TWI496189B - Method for producing thin, free-standing layers of solid state materials with structured surfaces - Google Patents

Description

Method of making a thin, separate layer of solid material having a structured surface

The present invention relates to the manufacture of solid material layers, and in particular to the fabrication of relatively thin separate layers of solid materials such as microelectronic materials. The invention also relates to techniques for fabricating geometries on the surface of this layer.

The fabrication of microelectronic devices generally involves two distinct processing steps: first, cutting a relatively thin separate layer from a larger solid material (eg, a semiconductor material such as germanium), and secondly using a number of further processing steps and techniques on the separate layer ( In particular, on its surface, a structure is formed. These surface structures often do not involve any additional material, but are purely fabricated by shaping (e.g., by etching) the material at the surface of the individual layers.

As an example, a thin wafer can be cut from a single crystal twin ingot in a first set of processing steps (eg, using a wire saw). The wafer surface is then further processed (eg, by polishing) to obtain a smooth surface. In a second set of processing steps, geometric structures such as channels, pyramids, slabs, pins, and the like are then formed on the surface of the wafer. It is done through a series of steps (usually complex and expensive), such as reticle deposition, patterning the reticle (eg, by lithography), and patterning the underside of the wafer (eg, borrowing (eg, RIE) Or wet anisotropy (such as KOH) or isotropic (such as HF) etching, and finally remove the mask. The structure formed on the surface of the wafer can be used, for example, to improve the photovoltaic conversion efficiency of a solar cell - for example, by creating a random retro-conical structure on the surface of the wafer that enhances the light dispersion into the active area of the solar cell. In this simple case, a mask may not be required, and a single etching step (for example, wet etching by NaOH) may be used. A more complex example can fabricate a structure such as "photonic crystallization" on the surface of the wafer to promote electro-optic features (especially band gaps) of the wafer material. Since it is necessary to precisely control the local alignment of the structure in this application, this technique is generally closely related to processing requirements (e.g., high quality reticle and RIE etching) and is therefore very expensive. Other applications include microelectromechanical systems in which fabrication of structures (e.g., channels, platforms) on the surface of a wafer is often a preliminary step (or steps) of complex three-dimensional devices, such as inductors and actuators.

One of the general disadvantages of current methods of making thin, individual layers of solid materials with structured surfaces is that by fabricating the individual layers themselves, and then structuring their surface, it typically requires a large number of processing steps. This makes the technique expensive and slow, especially where it is necessary to control the local alignment of the surface structure and be forced to use reticle and lithography. A further problem is the consumption of solid materials: for example, when using a wire saw to cut a thin wafer from an ingot, it loses about 50% of the ingot material by a so-called "cut loss" (saw dust, etc.). In addition, when the wafer is polished, the material is subsequently lost in a structural forming step such as etching. Since this solid state material is often expensive, the manufacturing cost is significantly increased. Moreover, while for most applications, a very thin layer of solid material is sufficient (in fact, often more advantageous, for example, for electronic or optical properties) to manufacture the desired device, most current methods are not economically capable of producing a thin, separate layer of such solid material. .

A method of producing a thin independent layer of a solid material with minimal kerf loss has been described recently. However, it still requires a locally definable structure to be fabricated on the surface of this thin individual layer in a controlled manner that is simpler and more economical than current methods.

In accordance with a particular embodiment of the present invention, the fabrication of a thin, separate layer of solid material having a structured surface is improved by the fabrication of the combined layers and the fabrication of previously separate surface structures. Particular embodiments of the present invention provide a single, simple, and inexpensive method of addressing most of the disadvantages presented. Particular embodiments of the present invention can produce thin, separate layers of solid material with locally controllable thickness and locally definable surface pattern.

In various embodiments, a thin, separate layer of solid material having a locally controllable surface pattern is fabricated by inducing a locally controllable three dimensional stress pattern in the solid state material. For example, local control stress can be set in the auxiliary layer to which the solid material is adhered. The auxiliary layer can be strongly adhered to the work piece combined with the solid material. The auxiliary layer is prepared in a manner that induces varying degrees of locally defined stress at the desired location of the layer. It also induces locally defined stresses in the adhesive worksheet.

For example, the auxiliary layer may be composed of regional patterns, some of which have a relatively high coefficient of thermal expansion (CTE), and some have a relatively low CTE. If the auxiliary layer is adhered to a work piece whose CTE is closer to "low CTE" ("higher CTE" than the auxiliary layer), and if the composite structure (auxiliary layer - work piece) is subjected to temperature change, then at a high CTE The auxiliary layer region induces a large stress (compared to the low CTE region). The adhesion sheet of the solid material thus induces a directly related locally defined stress pattern.

For example, the auxiliary layer can comprise a polymer characterized by a CTE greater than about 50*10 ^-6 K ^-1 ("high CTE") at room temperature. Preferably, the polymer is characterized by a CTE greater than about 100*10 ^-6 K ^-1 at room temperature, and more preferably the polymer is characterized by a CTE greater than about 200*10 ^-6 K ^-1 at room temperature. The polymer can be patterned in a "porous" region (i.e., a region where the polymeric material is partially removed). If the material ("hole") is removed by the full thickness of the auxiliary layer, stress is not locally induced in the auxiliary layer region, and the effect is similar to that of the auxiliary layer of these regions having a CTE equal to that of the adhesive sheet (for example, for a work piece of enamel, The CTE is a locally different CTE ("low CTE") of about 3*10 ^-6 K ^-1 ) at room temperature. If these "pore" regions are only corrugations (ie, the material in the auxiliary layer is only partially removed to a specific depth within the multiple auxiliary layers), the degree of locally induced stress is between the previous situation and other extremes where the material is not removed from the auxiliary layer. between. The resulting effect is similar to that of the auxiliary layer of these regions having a locally different CTE ("low CTE") between the CTE of the underlying worksheet and the CTE ("high CTE") of the untreated auxiliary layer material.

In another embodiment, in addition to partial removal of the polymer, the polymer may be treated physically or chemically to, for example, locally increase the degree of crosslinking of the polymer, which may result in, for example, a partial decrease in CTE (from "high CTE" To "low CTE"). The difference between the "high CTE" and the "low CTE" required to produce a thin separate layer having a structured surface from the adhesive sheet depends on the desired dimensions of the surface structure, the CTE of the bonded sheet, and the auxiliary layer and the working sheet. Other mechanical properties of the material (especially its thickness and modulus of elasticity) depend on it. For example, if the auxiliary layer contains a polydimethyl methoxyoxane (or PDMS) having a CTE at room temperature of about 300*10 ^-6 K ^-1 in an unpatterned state, and the work piece contains a CTE of about 3*10 ^-6 After K ^-1 , the auxiliary layer having a difference of at least 1% compared to the remaining auxiliary layer CTE is sufficient to fabricate the structural surface on the work sheet (for example, it can be used with CTE at room temperature of 297*10 ^-6 K) The area of ^-1 , and the auxiliary layer of PDMS of CTE at other areas of 300*10 ^-6 K ^-1 at room temperature, fabricate the surface of the structure on the sheet containing ruthenium).

In yet another embodiment, the auxiliary layer can comprise a material (e.g., metal) characterized by a CTE and a CTE of the worksheet having an absolute difference in room temperature of at least 10*10 ^-6 K ^-1 . For example, for a crucible working sheet having a CTE at a region of about 3*10 ^-6 K ^-1 at room temperature, an auxiliary layer containing aluminum having a CTE of about 24*10 ^-6 K ^-1 at room temperature can be used, and this The auxiliary layer may be patterned by partial removal of aluminum (completely or partially to any desired depth within the auxiliary layer).

In yet another embodiment, it is possible to fabricate locally controllable stress patterns, such as localized expansion (see below), in the auxiliary layer using local material properties other than localized CTE. In addition, other local material properties of the auxiliary layer may be locally modified (which may not necessarily effectively create a stress pattern in the auxiliary layer, but may affect the dynamic evolution of the stress pattern) to produce a locally defined surface structure on the worksheet, such as may be partially modified The modulus of elasticity of the auxiliary layer (e.g., Young's modulus), for example, by locally varying the degree of cross-linking of the polymer in the auxiliary layer.

As described below, other methods can be used to fabricate locally controllable stress patterns in the auxiliary layer. Regardless of the mechanism used to create the locally defined stress pattern in the auxiliary layer, the adhesion sheet of the solid material induces a directly related locally defined stress pattern.

Under suitable conditions, the mechanical stress pattern causes the thin layer to substantially peel off the interface between the working sheet and the auxiliary layer from the working sheet ("peeling"). Also under suitable conditions, it forms a pattern of surface structures on a thin layer originally fabricated inside the worksheet, and this pattern is specified by the local stress pattern of the auxiliary layer. In addition, a pattern of the surface structure is formed on the surface of the work piece which has just been exposed due to the peeling of the thin layer, and this pattern is substantially a mirror image of the pattern formed on the surface of the peeling layer (more precisely, three-dimensional complementarity). The area of the exfoliated layer substantially conforms to the area of the auxiliary layer. It is possible to reuse the two patterned surfaces which are formed when the thin layer is peeled off from the work piece, and the other exposed layer can be applied to the newly exposed face of the work piece or the newly exposed face of the peeling layer. Thus, embodiments of the present invention facilitate repeated peeling operations to produce other layers having surface structures, all from the remaining worksheets and exfoliation layers.

Embodiments of the invention are also directed to a thin, self-contained layer of solid material having a structured surface from a single or polycrystalline semiconductor material. The present invention can be arranged where necessary or desirable (e.g., due to cost considerations) thin single crystal or polycrystalline germanium discs, and the one or both sides of the thin discs are to be patterned into a surface composed of the same material as the disc itself. Structure. Advantageous applications include the fabrication of a cost effective and efficient single crystal germanium solar cell having a surface structure substantially as an antireflective layer or photonic crystal, or a structure for a microelectromechanical device on a thin mechanically flexible substrate. For example, embodiments of the present invention facilitate the stripping of a structured surface layer having a thickness of about 50 microns from a flat single crystal raft. On these thin twinned layers, for example, the present invention facilitates the fabrication of surface structure patterns having lateral dimensions ranging from significantly less than 1 micron to several centimeters. Also depending on the lateral dimensions of the pattern, the height of the patterns (i.e., the local thickness of the layer at the pattern) can be controlled to zero (i.e., the corresponding shaped aperture of the layer) to greater than a few hundred microns. In addition, these "macroscopic" patterns may each further be selected to specify a "microscopic" surface roughness pattern, wherein the micropatterns include or consist of vertical and lateral dimensions ranging from less than 100 nanometers to more than a few micrometers. Substantially periodic structures (eg, lines, valleys, edges, etc.), and spatial periods ranging from less than 100 nanometers to tens of micrometers. The dimensions of the "maize" and "micro" patterns produced can be controlled by the localized stress pattern of the auxiliary layer and the mechanical properties of the auxiliary layer.

A locally defined stress pattern of a composite (auxiliary layer and adhesion sheet) required to fabricate a thin, self-contained layer of a solid state material having a surface structure in accordance with an embodiment of the present invention, such that the composite accepts a composite Or a variety of external activation factors (such as temperature changes). External activation can be used to create locally defined stress patterns in two different ways: one method can use homogenous external activation (eg, subject all composites to the same temperature change), but the auxiliary layer is heterogeneous, ie, at least one material within the auxiliary layer The properties change according to a predefined pattern (eg, the CTE of the auxiliary layer changes locally according to the pattern). The second method may use a uniform auxiliary layer, but where the external activation is non-uniform according to a particular pattern (e.g., more intensely cooling the auxiliary layer having the same CTE everywhere at a particular predefined location). Both methods can be used individually or in combination. The stress can be locally produced by, for example, a partial volume change of the auxiliary layer material. It may use special active elements (such as embedding small actuators (such as piezoelectric elements) into the auxiliary layer material and then selectively actuating the next group), or more negatively using the material properties of the auxiliary layer (eg, in the auxiliary layer) Completed by inducing different thermal expansions at different locations. It is also possible to locally modify other material properties that affect the stress pattern of the composite (auxiliary layer - worksheet), in particular the thickness of the auxiliary layer and/or the modulus of elasticity of the auxiliary layer. Finally, it is also possible to locally modify the dynamic evolution of the stress pattern (eg, how the stress pattern changes locally during thin-layer cracking, such as the dynamics of crack propagation (such as crack tip oscillation), especially the elastic modulus. . For example, for the problem of pulling a specified boundary value, it is known that the non-size elastic modulus dependence of the two-material system can be expressed by the two material parameters σ (hardness ratio of the two materials) and ε (oscillation index). It is also known to have a two-material system consisting of a work piece of one material and an auxiliary layer of a second material (depending on the isotropic and linear elasticity of each material, the semi-infinite crack parallel interface already existing in the work piece, and the hypothetical operation) The sheet and the auxiliary layer are infinitely long. The steady state solution of the stripping problem depends substantially on the thickness of the auxiliary layer and the hardness ratio σ, but only slightly related to the oscillation index β. Thus, in one example of a particular embodiment of the invention, the localized and substantial variation in the thickness of the fabricated layer is accomplished by locally varying the thickness of the auxiliary layer and/or its hardness. Further varying the oscillation index locally modifies the relatively small (variation in thickness, i.e., amplitude) of the oscillation behavior at the tip of the crack on the surface of the thin layer, substantially the local nature of the periodic structure (e.g., period or amplitude).

The main advantage of the present invention is the significant reduction in the number of processing steps required to produce a thin, separate layer of solid material having a structured surface. A procedure for cutting thin layers from thicker sheets of solid material and subsequent procedures for forming controllable surface structures on such layers (eg, polishing, cleaning, reticle deposition, reticle patterning, pattern transfer) relative to conventional methods Both surface etching and reticle removal can be combined into a single, extremely simple and significantly less expensive program sequence. In addition, the method significantly reduces material losses that occur during the manufacture of thin, individual layers of solid materials having structured surfaces. The method hardly causes loss of valuable raw materials relative to previous methods using, for example, sawing, grinding, polishing, or etching. When the patterned thin layer is stripped from the work piece, the raw material is still almost completely distributed between the peeling layer and the remaining work sheets, and the surface structure patterns on the thin layer and the work sheet are substantially complementary to each other.

Another advantage of the present invention is the ability to use significantly less expensive equipment. Particular embodiments of the present invention can be easily integrated into existing manufacturing methods, such as for making thin tantalum solar cells with structured surfaces.

Finally, one advantage of the present invention is that it can be applied to many different types of solid materials.

The invention will be better understood with the aid of the description of the embodiments and the illustrated embodiments.

This invention relates to a method of making a thin, separate layer of solid material having a structured surface. Exemplary embodiments of the present invention are described below with reference to FIG.

In the first embodiment, the work sheet 2 is a commercially available single crystal germanium wafer. Figure 1 shows, in a front view, a representative sequence of programs in four steps in accordance with the present invention. The following reference symbols are related to Fig. 1.

Step 1: The base material here is a single crystal germanium wafer 2 manufactured according to the Czochralski method, which is used, for example, in the microelectronics or photovoltaic industry. Wafer 2 has a diameter of approximately 76 mm and a thickness of approximately 0.4 mm. The wafer is slightly n- or p-doped, has a specified resistivity of about 10 ohms, and is oriented with its sides 1a and 1b parallel to the <100> crystal plane. One of the two sides 1a and/or 1b of the wafer may be mirror polished or etched and polished only. The wafer 2 can be used directly after the wafer is manufactured, or it can be roughly cleaned by conventional methods (for example, cleaning with an organic solvent and water or by plasma oxidation).

Step 2: coating a thin layer of polydiorganotoxime 3a, 3b (for example, polydimethyloxane or PDMS) on each side 1a and 1b of the wafer 2; for convenience of discussion, it is called PDMS, but It should be understood that any suitable polyoxyl polymer or copolymer can be used and hardened (or hardened). The preferred thickness of these auxiliary layers 3a, 3b is between 0.01 mm and 10 mm, more preferably between about 0.3 mm and about 3 mm. The thickness of the two layers 3a, 3b is the same in the exemplary embodiment herein, but in other embodiments, the thickness of the two layers may vary. As for PDMS, for example, SYLGARD 184 of Dow Corning can be used, and the mixing ratio between the hardener and the base material is 1:10. The liquid PDMS mixture is first vacuum degassed for about one hour, then coated on the faces 1a, 1b of the wafer 2 to the desired thickness, and hardened on a hot plate (e.g., at 100 ° C for 30 minutes). In this illustrative embodiment, the PDMS layers 3a, 3b have a uniform thickness over most of the wafer area. It allows the wafer to be placed in a horizontal plane and the PDMS is gravity balanced before hardening. The three-layer composite (PDMS 3a - wafer 2-PDMS 3b) was cooled to room temperature after PDMS hardening. Then, any PDMS protruding along the circumference of the wafer 2 is removed with a sharp edge so that the edge of the wafer 2 is virtually free of PDMS, and the PDMS covers only the two sides 1a, 1b of the wafer 2. Carefully applying the PDMS to the wafer face and equalizing it on a horizontal plane avoids any PDMS protrusions that exceed the circumference of the wafer (and therefore the edge of the wafer); in this way the surface tension of the PDMS will prevent it from overflowing. To the edge of the wafer.

Step 3: The patterning step is then carried out: a pattern 6 of any line and/or other geometric figures (e.g., circles, etc.) is cut on the surface of one of the PDMS layers 3a using a tool such as a sharp edge or a doctor blade. In this particular embodiment, all of the cuts have the same depth in the PDMS layer 3a which is less than the thickness of the PDMS layer 3a (i.e., the PDMS layer 3a is never cut completely through the wafer surface 1a). For example, for a PDMS layer 3a having a thickness of preferably 1 mm, the preferred depth of these cuts ranges from 0.01 mm to 0.99 mm, more preferably from 0.1 mm to 0.9 mm.

Step 4: After the patterning step, the composite (PDMS 3a - wafer 2-PDMS (3b)) was completely immersed in a liquid nitrogen bath (temperature approximately -200 ° C). Since silicon (about 3 * 10 ^-6 K ^-1) and PDMS (about 300 * 10 ^-6 K ^-1) of very different thermal expansion coefficients, so that large mechanical stresses induced by cooling the composite body. However, in the region of the pattern 6 in which the PDMS layer 3a has been cut, the mechanical stress is locally different depending on the arrangement and depth of the incisions. After cooling for a few seconds, the wafer 2 spontaneously spliced into two thin single crystal cymbals 5 parallel to its surface 1a, and one side of each disc 5 still adheres to the corresponding PDMS auxiliary layer 3a or 3b.

It should be noted that the two discs 5 are each actually composed of a single piece, and the cleaved surface displays the image 7a or 7b of the pattern 6 on its surface 4. The image patterns 7a and 7b on the two discs 5 are substantially complementary. The pattern in each of the image patterns 7a and 7b may include a region having a different surface roughness than the surrounding region, a different surface height (i.e., corresponding to a partial thickness of the disk 5), or other surface properties. The lateral features of pattern 6 are essentially reproduced on the same scale in complementary images 7a and 7b. A pattern having a lateral dimension greater than about 0.1 mm in pattern 6 can be reproduced in image patterns 7a and 7b. In order to avoid additional cracking of the vertical surface 4, it is possible to remove the disc 5 - after cleavage - directly from the liquid nitrogen bath onto a 100 ° C hot plate (under the surface of the adhered PDMS auxiliary layer 3a or 3b) until its PDMS assist The layer has been warmed again to at least room temperature. Regardless of the heating step used, it is preferred to carefully press the warming plate 5 against the flat support so that any curling of the layer is reversed and the layer is flattened with warming.

The thin disk 5 on which the surface patterns 7a and 7b are manufactured in accordance with this method is substantially composed of the same single crystal germanium having the same properties as the original wafer 2, and can be used as it is. Alternatively, the PDMS auxiliary layer 3a or 3b may be removed from the disk 5, for example by immersing in a suitable liquid etchant such as NMP (N-methylpyrrolidone) and TBAF/THF (tetrabutylammonium fluoride). The volume ratio of tetrahydrofuran (1.0 M solution) is 3:1 or immersed in hydrochloric acid. A preferred mode of removing the PDMS auxiliary layer 3a or 3b is to wash or immerse in a bath with a hot sulfuric acid (H ₂ SO ₄ ) etchant, preferably at a temperature above 150 ° C (and more preferably above 200 ° C). Then, the resulting white vermiculite foam is mechanically removed (for example, using a brush, and may be a plurality of brushing cycles), and finally immersed in hydrochloric acid to clean the disc 5 .

In a second exemplary embodiment, the patterning step (step 3) is performed using laser beam illumination instead of cutting with a sharp edge. The laser is preferably of a frequency that the PDMS strongly absorbs (the CO ₂ laser conforms to this standard), and preferably controls the desired pattern of the beam to the strength and motion of the PDMS auxiliary layer 3a, either automatically or manually. Commercially available laser cutters (e.g., VERSA LASER VLS 6.60, which has a 60 watt CO ₂ laser) are acceptable. The depth of the cut can be varied in several ways, which can be used individually or in combination: the laser beam can be focused at different depths, the laser intensity can be varied, the scanning speed of the laser beam to the PDMS surface 3a can be varied, and the pulse rate of the laser The change, and the speed of the laser light, can be repeated through the same point on the PDMS surface 3a (each step can be a surface cleaning step).

In a third embodiment, the patterning step is performed using chemical etching instead of cutting with a sharp edge, which can use a mask layer on the surface of the PDMS, and can be combined with a knife or laser cut.

In a fourth embodiment, the patterning step is performed by locally burning the PDMS surface 3a at the selected location, but the hot stamping machine having the relief pattern of the desired pattern is pressed against the PDMS surface 3a instead of using a lightning Shoot the beam. The hot stamping machine is preferably at a temperature higher than the PDMS decomposition temperature, more preferably higher than 550 °C.

In a fifth embodiment, the patterning step is performed using any of the various possible cutting mechanisms previously described. In this case, however, not only the line but also the lateral extension of the PDMS surface 3a is extended, and a two-dimensional pattern (such as a dish) is cut into the PDMS surface 3a. It can be accomplished by, for example, using a laser in a raster manner to fabricate these patterns based on image data used to control laser combustion in a scanning manner.

In a sixth embodiment, the patterning step of the method is carried out using any of the various cutting mechanisms previously described. However, the depth of the cut is not fixed at all in the pattern 6 but locally in a predetermined manner. In other words, it can make the pattern of pattern 6 a different depth. In this way, for example, highly localized patterns can be produced in the image patterns 7a and 7b. An extreme example can cut the surface 1a of the wafer 2 until it passes through the PDMS layer 3a. If so, for example, for a pattern 6 composed of a filled circular shape (i.e., a dish), one of the two produced discs 5 has a perforated image pattern 7a, and the other has the same thickness as the original wafer 2. Corresponding complementary pattern 7b of the high platform.

In a seventh embodiment, the patterning step of the method does not by locally cutting the pattern into the PDMS auxiliary layer 3a, but locally modifying the properties of the PDMS layer 3a at a particular location corresponding to the pattern of the desired pattern. Implemented. The following techniques can be used, for example, [Huck et al. The Langmuir (2000), 16: 3497-3501 ] modified PDMS of local mechanical properties (in particular its CTE): The PDMS layer 3a was immersed in diphenyl ketone in methylene chloride 0.25 The M solution was passed for 5 hours. The PDMS layer 3a was then air dried for 24 hours in the dark. This treatment increases the sensitivity of PDMS to ultraviolet (UV) light illumination because diphenyl ketone, a sensitizer, generates free radicals upon irradiation; these free radicals crosslink PDMS. The PDMS layer 3a is then exposed to UV radiation (e.g., 254 nm, 10-30 minutes) via an amplitude mask showing the desired pattern 6. The exposed area of the PDMS layer 3a is hard and less elastic, and has a different CTE and modulus of elasticity than the surrounding area. Alternatively, sensitized PDMS exposure can be used, for example, using a UV laser to illuminate the sensitized PDMS with reticle patterned UV light. Furthermore, selective illumination enhancement of PDMS can be accomplished at a position corresponding to the pattern of the desired pattern, for example by irradiation with an infrared laser, which selectively heats but does not burn a particular pattern on the surface of the PDMS layer 3a. (This partially modifies its CTE and other mechanical properties that may affect local stress generation).

In the eighth embodiment, the patterning step is carried out without cutting the pattern into the PDMS auxiliary layer 3a, but locally modifying the properties of the PDMS layer 3a at the position corresponding to the pattern of the desired pattern. For example, the mechanical properties of PDMS can be locally modified by embedding other materials, such as glass beads, bubbles, metal particles, fibers, etc., with different properties (such as different CTE and/or different elastic modulus) into the PDMS layer, and in particular Its CTE and / or its modulus of elasticity.

In a ninth embodiment, the patterning step is performed using a piece of heterogeneous auxiliary layer 3a comprising at least one patterned layer and at least one other unpatterned layer, which may be made of different materials and may have Different properties (such as different CTE). An implementation method deposits a metal structure of pattern 6 onto the surface of wafer 2 prior to coating the PDMS, for example using screen printing techniques or lithography and physical vapor deposition. The PDMS is then coated on this metal structure and wafer (by which the metal structure is partially embedded) and then diced. Since the metal structural properties (e.g., CTE) are different from those of the PDMS, the manufactured disc 5 has a surface structure pattern 7a and 7b of the image of the pattern 6 of a substantially metallic structure.

In a tenth embodiment, the method is used to split the wafer 2 into two thin discs 5, and the pattern 6 used is a mirror-symmetric pattern. By thus producing two thin discs 5 having substantially identical image patterns 7a and 7b, two identical products ("devices") can be produced in a "single step", i.e., the method is applied only once. It is possible to select the properties of the PDMS auxiliary layers 3a and 3b (for example, the thickness thereof) such that the two manufactured discs 5 are identical or different from each other.

In an eleventh embodiment, the method uses a particular pattern 6 of the PDMS layer 3a on one side of the wafer and another pattern 6' of the PDMS layer 3b on the other side of the wafer. The pattern 6' may be the same as the pattern 6, or it may be a different pattern. The image patterns 7a and 7b on the thin disc 5 manufactured in accordance with the method of this embodiment are substantially a combination (e.g., overlap) of the patterns 6 and 6'.

In a twelfth embodiment, the method first uses the pattern 6 of the PDMS layer 3a and/or the pattern 6' of the PDMS layer 3b to fabricate the second thin disc 5, one of which has a corresponding image pattern on one side. 7a and the other has a corresponding mirror pattern 7b. The two thin discs 5 each typically still have a PDMS layer 3a or 3b adhered to the other side. These layers can then be replaced with new PDMS layers, but it is preferred to still adhere the layers 3a and 3b to their respective discs 5. Whether replaced or reused, these layers 3a and/or 3b can be patterned if desired, or if they are patterned during the first iteration of the method (ie for the manufacture of two thin discs 5) (with pattern 6 or 6') you can modify its graphics. This method is then applied again by depositing a new PDMS auxiliary layer on the side of the two wafers 5 that has not adhered to the PDMS layer (i.e., the side having the surface structure pattern 7a or 7b). If required (with any desired pattern), none, one or both of these new PDMS auxiliary layers are patterned. The second iteration of the method produces a total of four thinner discs, wherein the two thinner discs (usually) have locally controllable patterns of surface structure on both sides, i.e., similar to double-sided printing: An image pattern 7a (or its mirror image 7b) having overlapping patterns 6 and 6' corresponding to the original PDMS auxiliary layers 3a and 3b during the first repetition period on one side, and having an overlap corresponding to the original on the other side Any (possibly modified) pattern of the PDMS auxiliary layer 3a (or 3b) and an image pattern of any pattern corresponding to the new PDMS auxiliary layer. In this way, thin individual layers of solid materials with similar or different structural surfaces can be produced on both sides. (In accordance with the method of this embodiment, two other thinner discs having a surface structure corresponding to the second repeated image pattern on one side are also manufactured). It should be noted that the surface structure on the thin disc 5 manufactured during the first iteration may slightly affect the stress pattern, while the surface structure produced during the second iteration is also the same, however this effect is usually small (due to the manufacture) The thickness of the surface structure is usually much smaller than the thickness of the disc, and a suitable patterning compensation of the auxiliary layer for the second iteration can also be used.

In the thirteenth embodiment, other mechanisms may be used to induce local different stresses (ie, stress patterns) in the PDMS layer 3a instead of the pattern 6 having different regions of the CTE in the PDMS layer 3a and subjecting the composite structure to temperature changes. . For example, except that the same temperature change is used for all PDMS auxiliary layers, it can apply different temperature changes in different regions of the PDMS auxiliary layer, for example by using a cold-pressing press such as contact relief pattern 6 or by The entire layer is cooled and a particular zone is selectively reheated (e.g., by laser) while the selectivity cools a particular zone of the auxiliary layer more strongly than elsewhere. In this way, a pattern of locally different stresses can be produced, even if a homogeneous PDMS auxiliary layer is used (this embodiment preferably uses an auxiliary layer material having a low thermal conductivity such as PDMS). It is more often a pattern 6 that allows the auxiliary layer to undergo local changes, externally applied physical or chemical conditions (which may be further temporarily altered), to produce locally definable stress patterns, such as light patterns, heat patterns ( Different regions of solvent concentration), electrical or magnetic field patterns, external mechanical force patterns acting on the auxiliary layer, etc. Preferably, the auxiliary layer comprises a material that interacts with the pattern 6 of the physical or chemical conditions applied externally by (partially) changing its volume (for example, a material that expands under UV light or in an electric/magnetic field). ).

In a fourteenth embodiment, another alternative method of locally different stress-inducing patterns is to include an active device (such as a piezoelectric actuator) and an actuation (eg, electrical, optical) at a particular location of the PDMS layer 3a. Ground), and a stress pattern is generated in the PDMS layer 3a. It is more often possible to create a locally definable stress pattern by embedding a pattern 6 of a different material, which undergoes different volume changes upon actuation by a chemical or physical mechanism, into the PDMS layer 3a. In addition to temperature changes, mechanisms that can accomplish this volume change include humidity changes (eg, swelling, dehydration), solvent composition, and/or ionic strength changes (eg, osmotic pressure actuators, multi-electrolyte gels, ionic polymers) Metal complexes, conductive polymers, carbon nanotube actuators, pH changes, phase changes (eg, freeze-embedded solvents), chemical reactions (eg, polymer gels), electrical interactions (eg, piezoelectric or electrostrictive materials) , electrostatic actuators, electroactive polymers), magnetic interactions (eg, "magnetic" gels), optical effects (eg, liquid crystal elastomers, photoreactive materials), and the like, and combinations of any or all of them. The PDMS itself may also be modified locally (chemically) to achieve the desired localized different volume change behavior, for example by adding a side chain with a different functional group to the polymer, or locally varying the degree of crosslinking (eg by UV irradiation) instead of the material. Different patterns are locally embedded in the PDMS layer 3a.

In a fifteenth embodiment, it facilitates the cleave initiation of step 4 and improves the cleavage procedure by providing one or more weaker structural regions on the wafer 2 at a particular designated area on the wafer surface. Control. For example, one or more small defect areas can be fabricated at the edge of the wafer 2. This defective area can be mechanically (for example, hitting a specific point on the edge of the wafer with a sharp hammer, thereby partially pulverizing the crystal structure and making a recess or dent, or by sawing, filling or grinding, etc. to make a groove or slit ), chemically (eg, partially etched grooves), optically (eg, using a laser to partially melt the material, or ablated to make the groove structure), or by other suitable mechanism. Splitting then favors starting at the defect area and propagating from there to the remaining wafer area. In particular, it is advantageous to change the initial depth of the cleavage, that is, the thickness of the manufactured disc 5 at the edge, and generally improve the quality of the edge of the disc 5, by changing the position of these defective areas. . For example, the groove at the edge (i.e., around the circumference) between the two sides 1a and 1b of the wafer 2 can be cracked into two discs 5 of equal thickness and sharp edges. It may be that the weaker region in accordance with this embodiment is fabricated prior to stressing the work piece (e.g., prior to cooling), or it may be fabricated while the wafer is under stress. The second method can also preferably control the point at which the cracking begins: if the stress accumulates in the wafer to a level just below the critical value of the spontaneous start of the cracking process, once the weakness is created, the weak point is immediately preferred. The position begins to split.

In the sixteenth embodiment, the wafer 2 is subjected to controlled vibration (e.g., short vibrational waves) to facilitate the split-start of step 4, instead of merely causing the wafer to spontaneously rupture. For example, vibration can be induced in the wafer by one or more mechanical means (such as a hammer) to control the burst, by delivering an ultrasonic pulse, or by a strong laser pulse. The spatial distribution, intensity and instantaneous characteristics of the vibration wave facilitate the modulation and better control of the cracking process.

In a seventeenth embodiment, the method is applied to a wafer 2 having an existing surface structure on at least one of its two sides 1a or 1b. The existing surface structure (such as a channel, a platform, a film, a cantilever, a pyramid, etc.) may be formed by the wafer material itself, or it may comprise another material (eg, a metal contact, an anti-reflective layer, a dielectric layer, an epitaxial layer, etc.) , or any combination thereof. The PDMS is then coated on these existing structures, covering and conforming so that the existing structures are partially embedded in the PDMS layers 3a and/or 3b after the PDMS is hardened. When the wafer 2 is ruptured into the two thin discs 5, the existing surface structures remain on the side of each of the discs 5 which are still adhered to the corresponding PDMS auxiliary layer 3a or 3b, and the other side of each disc 5 is displayed. The method produces a new surface structure 7a or 7b of the image of Figure 6. In this way, a thin separate layer with a complex surface structure can be produced on one side (may also involve additional materials, and even provide a fully functional device such as an electronic, optical, chemical, or micromechanical device), and in another Other surface structures are fabricated on the sides, wherein these other surface structures are formed from the wafer material and are determined by the pattern 6 of the PDMS layer. It should be noted that the existing surface structure on the faces 1a and/or 1b may slightly affect the stress pattern, and the manufactured surface structures 7a and 7b are also the same, however this effect is often small (since the thickness of the existing surface structure is often much larger than the disk The thickness is small) and suitable patterning compensation of the auxiliary layers 3a and/or 3b can also be used.

In an eighteenth embodiment, the invention is applied to a wafer 2 that already has an existing internal (overall) structure (e.g., one or more dopant gradients). When the wafer 2 is split into two thin discs 5, these existing internal structures remain in the corresponding thin discs 5. In this way, a thin, separate layer of structured surface having an internal (integral) structure, such as a dopant gradient, can be fabricated.

In a nineteenth embodiment, the method combines the aspects of the first two embodiments for a wafer 2 having an existing surface structure and an existing internal (integral) structure. In particular, the wafer has a partial or complete functioning device (electronic, optical, micromechanical, chemical, etc.) on one or both of its faces 1a and/or 1b. Such devices may include LEDs, laser diodes, solar cells, tandem solar cells, power amplifiers, general integrated circuits, microelectromechanical devices such as sensors or actuators, and the like. The PDMS is then applied to the existing devices on the wafer face, the cover device, and externally surrounded so that the existing devices are partially embedded in the PDMS layers 3a and/or 3b after the PDMS is hardened. When the wafer 2 is ruptured into the two thin discs 5, the existing devices remain on the side of each of the discs 5 which are still adhered to the corresponding PDMS auxiliary layer 3a or 3b, and the other side of each disc 5 is displayed. A new surface structure 7a or 7b is produced as an image of the pattern 6. In this way, a thin, self-contained layer of solid material having a complex, partially or fully functional device on one side and other surface structures on the other side can be fabricated, wherein the other surface structures are formed from wafer material and The pattern 6 of the PDMS layer is determined.

As an illustrative example of the application of the prior embodiments, the surface structure and internal structure of the front portion of the conventional solar cell (ie, the side that is illuminated during normal operation) are formed (eg, the front side doped layer, including the pn junction, the front metal) Contact nets, anti-reflective coatings) are referred to below as "pre-structures". This "front structure" is now fabricated on both sides 1a and 1b of the thick single crystal germanium wafer 2, instead of being fabricated on one side of the wafer as is conventionally performed. The wafer 2 is then split into two thinner discs as described above, thereby retaining the device layer such that the two discs 5 are now only on one side (i.e., still adhered to the side corresponding to the PDMS layer 3a or 3b) Has a "pre-structure". On the other side of each of the two discs 5, a "new" surface is formed from the integral wafer material, and the surface 7a or 7b is determined by the pattern 6 of the PDMS layer. The "new" surface of the two-disc film can now be further processed using conventional methods of fabricating the back side of a solar cell (e.g., backside field doping, backside contact metallization, etc.) to complete the fabrication of two solar cells. This example shows a number of advantages: it can perform most of the solar cell fabrication steps on a relatively thick (and therefore less fragile) wafer 2, which facilitates the use of inexpensive procedures (such as contact screen printing) and substantially simplifies the crystal Round processing. The same (front side) dopant can be diffused into the full surface of the wafer, i.e., on both sides 1a and 1b, without the need to, for example, subsequently remove dopants from the back of the wafer (because it is a cracking procedure) Completed automatically). For example, it can also be fabricated on a full wafer (for example, oxidative growth of SiO ₂ and/or PECVD deposition of Si ₃ N ₄ nitride), and then automatically confined to one side of the anti-reflective coating via a cleavage procedure. with. In this way, many of the method steps of solar cell fabrication can be eliminated or simplified by the application of the present invention. These benefits are particularly apparent in another illustrative example where a back-contact solar cell is fabricated instead of a standard solar cell with front and back contacts: here almost all of the active structure is on one side of the cell (back side). If the back side is fabricated on both sides 1a and 1b of the thick single crystal germanium wafer 2, after the splitting using the method, the two manufactured sheets 5 are all nearly completed back contact batteries (may only need to be in another An anti-reflective coating is deposited on the side). Therefore, the method can be applied to fabricate a thin, single-crystal back-contact solar cell without processing the thin wafer through most of the procedures.

In another aspect, the invention relates to a device comprising a sheet of solid material (block, ingot, disc, etc.) which is divided into two pieces by a gap, one piece being geometrically complementary to the other piece, such that the gap is reduced Zero restores the shape, size and quality of the original sheet without losing any material (eg no internal porosity, etc.). At least one of the two sheets is a thin layer, i.e., a flat or curved sheet having an area of at least 1 square centimeter, and wherein the entire area has a thickness of less than 2 mm, preferably less than 0.5 mm. At least one of the laminae itself has a layer of at least one additional solid material (referred to as an auxiliary layer) adhered to the opposite side of the gap. The surfaces of the two sheets facing each gap do not contain materials other than those obtained in the entirety of the sheet (except for example, a native oxide layer if the surface is reactive to air and exposed).

In another embodiment, the present invention is directed to an apparatus as described above, but wherein the surfaces of the two facing surfaces of the gap exhibit a structure according to a pattern, and the surface structure 7a on one sheet is surfaced to the surface structure 7b on the other sheet. Substantially complementary, and the pattern is a substantially full-size image of at least one additional solid material (auxiliary layer) in at least one of the at least one of the two sheets of the corresponding pattern 6 adhered to at least one of the two sheets. The pattern 6 in the auxiliary layer is such that a portion of the auxiliary layer exhibits a local material property different from the surrounding area (such as a locally different CTE or a locally different modulus of elasticity), which may include, for example, partial or complete removal of the auxiliary layer. Part of the material (ie pore structure). In another embodiment, the pattern 6 can be a pattern (such as a light pattern, a heat pattern, an external mechanical force pattern acting on the auxiliary layer, etc.) by applying an external physical or chemical influence to the auxiliary layer. The stress pattern temporarily induced in the auxiliary layer.

The method of the present invention can also be used to produce a thin, self-contained layer having a structured surface from a worksheet composed of a solid material other than a single crystal germanium (e.g., polycrystalline germanium, sapphire, tantalum, quartz, or amorphous material such as glass). This method can also be used for a work piece composed of several different materials (homogeneous or heterogeneous composite materials, etc.) or having an internal structure (laminate, etc.). For example, the method can be applied to a work piece composed of a single crystal germanium wafer having an epitaxial growth layer such as gallium nitride (GaN) on its surface. Further, as for the auxiliary layer applied to the work sheet, it may use a material other than PDMS such as other polyoxyalkylene (which may include an organometallic group for, for example, electrical activity), other elastomers, other polymers, or general plastic. It is also possible to use an auxiliary layer composed of several different materials (homogeneous or heterogeneous composite materials, etc.) or having an internal structure (laminate, etc.). Usually the work piece is a fairly brittle solid material. It should be well adhered between the worksheet and the auxiliary layer and maintained throughout the procedure, and the auxiliary layer should accept a convenient procedure that imposes a sufficiently strong stress pattern without disintegrating the auxiliary layer itself.

Further, the PDMS (or other polymer) of the auxiliary layer can be hardened by heating it on a hot plate (i.e., its polymer chains are crosslinked). For example, it can be heated by blowing hot air or by, for example, infrared light. Alternatively or additionally, hardening can be accomplished using chemical additives, ultraviolet radiation or electron beams. PDMS (or other polymer, or substantially any material in the auxiliary layer) may also be chemically modified to facilitate a particular hardened form (or generally solidification, which may have created internal stresses within the layer during curing), such as The PDMS is advantageously cured by UV irradiation by, for example, immersing PDMS in diphenyl ketone, a sensitizer that generates free radicals upon irradiation, or by substituting a methyl group in PDMS, for example, with a photoreactive substituent.

Similarly, it is possible to remove the auxiliary layer from the disc 5 at the end of this procedure using a number of alternative methods. Instead of or in addition to chemically etching the auxiliary layer as described above, the layer may also be mechanically removed by irradiation, electron beam, and/or heat. For example, if the disc is temporarily fixed (for example, glued) to the support of the PDMS layer, and then the PDMS is peeled off, for example, by slowly starting and carefully pulling away from the surface of the substantially vertical disc surface, The single crystal germanium disc 5 mechanically strips the PDMS auxiliary layer, which may be inserted between the PDMS layer and the disc 5 to facilitate the growth. Alternatively, only PDMS (or other polymer) may be heated (eg, in a laser or in an oven) to above its decomposition temperature (ie, ash removal). It can also be removed by ashing in the plasma (for example in oxygen plasma). PDMS can also be chemically modified to make it more susceptible to decomposition, for example under UV irradiation. Finally, any or all of these methods can be combined (and modified if the material other than PDMS is used for the auxiliary layer).

The method can be applied to a work piece of almost any shape and is not limited to a flat wafer. In particular, the present invention can be used, for example, to directly peel a sheet having a surface structure from a single crystal flat ingot which is flat on one side. As for the peeling of the flat sheet, it is sufficient to fix at least one flat surface using the work sheet. An auxiliary layer is then applied to this surface. It can strip only one piece, or can simultaneously strip several pieces from different surfaces of the work piece. Finally, the method can also be applied to the manufacture of thin independent curved sheets or shells having a surface structure. In this regard, it coats the auxiliary layer on the corresponding curved surface of the work piece. The temperature change (or other stress inducing procedure) then causes the thin corresponding curved sheet or shell to rupture along the patterned rupture zone inside the worksheet and the remaining worksheet. The patterned rupture zone is equally dispersed about the same distance from the interface between the worksheet and the auxiliary layer, so that the manufactured sheet having the surface structure pattern has a substantially uniform thickness (except for the patterns 7a and 7b, wherein the thickness variation can be cautiously generated) .

The surface properties of the surface on which the auxiliary layer is applied are not critical. This interface can be polished smoothly or it can have a significant thickness. It is important to retain only the proper adhesion to the auxiliary layer. In particular, the rupture surface formed on the remaining work sheets when the sheet is peeled off from the work sheet can be used as the surface on which the auxiliary layer is applied. Therefore, the method can be applied to the remaining work pieces. In this way, one piece after another can be continuously peeled off from a single work piece.

Other (thinner) layers may also be stripped from the thin separate layers of the structured surface by repeating the same steps. For example, using the method, a single crystal germanium wafer can be split into two structured surface discs by coating a PDMS auxiliary layer on both sides; none of these auxiliary layers, one or both of them There are patterns 6, and if there are patterns, these patterns may be the same or different from each other. Then these two manufactured thinner discs can each again provide a PDMS auxiliary layer on both sides, again none of them, one or both of them have the same or different patterns (6), and this is repeated The steps of the method can be further split into thinner discs of different structural surfaces (having different surface structure patterns if necessary) and the like. In this way, a large number of thin single crystal discs having a structured surface can be obtained from a single single crystal germanium wafer. For example, eight wafers having a conventional structure surface of about 50 micrometers thick can be obtained in three steps from a conventional 0.4 mm thick wafer.

The size of the thin individual layers so typically produced, particularly their thickness, can be set by suitable selection of stress inducing mechanisms (e.g., temperature changes) and/or properties of the auxiliary layer. It is particularly the time course induced by stress, the degree of induced stress, the size of the auxiliary layer, the geometry of the auxiliary layer, and/or the mechanical and/or thermal/optical/chemical/hydrostatic/piezoelectric//the auxiliary layer/ Complete with the appropriate choice of properties.

The auxiliary layer can be applied, for example, in a liquid or gaseous state on the corresponding surface of the work sheet, and then cured therein. Alternatively, the auxiliary layer may be directly adhered to the surface in a solid state. Adhesion between the auxiliary layer and the surface of the work piece can be accomplished by chemical bonding, van der Waals force, or other strong adhesion. It is also feasible to apply the method by bonding the auxiliary layer to the sheet material at the interface or by adhering the auxiliary layer to the surface of the sheet by a third material (e.g., an adhesive).

Finally, other coolants (such as liquid helium, ice water, or cooling solids or cooling gas, etc.) can be used instead of liquid nitrogen to accumulate the necessary mechanical stress inside the auxiliary layer-working sheet composite by cooling. It is only necessary to cool the composite to room temperature in a specific case, so that no special coolant is required. In addition, in certain cases, the necessary mechanical stress can be obtained inside the composite by heating instead of cooling. The emphasis on accumulating the necessary mechanical stress at a particular temperature T is the sufficiently large difference in thermal expansion between the worksheet and at least a portion of the auxiliary layer, and the sufficiently large difference between the temperature T and the temperature of the auxiliary layer adhesion worksheet.

While the present invention has been shown and described with reference to the specific embodiments of the present invention, it will be understood by those skilled in the art . The scope of the invention is thus indicated by the scope of the appended claims.

1a. . . surface

1b. . . surface

2. . . Single crystal germanium wafer

3a. . . Auxiliary layer

3b. . . Auxiliary layer

4. . . surface

5. . . Single crystal germanium disc

6. . . Pattern

7a. . . Image pattern

7b. . . Image pattern

Figure 1 is a schematic view of the program sequence of the method in four steps in a front view.

1a. . . surface

1b. . . surface

2. . . Single crystal germanium wafer

3a. . . Auxiliary layer

3b. . . Auxiliary layer

4. . . surface

5. . . Single crystal germanium disc

6. . . Pattern

7a. . . Image pattern

7b. . . Image pattern

Claims (32)

A printing method comprising the steps of: providing a solid material having at least one exposed surface; applying an auxiliary layer to the exposed surface to form a composite structure; accepting the composite structure in the auxiliary layer and inducing stress in the solid material a condition of the pattern whereby the rupture of the solid material is substantially accelerated along a plane having a certain depth therein; and the auxiliary layer is removed, and a solid material terminating at the rupture depth is subsequently removed, and the exposed surface of the removal layer of the solid material has a corresponding a surface topology of a stress pattern, wherein the auxiliary layer comprises a polydiorganosiloxane, and wherein coating one or more auxiliary layers comprises coating at least one characteristic having a coefficient of thermal expansion (CTE) that differs from a CTE of the provided solid material by at least 10*10 ^-6 K ^-1 auxiliary layer. The method of claim 1, wherein the at least one material property of the auxiliary layer is changed according to a pattern depending on the position within the auxiliary layer. The method of claim 2, wherein the auxiliary layer is a composite structure. The method of claim 2, wherein the at least one material property of the auxiliary layer changed according to the pattern affects the extent and/or orientation of the local stress induced when the auxiliary layer is subjected to stress inducing conditions. The method of claim 2, wherein the at least one material property of the auxiliary layer changed according to the pattern affects the kinetics of crack propagation during the rupture of the solid material. The method of claim 2, wherein the at least one material property of the auxiliary layer changed according to the pattern affects the degree of volume change of the auxiliary layer material when subjected to stress inducing conditions. The method of claim 2, wherein the at least one material property of the auxiliary layer changed according to the pattern comprises a coefficient of thermal expansion (CTE). The method of claim 2, wherein the at least one material property of the auxiliary layer changed according to the pattern comprises an elastic modulus. The method of claim 2, wherein the at least one material property of the auxiliary layer changed according to the pattern comprises a partial thickness of the auxiliary layer. The method of claim 2, wherein the at least one material property of the auxiliary layer changed according to the pattern also changes over time during the execution of the method. The method of claim 1 or 2, wherein the stress inducing condition is changed according to a pattern depending on the position within the auxiliary layer. The method of claim 1 or 2, wherein the stress inducing condition affects the kinetics of crack propagation during the rupture of the solid material. The method of claim 1 or 2, wherein the stress inducing condition affects a volume change of the auxiliary layer material. The method of claim 11, wherein the stress inducing condition according to the pattern comprises maintaining different temperatures at different locations within the auxiliary layer. The method of claim 1 or 2, wherein the stress inducing condition comprises an external mechanical force applied to the auxiliary layer. For example, the method of claim 1 or 2, wherein the stress inducing condition Affects the modulus of elasticity of the auxiliary layer. The method of claim 1 or 2 wherein the stress inducing condition changes over time during execution of the method. The method of claim 17, wherein the stress inducing condition that changes over time during the performance of the method comprises cooling at least a portion of the auxiliary layer to below room temperature. The method of claim 1, wherein the fracture of the solid material is at a depth in the solid material and is substantially induced along a plane substantially parallel to the interface of the auxiliary layer and the solid material. The method of claim 1, wherein the removing step exposes a newly exposed surface of the solid material having a surface topography that complements the surface topography of the removal layer of the solid material. The method of claim 1, wherein at least one exposed surface of the solid material has an existing surface topology. The method of claim 1, wherein the at least one exposed surface of the solid material comprises existing microelectronics and/or micromechanical devices. The method of claim 1, further comprising the steps of: applying a new auxiliary layer to the exposed surface of the removal layer of the solid material to form a new auxiliary layer, a removal layer of the solid material, and a previously coated auxiliary layer a new composite structure consisting of the conditions for accepting a new composite structure in a new auxiliary layer, in a solid material, and in a previously applied auxiliary layer, thereby The plane along the new depth promotes the rupture of the removal layer of the solid material; and removes the new auxiliary layer, and subsequently removes a new layer of solid material that terminates at the new rupture depth, and the exposed surface of the new solid material removal layer has a corresponding The surface topology of the new stress pattern. The method of claim 20, further comprising the steps of: applying a new auxiliary layer to the newly exposed surface of the solid material to form a new composite structure; accepting the new composite structure in the new auxiliary layer and in the solid material Conditions for inducing a new stress pattern, thereby substantially promoting the rupture of the solid material along a plane of the new depth; and removing the new auxiliary layer, and subsequently removing a new layer of solid material that terminates at the new rupture depth, while the new solid material The exposed surface of the removal layer has a surface topology corresponding to the new stress pattern. A printing method comprising the steps of: providing a solid material having two opposing and substantially parallel exposed surfaces; applying an auxiliary layer to each exposed surface to form a composite structure; and accepting the composite structure in the second auxiliary layer and A condition for inducing a stress pattern in a solid material whereby the plane of solidification of the solid material is substantially accelerated along a plane of a certain depth between the two opposing exposed surfaces; and removing the second auxiliary layer, the first layer is removed along with the first auxiliary layer a solid material of rupture depth, and the exposed surface of the first removal layer of the solid material has a surface topology corresponding to the overlapping stress pattern of the two auxiliary layers, and as the second auxiliary layer removes the second layer of solid material, it is provided relative to the original The solid material is complementary to the first removal layer of the solid material, and the exposed surface of the second removal layer of the solid material has a surface topology that is complementary to the first removal layer of the solid material. The method of claim 25, wherein providing the solid material comprises providing a structure selected from the group consisting of a substrate, a wafer, a wafer, and a disk. The method of claim 25, wherein one or both of the exposed surfaces of the solid material comprise existing microelectronics and/or micromechanical devices. The method of claim 1 or 25, wherein providing the solid material comprises providing a structure comprising ruthenium, osmium, sapphire, tantalum carbide, gallium arsenide, gallium nitride, zinc oxide, or quartz. The method of claim 1 or claim 25, wherein coating the one or more auxiliary layers comprises coating at least one auxiliary layer comprising a polymer. The method of claim 1 or 25, wherein the rupture of the solid material is further facilitated by providing a zone of one or more relatively low burst strengths in the solid material prior to or simultaneously with the stress-inducing condition of the composite structure. The method of claim 1 or 25, wherein the surface topology produced substantially corresponds to a surface topography of a surface having a vertical stress intensity coefficient KII of zero in the composite structure. The method of claim 1 or claim 25 wherein the surface topology produced comprises a substantially periodic pattern having a spatial period of less than 10 microns.