TWI430338B - Methods and apparatus for producing semiconductor on insulator structures using directed exfoliation - Google Patents

Description

Method and apparatus for fabricating a semiconductor-on-insulator structure using directional stripping

The present application claims priority to U.S. Patent Application Serial No. 12/290,384, filed on Oct. 30, 2008, and to This is used as a reference.

This invention relates to the fabrication of semiconductor-on-insulator (SOI) structures, such as SOI structures having a non-circular cross section and/or SOI structures having a relatively large cross-sectional area.

As market demand continues to increase, semiconductor-on-insulator (SOI) devices are becoming more and more important. SOI technology is also becoming more and more important for high performance thin film transistors (TFTs), solar cells, and displays, such as Active matrix display, organic light emitting diode (OLED) display, liquid crystal display (LCD), integrated circuit, photovoltaic device, and the like. The SOI structure can include a thin layer of semiconductor material on the insulating material, such as germanium.

Various ways of achieving the SOI structure include germanium (Si) epitaxial growth on a lattice matching substrate, and bonding of a single crystal germanium wafer to another germanium wafer. Further methods include ion implantation techniques in which hydrogen or oxygen ions are implanted, in the case of oxygen ion implantation, a buried oxide layer is formed in a Si-covered germanium wafer, or in the case of hydrogen ion implantation. The thin Si layer is (stripped) to be bonded to another Si wafer having an oxide layer.

U.S. Patent No. 7,176,528 describes a process for producing a semiconductor-on-glass (SOG) structure using a lift-off technique. These steps include: (i) exposing the surface of the germanium wafer to hydrogen ion implantation to create a bonding surface; (ii) contacting the bonding surface of the wafer with the glass substrate; (iii) applying pressure, temperature, and voltage to the wafer and glass substrate to facilitate Bonding therebetween; and (iv) separating the glass substrate and the tantalum film layer from the tantalum wafer.

The above methods are prone to annoying effects in some cases and/or in some applications. Referring to FIGS. 1A-1D, the semiconductor wafer 20 is implanted via the surface 21 with ions such as hydrogen ions such that the implantation amount is uniform throughout the density and depth of the semiconductor wafer 20.

Referring to FIG. 1A, when a semiconductor material such as germanium is implanted with ions such as hydrogen ions, a damage site is generated. The injury site layer defines a release layer 22. Some lesions form nucleation in the lamella at very high aspect ratios (they have large effective diameters with little height). Implanting ions generated from the gas, such as H ₂ diffusion sheet to form a relatively high aspect ratio of bubbles. The gas pressure in these bubbles is very high and is estimated to be up to about 10 kilobars.

As indicated by the double arrow in Figure 1B, the sheets and bubbles grow within the effective diameter until they are in close proximity to one another, leaving the remaining turns too weak to withstand the high pressure of the gas. Since no optimal point begins to separate, a plurality of discrete leading edges are randomly generated, and thus a plurality of cracks propagate through the semiconductor wafer 20.

Near the edge of the semiconductor wafer 20, a large amount of implanted hydrogen can escape from the hydrogen-rich plane. This is due to the relationship near the leak (i.e., the side panels of the wafer 20). More specifically, ions (such as hydrogen protons) decelerate through the structure of the semiconductor wafer 20 (e.g., helium) during implantation and replace some germanium atoms from the lattice sites to create a plane of defects. When a hydrogen ion loses kinetic energy, it becomes atomic hydrogen and further defines an atomic hydrogen plane. At room temperature, both the defect plane and the atomic hydrogen plane in the germanium lattice are unstable, and therefore, the defects (voids) and atomic hydrogen move to each other to form a thermally stable void-hydrogen component. The multiple components are brought together to create a hydrogen-rich plane. (When heating, the germanium lattice usually splits along the hydrogen-rich plane).

Not all voids and hydrogen will disintegrate into void-hydrogen components. Some of the atomic hydrogen components will diffuse from the void plane and eventually exit the germanium wafer 20. Therefore, some atomic hydrogen does not cause splitting of the peeling layer 22. Near the edge of the germanium wafer 20, the hydrogen atoms have a path that is otherwise escaping from the crystal lattice. Therefore, the hydrogen concentration in the edge region of the germanium wafer 20 may be low. Lower hydrogen concentrations will require higher temperatures or longer to develop enough power to support separation.

Thus, the tent-like structure 24 is created with no separate edges during the separation process. At the critical pressure, cracks in the remaining semiconductor material appear along the relatively weak plane of the {111} plane (Fig. 1C), and the peeling layer 22 is self-twisted. The separation of the wafer 20 (Fig. 1D). However, the edges 22A, 22B are the major split planes defined from the injury site. This non-planar split is annoying. Other features of the separation include that the release layer 22 can be described as a "station" in which the sheet or bubble is located, surrounded by a "canyon" where cracks appear. It should be noted that these terraces and canyons cannot be accurately displayed in Figure 1D because these details are beyond the scale of the scale shown.

Without wishing to limit the invention in any theory of operation, the inventors of the present invention believe that the time from the onset of separation to the completion of separation using the aforementioned techniques is on the order of tens of microseconds. In other words, the random beginning of the separation occurs and propagates at approximately 3000 meters per second. Further, without wishing to limit the invention in any theory of operation, the inventors of the present invention believe that this separation rate is caused by the annoying characteristics of the aforementioned split surface of the peeling layer 22 (Fig. 1D).

U.S. Patent No. 6,010,579 describes a technique for uniformly implanting ions into a semiconductor substrate 10 which is uniformly implanted to a depth of Z0 which reduces the temperature of the wafer below the temperature at which the initial separation begins, and then at the depth of implantation. A plurality of energy pulses are introduced at the edge of the substrate 10 near Z0 to achieve "control splitting front". U.S. Patent No. 6,010,579 claims that the aforementioned mode is an improvement of the so-called "random" splitting, at least in terms of surface roughness. The present invention adopts a directional separation method which is significantly different from the "controlling the splitting leading edge" of U.S. Patent No. 6,010,579, and is also different from the "random" splitting mode.

The previously discussed challenges associated with the separation of the release layer 22 from the semiconductor wafer 20 are exacerbated as the size of the SOI structure increases, particularly when the shape of the semiconductor wafer is rectangular. Such rectangular semiconductor wafers can be used in applications where multiple semiconductor wafers are coupled to an insulator substrate. Further on the tiled SOI Details of the fabrication of the structure can be found in U.S. Patent Application Publication No. 2007/0117354, the entire disclosure of which is incorporated herein by reference.

For ease of explanation, the following discussion will sometimes be based on the SOI structure. With reference to this particular type of SOI structure, the description of the present invention is made easier, but it is not intended or should be construed as limiting the scope of the invention in any way. As used herein, the acronym for SOI generally refers to a semiconductor-on-insulator structure, including but not limited to, an insulator-on-insulator structure. Likewise, the SOG abbreviation used generally refers to a semiconductor structure on glass including, but not limited to, a glass upper structure. The SOI abbreviation covers the SOG structure.

In accordance with one or more embodiments of the present invention, a method and apparatus for forming a semiconductor-on-insulator (SOI) structure provides an ion implantation step on an implanted surface of a donor semiconductor wafer to define a stripping of a donor semiconductor wafer Forming a weakened sheet on the cross section of the layer; and applying a spatially varying step to the donor semiconductor wafer before, during or after the ion implantation step such that one or more parameters of the weakened sheet are at X- and Y - at least one direction of the axis, spatially varying throughout the wafer.

The step of spatially varying can promote the separation of the release layer from the semiconductor wafer such that the separation is directional and/or temporally controllable.

The parameter may comprise one or more of the following single items or combinations: (i) the density of nucleation sites produced by the ion implantation step; (ii) the depth of the weakened layer from the implanted surface (or reference plane) (iii) at least the artificially injured site (such as a blind hole) that passes through the implanted surface to weaken the slice; and (iv) utilizes a temperature ladder The degree of nucleation and/or pressure at the defect site is increased throughout the weakened sheet.

The method and apparatus further provide for raising the temperature of the donor semiconductor wafer sufficiently to initiate separation of the weakened sheet from a point, edge, and/or region of the weakened sheet. The temperature of the donor semiconductor wafer can be further sufficient to continue to separate along the weakened sheet in a substantially oriented manner as a function of the varying parameters.

Other aspects, features, advantages, and the like will become apparent to those skilled in the art.

10‧‧‧Substrate

20‧‧‧Semiconductor wafer

21‧‧‧ implanted surface

22‧‧‧ peeling layer

Edge of 22A, 22B‧‧

24‧‧‧structure

102‧‧‧Substrate

120‧‧‧Sensor semiconductor wafer

121‧‧‧ implant surface

122‧‧‧ peeling layer

125‧‧‧Weakened slices

Edges of 130A, 130B, 130C, 130D‧‧

200‧‧‧ platform

202‧‧‧ ion beam

204‧‧‧Band beam

220‧‧‧ mask film

220A, 220B‧‧‧ mask

230‧‧ ‧ blind holes

The preferred embodiments are shown to illustrate various aspects of the invention, and it is understood that the invention is not limited to the precise arrangements and methods illustrated.

In all the drawings, "X" indicates the X-axis direction, and "Y" indicates the Y-axis direction.

1A, 1B, 1C and 1D are block diagrams showing the stripping process in accordance with the prior art.

2A-2B are block diagrams showing the stripping process in accordance with one or more aspects of the present invention.

3A is a top plan view of a donor semiconductor wafer having one or more aspects in accordance with the present invention having spatially varying parameters associated with a weakened layer or a weakened sheet.

Figure 3B is a graph showing the spatial variation parameters of Figure 3A.

Figure 3C is a graph showing the spatial variation parameter of Figure 3A as the depth of the weakened sheet.

4A, 4B and 4C are diagrams of one or more further aspects in accordance with the present invention A top view of the respective donor semiconductor wafers having further spatial variation parameters.

5A, 5B, and 5C are simplified diagrams of some ion implantation devices that can be used to achieve spatial variation parameters of a donor semiconductor wafer. In FIG. 5A, dX/dt represents a dX/dt scan; and dY/Dt represents a dY/dt scan.

Figures 6A-6B show ion implantation techniques used in donor semiconductor wafers to achieve a spatially varying density of nucleation sites.

Figures 7A-7B show ion implantation techniques used in donor semiconductor wafers to achieve spatially varying implant depths.

Figures 7C-7D are graphs showing the relationship between ion implantation tilt angle and implant depth.

Figures 8A-8B show ion implantation techniques used to achieve spatially varying ion implantation distribution widths in donor semiconductor wafers.

Fig. 8C is a graph showing the relationship between the ion implantation tilt angle and the dispersion.

Figures 9A-9D show a further ion implantation technique used in a donor semiconductor wafer to achieve a spatially varying ion implantation depth.

Figures 10A-10D and 11 show further ion implantation techniques used in donor semiconductor wafers to achieve a spatially varying distribution of defect sites.

Figures 12A-12B show time-temperature variability curves techniques used in a donor semiconductor wafer to achieve a spatially varying parameter magnitude curve.

Referring to the drawings, like numerals represent like elements, and in accordance with one or more embodiments of the present invention, Figures 2A-2B show intermediate SOI structures (especially SOG structures). The intermediate SOI structure includes an insulator substrate such as a glass or glass ceramic substrate 102, and a donor semiconductor wafer 120. The glass or glass ceramic substrate 102 and the donor semiconductor wafer 120 can be coupled together using any known process of the art, such as bonding, melting, adhering, and the like.

The donor semiconductor wafer 120 includes an exposed implant surface 121 prior to coupling the glass or glass ceramic substrate 102 and the donor semiconductor wafer 120 together. The implanted surface 121 of the donor semiconductor wafer 120 is subjected to an ion implantation step to create a weakened sheet 125 on the cross-section defining the lift-off layer 122. The weakened sheet 125 is substantially parallel to the reference plane defined by the X-Y orthogonal axis direction (possibly anywhere, and thus not shown). The X-axis direction is shown from left to right in Fig. 2A, and the Y-axis direction is orthogonal to the X-axis direction to the page (and thus not shown).

The feature of applying the spatially varying step to the semiconductor wafer 120 before, during, or after the ion implantation step to separate the release layer 122 from the donor semiconductor wafer 120 is directional and/or temporally controllable. While not intending to limit the invention in any theory of operation, it is believed that such orientation and/or temporal control may improve separation characteristics, such as (after separation) the smoother exposed surface of the release layer 122 and the donor semiconductor wafer 120. We also believe that such orientable and/or temporal control may improve edge characteristics, such as improving the yield of the exposed surface of the release layer 122 and the donor semiconductor wafer 120 in the primary split plane defined by the weakened sheet 125. .

The directional and/or temporal control characteristics of the separation layer 122 from the donor semiconductor wafer 120 can be achieved in several ways, such as by spatially dissipating the entire weakened layer 125 in at least one of the X- and Y-axes. Change one or more parameters. These parameters may include a single item or combination of one or more of the following: (i) the density of nucleation sites produced by the ion implantation step; (ii) the weakened slices from the implanted surface 121 (or reference plane) The depth of layer 125; (iii) at least the artificially created injury site (such as a blind hole) through the implanted surface 121; and (iv) the use of a temperature gradient to increase the crystal of the defect at the entire weakened sheet 125 Nuclear formation and / or pressure.

As shown by the arrow A of FIGS. 2A-2B, the release layer 122 can be oriented and/or temporally controlled from the donor semiconductor wafer 120, resulting in a point, edge and/or region from the weakened sheet 125 to other points, The separation of edges and/or regions is separated as a function of time. This can generally be achieved by first varying the one or more parameters of the entire weakened sheet 125 spatially as discussed above, and second, raising the temperature of the donor semiconductor wafer 120 to a point sufficient to weaken the sheet 125. , edge and / or area start separation. Thus, the temperature of the donor semiconductor wafer 120 is further increased to be sufficient to continue to separate substantially along the weakened sheet layer 125 as a spatially varying function of the parameters of the entire weakened sheet 125. Preferably, the varying parameters are established such that the time-temperature magnitude curve of the elevated temperature is about a few seconds and the separation propagation along the weakened sheet 125 occurs for at least one second.

Referring now to Figures 3A-3C, details regarding the spatially changing one or more parameters throughout the weakened sheet 125 are shown. FIG. 3A is a top view of the donor semiconductor wafer 120 viewed through the implant surface 121. X-axis direction The change in shadow is representative of the spatial variation of the parameters (such as the density of nucleation sites, the pressure within the site, the degree of nucleation, the distribution of artificially created lesions (holes), the depth of implantation, etc.). In the illustrated example, one or more parameters change from one edge 130A of the donor semiconductor wafer 120 (and thus its weakened sheet 125) toward the opposite edge 130B in the X-axis direction, and vice versa.

Referring to Figure 3B, this is a plot of separation parameters showing, for example, a cross-sectional quantitative variation of the density of nucleation sites in the weakened sheet 125 as a function of the X-axis direction. Alternatively or in addition, the separation parameter may be expressed as one or more of pressure in the nucleation site, degree of nucleation formation, distribution of artificially generated damage sites (holes), etc., each of which may be used as an X-axis space. The function of the sex measure. Please refer to FIG. 3C, which is a plot of separation parameters showing, for example, a cross-sectional volume change plot of the depth of the weakened sheet 125 (corresponding to the depth of ion implantation) as a function of the X-axis direction.

Without wishing to limit the invention in any theory of operation, it is believed that when the density of the nucleation sites of the edge 130A is relatively high and the density of the nucleation sites at the spatial position toward the edge 130B drops to a low level, it occurs from the edge 130A toward the edge 130B. Separation propagation (indicated by dashed arrows). This theory is also considered to be related to other parameters, such as the gas pressure in the nucleation site, the extent to which the nucleation sites are merged prior to separation, and the distribution of artificially created lesions (holes). As for the parameters related to the depth of the weakened sheet 125, it is believed that when the substantially shallow depth occurs along the starting edge 130B of the weakened sheet 125 and the deeper depth occurs at a continuously further distance toward the edge 130A Separate propagation from the edge 130B toward the edge 130A occurs (indicated by the solid arrows).

Referring now to Figures 4A-4C, details regarding the spatially changing one or more parameters throughout the weakened sheet 125 are shown. The figure shows a top view of the donor semiconductor wafer 120 viewed through the implant surface 121. The change of the shadows in the X-axis and Y-axis directions represents the spatial variation of the parameters, that is, the density of the nucleation sites, the pressure within the sites, the degree of nucleation, the distribution of artificially created lesions (holes), the depth of implantation, etc. . In each of the illustrated examples, the parameters vary spatially in both the X-axis and the Y-axis.

Referring specifically to Figure 4A, the shading is representative of spatially varying parameter changes from the two edges 130A, 130D toward the other edges 130B, 130C, and at successively further distances, in both the X-axis and the Y-axis. Variety. In order to keep up with the above discussion, in considering the parameters of the nucleation site formation density, if there is a higher density at the beginning edge of the edges 130A, 130D, then the separation propagation (indicated by the dashed arrow) is considered to be from the edge 130A, The corners of 130D radiate toward the center of wafer 120 and toward the other edges 130B, 130C. This theory is also considered to be related to other parameters, such as the gas pressure in the nucleation site, the extent to which the nucleation sites are merged prior to separation, and the distribution of artificially created lesions (holes). As for the parameters related to the depth of the weakened sheet 125, when the lower depth begins to decrease depth along the edges 130B, 130C, the separated propagation (indicated by solid arrows) radiates from the corners of the edges 130B, 130C toward the wafer 120. Centered and facing the other edges 130A, 130D.

With particular reference to Figures 4B and 4C, the shading represents a change in the parameters spatially from all edges 130 and toward the center of the donor semiconductor wafer 120, and vice versa.

Further details are now provided, with reference to specific parameters of the spatial variation in density of nucleation sites created by ion implantation in the one or both directions of the X-axis and the Y-axis throughout the weakened sheet 125. Regardless of the technique used to achieve such a spatial change, the maximum density of the nucleation sites is preferably present at a point, edge or region of the weakened sheet 125 of about 5x10 ⁵ parts/cm ² , and the minimum density of the nucleation sites is preferably present in the distance. The point, edge or region in the weakened sheet 125 is about 5 x ^{10 4} parts/cm ² . Looking at this change in another way, the difference between the maximum nucleation site density and the minimum nucleation site density is about 10 times.

In accordance with one or more aspects of the present invention, the density of the nucleation sites in the sheet 125 can be weakened by varying the dose of the ion implantation step. The implanted surface 121 is subjected to one or more ion implantation steps by prior art techniques to produce a weakened sheet 125 (and thus a peeling layer 122). Although a wide variety of ion implantation techniques, machines, etc. can be used in this regard, a suitable method indicates that the implanted surface 121 of the donor semiconductor wafer 120 can be subjected to a hydrogen ion implantation step to at least initiate the generation of a donor semiconductor wafer. The peeling layer 122 of 120.

Referring to FIG. 5A, a schematic diagram of the Axcelis NV-10 type bulk implanter is shown. By varying the dose of the implanted ions, the spatial variation of the density of the nucleation sites in the weakened sheet 125 can be modified. .

A plurality of donor semiconductor wafers 120, in this example rectangular patches, may be azimuthally distributed at a fixed radius on a platform 200 relative to the incident ion beam 202 (oriented into the page). The rotation of the platform 200 provides a pseudo-X-scan (dX/dt), while the mechanical translation of the entire platform 200 provides a Y-scan (dY/dt). The word quasi-X-scan is used because of the smaller platform 200 radius, and large The X-scan is relatively curved compared to the platform 200 radius, so a completely straight scan is not obtained on such a platform 200. Adjusting the X-scan speed and/or Y-scan speed can cause spatial variations in the dose. In the past, when the ion beam 202 was directed radially toward the center of the platform 200, an increased Y-scan speed could be used to ensure a uniform dose. Indeed, the conventional wisdom of the art is to achieve a spatially uniform dose that must be correspondingly increased as the angular velocity relative to the donor semiconductor wafer 120 is reduced to near the center of the platform 200. However, in accordance with the present invention, it is possible to achieve a spatially varying dose without adhering to conventional scanning protocols, resulting in a pattern as shown in Figures 3A and 4A. For example, the Y-scan speed can be kept uniform as the ion beam 202 passes radially toward the center of the platform 200. Alternatively, we can also reduce the Y-scan speed as the ion beam 202 passes radially toward the center of the platform 200. Other possibilities are known to those skilled in the art from this disclosure. Another way is to change the beam energy as a function of scan rate and position. This change can be made by modifying the control algorithm of the implanter in the software, the electronic interface between the control software and the end station driver, or other mechanical modifications.

Referring to Figure 5B, a simplified diagram of a single substrate X-Y implanter is shown, which can be modified to mitigate the spatial variation in the density of nucleation sites in the sheet 125 by varying the dose of implanted ions. In this example, the electron beam 202 scan is faster than the mechanical substrate scan (Fig. 5A). Furthermore, the traditional thinking of this technology is to achieve a spatially uniform dose, thus setting the X and Y scan rates and beam energy to achieve a uniform dose. Furthermore, it is possible to achieve a dose of spatial variation without adhering to conventional scanning protocols. Significant spatiality within the implant dose with several varying X and Y scan rates and/or beam energy combinations Variety. A vertical or horizontal, one- or two-dimensional gradient can be produced, via which the pattern of Figures 3A, 4A, 4B and 4C is produced.

Referring to Figure 5C, a schematic of the implanter in accordance with the ion bath technique is shown. Strip beam 204 is produced from an extended source of ions. According to conventional techniques, a single uniform velocity scan (proportional to the uniform beam energy in the orthogonal direction) achieves the conventional goal of spatially uniform dose. However, in accordance with various aspects of the present invention, a one-dimensional gradient (i.e., rotated 90 degrees in FIG. 3A) can be produced by varying the mechanical scanning rate of the donor semiconductor wafer 120 through the strip beam 204. By twisting the donor semiconductor wafer 120 at an angle relative to the strip beam 204, and in conjunction with changes in the mechanical scan rate, spatial variations within the dose can be produced in a manner similar to that of Figure 4A. Alternatively or additionally, the spatially varying beam current along the beam source will provide a co-orthogonal gradient in the direction of the gaze, providing additional degrees of freedom to produce a dominant spatially varying dose.

Regardless of the particular implantation technique used to achieve the dose change, regardless of the location of the highest dose (along one or more starting edges, starting points, or starting regions), the substantially highest dose is within the desired range as atoms/ The unit of cm ² is the unit, and the lowest dose is in units of atoms/cm ² in at least one of the X- and Y-axes in other desired ranges. The difference between the highest dose and the lowest dose can be between about 10-30% with a maximum change of about 3 fold. In some applications, at least about 20% of the difference is important.

In accordance with one or more further aspects of the present invention, the first ionic component can be implanted in a substantially uniform manner, spatially varying to weaken the density of nucleation sites in the sheet 125 to create a substantially uniformly distributed weakened sheet. Layer 125. Thereafter, the second ionic component can be implanted in a substantially non-uniform manner Body semiconductor wafer 120. The non-uniform implantation is established such that the second ionic component causes the atoms to migrate to the weakened sheet 125, resulting in a spatially varying density of nucleation sites on the entire weakened sheet 125.

For example, the first ionic component can be a hydrogen ion and the second ionic component can be a cerium ion.

Non-uniform implantation can be performed using the techniques described above, as described later in this description, or from other sources. For example, the dose of the second ionic component can be varied spatially. A dose change of the second ionic component (e.g., He ion) results in a non-uniform migration of the second component to the location of the first ionic component, thereby establishing a non-uniform nucleation site density. This change can change the pressure inside the sheet, which is also helpful.

Alternatively, non-uniform implantation of the second ionic component can include implanting the second ionic component to a spatially different depth of the entire donor semiconductor wafer 120. Those skilled in the art will be able to modify any known technique of implanting ions to a uniform depth to achieve a non-uniform depth quantitative curve in accordance with the teachings herein. In the prior art, we know that He ions can be implanted deeper than hydrogen ions, such as twice the depth or above. As the wafer temperature increases, many of the He ions migrate to the site where the shallower hydrogen ions are implanted, providing a gas pressure that is later separated. In accordance with this aspect of the invention, the damage caused by implanting a deeper He is at a depth away from the shallower hydrogen ion implantation of the donor semiconductor wafer 120, and very little such He ions will arrive in a certain amount of time. The same is true for the opposite case of implanting the lesser He ions, thus causing the density of the nucleation sites of the entire weakened sheet 125 to be spatially changed.

Although theoretically regardless of the order of the first and second ionic components (such as The density of spatial variation of the nucleation sites can be achieved by first implanting He or implanting H) first, but the order of multiple ion implantation steps can also achieve the desired results. Indeed, depending on the ionic composition, the order of implantation may have an overall effect on density, and even the density will vary spatially. Although somewhat counter-intuitive and surprised by many people familiar with the technology, we found that the first implantation of hydrogen ions produced more nucleation sites. With a certain amount of measurement, He is known to be familiar with this technology and will cause 10 times more damage than hydrogen ions. However, it should be noted that He ion damage (voids and voided semiconductor atoms, or Frankel pairs) will quickly self-anneal even at room temperature. Therefore, many, but not all, He injuries can be repaired. In other words, hydrogen ions and semiconductor atoms such as Si atoms are bonded (forming a Si-H chain) to stabilize the damage generated. If H is present before He implantation, more nucleation sites will be produced.

Referring now to Figures 6A-6B, there is shown a further example suitable for achieving spatial variations in the density of nucleation sites. In this example, as shown in FIG. 6A, a spatial variation in density of nucleation sites can be achieved by adjusting the beam angle of the ion beam during the ion implantation step. While the beam angle can be adjusted in a number of ways, one way is to tilt the donor semiconductor wafer 120 against an ion beam (e.g., spot beam 202), as shown in Figure 6A. The donor semiconductor wafer 120 has a width (such as a page display from left to right), a depth (inside the page), and a height (such as a page display from top to bottom). The width and depth may define the X- and Y-axis directions, while the height may define a longitudinal axis Lo that is perpendicular to the implant surface 121. The donor semiconductor wafer 120 is tilted such that the longitudinal axis Lo is at an angle Φ for the ion implantation beam direction axis (shown by solid arrows) during the ion implantation step. The angle Φ can be between about 1 and 45 degrees.

In the case of tilting, the beam source is scanned from position A to position B, and the width W of the beam 202 varies from width Wa to Wb at the implant surface 121 of the donor semiconductor wafer 120, and vice versa. A change in the width W causes a change in the density of the nucleation sites formed by ion implantation on the scanning direction (which can be set to vary in at least one direction along the X- and Y-axes).

Implanted beam 202 can include hydrogen ions having the same (positive) charge. When particles of the same charge are driven away from each other, beam 202 is wider at a greater distance from the ion source (position A) and narrower at a closer distance from the ion source (position B). The ion beam of position B is more concentrated (lower width Wb) than the ion beam of position A (higher width Wa), and the local area of the donor semiconductor wafer 120 is heated to a higher degree. At higher temperatures, more hydrogen ions will diffuse from this localized area, leaving less hydrogen ions than other regions. As shown in FIG. 6B, this creates a lateral hydrogen non-uniform distribution (and thus a density of nucleation sites) within the weakened sheet 125 of the donor semiconductor wafer 120.

Similar spatial variations in nucleation site density can be achieved by adjusting the angle of the beam source or by incorporating some known mechanisms for adjusting the alignment of ion beam 202.

A further technique suitable for achieving spatial variations in the density of nucleation sites is to use a two-stage ion implantation step. The first ion implantation step is to perform ion implantation with the effect of attracting the second ion component. Thereafter, a second ionic component is implanted. The first ionic component is implanted in a spatially non-uniform manner using any suitable aforementioned or later described techniques herein. Therefore, when the second ion component is implanted, it migrates to the first component, and the resulting weakened sheet 125 It will show the density of non-uniform nucleation sites.

For example, the first ionic component can be implanted within the donor semiconductor wafer 120 in accordance with the material of the donor semiconductor wafer 120, such as using erbium ions. This characteristic of Si ions captures a second ion component such as a hydrogen ion. As explained above, hydrogen ions and some semiconductor atoms such as Si atoms are bonded to form a Si-H chain. For example, implants of sputum can be performed at doses and energies known in the art, as described in U.S. Patent No. 7,148,124, the entire disclosure of which is incorporated herein by reference. However, unlike previous techniques, the captured ion composition (in this example is Si) spatially has a non-uniform density distribution (eg, the highest on one side of the donor semiconductor wafer 120 and the lowest on the opposite side, or discussed herein). Other changes). Next, a second ionic component such as hydrogen is implanted, which may be a uniform distribution. The amount of hydrogen remaining in the weakened sheet 125 of the donor semiconductor wafer 120 depends on two factors: (1) a concentrated distribution of the second ionic component that captures, for example, hydrogen, and (2) hydrogen that can be used (implanted Hydrogen and implanted dose of residual hydrogen).

It is to be noted that the non-uniform spatial distribution of the components can be reversed to achieve similar results. For example, the first component can be implanted uniformly, followed by non-uniform implantation of the second component. Alternatively, both implants are spatially non-uniform. The non-uniform distribution of the second component (e.g., hydrogen) within the weakened sheet 125 produces a point, edge or region of highest hydrogen concentration, i.e., the lowest temperature position at which the split begins.

Referring again to Figures 2A-2B, arrow A shows the separation and/or temporally controlled separation characteristics of the release layer 122 from the donor semiconductor wafer 120 to achieve a point, edge and/or region from the weakened sheet 125 to other points, edges. And/or the separation of the regions as a function of time. Density space in the nucleation site In the case of a sexual change, the temperature of the donor semiconductor wafer 120 is raised enough to initiate separation from the point, edge and/or region of the highest density of the weakened sheet 125. We have found that high concentrations of hydrogen in helium can be separated at temperatures of 350 ° C or below, while lower concentrations of hydrogen are separated at higher temperatures, such as 450 ° C or higher. The donor semiconductor wafer 120 is lifted to a further temperature sufficient to continue to separate in a substantially oriented direction along the weakened sheet 125 as a function of the spatial variation of the density of the entire weakened sheet 125.

Further details are now provided, with reference to the spatial variation of ion implantation in one or both directions of the X-axis and the Y-axis to attenuate specific parameters of the depth of the sheet 125. Regardless of the technique used to achieve this spatial variation, the substantially low depth is preferably between about 200-380 nm and the highest depth is between about 400-425 nm. Looking at this change in another way, the difference between the maximum and minimum depths can be between about 5-200%.

In accordance with one or more aspects of the present invention, the spatial variation can weaken the depth of the sheet 125 by adjusting the beam angle of the ion beam during the ion implantation step. Indeed, the process discussed with respect to Figures 6A-6B can be applied to adjust the depth of the weakened sheet 125 (note the mechanism of changing the temperature as a function of beam width, and is not considered to be the reason for achieving the depth variation of the weakened sheet 125) .

Referring to Figures 6A and 7A-7B, the spatial variation of the depth of the weakened sheet 125 can be achieved by changing at least one of the following: (1) tilt angle Φ (please refer to the display and illustration of Figure 6A), (2) for ions The direction axis of the implanted beam 202 is applied to the torsion of the longitudinal axis Lo of the semiconductor wafer 120. Adjusting the tilt and/or twist to adjust an angle directed through the donor semiconductor wafer 120 lattice structure such that when the ion beam 202 scans the entire implant surface 121, The orientation of the bulk crystal structure of the bulk semiconductor wafer 120 has a tendency to align and misalign the ion beam 202. When the angle of the orientation changes spatially, the depth of the weakened sheet 125 also changes.

The angle Φ can be between about 1-10 degrees and the twist angle can be between about 1-45 degrees.

As with the above inference, with further reference to Figures 7C and 7D, the implant depth will become smaller as the tilt becomes larger. For relatively small angles (such as 0-10 degrees), the relationship between implant depth and tilt is controlled by steering. For a relatively large angle, the official is controlled by the cosine effect. In other words, the resulting peel film thickness is proportional to the cosine of the angle of incidence.

Alternatively or in addition, the spatially varying step can include varying the energy level of the ion beam 202 such that when the ion beam 202 scans the entire implant surface 121 of the donor semiconductor wafer 120, the weakened sheet from the implanted surface 121 The depth of layer 125 will also vary spatially throughout the donor semiconductor wafer 120.

As shown in FIG. 7B, the above technique produces a laterally non-uniform depth of the weakened sheet (or implant depth) of the donor semiconductor wafer 120.

Further parameters can be adjusted along with the tilt of the donor semiconductor wafer 120 to achieve a spatial variation in the width (or dispersion) of the ion deposition distribution. As shown in FIG. 8A, the change in ion distribution width through the weakened sheet 125 (from top to bottom) is a function of the tilt angle (and more generally the beam angle) of the donor semiconductor wafer 120. Therefore, the distribution width of the spatial variation in the weakened sheet 125 can be achieved by changing the tilt angle (as shown in Fig. 8B). However, without wishing to be limited to any theory of operation, the partially weakened sheet 125 having a narrower distribution width will be lower in comparison with the partially weakened sheet 125 having a wider distribution width. Separated at temperature. Thus, the orientation and/or temporally controlled separation characteristics of the salt stripping layer 122 from the donor semiconductor wafer 120 can be propagated from a point, edge and/or region of the weakened sheet 125 to other points, edges and/or regions. Separation as a function of time and temperature.

Referring to Figure 8C, additional information on the effect of the tilt on the dispersion effect will again impact the width of the dose curve of the implant. The doses of the two implants shown in Figure 8C are the same. Although the peak H concentration is different, both implants are separated. Therefore, the difference between the ±0.1 degree and ±3 degree tilt changes is apparent for dispersion.

Referring to Figures 9C-9D, another technique for weakening the spatially varying depth of the sheet 125 includes applying the donor semiconductor wafer 120 to an implanted material removal process such that the depth of the weakened sheet 125 from the implanted surface 121 is The entire donor semiconductor wafer 120 is spatially variable. As shown in FIG. 9A, the donor semiconductor wafer 120 can be subjected to some decisive grinding process or plasma assisted chemical etching (PACE). These techniques can locally control the amount of material removed by the grinding step. Other methods include reactive ion etching (RIE), chemical mechanical polishing (CMP), and wet chemical etching, as well as regular and reproducible material removal across the exposed surface. One or more of these or other techniques may be used to cause slight variations in the depth of the weakened sheet 125 from the implanted surface 121, as shown in Figures 3A, 4A, 4B, 4C and other figures. The ion implantation step prior to material removal may be spatially uniform or non-uniform.

Referring to Figures 9B and 9C, the step of spatially varying may include using the mask 220A or 220B in a spatially non-uniform manner on the implanted surface 121 of the donor semiconductor wafer 120 such that when the ion beam 202 scans the entire implant table When the face 121 is 121, the penetration of ions is prevented to a different extent. The mask film 220 may include ruthenium dioxide, such as a photoresist organic polymer and others. Possible deposition techniques include enhanced chemical vapor deposition of plasma (PECVD), spin coating, polydimethylsiloxane (PDMS) stamping, and the like. The thickness of the mask film 220 can be less than or less than the desired depth of the sheet 125. Because the depth of the implanted ions is determined by the energy of the incident ions, the blocking action of the mask 220 translates into a spatial modulation of the depth of the primary implant component within the donor semiconductor wafer 120. Depending on the nature of the deposition mask 220, the desired characteristics can be achieved by increasing the length of the ion path, diffusing ions to change the degree of orientation, or other phenomena.

As shown in FIG. 9D (showing the lower depth of all edges of the weakened sheet 125 and the higher depth toward the center), the donor semiconductor wafer 120 is elevated to a temperature sufficient to weaken the sheet 125 after and during bonding to the substrate 102. A point, edge and/or area of low depth begins to separate. The temperature of the donor semiconductor wafer 120 is further increased to be sufficient to continue to separate along the weakened sheet 125 substantially as a function of spatial variation from the lowest depth to the highest depth.

Referring to Figures 10A-10D and 11, the step of spatially varying may include drilling one or more blind holes 230 through the implant surface 121 at least to the weakened sheet 125, preferably through the weakened sheet 125 (Figure 10B). . Without wishing to limit the invention in any theory of operation, the donor semiconductor wafer 120 is lifted to a higher temperature during or after bonding to the substrate 102 (Fig. 10C), before being separated at a location without the blind via 230, in a blind via. The separation was initiated at 230 (Fig. 10D). As shown in Figure 11, drilling an array of blind holes 230 through the implant surface 121 can create a non-uniform spatial distribution of the holes. Thus, the temperature of the donor semiconductor wafer 120 can be oriented to be sufficient to initiate substantially along the weakened sheet 125. And continue to separate, from highest to lowest concentration, as a function of the distribution of the blind holes 230 array.

Referring to Figures 12A-12B, the step of spatially varying may include applying a non-uniform time-temperature variability curve to the donor semiconductor wafer 120 such that the nucleation site density or pressure across the various spatial locations of the weakened sheet 125 is The entire donor semiconductor wafer 120 varies spatially. For example, the temperature gradient shown in FIG. 12A applies a higher temperature than the right to the left of the wafer 120. This temperature gradient can be applied in situ prior to bonding, or during bonding to the substrate 102. After a period of time, if the processing time is maintained at a separation threshold below a certain processing temperature, at least one of the defect portion formed by the nucleus and the gas pressure therein may increase to a different extent throughout the weakened sheet layer 125, spatially throughout Wafer 120 acts as a function of temperature gradient (see Figure 12B). It is expected that the separation threshold time for a particular treatment temperature follows the Arrhenius relationship, and the separation threshold time is exponentially proportional to the reciprocal of the treatment temperature. The important parameters are the ratio of processing time at the processing temperature to the separation threshold time. Any of the aforementioned spatially varying parameter magnitude curves discussed or required herein can be achieved by adjusting the process time-separation time ratio. Next, the temperature of the donor semiconductor wafer 120 is raised sufficiently to initiate separation at a point, edge and/or region of the maximum processing time-separation time ratio at the weakened sheet layer 125. In the example shown, the maximum processing time-to-separation time ratio is on the left side of the wafer 120. Next, the temperature of the donor semiconductor wafer 120 is further increased to be sufficient to continue to separate along the weakened sheet layer 125 substantially in a direction, from a maximum processing time-separation time ratio to a minimum processing time-separation time ratio as a change time. - A function of the temperature variation curve. Based on material characteristics and other factors, including ionic composition, dose, and implant The depth, substantially high processing time-to-separation time ratio is between about 0.9 and 0.5, and the lowest processing time-separation time ratio is between about 0 and 0.5.

A time-temperature variability curve for spatial variation can be achieved using a variety of pre-bonded or in-situ bonding mechanisms. For example, the donor semiconductor wafer 120 can be heated using one or more spatially non-uniform conductive, convective or radiant heating techniques (heating plates, laser radiation, visible/infrared lamps, or the like). The controlled time/temperature gradient can be achieved by direct or indirect thermal contact (conduction) to achieve any desired quantitative curve. Depending on the computer control or programming, an addressable two-dimensional array of heating plate elements can be used to achieve different quantitative curves. For example, rapid thermal annealing (radiation) lamps are used for local infrared radiation, and/or visible or near-infrared laser radiation is used to provide localized and spatially non-uniform heating (radiation). Alternatively, spatially non-uniform cooling mechanisms such as direct contact (conduction), or gas or fluid jet (conduction/convection) and uniform or non-uniform thermal curves can be used in any way to achieve the desired time. -Temperature gradient.

Furthermore, these heating/cooling techniques can be used in advance bonding or in situ. With regard to the in-situ bonding technique, the bonding device is described, for example, in the patent entitled "HIGH TEMPERATURE ANODIC BONDING APPARATUS", US Patent No. 11/417,445, the entire disclosure of which is incorporated herein by reference, For use in the present invention, the thermal radiation loss management of the bonding device can be controlled and utilized to achieve a time-temperature gradient by combining the infrared reflecting elements around the bonding device to minimize radiation loss and maximize edge temperature. Conversely, controllable Heat radiation loss management of the bonding device, through the combined cooling of the infrared absorber, to the maximum Radiation loss and minimize edge temperature. A variety of variations of the above subject matter can be used to achieve the desired time-temperature gradient.

While the invention has been described herein with respect to the specific embodiments, these embodiments Thus, it is to be understood that various modifications may be made in the exemplified embodiments, and other configurations may be devised without departing from the spirit and scope of the invention as defined by the following claims.

102‧‧‧Substrate

120‧‧‧Sensor semiconductor wafer

121‧‧‧ implant surface

122‧‧‧ peeling layer

125‧‧‧Weakened slices

Claims (23)

A method of forming a semiconductor-on-insulator (SOI) structure, comprising: providing a donor semiconductor wafer having a width, a depth, and a height, the width and the depth defining an X- and Y-axis And a height defining a longitudinal axis; applying an ion implantation step to an implant surface of the donor semiconductor wafer to create a weakened layer on a cross section defining a release layer of the donor semiconductor wafer And applying a spatially varying step to the donor semiconductor wafer before, during or after the ion implantation step such that the depth of the weakened layer from the implanted surface is perpendicular to the longitudinal axis Spatially varying across the donor semiconductor wafer in a reference plane extending in the X- and Y-axis directions such that a substantially lower depth occurs along a starting edge of the weakened sheet layer, together a starting point or a starting area, and a continuous higher depth appearing in the at least one direction of the X- and Y-axis from the starting edge, the starting point, or the starting region Distance away. The method of claim 1, wherein a maximum depth of the weakened sheet layer occurs at about 400-425 nm in a first region, and a minimum depth occurs in a second region of the weakened sheet layer about 200- At 380 nm, the second region is separated from the first region in at least one of the X- and Y-axis directions. The method of claim 1 or 2, wherein the weakening in a first region The maximum depth of the layer is about 1.05 to 2.00 times the minimum depth of the weakened sheet in a second region. The method of claim 1 or 2, further comprising elevating the donor semiconductor wafer to a temperature sufficient to be at the weakened sheet layer by a point, edge of the minimum depth of the weakened sheet for the reference plane And / or the area begins to separate. The method of claim 4, further comprising: elevating the donor semiconductor wafer to a further temperature sufficient to continuously separate substantially vertically along the weakened sheet layer as the weakened sheet layer from a minimum depth to a maximum depth A function of different depths. The method of claim 5, wherein the time-temperature variability curve of the elevated temperature is a few seconds such that a separate propagation from the minimum depth to the maximum depth along the weakened sheet occurs for at least one second. The method of claim 1 or 2, wherein the spatially varying step comprises tilting the donor semiconductor wafer such that during the ion implantation step, the longitudinal axis of the donor semiconductor wafer is directed to one of the ion implanted beams The direction axis is a non-zero angle Φ and the depth of the weakened sheet from the implant surface varies spatially throughout the donor semiconductor wafer. The method of claim 7, wherein the angle Φ is between about 1 and 45 degrees. Within the scope. The method of claim 7, wherein the spatially varying step further comprises varying at least one of: an angle Φ of the tilt; and a longitudinal axis of the donor semiconductor wafer for a direction axis of the ion implant beam A twist such that when the ion implant beam scans the implant surface of the donor semiconductor wafer, the lattice structure directed through the donor semiconductor wafer has a tendency to align and misalign the ion implanted beam. The method of claim 9, wherein the spatially varying step further comprises varying an energy value of the ion implanted beam when the ion implant beam scans the implant surface of the donor semiconductor wafer. The depth of the weakened sheet from the implanted surface is spatially varied throughout the donor semiconductor wafer. The method of claim 7, wherein the step of spatially varying comprises masking the implanted surface of the donor semiconductor wafer in a spatially non-uniform manner such that when the ion implanted beam scans the implant At the surface, the penetration of the ions is prevented to a different extent. The method of claim 1 or 2, wherein the spatially varying step comprises: Applying the implanted surface to a substantially uniform ion implantation step to produce the weakened sheet at a substantially uniform depth for the reference plane; and applying the donor semiconductor wafer to an implanted surface The material removal process causes the weakened sheet depth from the implanted surface to vary spatially throughout the donor semiconductor wafer. The method of claim 1 wherein the substantially lower depth is in the range of about 200-380 nm and the highest depth is in the range of about 400-425 nm. The method of claim 1, wherein: the donor semiconductor wafer is rectangular; and the spatially varying step comprises spatially varying depth such that a substantially lower depth occurs at at least two edges of the weakened sheet At each of the edges, and at a relatively high depth, at least two of the edges of the weakened sheet layer are at a greater distance from the center of the weakened sheet. The method of claim 1, wherein the step of spatially varying comprises spatially varying the depth such that a substantially lower depth occurs at all edges of the weakened sheet and a relatively higher depth occurs Towards the center of the weakened sheet at a continuously further distance. A method of forming a semiconductor-on-insulator (SOI) structure comprising: Applying an ion implantation step to an implant surface of a donor semiconductor wafer to create a weakened layer on a cross section defining a release layer of the donor semiconductor wafer; and applying the donor semiconductor wafer to Non-uniform time-temperature variability curve processing, thereby adjusting a process time-separation time ratio variability curve such that at least one of defect site nucleation and pressure increase is present throughout the weakened slab at respective spatial locations At least one direction of the X- and Y-axis changes spatially. The method of claim 16, wherein the time-temperature variability curve is not sufficient to separate the release layer from the donor semiconductor wafer. The method of claim 16 or 17, comprising the step of: applying the non-uniform time-temperature amount curve processing step before bonding the implant surface to an insulating substrate; In the process of bonding the surface to an insulating substrate, the non-uniform time-temperature variable curve processing step is applied in situ. The method of claim 17, further comprising increasing a temperature of the donor semiconductor wafer at a point, edge and/or at a maximum ratio of the processing time-separation time of the weakened sheet at the weakened sheet layer. Or the area begins to separate. According to the method of claim 19, further comprising increasing the donor half The conductor wafer is further heated to a temperature that is substantially continuously separated along the weakened sheet layer as a function of the time-temperature variation curve of the weakened sheet, the function being ranged by the processing time-separation time The ratio of the maximum ratio to the processing time - the minimum ratio of the separation time. The method of claim 16 or 17, wherein the non-uniform time-temperature variability curve causes a substantially high processing time-to-separation time ratio to occur along a starting edge, a starting point of the weakened sheet or a starting region, and a relatively low processing time-separation time ratio appearing in at least one direction of the X- and Y-axis from the starting edge, the starting point, or the starting region Far away. The method of claim 21, wherein the substantially high processing time-to-separation time ratio is in the range of about 0.5 to 0.9, and the minimum processing time-separation time ratio is in the range of about 0 to 0.5. According to the method of claim 16 or 17, wherein a substantially high processing time-to-separation time ratio occurs at a starting point or region along one or more edges of the weakened sheet layer, and relatively low The processing time-to-separation time ratio occurs at successively longer distances from the starting point or region in both the X- and Y-axis directions.