DE102006017708A1 - Scale attaching method for use in support, involves providing surfaces with adhesives between scale and support, and forming wringing surfaces in direct proximity to dosing channel, where wringing surfaces are separated from one another - Google Patents

Abstract

The method involves effecting a bond connection at multiple surface areas of scales (11), where the surface areas are spaced apart from one another. The scales are separated from one another by a channel. The bond connection takes place through direct bonding, low-temperature bonding or anodic bonding. Adhesive surfaces with adhesives are provided between the scale and a support (51). Wringing surfaces are formed in direct proximity to dosing channel and within an adhesive area by the adhesive surfaces, where the wringing surfaces are separated from one another. Independent claims are also included for the following: (1) a support with a scale (2) a scale with an attachment surface for attaching to the support.

Description

The The invention relates to a method of attaching a scale a carrier.

to Measurement of the relative position of two machine parts is on one of the machine parts a yardstick too fasten and on the other of the mutually movable machine parts a scanning unit. When measuring position, a division of the Scale of scanned the scanning unit.

at the attachment of a scale to a carrier one distinguishes two basic principles. At the first basic principle becomes the benchmark on the carrier fixed so that it is in temperature changes with respect to the carrier can expand freely. The attachment takes place here by means in the measuring direction deflectable fasteners or by means of an elastic Adhesive layer.

at the second basic principle, the scale is rigidly attached to the carrier. there can Carrier and scale consist of a material with the same expansion coefficient. Consist of vehicles and scale made of different materials, the temperature behavior becomes the benchmark imposed on the wearer. The attachment takes place here over firmly hardening thin adhesive layers or over Wringing.

For highly accurate position measurement, scales made of glass or glass ceramic with negligible expansion coefficients are preferably used. These scales can be edited well, so that here the wringing of counter surfaces is common, as in the DE 101 53 147 A1 described.

The Problem when wringing a scale is that the connection easily disturbed by impurities or bubble formation can. Furthermore, a high flatness of the connecting surfaces is required, which requires a lot of effort.

task The invention is to provide a method that addresses these problems fixes.

Is solved This object is achieved by a method according to claim 1.

A Another object of the invention is to provide a carrier with a stable thereto fixed scale specify.

Is solved this task by a carrier according to the claim 5th

advantageous Embodiments of the invention are specified in the dependent claims.

embodiments The invention will be explained in more detail with reference to the drawings.

It demonstrate:

1 a first scale and a first support for fixing the scale;

2 the scale attached to the carrier according to 1 ;

3 a longitudinal section through the scale and the carrier according to 2 ;

4 a second carrier and a second scale;

5 the scale attached to the carrier according to 4 ;

6 a third carrier and a third scale in plan view;

7 the scale attached to the carrier according to 6 on average;

8th two variants for the formation of the third scale in cross section;

9 the two variants according to 8th in plan view;

10 a fourth carrier and a fourth scale;

11 the fourth carrier and fourth scale in plan view;

12 a cross section AA 11 ;

13 an enlarged view B from 12 ;

14 an enlarged view C from 11 ;

15 a fifth carrier and a fifth scale;

16 the fifth carrier and fifth scale in plan view;

17 a cross section AA 16 ;

18 an enlarged view B from 17 and

19 an enlarged view C from 16 ,

Based on 1 to 5 is the basis of the invention wringing a scale 11 explained.

In the 1 to 3 is a standard 11 made of glass or glass ceramic (eg ZERODUR) with a measuring graduation 21 shown. The measurement graduation 21 is an incremental graduation that can be scanned for position measurement in measuring direction X. The measurement graduation 21 may be a reflective amplitude grating or a phase grating, which serves in a known manner for highly accurate interferential position measurement. The scale 11 has surveys in the area of its Bessel points 31 on, as a support for hanging on a counter surface 41 a carrier 51 serve. The carrier 51 preferably also consists of glass or glass ceramic (eg ZERODUR).

The counter surface 41 of the carrier 51 opposite surfaces 61 the surveys 31 as well as the counter surface 41 are clean and highly polished surfaces. The required surface finish is achieved by mechanical abrasive polishing or chemomechanical polishing.

The surveys 31 on the scale 11 are preferably produced by known structuring methods, by the regions of the elevations 31 be covered and the material around the surveys 31 is etched away around. The surveys 31 are thus one piece on the scale 11 educated.

The connection of the scale 11 with the carrier 51 done by bonding the surfaces 61 the surveys 31 with the counter surface 41 of the carrier 51 , The basis of the bonding on which the invention is based is adhesion in that clean, conformable and polished surfaces adhere to one another when their distance comes within the range of atomic bonding forces. The surfaces 61 The elevations are therefore designed so that they have a bondable surface 61 for making a bond with the mating surface 41 of the carrier 51 exhibit.

This bonding may be direct bonding, also referred to as wringing. In direct bonding, the bonding effect can be enhanced by exposure to heat, or by applying surfactants. Direct bonding with surface-active agents provides good bond strength even at relatively low temperatures. One particular type of surfactant is the introduction of crystallizing liquid. This bonding process is also referred to as Low Temperature Bonding (LTB) technology and is available in an Internet accessible paper from SCHOTT entitled: "Carol Low Temperature Bonding for Precision Optics" by Carol Click, Leo Gilroy and Dave Vanderpool to which reference is expressly made to the LTB method 11 and the carrier 51 each of glass ceramic with a coefficient of expansion close to zero, in particular ZERODUR.

The bonding may also be an anodic bonding, in which on one of the surfaces to be joined together 61 . 41 by scale 11 or carrier 51 a metallic electrically conductive auxiliary layer, for example aluminum as an intermediate layer between the elevations 31 and the counter surface 41 is applied. This auxiliary layer may be a vapor-deposited layer. In anodic bonding, between the auxiliary layer and the carrier 51 applied a voltage so that ions of the auxiliary layer in the carrier 51 and / or ions of the carrier 51 wander into the auxiliary layer. The applied voltage generates an electrostatic attractive force which causes atomic contact between the scale and the carrier.

Increasingly, standards are being used for multi-dimensional position measurement 12 with a two-dimensional measuring graduation 22 used. There are relatively large-scale standards 12 (For example, 40 cm × 40 cm) on a surface 42 a machine part 52 attached. Especially in lithography equipment where the machine parts 52 at which the scale 12 is to be fastened, made of glass ceramic (eg ZERODUR) with a coefficient of expansion close to zero, the invention can be used advantageously. Such a machine with a scale with a two-dimensional measuring graduation is explained in US 2004/0263846 A1, to which reference is made here.

It may be necessary to use several scales 12 two-dimensionally side by side mosaic-like on a machine surface 52 of, for example, must be attached to cover the required measuring range of about. The standards 12 with the particular photoelectric scannable measuring graduation 22 are in the required precision namely only in sizes of about 40cm × 40cm manufacturable. Each of these standards 12 can now according to the invention on the carrier 52 be attached, as shown in the following figures.

at This attachment the above-mentioned bonding methods are used.

In the 4 and 5 is such a yardstick 12 with a two-dimensional measuring graduation 22 - also called cross grid - exemplified. On the carrier 52 facing surface of the scale 12 are surveys 32 with bondable surfaces 62 educated. This marriage exercises 32 For example, they are two-dimensionally geometrically evenly distributed in a regular grid or statistically distributed.

The surveys 32 may each be circular, with a diameter of less than 30 mm, typically 1 mm to 4 mm and with a mutual distance of preferably smaller than the thickness of the scale 12 , The height of the surveys 32 is advantageously greater than 100 nm, favorable values are in particular 100 nm to 50 microns. The flatness of the surfaces 62 the surveys 32 is in the range of less than 500 nm to a diameter of about 10 mm, typically 30 nm to 10 mm. The surfaces designed as bonding surfaces 62 the surveys 32 lie again in a common plane. Typical values for the thickness of the scale 12 are 3 to 10 mm.

The two-dimensional spatial distribution of the surveys 32 should be done so that between the surveys 32 Opening channels are created, which - based on the XY plane - up to the edge of the scale 12 pass. By this measure, surfactants can easily be removed from the space between scale after bonding 12 and carriers 52 escape. Furthermore, air pockets can cover the entire area of the scale 12 Easily escape through the opening channels, which increases the bond strength and a good flatness of the scale 12 ensures.

The surveys 32 are formed so that the edges - transitions to the adjacent recesses - which form the opening channels, are rounded. This allows the surfaces to be bonded 62 be better cleaned and possibly surface activated. Another advantage is that the risk of material chipping is significantly reduced.

In case of maintenance, the bond can be solved by at least one hole in the carrier or scale in the space of scale 13 and carriers 53 a pressure is built up, for example by compressed air is introduced.

Especially with the carrier 53 cantilevered scales 13 (exemplified in 6 shown) there is a risk that by vibration excitation an alternating peeling and re-wringing the edge regions of the scale 13 arises. This process leads to unpredictable change in the short-period length deviations of the projecting scale range. To avoid this, additional measures are advantageous. So can an extra fuse to hold the scale 11 to 15 on the carrier 51 to 55 be provided. This additional security can be holding elements in the form of springs, retaining clips, magnetic holding elements, electrostatic clamping or vacuum holders, or adhesive holders such as oil films or adhesive methods can be used. This additional securing makes sense at least at the edge region of the Ansprengverbindung, ie at the edge region of the scale 13 and / or the vehicle 53 that is, at the edge of the overlap of scale 13 and carriers 53 ,

Hereinafter, particularly advantageous adhesive connections are described to supplement the Aufengens. This is done by biasing discrete Ansprengflächen 63 , especially in the edge zone of the compound of scale 13 and carriers 53 , by means of glue 7 the surface pressure between the boarding partners 13 and 53 elevated.

By securing with glue 7 is a breaking off and losing the standards 13 eg if accidentally touched by an assembly worker.

The adhesive layer generates at most locally minimal deformations of the scale 13 , Position and flatness are still extremely precise and largely drift-free given by the Ansprengverbindung.

6 shows one on edge areas over the carrier 53 supernumerary scale 13 , Some of the crescent-shaped elevations 33 of the scale 13 are additionally provided with a splice, one of which in 7 is shown in cross section. To distinguish the only raised surveys 32 and in addition by glue 7 secured surveys 33 These are provided with different reference numerals and those with adhesive 7 secured surveys 33 in 6 shown blackened. At the with glue 7 additionally secured surveys 33 is located inside the circular blanks 63 a circular adhesive surface 73 passing through a groove-shaped depression 83 as an adhesive stop from the Ansprengfläche 63 is disconnected. This will prevent when applying the glue 7 this in the Ansprengfläche 63 arrives.

Out establish the clarity the measurement graduation is no longer shown.

The production of opposite the Ansprengfläche 63 deeper areas, so the adhesive surfaces 73 and the wells 83 takes place, for example, by lithographic means. Alternatively, a mechanical processing, such as milling or laser processing is conceivable with appropriate material.

The adhesive surface 73 and the modulus of elasticity of the adhesive 7 should only be kept as large as absolutely necessary to the bending deformation of the measure stabs 13 To keep as small as possible by tensile forces after the adhesive curing.

Negligible short-period deflection of the scale 13 can with the same size of the adhesive surface 73 also by a in 8th and 9 each on the right side shown oval shape of the Ansprengfläche 63 as well as the adhesive surface 73 be achieved. Regardless of the structural design, it is important that the adhesive 7 when hardened forces are intercepted with the shortest possible support distance and as completely as possible, which by the adhesive surface 73 surrounding survey or Ansprengfläche 63 guaranteed.

• – in Kontakt bringen des Maßstabs 13 mit dem Träger 53
• – Justieren des Maßstabs 13 am Träger 53, wobei das Justieren erleichtert werden kann, indem z. B. über die Bohrung 93 ein Gas, z. B. Luft in den Zwischenraum von Maßstab 13 und Träger 53 eingebracht wird um ein Ansprengen in diesem Zustand zu verhindern
• – Andrücken des Maßstabs 13 am Träger 53 und damit Ansprengen des Maßstabs 13, wobei das Andrücken durch Erzeugen eines Vakuums (Evakuieren) im Zwischenraum von Maßstab 13 und Träger 53 generiert werden kann
• – Einbringen des Klebers 7 zur Klebefläche 73 über Bohrungen 93 im Träger 53.

Procedure for wringing and adhesive securing:

• - bring the scale into contact 13 with the carrier 53
• - Adjust the scale 13 on the carrier 53 , wherein the adjustment can be facilitated by z. B. over the hole 93 a gas, z. B. Air in the space of scale 13 and carriers 53 is introduced to prevent wringing in this state
• - pressing the scale 13 on the carrier 53 and thus wringing the scale 13 wherein the pressing by generating a vacuum (evacuation) in the space of scale 13 and carriers 53 can be generated
• - Applying the glue 7 to the adhesive surface 73 about holes 93 in the carrier 53 ,

To shape changes of the scale 13 by shrinking or swelling the glue 7 , z. B. by changing the humidity, to prevent the hole 93 after the introduction of the adhesive 7 be sealed airtight. Alternatively, over the hole 93 after wringing, a gas of defined humidity (eg, nitrogen or helium) in the space of scale 13 and carriers 53 and thus to the adhesive surfaces 73 be passed to an aging of the adhesive 7 to prevent.

When using a suitable adhesive 7 can the glue-secured Ansprengverbindung in case of maintenance z. B. by heating the adhesive 7 or by cracking with the help of light of defined wavelength. It can be a heating element in the hole 93 be introduced to the adhesive surface 73 to heat locally. Alternatively or additionally, via the bore 93 in the space of scale 13 and carriers 53 a pressure is built up to solve the Ansprengverbindung.

The following examples according to the 10 to 19 show advantageous variants, the introduction of the adhesive 7 facilitate.

In the embodiment according to the 10 to 14 becomes the glue 7 from the edge of the scale 14 or the carrier 54 doses and pulls by capillary forces in the adhesive surface 74 , The groove-shaped or groove-shaped depressions 84 between the surfaces 64 the knob-shaped elevations 34 and the adhesive surfaces 74 Prevents adhesive contact to the bleaching surface 64 ,

The support by Ansprengflächen 64 in the immediate vicinity of the dosing channel and within the adhesive area, formed by the adhesive surfaces 74 , is guaranteed. The wells 84 prevent the contact of glue 7 to the Ansprengflächen 64 (Breaking off by feeding glue 7 will be prevented).

In the embodiment according to the 15 to 19 is in the carrier 55 a recess 95 introduced, for the introduction of the glue 7 to the adhesive surface 75 serves. The glue 7 draws by capillary action from the recess, starting to the adhesive surface 75 , This will cause a shrinking glue dot on the overhanging portion of the scale 15 avoided and the glue 7 can be the supernumerary standard 15 do not pull down.

In all embodiments, the carrier 55 towards the edge a rejuvenation 100 exhibit. The carrier 55 is thus softer and exerts deformations of the supreme scale 15 with out. The risk of detachment in the edge area is thereby reduced. An embodiment is in 15 shown.

A rejuvenation 100 the edge area of the carrier 51 to 55 Can be used with and without additional adhesive fixation to improve Ansprengstabilität.

The of the surveys 33 to 35 formed bearing surfaces 63 to 65 that the adhesive surface (s) 73 to 75 should wrap around the adhesive surface 73 to 75 be arranged as symmetrically as possible. As a result, the deformation of the partition surface is also kept low.

Instead of the knob-shaped elevations 31 to 35 are also individual channels in an otherwise flat Ansprengfläche conceivable (escape of air, improving the Ansprengverhaltens). There are various mixtures of surfaces / nubs / grooves with or without adhesive stop depressions 83 . 84 . 85 conceivable.

In the examples presented above, the spaced elevations are 31 to 35 in the form of pimples on the scale 11 to 15 educated. The surveys 31 to 35 may alternatively or additionally also on the carrier 51 to 55 educated be.

The shape and arrangement of the surveys 31 to 35 is not limited to the illustrated embodiments. Instead of circular elevations 31 to 35 For example, rectangular surveys can be used.

at at least approximately square or round scales can be the Elevations form a kinematically determined edition by only three surveys are distributed in one level.

All bonding methods of the invention have in common that the surfaces to be joined 61 to 65 ; 41 to 45 be brought to a few atom distances to each other, either by Vander-Waals forces can be pulled together (direct bonding), or by establishing fewer atomic layers in the form of an interconnector to make an atomic compound (LTB, anodic bonding).

The Dimensions given in the drawings are in mm and show only by way of example the orders of magnitude.

Claims (13)

Method for fixing a scale ( 11 to 15 ) to a carrier ( 51 to 55 ) by establishing a bond between the scale ( 11 to 15 ) and the carrier ( 51 to 55 ), characterized in that the bonding connection at a plurality of spaced-apart surface areas ( 61 to 65 ) of the scale ( 11 to 15 ) is performed. Method according to claim 1, characterized in that that the bond connection by direct bonding, low-temperature bonding or anodic bonding takes place. Method according to one of the preceding claims, characterized marked that in addition for bonding a further connection is performed. A method according to claim 3, characterized in that said further connection is an adhesive bond by passing between the scale ( 13 . 14 . 15 ) and the carrier ( 53 . 54 . 55 ) an adhesive ( 7 ) is introduced. Carrier with a scale, the scale ( 11 to 15 ) on the carrier ( 51 to 55 ) is attached by bonding, characterized in that the bonding at a plurality of spaced-apart surface areas ( 61 to 65 ) of the scale ( 11 to 15 ) is executed. Carrier with a scale according to claim 5, characterized in that the scale ( 11 to 15 ) and / or on the carrier ( 51 to 55 ) Surveys ( 31 to 35 ) are formed, which the spaced-apart surface areas ( 61 to 65 ) form. carrier with a scale according to claim 5 or 6, characterized in that in addition to the bond another connection is provided. Carrier with a scale according to claim 7, characterized in that the additional connection is an adhesive bond in which between the scale ( 13 . 14 . 15 ) and the carrier ( 53 . 54 . 55 ) Adhesive areas ( 73 . 74 . 75 ) with an adhesive ( 7 ) are provided. Carrier with a scale according to claim 8, characterized in that the adhesive surfaces ( 73 . 74 . 75 ) each of the surveys ( 33 . 34 . 35 ) through a groove-shaped depression ( 83 . 84 . 85 ) are separated. Carrier with a scale according to claim 9, characterized in that the carrier ( 53 . 54 . 55 ) the scale ( 13 . 14 . 15 ) on the surveys ( 33 . 34 . 35 ) directly contacted, the adhesive surfaces ( 73 . 74 . 75 ) compared to the surveys ( 33 . 34 . 35 ) are set back so that between the scale ( 13 . 14 . 15 ) and the carrier ( 53 . 54 . 55 ) a gap for receiving the adhesive ( 7 ) and that the groove-shaped recesses ( 83 . 84 . 85 ) opposite the adhesive surfaces ( 73 . 74 . 75 ) are arranged reset. Carrier with a scale according to one of claims 5 to 10, characterized in that in the carrier ( 53 . 55 ) at least one opening ( 93 . 95 ) for introducing the adhesive ( 7 ) to the adhesive surface ( 73 . 75 ) is provided. Carrier with a scale according to one of claims 5 to 11, characterized in that the adhesive surface ( 74 . 75 ) to an edge of the scale ( 14 . 15 ) and / or the carrier ( 54 . 55 ) is guided, and is formed such that the adhesive ( 7 ) by capillary forces from the edge to the adhesive surfaces lying away from the edge ( 74 . 75 ). Carrier with a scale according to one of claims 5 to 12, characterized in that the support ( 55 ) to its edge a rejuvenation ( 100 ) having.