CN101870165B - Stop grating structure of continuous relief male die - Google Patents

Abstract

A stop grating structure of a continuous relief male die belongs to a micro-optics element processing technology. The stop grating structure is arranged on the periphery of the continuous relief structure of the male die, the lower end surface of the stop grating structure is lower than the lower end surface of the continuous relief structure so as to bear total pressure applied on the die, and a grating shape design is used for reducing the required horizontal flow distance of a slushing compound below the structure so as to overcome the problem that the pointed top structure of the continuous relief male die is easily damaged in the process of impressing and maintain the good filling effect of the male die.

Description

The stop grating structure of continuous relief male die

Technical field

The invention belongs to micro-optics element processing technology, relate generally to a kind of grid shape stop configurations of the continuous relief male die for hot padding, i.e. stop grating structure.

Background technology

Micro optical element is the key element of making the low profile photovoltaic subsystem.Hot padding association reaction ion etching technology can realize quartz material continuous relief micro optical element high accuracy, high duplication and batch machining cheaply.

Hot padding (Hot Embossing Lithography, HEL) be a branch of nanometer embossing, propose first and propose patent application by Stephen Y.Chou in nineteen ninety-five, referring to patent US5772905 " Nanoimprint lithography ".With respect to ultraviolet stamping, hot padding polymer selectable range is more extensive, and process equipment is simpler, and cost is lower.

Yet hot padding processing continuous relief micro optical element can produce the problem that pressing mold service life and impression filling effect can not be taken into account.Fancy price has determined that the continuous relief pressing mold need to have sufficiently long service life; Desirable filling effect is the basic premise that obtains high accuracy continuous relief optical element.On the one hand, for identical pressing mold graphic structure, although formpiston impression has desirable filling effect, its sharp-pointed top structure damaged very easily in impression causes its service life limited; On the other hand, in the former impression, although the raised structures beyond the graphics field can effectively be protected embossment safety, often be difficult to realize the fully filling of pressing mold.Therefore how taking into account the service life of formpiston and the desirable filling effect of former, is to utilize hot padding to realize high accuracy continuous relief optical element batch machining institute problem needing to overcome.

A kind of method of photoresist shaping has been proposed for this this seminar, address the above problem by improving method for stamping, referring to patent 200910073198.5 " with photoresist shaping improves the method for filling and reducing cull in the concave die hot coining ", and document (Peng Jin, et al.Resist Shaping for Replication of Micro-optical Elements with Continuous Relief in Fused Silica.Optics Letters.2010,35 (8): 1169～1171).The method is to have increased on the basis of traditional handicraft 1. the shaping of on-chip photoresist thin layer, obtains the photoresist zone consistent with the pressing mold area of the pattern; 2. pressing mold is aimed at two steps with the photoresist after the shaping.Although the method has been improved the filling effect of former, introduces additional process steps, has reduced operating efficiency.

For this reason, this patent under the prerequisite of not introducing additional process steps, solves the problem that pressing mold service life and impression filling effect can not be taken into account by improving stamper architecture.

Summary of the invention

The present invention is intended to overcome the deficiencies in the prior art, and a kind of formpiston structure for hot padding is provided.Under the prerequisite of not sacrificing impression efficient, overcome existing hot press printing technology and made the ubiquitous continuous relief pressing mold of continuous relief micro optical element service life and impress the problem that filling effect is difficult to take into account.

Technical solution of the present invention is: a kind of stop grating structure of continuous relief male die, stop grating structure is peripheral at the continuous relief structure of formpiston, the design parameter of described stop grating structure is: 1. structure height is 1385nm, and the lower surface of described backstop grid is lower than continuous relief structure lower surface 100nm; 2. the gross area of lower surface is 1.76mm2; 3. live width is 30 μ m; 4. dutycycle is 30%; 5. the inward flange of stop grating structure and the radial distance 0.5mm of continuous relief structure outermost edge; The imprint parameters that described stop grating structure was suitable for is: 1. resist is the polymethyl methacrylate of molecular weight 75Kg/mol, thickness 850nm; 2. maximum pressure is 600 newton; 3. imprint temperature is 180 degrees centigrade; 4. impress 10 minutes time.

The present invention has following characteristics and good result:

Stop grating structure for the protection of continuous relief male die proposed by the invention.This stop grating structure lower surface is lower than the continuous relief structure lower surface, can be used for carrying the gross pressure that acts on pressing mold, and reduce the distance of the required lateral flow of structure below resist with grid shape design, overcome sharp-pointed top structure easily vulnerable problem in impression of continuous relief male die, and kept the good filling effect of formpiston.Experiment shows: the formpiston with stop grating structure can under the injury-free prerequisite of embossment, realize that in 10 minutes the ideal of the continuous relief lenticule graphics field of diameter 7mm, degree of depth 1390nm is filled.

Description of drawings

Fig. 1 is the formpiston generalized section with stop grating structure

Fig. 2 is the formpiston actual design result with stop grating structure

A) has the formpiston design structure diagram of stop grating structure

B) has the formpiston profile diagram of stop grating structure

Fig. 3 is the formpiston impression schematic diagram with stop grating structure

Fig. 4 is the wide resulting impression curves of different backstop grid lines

The filling effect contrast that Fig. 5 obtains for adopting identical imprint parameters and different pressing mold

A) the central endless belt filling effect of former impression

B) the edge endless belt filling effect of former impression

C) the central endless belt filling effect of backstop grid formpiston impression

D) the edge endless belt filling effect of backstop grid formpiston impression

The specific embodiment

The invention belongs to a kind of continuous relief male die stop grating structure for hot padding, as shown in Figure 1 and Figure 2; This stop grating structure 12 is positioned at the periphery of continuous relief structure 11, and stop grating structure lower surface 13 is lower than continuous relief structure lower surface 14.The design principle of continuous relief male die stop grating structure 12 parameters comprises following five aspects:

1. stop grating structure 12 highly: precision and uniformity in the actual processing of pressing mold can guarantee that stop grating structure lower surface 13 is lower than under the prerequisite of continuous relief structure lower surface 14, chooses minimum of a value;

2. the gross area of stop grating structure lower surface 13: when pressure acted on stop grating structure 12 fully, its maximum pressure should be less than 1/3rd of die material compression strength;

3. stop grating structure 12 live widths: under the prerequisite that the gross area is constant and structure is smooth of its stop grating structure 12, take into account pressing mold processing practical capacity, and according to stamper architecture, imprint parameters and resist flow behavior, suitably choose less live width.

4. the dutycycle of stop grating structure 12: the dutycycle of stop grating structure 12 is less than the dutycycle of continuous relief structure 11.

5. the distance at stop grating structure 12 and continuous relief structure 11 edges: the stop grating structure 12 of introducing can be ignored the impact of continuous relief optical property.

The stop grating structure 12 design concrete grammars of continuous relief male die are as follows, impress schematic diagram as shown in Figure 3:

1. stop grating structure 12 highly is 1485nm.The height of pressing mold graph area continuous relief structure 11 is 1385nm, backstop grid lower surface 13 is lower than continuous relief structure lower surface 100nm, thereby backstop grid lower surface 13 can touch hard substrate 31 prior to continuous relief structure lower surface 14, has reduced the impaired possibility in continuous relief structure 11 tops.100nm only is 1/14 of continuous relief height, and is less on subsequent diagram transmission impact.

2. the gross area of backstop grid lower surface 13 is 1.76mm ²Its maximum pressure of choosing is 600N according to stamper architecture, and the stress when all pressure all act on stop grating structure 12 is about 340MPa, only be vitreous silica compression strength 1100MPa 30%.Therefore enough the large gross area has guaranteed that stop grating structure 12 avoids crushing.

3. stop grating structure 12 live width s=30 μ m.Theoretical according to the Schift extrusion flow, in the graphics field of pressing mold radius r ⁰=5mm, resist are the PMMA of the molecular weight 75Kg/mol of MicroResist company, its zero-shear viscosity η when 180 ℃ of temperature ⁰=0.6MPas, pressure F=600N, initial resist thickness h ⁰=850nm, according to following formula:

$\frac{1}{h^2\left(t\right)}=\frac{2\mathrm{Ft}}{2\mathrm{\&pi;}{\mathrm{\&eta;}}_0({\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="HSA00000162488200021.png"\; state="\{\{state\}\}">r</figure-callout>}}_0+\frac{s}{2})s^3}+\frac{1}{{\mathrm{<figure-callout\; id="0"\; label="h"\; filenames="HSA00000162488200021.png"\; state="\{\{state\}\}">h</figure-callout>}}_0^2}$

Resist thickness h (t) relation in time that obtains under different live widths as shown in Figure 4.Can find out that resist thickness can decay to below the 100nm rapidly when stop grating structure 12 live widths were 30 μ m in 1 minute.So the inhibition that 12 pairs of impressions of above-mentioned stop grating structure cause almost can be ignored.And if do not use grid shape design, then the stop configurations width is 120 μ m, this moment, resist thickness just can be down to 200nm in 10 minutes, and is more remarkable to the impression inhibition.

4. the dutycycle of stop grating structure 12 is

Dutycycle 50% less than continuous relief structure 11.

5. stop grating structure 12 is 0.5mm with the distance at continuous relief structure 11 edges.The laser direct writing system exposure area radius 5mm that this paper pressing mold machining is used, therefore distance is excessive, can cause part stop grating structure 12 to process.4.5mm place radially simultaneously, the light intensity of incident Gaussian beam has decayed to 8.83 * 10-4 of peak value, so the phase place variation that light beam is caused of stop grating structure 12 can be ignored on the impact of entire light.

Adopt identical imprint parameters: initial resist thickness 850nm, 180 ℃ of temperature, pressure 600N, time 10min, the former impression contrasts as shown in Figure 5 with the filling effect of stop grating structure formpiston impression.Wherein be respectively former shown in Fig. 5 (a) and Fig. 5 (b) and be stamped in central authorities and the filling effect of edge endless belt, can find out that imprint result reaches far away fully filling; Be respectively the formpiston with stop grating structure 12 shown in Fig. 5 (c) and Fig. 5 (d) and be stamped in central authorities and the filling effect of edge endless belt, can find out that imprint result has reached desirable fully filling.This shows that the formpiston with stop grating structure 12 still has the filling effect that significantly is better than former; Repeatedly repeated experiments shows that the top of 12 pairs of continuous relief structures 11 of stop grating structure played effective protective effect in addition.

In sum, the stop grating structure 12 of setting up in formpiston continuous relief structure 11 peripheries that the present invention proposes has been realized the protection to continuous relief structure 11, and has realized taking into account of pressing mold service life and impression filling effect under the prerequisite that does not reduce impression efficient.

Claims (1)

1. the stop grating structure of a continuous relief male die, it is characterized in that stop grating structure (12) is in continuous relief structure (11) periphery of formpiston, the design parameter of described stop grating structure (12) is: 1. structure height is 1385nm, and the lower surface of described backstop grid (13) are lower than continuous relief structure lower surface (14) 100nm; 2. the gross area of lower surface (13) is 1.76mm ²3. live width is 30 μ m; 4. dutycycle is 30%; 5. the inward flange of stop grating structure (12) and the radial distance 0.5mm of continuous relief structure (11) outermost edge; The imprint parameters that described stop grating structure was suitable for is: 1. resist is the polymethyl methacrylate of molecular weight 75Kg/mol, thickness 850nm; 2. maximum pressure is 600 newton; 3. imprint temperature is 180 degrees centigrade; 4. impress 10 minutes time.

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