

50‧‧‧ cross arm

51‧‧‧ horizontal line

43‧‧‧ third mark

60‧‧‧ longitudinal arm

61‧‧‧ vertical line

70‧‧‧ area

1 is a plan view of a metal plate formed with a first mark according to a first embodiment of the present invention.

Figure 2 is a top plan view of the mold core formed by further processing of the metal sheet of Figure 1.

3 is a plan view of a substrate having a third mark according to a first embodiment of the present invention.

4 is an effect diagram of alignment of a mold core with a substrate according to a first embodiment of the present invention.

Figure 5 is an enlarged schematic view showing a third mark provided by the second embodiment of the present invention.

The invention will now be described in further detail with reference to the accompanying drawings.

Referring to FIG. 1, the first embodiment of the present invention for fabricating a micro-optic lens array first provides a metal plate 10. The metal plate 10 has a circular first surface 12 having a diameter of 8 inches, and two first marks 21 are formed on the first surface 12 by a lithography process. Each of the first marks 21 has a "ten" shape. Theoretically, the first mark 21 can be located at any position of the first surface 12. The relative positional relationship between the two first marks 21 can also be arbitrary, but preferably, two. The first marks 21 are located substantially at the center of the first surface 12 and are symmetrically disposed with respect to the center of the first surface 12, such marks being easily identifiable.

Preferably, the line width of the first mark 21 produced by the lithography process is controlled to be 10 micrometers to 30 micrometers.

Of course, the number of the first marks 21 is not limited, and may be one or three, four, etc., in addition to the two shown in the embodiment of the present invention.

The shape of the first mark 21 is not limited, and may be, for example, a triangle, a square, or the like, as long as it can function as a mark for easy identification and alignment.

The first mark 21 is fabricated in a yellow light chamber using a lithography process.

Referring to FIG. 2, next, the metal plate 10 is placed on an ultra-precision processing machine for processing to form a replica structure on the first surface 12, such as a cavity array 14, which includes a plurality of cavity portions. 140, thereby forming a mold core 20.

The replication structure can also be an array of raised structures.

In general, thousands of cavities 140 can be fabricated on a metal plate 10 having a diameter of 8 turns using an ultra-precision processing machine.

At the same time as the cavity array 14 is fabricated, the second mark 22 is also fabricated using an ultra-precision processing machine. In order to facilitate alignment, the shape of the second mark 22 is the same as the shape and number of the first mark 21, that is, the surface 12 is provided with two "ten" shaped marks.

The relative positional relationship between the second mark 22 and the center of the cavity array 14 is the same as the relative positional relationship between the first mark 21 and the center of the surface 12. For example, if the center of each of the first marks 21 is 2 mm from the center of the first surface 12, the center of each of the second marks 22 is also 2 mm apart from the center of the cavity array 14.

Ideally, the center of the cavity array 14 coincides with the center of the first surface 12, and likewise, the center of the second mark 22 and the center of the first mark 21 should coincide, however, due to the precision of the ultra-precision processing machine. The center of the cavity array 14 and the center of the first surface 12 are substantially offset by a factor of ten or tens of micrometers, which is the same as the offset between the first mark 21 and the second mark 22. The offset can be measured by making the coordinate axis from the center of one mark and calculating the distance from the center of the other mark to the origin; recording the offset.

Referring to FIGS. 3 and 4, prior to fabricating the micro-optic lens array, a substrate 30 is also prepared. The substrate 30 has a second surface 32 on which the micro-optical lens array is fabricated. The substrate 30 can be a transparent substrate, such as a germanium wafer.

Generally, the second surface 32 is processed to form an array of grooves and a scribe line (not shown) between the grooves for determining the forming position of the micro-optical lens, which should be on the mold core. The array of holes is aligned, otherwise the micro-optical lens may be formed outside the predetermined position and become a defective or defective product.

The size of the substrate 30 corresponds to the first surface 12 of the mold core 10 and is also 8 inches.

A third mark 23 is made on the second surface 32. For convenience of alignment, the shape and number of the third marks 23 are the same as those of the second marks 22 and the first marks 21, that is, the second surface 32 is formed with two third marks 23.

Like the first mark 21, the third mark 23 is also obtained by a lithography process, and its line width is controlled to about 1 micrometer, and the third mark 23 is aligned with the first mark 21 during production. For example, the laser light can be penetrated from below the substrate 30 and mapped to the third mark 23 of the mold core 20. When the spot of the laser light is aligned with the third mark 23, the spot on the substrate 30 can be Etching at the location.

Although the accuracy of the third mark 23 is about 1 micrometer, the accuracy of the first mark 21 is between 10 micrometers and 30 micrometers, but only one order of magnitude difference, so that a more precise alignment can be achieved.

Then, according to the previously recorded offset of the second mark 22 relative to the first mark 21, the third mark 23 is moved by the same offset so that the third mark 23 is aligned with the second mark 22. This alignment enables the third mark 23 on the substrate to be sequentially aligned with the first mark 21 and the second mark 22, thereby improving alignment accuracy. The purpose.

After the substrate 30 is aligned with the mold core 20, a molding material can be applied to the mold core 20 or the substrate 30, and then the molding material is embossed with the mold core 20 to fabricate a micro-optical lens array.

Referring to FIG. 5, a third mark 43 on the surface of the substrate (not shown) according to the second embodiment of the present invention includes a cross arm 50 and a trailing arm 60 which are perpendicular to each other, and the cross arm 50 includes a plurality of horizontal lines parallel to each other. 51, the trailing arm 60 includes a plurality of longitudinal lines 61 which are parallel to each other, and the third mark 43 is composed of a plurality of intersecting "ten" characters, and the line width of the horizontal line 51 and the vertical line 61 is 1 micrometer, and each The distance between two adjacent horizontal lines 51 is 1 micrometer, and the distance between each two adjacent vertical lines 61 is 1 micrometer. In the present embodiment, there are five horizontal lines 51 and one vertical line 61, and the arm width of each arm is about 9 micrometers.

The advantage of designing the third indicia 43 in such a configuration is that it does not change its accuracy and extends its length in each arm so that the width of each direction of the third indicia 43 is extended to about 10 microns to match the line. With the alignment of the first mark 21 between 10 microns and 30 microns wide, the result of this alignment will be more accurate.

The third indicia 43 is then moved a known offset to align it with the second indicia 22. Thus, the alignment accuracy is controlled to about 1 micrometer. Then, the subsequent coating molding material and the embossed lens array process can be performed.

Preferably, the central region of the cross arm 50 and the central region of the trailing arm 60, that is, the region 70 where the cross arm 50 and the trailing arm 60 intersect each other are left white, that is, no etching is performed, thereby reducing the transparent wafer. Processing time, and because the interior is empty, it is easier to align it with the second mark.

Of course, the region 70 can also be etched, i.e., etched lines with vertical and horizontal crossings.

21‧‧‧ first mark

22‧‧‧second mark

23‧‧‧ third mark

Claims (10)

A method of manufacturing a micro-optical lens array, comprising the steps of: providing a mold core having a first surface having a first mark made by a lithography process and being fabricated by ultra-precision processing Copying the structure and the second mark; measuring an offset of the second mark from the first mark; providing a substrate having a second surface; and forming a third mark on the second surface by using a lithography process, The third mark is located at the second surface at the same position as the first mark at the first surface; the third mark is first aligned with the first mark; and the substrate is moved according to the offset to make the The third mark is aligned with the second mark; a molding material is applied to the area where the replication structure is located or the substrate, and the micro-optical lens array is embossed. The method of manufacturing a micro-optical lens array according to claim 1, wherein the first mark is formed before the first surface, and the second mark is formed on the first surface. The method for manufacturing a micro-optical lens array according to claim 1, wherein the first mark, the second mark and the third mark are both "ten" shaped marks. The method for manufacturing a micro-optical lens array according to any one of claims 1 to 3, wherein the line width of the first mark is less than 30 μm and greater than 10 μm, and the line width of the third mark is 1 micron. The manufacturing method of the micro-optical lens array of claim 1, wherein the third mark comprises a cross arm and a trailing arm perpendicular to each other, each cross arm comprising a plurality of horizontal lines, each of the trailing arms comprising a plurality of The longitudinal lines are parallel to each other and have a pitch of 1 micrometer, and the plurality of horizontal lines are parallel to each other with a pitch of 1 micrometer. The method of manufacturing a micro-optical lens array according to claim 5, wherein the region where the vertical line intersects the horizontal line is left white. The method for manufacturing a micro-optical lens array according to claim 1, wherein the first mark is produced by a lithography process in a yellow light chamber. A mold core, the improvement comprising: the mold core having a first surface, the first surface having a first mark made by a lithography process, and a copy structure and a second mark produced by an ultra-precision machining method, two of the a mark is symmetrically disposed with respect to a center of the first surface, the second mark has the same shape and number as the first mark, and the first surface further includes a cavity array formed by a plurality of cavity The relative positional relationship between the second mark and the center of the cavity array is the same as the relative positional relationship between the first mark and the center of the first surface. The mold core of claim 8, wherein the first mark has a line width of less than 30 microns and greater than 10 microns. The mold core according to claim 8, wherein the first mark and the second mark are both "ten" shaped marks.