KR20220094253A - Method for manufacturing mold of micro lens array - Google Patents

Abstract

The present invention relates to a method for manufacturing a micro lens array mold. A method for manufacturing a micro lens array mold according to the present invention includes a step of processing a hole array on a substrate; a step of filling the inside of the hole array with a polymer resin; a step of adding a solvent to the polymer resin to expand the volume of the polymer resin and form a convex part protruding from one surface of the substrate; and a step of manufacturing a mold by using the substrate and the shape of the convex part. According to the present invention, uniform lens arrays can be manufactured.

Description

Micro lens array mold manufacturing method {METHOD FOR MANUFACTURING MOLD OF MICRO LENS ARRAY}

The present invention relates to a method for manufacturing a microlens array mold, and more particularly, in an image sensor for detecting a visible ray region or an image sensor for detecting a (far) infrared region, from an upper portion of a sensing element arranged in a pixel array. The present invention relates to a method for manufacturing a mold for a micro-lens array to increase detection efficiency by concentrating light entering each pixel.

A pixel-type sensor array is widely used in an image sensor that detects a visible light region or an image sensor that detects a (far) infrared region. A micro lens array is used in the image sensor to increase detection efficiency.

1 is a view for explaining the operation of a micro lens array.

As shown, on the bottom surface of the sensor, a detection element (detector) for sensing light is disposed to be spaced apart by n x m pixels, and a micro lens array 10 corresponding to the pixel of the detection element is disposed on the top of the detection element array. At this time, each microlens condenses the light entering each pixel to an effective area where the sensing element is located. Accordingly, since the sensing elements can be spaced apart from each other on the bottom surface, image detection efficiency can be increased. In this case, the active area occupied by the sensing element in each pixel of the sensor array occupies a part of the total area of the pixel, which is referred to as a fill factor.

In order to manufacture the high quality micro lens array 10, it is common to manufacture a mold for making the lens array through mechanical processing. For example, a method of directly processing a mold for forming a micro lens array using a laser is known. However, this method requires expensive equipment, and there is a problem in that a mold must be directly processed for each micro lens. In addition, when it is necessary to newly manufacture a mold having different characteristics of the micro lens array, there is a problem in that it takes a lot of time and money.

In order to solve the above problems of laser processing, a conventional thermal reflow method is known.

2 is a view for explaining a thermal reflow method as an example of a method of manufacturing a mold for manufacturing a conventional micro lens array.

First, in this method, a cylindrical photoresist is formed on a substrate by using a lithography process among existing semiconductor manufacturing processes. Next, when the photoresist is liquefied by heating it, reflow occurs. A curved droplet shape can be formed on the substrate by surface tension. After that, it is hardened and a mold is manufactured based on it.

The thermal reflow method has the advantage of being able to manufacture a microlens array at once, but in order to prevent the aggregation of neighboring droplets when fluidity occurs due to liquefaction by heating, a dead space between each lens is required to fill There is a limit to increasing the factor. In addition, since the size of the microlens array made by reflow is determined by the thickness of the deposited resin, precise control of the thickness and uniformity of the resin is required, but a resin material having desired optical properties is deposited uniformly and thickly. It is not easy to do, and as a result, there is a problem in that it is difficult to obtain a smooth and uniform surface of the micro lens array.

Republic of Korea Patent Registration 10-1397553

Accordingly, an object of the present invention is to solve such a problem in the prior art, and by processing a hole array on a substrate and using the volume swelling phenomenon of a polymer resin filling the hole array, it is easy to mold the micro lens array. An object of the present invention is to provide a method for manufacturing a micro lens array mold that can be manufactured.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

The above object, according to the present invention, processing the hole array in the substrate; filling the hole array with a polymer resin; adding a solvent to the polymer resin to expand the volume of the polymer resin to form a convex portion convexly protruding over one surface of the substrate; and manufacturing a mold using the shape of the substrate and the convex portion.

Here, the hole is preferably a circular hole.

Here, the filling of the polymer resin in the hole array may include: applying the polymer resin to the substrate; and pushing the polymer resin applied with a blade to fill the hole array with the polymer resin, and removing the polymer resin from one surface of the substrate.

Here, in the forming of the convex portion, the expansion rate may be adjusted by changing the type of the solvent.

Here, in the step of forming the convex portion, the expansion rate may be adjusted by adjusting the concentration of the solvent.

Here, in the step of forming the convex portion, the expansion rate may be controlled by adjusting the reaction time with the solvent.

Here, the manufacturing of the mold may include plating one surface of the substrate on which the convex portion is formed.

Here, the manufacturing of the mold may include transferring the pattern of the convex part by pressing one surface of the substrate on which the convex part is formed to a microlens array mold.

The above object, according to the present invention, processing the hole array in the substrate; filling the hole array with a material that increases in volume upon curing; curing the material filled in the hole array to form a convex portion convexly protruding from one surface of the substrate when the volume is expanded; and manufacturing a mold using the shape of the substrate and the convex portion.

According to the method for manufacturing the micro lens array mold of the present invention as described above, there is an advantage that it can be quickly manufactured at a low cost without expensive equipment.

In addition, there is an advantage that a uniform lens array can be manufactured.

In addition, there is an advantage that the shape of the lens can be variously controlled by adjusting the type, concentration, reaction time, etc. of the solvent applied to the polymer resin.

In addition, there is an advantage that a large-area process is possible.

1 is a view for explaining the operation of a micro lens array.
2 is a view for explaining a thermal reflow method as an example of a method of manufacturing a mold for manufacturing a conventional micro lens array.
3 is a process flow diagram illustrating a method of manufacturing a micro lens array mold according to an embodiment of the present invention.

The specific details of the embodiments are included in the detailed description and drawings.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout

Hereinafter, the present invention will be described with reference to the drawings for explaining a method of manufacturing a micro lens array mold according to embodiments of the present invention.

3 is a process flow diagram illustrating a method of manufacturing a micro lens array mold according to an embodiment of the present invention.

The method for manufacturing a microlens array mold according to an embodiment of the present invention comprises the steps of processing an array of holes 102 on a substrate 100 (FIG. 3 (a)), a polymer resin 110 inside the hole 102 array. In the step of filling (110) ((b) to (d) of FIG. 3), a solvent is added to the polymer resin 110 to expand the volume of the polymer resin 110 so that it is convex on one surface of the substrate 100 Forming the protruding convex part 112 (FIG. 3(e) to (f)) and manufacturing the mold 120 using the shape of the substrate 100 and the convex part 112 (FIG. 3) of (g) to (h)).

First, an array of holes 102 is processed in a substrate 100 made of silicon or other solid material (FIG. 3(a)). The hole 102 array may be formed by an etching process, but is not limited thereto, and other known processing processes may be used as long as the micro-sized hole 102 array can be processed.

In the present invention, the hole 102 is preferably not a hole in the form of penetrating the substrate, but a hole 102 in the form of an intaglio. At this time, the hole 102 is preferably a circular hole (102).

Next, a polymer resin 110 is filled in the hole 102 array.

In order to fill the polymer resin 110 in the hole 102 array, first, the polymer resin 110 is applied to one surface of the substrate 100 (FIG. 3 (b)). In this case, the polymer resin 110 may be applied around the area in which the hole 102 array is processed, but the polymer resin 110 may be applied to the entire area of the substrate 100 .

After coating the polymer resin 110 on one surface of the substrate 100, push the polymer resin 110 coated on the substrate 100 with the blade 200 to push the polymer resin 110 inside the hole 102 array. and to remove the polymer resin 110 on the substrate 100 rather than the hole 102 array (FIG. 3(c)). Accordingly, as shown, the polymer resin 110 is filled only inside the hole 102 array (FIG. 3(d)).

Next, a solvent is added to the polymer resin 110 filled with the hole 102 array to expand (swell) the volume of the polymer resin 110 (FIG. 3(e)).

The swelling phenomenon is a phenomenon in which a substance absorbs a solvent and swells. When a polymer material is in a solid state, the interaction between the polymer chains is strong, but when a solvent is added, the solvent molecules are interposed between the polymer chains and the volume expands. In particular, when the polymer material has a structure (crosslinked structure) in which the polymer chains are bonded to each other, the polymer chains cannot separate from each other, so they swell in the solvent but do not dissolve.

As the volume of the polymer resin 110 filling the hole 102 array expands, it swells to the top of the open hole 102 to form a convex portion 112 convexly protruding like a droplet on one surface of the substrate 100. .

Table 1 below shows examples of the polymer resin 110 that can be used in the present invention and a solvent used therein.

Polymer Solvent Matrimid Cyclohexanone P84 NMP PES NMP PSf NMP PEBAX Butanol, reflux at 60 °C, spin-coating at room temperature PTMSP Toluene PAN NMP PEI NMP PDMS Toluene

<Table 1>

Table 1 shows an example of a solvent that can be typically used for each polymer resin 110, and other solvents may be used in addition to the solvent. For example, Table 2 below shows the swelling ratio when PDMS is used as the polymer resin 110 and different solvents are reacted. It can be confirmed that there is no swelling or the expansion ratio is different depending on the solvent.

Solvent Swelling Ratio perfluorotributylamine 1.00 perfluorodecalin 1.00 pentane 1.44 diisopropylamine 2.13 hexanes 1.35 n -heptane 1.34 triethylamine 1.58 ether 1.38 cyclohexane 1.33 trichlorethylene 1.34 dimethoxyethane (DME) 1.32 xylenes 1.41 toluene 1.31 ethyl acetate 1.18 benzene 1.28 chloroform 1.39 2-butanone 1.21 tetrahydrofuran (THF) 1.38 dimethyl carbonate 1.03 chlorobenzene 1.22 methylene chloride 1.22 acetone 1.06 dioxane 1.16 pyridine 1.06 N -methylpyrrolidone (NMP) 1.03 tert -butyl alcohol 1.21 acetonitrile 1.01 1-propanol 1.09 phenol 1.01 dimethylformamide (DMF) 1.02 nitromethane 1.00 ethyl alcohol 1.04 dimethyl sulfoxide (DMSO) 1.00 propylene carbonate 1.01 methanol 1.02 ethylene glycol 1.00 glycerol 1.00 water 1.00

<Table 2>

Therefore, in the present invention, it is possible to control the shape of the convex portion 112 convexly protruding over one surface of the substrate 100 by changing the type of solvent applied to the polymer resin 110 to adjust the expansion rate (see FIG. 3 ). (f)).

Alternatively, by changing the concentration of the solvent applied to the polymer resin 110 to adjust the expansion rate, it is possible to control the shape of the convex portion 112 convexly protruding over one surface of the substrate 100 (FIG. 3 (f)). ).

Alternatively, it is possible to control the shape of the convex portion 112 convexly protruding over one surface of the substrate 100 by changing the reaction time between the polymer resin 110 and the solvent to adjust the expansion rate (FIG. 3(f)). ).

Next, the mold 120 is manufactured using the shapes of the substrate 100 and the convex portion 112 (FIG. 3(g) to (h)).

As an example of manufacturing the mold 120 , the mold 120 for forming the micro lens array may be manufactured by performing electroplating on one surface of the substrate 100 on which the convex portion 112 is formed.

Alternatively, a method for transferring the pattern of the convex part 112 to the mold 120 by pressing one surface of the substrate 100 on which the convex part 112 is formed on the micro lens array mold 120 is used for molding the micro lens array. The mold 120 can be manufactured.

As described above, according to the method for manufacturing a micro lens array mold of the present invention, it is possible to quickly manufacture a micro sensor array at a low cost without expensive equipment such as a laser.

In addition, the shape of the lens can be variously modified by adjusting the type, concentration, reaction time, etc. of the solvent applied to the polymer resin, and each lens can be uniformly manufactured.

A method for manufacturing a microlens array mold according to another embodiment of the present invention comprises the steps of processing a hole array on a substrate, filling the hole array with a material, and expanding the volume of the material filled in the hole array to be convex on one surface of the substrate. It may be configured to include the steps of forming the protruding convex portion and manufacturing a mold using the shape of the substrate and the convex portion.

The material filled in the hole may be a liquid or gel-type material that increases in volume when cured. For example, the inside of the hole may be filled with a thermosetting resin or an ultraviolet curable resin, and heat or ultraviolet light may be applied toward the hole to harden the material filling the inside of the hole. When the volume expands during the curing process, it swells to the top of the open hole as in the above-described embodiment to form a convex portion protruding convexly like a droplet on one surface of the substrate.

After the convex portion is formed, a mold for forming the microlens array may be manufactured as in the above-described embodiment.

The scope of the present invention is not limited to the above-described embodiments, but may be implemented in various types of embodiments within the scope of the appended claims. Without departing from the gist of the present invention claimed in the claims, it is considered to be within the scope of the claims of the present invention to various extents that can be modified by any person skilled in the art to which the invention pertains.

100: substrate
102: Hall
110: polymer resin
112: convex part
120: mold
200: blade

Claims (9)

processing the hole array in the substrate;
filling the hole array with a polymer resin;
adding a solvent to the polymer resin to expand a volume of the polymer resin to form a convex portion convexly protruding from one surface of the substrate; and
and manufacturing a mold using the shape of the substrate and the convex portion. The method of claim 1,
The hole is a circular hole in the micro lens array mold manufacturing method. The method of claim 1,
The step of filling the inside of the hole array with a polymer resin is
applying the polymer resin to the substrate; and
and pushing the polymer resin applied with a blade to fill the hole array with the polymer resin, and removing the polymer resin on one surface of the substrate. The method of claim 1,
The forming of the convex part is a method of manufacturing a microlens array mold to control the expansion rate by changing the type of the solvent. The method of claim 1,
The forming of the convex portion is a method of manufacturing a micro lens array mold to control the expansion rate by adjusting the concentration of the solvent. The method of claim 1,
The step of forming the convex portion is a method of manufacturing a microlens array mold to control the expansion rate by adjusting the reaction time with the solvent. The method of claim 1,
The step of making the mold is
and plating one surface of the substrate on which the convex portion is formed. The method of claim 1,
The step of making the mold is
and transferring the pattern of the convex part by pressing one surface of the substrate on which the convex part is formed to the micro lens array mold. processing the hole array in the substrate;
filling the hole array with a material that increases in volume upon curing;
forming a convex portion convexly protruding from one surface of the substrate when the volume is expanded by curing the material filled in the hole array; and
and manufacturing a mold using the shape of the substrate and the convex portion.

Images