Method for producing a wafer equipped with transparent plates
09663351 ยท 2017-05-30
Assignee
Inventors
- Simon Armbruster (Wannweil, DE)
- Dietmar Haberer (Reutlingen, DE)
- Stefan Pinter (Reutlingen, DE)
- Jochen Tomaschko (Herrenberg, DE)
- Benjamin Steuer (Waldenbuch, DE)
Cpc classification
Y10T29/49888
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B81C2203/0109
PERFORMING OPERATIONS; TRANSPORTING
Y10T29/49799
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T29/49885
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T428/24331
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B81B7/0067
PERFORMING OPERATIONS; TRANSPORTING
Y10T29/49789
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B81B2201/042
PERFORMING OPERATIONS; TRANSPORTING
Y10T29/49947
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
B81B7/00
PERFORMING OPERATIONS; TRANSPORTING
B81C3/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A production method for a wafer equipped with transparent plates includes: formation of a row of through-holes in a wafer; formation of at least one strip-shaped recess in a wafer surface, each of the through-holes of the same row intersecting partly with the respectively associated strip-shaped recess; an uninterrupted groove being formed in each intermediate region between two adjacent through-holes of the same row, the floor surface of the groove being oriented so as to be inclined relative to the wafer surface by an angle of inclination greater than 0 and less than 90; and covering at least one through-hole with at least one transparent plate made of at least one material transparent to at least a sub-spectrum of electromagnetic radiation.
Claims
1. A production method for a wafer equipped with transparent plates, comprising: formation of at least one row of through-holes in a wafer; formation of at least one strip-shaped recess in a wafer surface of the wafer, using a mechanical tool; wherein the formation of the at least one row of through-holes and the formation of the at least one strip-shaped recess are carried out in such a way that each of the through-holes of the same row intersects partly with the respectively associated strip-shaped recess, and an uninterrupted groove is formed in each intermediate region between two adjacent through-holes of the same row, the floor surface of the groove being oriented so as to be inclined relative to the wafer surface by an angle of inclination greater than 0 and less than 90; and covering at least one through-hole with at least one transparent plate made of at least one material transparent to at least a sub-spectrum of electromagnetic radiation.
2. The production method as recited in claim 1, wherein the at least one strip-shaped recess is configured so as to extend, in each case, from a first segment of a side edge of the wafer up to a second segment of the side edge of the wafer in the wafer surface.
3. The production method as recited in claim 1, wherein at least two through-holes which are adjacent and which intersect with the same strip-shaped recess are covered by a single transparent plate.
4. The production method as recited in claim 1, wherein the at least one transparent plate covering the at least one through-hole is at least one of: an optical window, a UV window, a window having an anti-reflective coating, a lens, a prism, and a filter.
5. The production method as recited in claim 1, wherein the at least one transparent plate is fastened on the at least one through-hole by a fastening element.
6. The production method as recited in claim 5, wherein the at least one through-hole is hermetically sealed by the fastening element and by the at least one transparent plate.
7. The production method as recited in claim 6, wherein an outer side of the at least one transparent plate, oriented toward the wafer surface, is covered with at least one protective lacquer.
8. The production method as recited in claim 1, further comprising: structuring out a covering cap from the wafer provided with the at least one transparent plate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
DETAILED DESCRIPTION OF THE INVENTION
(7)
(8) In the method described here, at least one row of through-holes 10 is fashioned in a wafer 12. Here, a through-hole 10 is understood as an opening going through wafer 12. This can also be described by saying that through-holes 10 extend from a first wafer surface 14a of wafer 12 to a second wafer surface 14b oriented away from first wafer surface 14a. Preferably, first wafer surface 14a is oriented parallel to second wafer surface 14b.
(9) Wafer 12, used to carry out the method described here, is preferably a semiconductor wafer. In particular, wafer 12 can be a silicon wafer. However, it is to be noted that the practicability of the method described here is not limited to a particular material of wafer 12.
(10) Through-holes 10 can for example be etched through wafer 12. In the case of a wafer 12 made of silicon, the formation of the at least one row of through-holes 10 can take place for example via KOH etching (potassium hydroxide etching). In order to form through-holes 10, however, a multiplicity of other etching materials may also be used. Likewise, the formation of the at least one row of through-holes 10 can also be accomplished mechanically, e.g. by boring.
(11) Preferably, through-holes 10 fashioned in a row are situated relative to one another in such a way that for their surfaces of intersection with a plane running through first wafer surface 14a, mid-points (not shown) can be defined that are situated on a line A-A. The lines A-A of a plurality of rows of through-holes 10 can run parallel to one another. In particular, through-holes 10 of a plurality of rows can form a grid. In this case, the mid-points of the intersecting surfaces (of through-holes 10 of different rows with the plane running through first wafer surface 14a) are also situated on lines B-B. Preferably, the lines B-B are oriented perpendicular to the lines A-A that run parallel to one another. The configuration of through-holes 10 shown in
(12) In the specific embodiment described here, through-holes 10 having a rectangular cross-section are fashioned along a sectional plane running parallel to first wafer surface 14a. All through-holes 10 of the same row for example have two side walls 10a and 10b oriented perpendicular to the line A-A, the walls being oriented perpendicular to first wafer surface 14a and to second wafer surface 14b. In contrast, only one side wall 10c per through-hole 10, fashioned parallel to line A-A of the associated row of through-holes 10, is oriented perpendicular to first wafer surface 14a and to second wafer surface 14b. Another side wall 10d per through-hole 10, running parallel to line A-A, is oriented at an angle greater than 0 and less than 90 to first wafer surface 14a and to second wafer surface 14b. It is to be noted that through-holes 10, even without a rectangular cross-section, can each have a side wall 10d running parallel to the line A-A of their row, the wall being oriented to first wafer surface 14a and to second wafer surface 14b at an angle greater than 0 and less than 90. In addition to side wall 10d, oriented at an angle to wafer surfaces 14a and 14b, each of the through-holes 10, without a rectangular cross-section, can also have a side wall 10c running parallel to line A-A of its row, said wall running perpendicular to first wafer surface 14a and to second wafer surface 14b.
(13) Through-holes 10 can for example all be fashioned having the same first (minimum) through-hole width b1 along their associated line A-A (and parallel to first wafer surface 14a), and/or having the same second (minimum) through-hole width b2 perpendicular to their associated line A-A (and parallel to first wafer surface 14a). Through-holes 10 can however also have different through-hole widths b1 and b2.
(14) In a further method step, optionally carried out before or after the formation of the at least one row of through-holes 10 in wafer 12, at least one strip-shaped recess 16 is fashioned in first wafer surface 14a of the wafer. Preferably, a strip-shaped recess 16 is formed in first wafer surface 14a for each row of through-holes 10.
(15) The formation of the at least one strip-shaped recess 16 in first wafer surface 14a of wafer 12 is accomplished using a mechanical tool.
(16) Preferably, for this purpose a relative movement is carried out between the mechanical tool and wafer 12. During the relative movement between the mechanical tool and wafer 12, carried out in order to form exactly one strip-shaped recess, the mechanical contact is maintained between the processing surface of the mechanical tool and wafer 12. This can be understood for example as meaning that, during the formation of exactly one strip-shaped recess 16, the same part of the processing surface of the mechanical tool is in uninterrupted mechanical contact with wafer 12. Alternatively, during the formation of exactly one strip-shaped recess 16, a new part of the processing surface of the mechanical tool can continuously contact wafer 12 in such a way that the mechanical contact between the processing surface of the mechanical tool as a whole and the wafer is never interrupted.
(17) The processing surface of the mechanical tool is understood to be a surface of the mechanical tool that, through mechanical contact with wafer 12, brings about a removal of wafer material from first wafer surface 14a of wafer 12. As a rule, the processing surface of the mechanical tool is held/pressed on first wafer surface 14a in such a way that friction occurs between the processing surface and the wafer material, resulting in the desired removal of the wafer material from first wafer surface 14a of wafer 12. Examples of a mechanical tool that can be used are described further below.
(18) In the method described here, the formation of the at least one row of through-holes 10 and the formation of the at least one strip-shaped recess 16 are matched to one another in such a way that each of the through-holes 10 of the same row partly intersects with the respectively associated strip-shaped recess 16, and an uninterrupted groove 18 is formed in each intermediate region 20 between two adjacent through-holes 10 of the same row (which intersect with the same strip-shaped recess 16). The respective uninterrupted groove 18 extends without interruption from a first through-hole 10 of the two adjacent through-holes 10 up to a second through-hole 10 of the two adjacent through-holes 10. In the formation of each uninterrupted groove 18, floor surface 18a thereof is oriented so as to be inclined to first wafer surface 14a. This is to be understood as meaning that floor surface 18a of each uninterrupted groove 18 is oriented at an angle of inclination to first wafer surface 14a that is greater than 0 and less than 90. Preferably, floor surface 18a of each uninterrupted groove 18 is fashioned so as to be inclined, in a direction oriented perpendicular to the relative movement, by the angle of inclination relative to first wafer surface 14a that is greater than 0 and less than 90. Preferably, floor surface 18a of each uninterrupted groove 18 is also (in particular in a direction oriented perpendicular to the relative movement) fashioned with the same angle of inclination to second wafer surface 14b, greater than 0 and less than 90. (Floor surface 18a is understood as a wafer material surface, oriented away from first wafer surface 14a, on the respective uninterrupted groove 18.)
(19) The formation of the at least one strip-shaped recess 16 can take place via grinding, milling, and/or sawing. For each strip-shaped recess 16, a floor surface 16a is ground, milled, or sawed, this floor surface also being fashioned so as to be inclined to first wafer surface 14a with an angle of inclination greater than 0 and less than 90.
(20) In the specific embodiment described here, first through-holes 10 are fashioned in wafer 12 (see
(21) The formation of the at least one strip-shaped recess 16 in first wafer surface 14a can however also take place after a formation/etching of the at least one row of through-holes 10. In this case, first the at least one strip-shaped recess 16 is formed in first wafer surface 14a, for which purpose first wafer surface 14a is preferably gone over by the processing surface of the mechanical tool the same number of times as the number of strip-shaped recesses 16 that are to be formed in first wafer surface 14a. During the going over of first wafer surface 14a with (at least a part) of the processing surface of the mechanical tool, the processing surface remains in (uninterrupted) mechanical contact with wafer 12. The mechanical contact between the processing surface of the mechanical tool and wafer 12 can be (briefly) interrupted only between a formation of a first strip-shaped recess 16 and a subsequent formation of a second strip-shaped recess 16 on the same wafer 12. Subsequently, for each strip-shaped recess 16 that is fashioned, a row of through-holes 10 is formed in such a way that the row of through-holes 10 partly intersects with the associated strip-shaped recess 16. Preferably, the at least one row of through-holes 10 is fashioned having a maximum extension Am (along the line A-A of the row), which is smaller than a longitudinal extension L of the associated recess 16 (along the respective line A-A).
(22) It is again to be noted that in the two above-described process sequences, in each intermediate region 20 between two adjacent through-holes 10 of the same row a respective uninterrupted groove 18 is fashioned with its floor surface 18a situated at an incline to first wafer surface 14a. If the maximum extension Am of a row of through-holes 10 is smaller than the longitudinal extension L of the associated strip-shaped recess 16, the outer through-holes 10 of the same row of through-holes 10 have, at their sides oriented away from adjacent through-hole 10, outer grooves 24 whose floor surfaces 24a are also oriented at an inclination to first wafer surface 14a with angle of inclination greater than 0 and less than 90. (Floor surface 24a of an outer groove 24 is understood as a wafer material surface, oriented away from first wafer surface 14a, on respective outer groove 24.) Specifically, outer grooves 24 can also extend up to an adjacent side edge 14c of wafer 12 (between wafer surfaces 14a and 14b).
(23) Preferably, the at least one strip-shaped recess 16 is formed having a width Bh, perpendicular to the associated longitudinal extension, that is larger than the second (minimum) through-hole width b2 (oriented perpendicular to maximum extension A of the associated row of through-holes 10) of through-holes 10. In this way, at through-holes 10, adjacent to first wafer surface 14a, a first widening region 25a and a second widening region 25b are further formed that extend parallel to associated line A-A, and between which the contacted through-hole 10 is situated. Widening regions 25a and 25b also have floor surfaces that are oriented at an angle to first wafer surface 14a by the angle of inclination greater than 0 and less than 90 and in the following are designated support surfaces 26a and 26b for at least one transparent plate. (Support surfaces 26a and 26b are also oriented at an inclination to second wafer surface 14b by angle of inclination greater than 0 and less than 90.)
(24) Preferably, the at least one strip-shaped recess 16 is fashioned in each case going out from a first segment of side edge 14c of wafer 12 up to a second segment of side edge 14c of wafer 12 in first wafer surface 14a. By going over first wafer surface 14a at least once with the mechanical tool, in this way the at least one strip-shaped recess 16 can be fashioned comparatively easily and quickly.
(25) In a further method step, the at least one through-hole 10 is covered by at least one transparent plate 28. The at least one transparent plate 28 is understood to be a covering element that is made of at least one material that is transparent at least to a sub-spectrum of electromagnetic radiation. The at least one transparent plate 28 thus has, for at least the sub-spectrum of electromagnetic radiation, a comparatively high transmission coefficient, or a relatively low coefficient of reflection. For example, the at least one through-hole 10 can be covered by at least one optical window, at least one UV window, at least one window having an anti-reflective coating, at least one lens, at least one prism, and/or at least one filter, as the at least one transparent plate 28. Wafer 12 produced by the method described here is thus suitable for a large number of possible applications.
(26) The at least one transparent plate 28 can be fastened/glued to the at least one through-hole 10 using at least one fastening means/joining means (not shown). For example, before placing the at least one transparent plate 28 into the at least one strip-shaped recess 16, the fastening means/joining means can be deposited on the at least one transparent plate 28. Alternatively, however, before attachment of the at least one transparent plate 28, the fastening means/joining means can also be deposited on the contact surface thereof fashioned on wafer 12, e.g. at least on support surfaces 26a and 26b.
(27) Preferably, the at least one through-hole 10 is hermetically sealed by the fastening means and by the at least one transparent plate 28. A hermetic sealing of the at least one through-hole 10 is easy to realize due to the reliable ensuring of a smooth contact surface (such as support surfaces 26a and 26b) when carrying out the method described here.
(28) For example, a glass solder (seal glass) can be used as a fastening means/joining means. If a glass solder is used as fastening means/joining means, wafer 12 can be heated after the attachment of the at least one transparent plate 28 and of the fastening means/joining means, whereby a hermetically sealed joint connection can be produced between the at least one transparent plate 28 and the material of wafer 12. However, it is to be noted that for the fastening of the at least one transparent plate 28 it is also possible to use a multiplicity of glues, in particular hermetically sealing glues.
(29) In the specific embodiment of
(30) Preferably, the at least one transparent plate 28 is placed in the at least one strip-shaped recess 16 in such a way that an outer side, oriented away from the at least one covered through-hole 10, of transparent plate 28 does not protrude from first wafer surface 14a. In particular, a position for the outer side of the at least one transparent plate 28 is preferred that is inwardly offset relative to first wafer surface 14a. This is easy to realize via a suitable choice of a maximum layer thickness of the at least one transparent plate 28, and a minimum depth of strip-shaped recess 16.
(31)
(32) In a further optional method step, shown in
(33)
(34) In the specific embodiment shown in
(35) During operation of cylindrical grinding or milling pin 40, its processing surface 42 rotates about an axis of rotation 44. During a formation of a respective strip-shaped recess, a relative movement between cylindrical grinding or milling pin 40 and wafer 12 along a specified scanning direction 46 is carried out. This can take place via a movement of cylindrical grinding or milling pin 40 relative to (stationary) wafer 12, or via a movement of wafer 12 relative to cylindrical grinding or milling pin 40 (held stationary). Moreover, during the formation of a respective strip-shaped recess 16, cylindrical grinding or milling pin 40 (given an uninterrupted mechanical contact between at least a part of its processing surface 42 and wafer 12) is held in such a way that axis of rotation 44 encloses, along scanning direction 46, a right angle with first wafer surface 14a (
(36)
(37) In the specific embodiment of
(38)
(39) In the specific embodiment of
(40) A wafer 12 produced by one of the above-described methods is recognizable by at least one row of through-holes 10 fashioned in wafer 12, and at least one strip-shaped recess 16 fashioned in a wafer surface 14a of wafer 12, each of the through-holes 10 of the same row intersecting partly with the respectively associated strip-shaped recess 16, and an uninterrupted groove 18 being fashioned in each intermediate region 20 between two adjacent through-holes 10 of the same row, the floor surface 18a of this groove being oriented so as to be inclined to wafer surface 14a by an angle of inclination greater than 0 and less than 90, and the at least one through-hole 10 being covered by at least one transparent plate 28 made of at least one material that is transparent at least to a sub-spectrum of electromagnetic radiation.
(41) It is to be noted that wafer 12 produced by the advantageous technology described herein is equipped with at least one transparent plate 28 whose outer surface and whose inner surface are inclined relative to first wafer surface 14a (and preferably also relative to second wafer surface 14b) by the angle of inclination greater than 0 and less than 90. The inclination of the outer surface and inner surface of the at least one transparent plate 28 acts, during later use of a covering cap obtained from wafer 12, to screen out disturbing reflections from an image surface.
(42)
(43) In order to carry out the production method described here, first a wafer 12 equipped with transparent plates 28 is produced. For this purpose, the already-described method steps of the production method for a wafer 12 equipped with transparent plates 28 can be carried out.
(44) Subsequently, as shown in
(45) Subsequently, as shown in
(46) The finally produced covering caps 70 can subsequently be used to cap a micromechanical component, such as for example a micro-mirror.
(47)
(48) Covering cap 70 shown schematically in
(49) Covering cap 70 includes a bearer element 74 structured out from a wafer, having on a bearer element side 76 at least one through-hole 10 that is covered by at least one transparent plate 28 made of at least one material that is transparent at least to a sub-spectrum of electromagnetic radiation. Moreover, bearer element side 76 has at least one uninterrupted groove 18 that runs from an edge 78 of bearer element side 76, at which reflective element 74 is structured out from the wafer, to the single through-hole 10 fashioned on bearer element side 76, a floor surface 18a of the at least one uninterrupted groove 18 being oriented at an inclination to bearer element side 76 by an angle of inclination greater than 0 and less than 90. In the specific embodiment shown in
(50) After the capping of a micromechanical component with covering cap 70, the at least one transparent plate 28 ensures an entry and/or exit of a light beam into the micromechanical component packed by covering cap 70. The micromechanical component preferably includes a (possibly adjustable) reflective element that can easily be configured in such a way that its reflective surface, at least in its initial position, is oriented so as to be inclined relative to the at least one transparent plate 28. This can be used for the (automatic) screening out of disturbing reflections from an image surface.