KR20110053387A - Managing thermal budget in annealing of substrates - Google Patents

Abstract

A method and apparatus for processing a substrate are provided. The substrate is disposed on a support in the heat treatment chamber. Electromagnetic radiation is directed towards the substrate to anneal a portion of the substrate. The other electromagnetic radiation is directed towards the substrate to preheat a portion of the substrate. Preheating reduces the thermal stress at the interface between the preheating zone and the annealing zone. As required in certain embodiments, a certain number of annealing and preheating zones are contemplated, with varying shapes and temperature profiles. Any convective source of electromagnetic radiation can be used, such as a laser, heat lamp, white light lamp, or flash lamp.

Description

Manage heat dissipation costs when annealing substrates {MANAGING THERMAL BUDGET IN ANNEALING OF SUBSTRATES}

Embodiments of the present invention relate to a method of manufacturing a semiconductor device. More specifically, embodiments of the present invention relate to a method of thermally treating a substrate.

The integrated circuit (IC) market continues to demand larger memory capacities, faster switching speeds, and smaller feature sizes. One of the key steps in the industry taken to address this need is to convert batch processed silicon wafers in large furnaces into single wafers processed in small chambers.

During such single wafer processing, the wafer is typically heated to high temperatures so that various chemical and physical reactions can occur in multiple IC devices formed within the wafer. Of particular interest, the preferred electrical performance of the IC device requires that the implanted area be annealed. Annealing reforms more crystalline structures from regions of the wafer that are previously made amorphous, and the dopants are activated by bonding atoms of the dopant into the crystalline lattice of the substrate or wafer. Thermal processes, such as annealing, provide a relatively large amount of thermal energy to the wafer within a short amount of time, and then require rapid cooling of the wafer to terminate the thermal process. Examples of thermal processes currently used include rapid thermal treatment (RTP) and impulse (spike) annealing. While such processes are widely used, the current technology is not ideal for large substrates which are intended to be exposed to elevated temperatures over long periods of time. These problems are compounded by increasing switching speed and / or reducing feature size.

In general, these thermal processes heat the substrate under controlled conditions in accordance with a predetermined thermal regimen. This thermal regimen essentially leaves the semiconductor substrate at a special temperature and the temperature at which the semiconductor substrate must be heated at a rate of temperature change, i.e., temperature ramp-up and ramp-down rates. It takes place in time. For example, some thermal regimens may require the entire substrate to be heated from a thermal room temperature to 400 ° C. or higher for processing times that exceed the thermal budget of the device formed on the substrate.

Moreover, the amount of time each semiconductor substrate is treated at high temperatures should be limited to meet certain goals, such as minimal inter-diffusion of material between different regions of the semiconductor substrate. To achieve this, it is desirable that both the temperature ramp rate, increase and decrease be high. That is, it is desirable to be able to adjust the temperature of the substrate from low temperature to high temperature or vice versa within the shortest time possible.

The need for a high temperature ramp rate is the development of rapid thermal treatment (RTP) in which a typical temperature ramp-up rate is in the range from 5 to 15 ° C./min for conventional furnaces as compared from 200 to 400 ° C./s. Brings about. Typical ramp-down rates are in the range of 80-150 ° C./s. The disadvantage of RTP is that RTP heats the entire wafer, even though the IC device is just within the top few microns of the silicon wafer. This limits how fast the wafers are heated and cooled. Moreover, when the entire wafer is at elevated temperature, heat can only dissipate into the surrounding space or structure. As a result, in today's state of the art, RTP systems deal with efforts to achieve 400 ° C./s ramp-up rates and 150 ° C./s ramp-down rates.

As device sizes on the substrate become smaller in the future, the cost of heat consumption must also be reduced, since smaller devices can be more easily degraded by the co-diffusion of the material. The temperature ramp-up and ramp-down rates should be increased to compress the annealing time, for example below one second.

To address some of the problems posed by conventional RTP type processes, various scanning laser annealing techniques are used to anneal the surface (s) of the substrate. In general, these techniques deliver a constant energy flux to a small area on the surface of the substrate, during which the substrate is moved or scanned for energy delivered to the small area. Other energy scanning processes still hold the substrate and move the laser across the substrate surface. Due to stringent uniformity requirements and the complexity of minimizing the overlap of scanned areas across the substrate surface, this type of process is not effective for thermally treated contact level devices formed on the surface of the substrate. In addition, thermal stresses generated on the substrate by high thermal gradients associated with extreme intensive heating can result in damage to the substrate.

In view of the foregoing, there is a need for a novel apparatus and method for annealing semiconductor substrates at high ramp-up and ramp-down rates. This provides greater control over the fabrication of smaller devices resulting in increased performance.

One embodiment of the present invention generally provides a method of processing a substrate. One aspect of the invention provides a method of processing a substrate, the method comprising positioning a substrate on a movable substrate support, directing a first amount of heating energy toward a first fixed position below a portion of the substrate Moving the substrate support to treat the selected zone of the substrate by sequentially positioning each selected zone over the first fixed position and then the second fixed position, and maintaining a portion of the substrate at a temperature below 500 ° C. Steps.

Other embodiments provide a method of processing a substrate, the method comprising: positioning a substrate on a fixed substrate support, facing the substrate to form one or more hot zones and one or more annealing zones on the substrate surface; Directing the heating energy, and moving the heating energy to treat the selected zone of the substrate by sequentially placing the hot zone and the annealing zone over each selected zone.

Other embodiments provide an apparatus for thermally treating a substrate, the apparatus comprising a movable substrate support, a first energy source directing annealing energy towards a first portion of the surface of the substrate support, and a second of the surface of the substrate support. A second energy source oriented to direct preheat energy towards the portion, and an optical assembly to receive the first energy source and the second energy source.

Other embodiments provide an apparatus for thermally treating a substrate, which directs annealing energy towards a fixed substrate support, a first portion of the surface of the substrate support, and a preheat energy towards a second portion of the surface of the substrate support. One or more energy sources oriented so as to be oriented, and an actuator for moving the annealing energy and the preheating energy relative to the fixed substrate support.

BRIEF DESCRIPTION OF DRAWINGS In order that the above-described features of the present invention may be understood in detail, reference is made to the embodiments, some of which are illustrated in the accompanying drawings in which a more specific detailed description, briefly summarized above, is attached. It is to be noted, however, that the appended drawings illustrate only typical embodiments of the invention and, therefore, are not to be considered as limiting the scope of the invention, and other equivalent embodiments may be recognized for the invention.

1A is a schematic perspective view of an apparatus according to an embodiment of the present invention,
FIG. 1B is a schematic bottom view of one embodiment of the energy source of FIG. 1A, and FIG.
2 is a schematic perspective view of an apparatus according to another embodiment of the present invention,
3A is a graph of temperature versus location on a substrate undergoing a process in accordance with one embodiment of the present invention,
3B-3C are schematic plan views of a substrate undergoing a process according to two embodiments of the invention,
4 is a schematic side view of an apparatus according to an embodiment of the present invention,
5 is a schematic cross-sectional view showing a processing chamber according to an embodiment of the present invention,
6 is a schematic plan view of a substrate undergoing a process according to one embodiment of the invention,
7 is a schematic cross-sectional view showing a processing chamber according to an embodiment of the present invention,
8A-8B are graphs of temperature versus time on a substrate undergoing processes in accordance with one embodiment of the present invention,
9 is a flow diagram summarizing a method according to an embodiment of the present invention;
10 is a flow diagram summarizing a method according to another embodiment of the present invention;
11 is a flowchart summarizing a method according to another embodiment of the present invention.

To facilitate understanding, the same reference numerals are used to denote the same elements that are common to the figures. The element disclosed in one embodiment may be beneficially used in other embodiments without particular citation.

The smaller the device dimensions on the substrate and the larger the substrate itself, it is very impractical to perform the heat treatment of the entire substrate at once. The power required to energize the entire surface is heavy, as is the opportunity for non-uniform processing. Thermal processing tools, such as RTP chambers, are therefore sometimes configured to process portions of the substrate surface by turn. Exemplary heat treatment devices, such as DSA® chambers, available from Applied Materials, Inc. of Santa Clara, California, USA, are used to irradiate a small portion of the substrate surface with laser light to anneal the surface. Can be. At the edge of the lazy beam, the substrate surface can be heated in extreme proportions, and the temperature gradient between the irradiated and untreated portions can damage the substrate with thermal stress. For this reason, the substrate is generally placed on a heated chuck that maintains the entire substrate at an elevated ambient temperature to reduce the stress of heating to the annealing temperature. Frequently, however, the need to maintain the substrate at elevated temperatures reduces the benefits of heat treatment. Embodiments of the present invention generally contemplate an improved way of thermally treating a substrate.

As used herein, the term “substrate” as used herein may refer to any material having a given natural electrical conducting performance or to an article formed of a material that can be modified to provide the ability to conduct electricity. Typical substrate materials include, but are not limited to, semiconductors, such as silicon (Si) and germanium (Ge), as well as other composites showing semiconductor properties. Such semiconductor composites generally include group III-V and group II-VI composites. Representative Group III-V semiconductor composites include, but are not limited to, gallium arsenide (GaAs), gallium phosphide (GaP), and gallium nitride (GaN). In general, the term “semiconductor substrate” includes a substrate having a bulk semiconductor substrate as well as a deposition layer disposed thereon. To this end, the deposition layer in some semiconductor substrates treated by the methods of the present invention is formed by homogeneous epitaxial (eg, silicon on silicon) or heteroepitaxial (eg, GaAs on silicon) growth. For example, the method of the present invention is used for gallium arsenide and gallium nitrogen substrates formed by heteroepitaxial methods. Similarly, the invention is also applied to form integrated devices such as thin film transistors (TFTs) on relatively thin crystalline silicon layers formed on insulating substrates (eg, silicon-on-insulator [SOI] substrates). Can be.

Certain embodiments of the present invention provide methods for thermally treating a substrate. 1A is a schematic perspective view of an apparatus 100 according to an embodiment of the present invention. 1A features an energy source 102 adapted to project a certain amount of energy onto a confined region, or annealing region 104, of a substrate 106 disposed on a work surface 108. The amount of energy projected onto the annealing zone 104 is selected to cause annealing of the surface of the substrate 106. The energy delivered by the energy source is less than required to melt a portion of the substrate 106. In other embodiments, the delivered energy is selected to cause preferential melting of a portion of the substrate 106.

In certain embodiments, energy source 102 includes a plurality of emitters, as shown schematically in FIG. 1B, and emitters 102A-102E are shown embedded in energy source 102. Emitters 102A-102E generally emit radiation directed onto the substrate 106. In certain embodiments, each emitter 102A-102E emits the same amount of energy. In other embodiments, emitters 102A-102E can emit different amounts of energy. In one exemplary embodiment, emitter 102A may emit an amount of energy selected to anneal annealing region 104 of substrate 106, while emitters 102B-102E may anneal region 104. Radiates a certain amount of energy selected to preheat one or more portions of the substrate 106 near, adjacent to, or overlapping the anneal zone.

In one example, as shown in FIG. 1A, only one confined region of the substrate, such as annealing region 104, is exposed to radiation from energy source 102 at any given time. In one aspect of the invention, multiple regions of the substrate 106 are continuously exposed to a target amount of energy delivered from the energy source 102 to cause preferential melting of the target region of the substrate. In another aspect, multiple regions of the substrate 106 are continuously exposed to a certain amount of energy from the energy source 102 selected to anneal the target region of the substrate without melting.

In general, the area on the surface of the substrate is continuously exposed by moving the substrate relative to the output of the electromagnetic radiation source (eg, conventional X / Y stage, precision stage) and / or by moving the output of the radiation source relative to the substrate. Can be. Typically, one or more conventional electric actuators 110 (eg, linear DC servo motors, lead screws, and servo motors), which may be part of an individual precision stage (not shown), move the substrate 106. And position control. Conventional precision stages that can be used to support and hold the substrate 106 are available from Parker Hannifin Corporation of Lonert Park, California, USA.

In another embodiment, the source of electromagnetic radiation can move relative to the substrate. In the embodiment of FIG. 1A, for example, the energy source 102 is a positioning device, such as a Cartesian frame, configured to position the energy source 102 over a target region of the substrate 106. Not shown). The positioning device may additionally be configured to adjust the rise of the energy source over the substrate 106.

Referring again to FIG. 1A, a preheating zone 112 is formed on the surface of the substrate 106. In certain embodiments, the preheating zone 112 surrounds the annealing zone 104. In other embodiments, the preheating zone may be adjacent to the annealing zone 104 or may overlap with the annealing zone 104. In still other embodiments, the preheating zone 112 may be near the annealing zone 104 with a gap or space between the preheating zone 112 and the annealing zone 104. In certain embodiments, the preheating zone may be spaced apart from the annealing zone. The preheat zone can thus have any convenient shape, such as the circular preheat zone 112 shown in the embodiment of FIG. 1A.

2 is a schematic perspective view of an apparatus 200 according to another embodiment of the present invention. The energy source 202 is configured to direct energy towards the substrate 204 disposed on the working surface 206. In certain embodiments, energy source 202 includes a plurality of emitters 202A that emit electromagnetic energy of a selected characteristic to thermally treat the surface of substrate 204. One or more of the emitters 202A may be configured to anneal the annealed portion 208 of the substrate 204, while one or more of the emitters 202A may preheat the preheated portion 210 of the substrate 204. Is configured for. In the embodiment of FIG. 2, the preheating portion 210 is shown adjacent to the annealing portion 208. Other embodiments may feature a preheating portion 210 that overlaps or is spaced apart from the annealing portion 208.

3A is a generalized graph showing the effect on a substrate implementing one embodiment of the present invention. As shown in FIG. 3A, portions of the substrate are maintained at different temperatures in different zones. The graph of FIG. 3A shows a point of temperature on the surface of the substrate undergoing an annealing process, which point is placed on the line shown through the treatment zone. The first zone 302 can be maintained at a high temperature selected to anneal the substrate surface. Such zones may correspond to the annealing zone 104 of FIG. 1A, the annealing zone 204 of FIG. 2, or any zone of the substrate that is heated to a high temperature.

The embodiment of FIG. 3A features a second zone 304 that is generally maintained at different temperatures, which is lowered in the example of FIG. 3A. The second zone 304 may surround the first zone 302 in some embodiments. In another embodiment, the second zone 304 may be adjacent to the first zone 302, overlap with the first zone 302, or may be spaced apart from the first zone 302. The temperature of the second zone 304 is generally lower than the temperature of the first zone 302. The temperature of the second zone 304 can be selected to preheat the portions of the substrate, reducing the thermal stress on the substrate by a very sudden temperature change.

The third zone 306 is generally also formed on the substrate. In most embodiments, the third zone 306 will be a zone where ambient temperature prevails. The third zone 306 may thus be a peripheral zone in many embodiments. However, in certain embodiments, the third zone 306 may also receive applied thermal energy, for example by surroundings heated with a heated support or by further use of electromagnetic energy. Along with the idea of gradual preheating closer to the first zone 302, the temperature of the third zone 306 may generally be less than the temperature of the second zone 304. The third zone 306 may surround the second zone 304 in some embodiments or may be adjacent to the second zone in other embodiments. In certain embodiments, the temperature of the third zone will be maintained below about 500 ° C.

The second zone 304 can have a temperature between the temperatures of the first zone 302 and the third zone 306. To achieve the target preheat, the temperature of the second zone 304 results in a temperature rise of about 30% to about 70% of the total temperature rise from the temperature of the third zone 306 to the temperature of the first zone 302. do. In certain embodiments, the temperature rise of the second zone 304 relative to the third zone 306 is about 50% of the temperature rise of the first zone 302 relative to the third zone 306.

In certain embodiments, the temperature of the first zone 302 may be about 1,100 ° C. to about 1,400 ° C., such as about 1,250 ° C. to about 1,350 ° C. In certain embodiments, the temperature difference between the first zone 302 and the ambient temperature will be about 90% to about 99%, such as about 95% of the temperature difference between the melting point of the substrate and the ambient temperature. In certain embodiments, the temperature of the second zone 304 may be about 300 ° C to about 800 ° C. The temperature of the second zone 304 is generally chosen to be able to reduce the thermal stress at the boundary of the first zone 302 to the second zone 304, but also generally the portions of the substrate are amorphous. Is below the level. The temperature of the second zone 304 will generally be selected to preheat the portions of the substrate that are to be annealed and the annealed portion is cooled. The temperature of the second zone 304 is generally below the temperature required to remove atoms from the crystal lattice. In one exemplary embodiment characterizing a silicon containing substrate, the temperature of the first zone 302 may be about 1,350 ° C., the temperature of the second zone 304 is about 650 ° C., and the third zone 306 ) May be about 20 ° C. and may be another ambient temperature.

3B and 3C are schematic views of a substrate, each having a plurality of processing zones formed thereon. The treatment zone represents an area of the substrate that is heated by electromagnetic radiation. The embodiment of FIG. 3B has a first zone 302 surrounded by a second zone 304B and a third zone 306B. It should be noted that the zones may have similar or different shapes. The embodiment of FIG. 3B features a rectangular first zone 302 with circular second and third zones 304B, 306B. Optional embodiments may have a circular shape for all three zones. The embodiment of FIG. 3C is a rectangular first zone, with a rectangular or square second zone 304C adjacent to the first zone 302C on either side, all surrounded by a third zone 306 that is a peripheral zone. 302C. In addition, the second zone may all be maintained at a single temperature or portions of the second zone may be maintained at different temperatures. For example, the second zone 304B of the embodiment of FIG. 3B may all be a single temperature while the second zone 304B of the embodiment of FIG. 3C may have portions of different temperatures. If one portion of the second zone 304C is intended as a preheating zone and another portion is intended as a cooling zone, the preheating portion may be maintained at a higher temperature than the cooling portion. Certain suitable shaped substrates, such as circular, rectangular, or any other planar shape, are beneficial from the embodiments of the present invention disclosed herein.

In certain embodiments, there may be multiple zones of elevated temperature between the ambient zone and the annealing zone. Certain embodiments may feature multiple preheat zones with a single annealing zone. Certain embodiments may feature a first plurality of preheat zones and a second plurality of cooling zones. In some embodiments, one zone may surround the next higher temperature zone, such that each zone is surrounded and surrounded by another zone. Such an embodiment may have zones approaching concentric circles whose shape is centered at different points (ie, non-concentric circles). Various different polygonal shapes, such as triangles, rectangles, squares, trapezoids, hexagons, and the like, may be useful in certain embodiments with zones of different shapes. Naturally, different shapes may be useful for different zones. In other embodiments, the zone may be adjacent to the next higher temperature zone on one side and the next lower temperature zone on the other side. In other embodiments, certain zones may be adjacent to other zones and certain zones may surround other zones. For example, the first zone can be defined as an annealing zone, the adjacent second zone is for preheating on the first side of the first zone and cooling on the second side of the first zone, and the first and second zones. All are surrounded by a third zone, the third zone is maintained at a temperature above ambient temperature, and the fourth zone surrounding all other zones is maintained at ambient temperature.

In one exemplary embodiment, the rectangular annealing zone may be surrounded by one or more preheating zones formed as rectangles with triangles on opposite sides. This tapered shape can promote heating and cooling of the substrate surface in a desired manner. In another exemplary embodiment, the annealing zone, which may be rectangular or circular, may be surrounded by one or more preheating zones having a teardrop shape. The teardrop shaped rounded portion may be a preheating zone, while the “tail” of the teardrop may be a cooling zone.

In certain embodiments, one or more of the preheating or cooling zones may have a gap between the anneal zone and the preheating and / or cooling zones and may be spaced apart from the anneal zone. For example, four zones such as ambient zone, preheat zone, annealing zone, and cooling zone can be formed on the substrate surface to anneal. The annealing zone may be rectangular with two long sides of 11 mm and two short sides of 100 μm. The preheating zone may be a base that is 13 mm and an isosceles triangle with a height of 5 mm, the base being parallel to the long side of the annealing zone and spaced about 1 mm from the long side of the annealing zone, and the line bisecting the isosceles triangle It is also centered for the annealing zone to be bisected into two rectangles 5.5 mm long and 100 μm wide. The cooling zone may also be an isosceles triangle similar to the preheating zone. If the anneal zone temperature is 1,200 ° C., the temperature of the preheat zone may be between about 600 ° C. and about 700 ° C. such that the temperature of the substrate surface drops slightly as the substrate passes through the gap between the preheat zone and the anneal zone. The temperature of the substrate surface may drop to about 500 ° C., for example, before passing into the annealing zone. Such preheating profile may be useful to minimize perturbation of deep atoms in the bulk of the substrate while preheating the substrate. By extending the length of the base of the isosceles triangles forming the preheat zone, it is possible to provide heating to the area of the substrate surface adjacent the short side of the annealing zone to prevent damage by thermal stress on the substrate. Similar cooling zones located adjacent to the opposite long side of the anneal zone from the preheat zone may be useful to accelerate cooling while avoiding damage by thermal stress.

Certain embodiments may feature a plurality of annealing zones and a plurality of zones having different intermediate temperatures. Each annealing zone may be maintained at the same temperature, or at different temperatures as required by the individual embodiments. In this kind of embodiment, the preheating zone may be formed between the annealing zones, among the annealing zones, around the annealing zones, adjacent to the annealing zone, surrounding the annealing zone, or spaced apart from the annealing zone. For example, in one embodiment, the substrate may be processed in four portions by an apparatus that forms a plurality of processing zones in each portion. Thus, each portion may have an annealing zone surrounded by the preheating zone and further by the surrounding zones, which zones move across each portion to simultaneously process the substrate. In one such embodiment, the zones may be formed and configured in any of the manners described herein, with the location of the preheat zone in each of the portions being in other portions to maintain the overall heat dissipation cost of the substrate. It may be maintained at a pre-selected distance from the heated zone.

In certain embodiments, the preheating zone, or preheating and cooling zone, may be formed in a convenient manner. Embodiments have been described, as described in the embodiment of FIG. 3C, wherein the preheating and cooling zones are rectangular and disposed on two sides of the annealing zone. In other embodiments, the shape of the preheating and cooling zones may taper away from the anneal zone. In embodiments where the preheating and cooling zones do not surround the anneal zone, the preheating and cooling zones may generally span the same space as one or more sizes of the anneal zone. In certain embodiments, the preheating and cooling zones can be narrowed with distance from the annealing zone. In certain embodiments, the preheating and cooling zones may have a triangular, trapezoidal, parabolic, elliptical, oval, or irregular shape. In other embodiments, the preheating and cooling zones may have a rectangular shape that is joined in a semicircle. The shape may be mixed with a preheating zone having one shape and a cooling zone having another shape. In embodiments where the preheating and cooling zones surround the anneal zone to form a single mid-temperature zone, a single mid-temperature zone may also be formed. The mid-temperature zone surrounding the anneal zone may be oval, oval, or diamond shaped in one embodiment. In another embodiment, the rectangular zone may surround the anneal zone. In other embodiments, the mid-temperature zone may have an irregular, or double-regular shape, such as a pair of tangent trapezoids.

In one embodiment, the mid-temperature zone may have a generally elliptical shape and may be arranged irregularly with respect to the annealing zone. In such an embodiment, the center of the annealing zone may be displaced away from the center of the mid-temperature zone. Thus, a plurality of lines formed from the starting point on the edge of the mid-temperature zone to the ending point on the edge of the annealing zone will have a length ranging from maximum to minimum. When the annealing energy moves across the surface of the substrate, sufficient preheating energy is applied to prevent damage to the substrate, and sufficient energy is applied to the cooling zone to promote rapid cooling without damage after the annealing is finished, in the direction of the annealing path. It may be useful to maintain more distance between the edge of the zone and the edge of the mid-temperature zone. In one such embodiment, a plot of temperature versus time for a particular point on the substrate surface may be half the shape of a tear drop.

4 is a schematic side view of an apparatus 400 according to another embodiment of the present invention. The first energy source 402 and the second energy source 404 are arranged to direct energy towards each of the first surface 406 and the second surface 408 of the substrate 410. The first energy source 402 directs energy towards the first zone 412 of the substrate 410. The second energy source 404 directs energy towards the second zone 414 of the substrate 410. In most embodiments, the first zone 412 is smaller than the second zone 414, and the boundaries of the second zone 414 extend beyond the boundaries of the first zone 412 on all sides. In most embodiments, the first energy source 402 directs electromagnetic energy towards the substrate 410 to irradiate the first zone 412 with energy selected to heat the first zone 412 to an annealing temperature. While the second energy source 404 irradiates the second zone 414 with energy selected to heat the second zone 414 to an intermediate temperature. Heating of the second zone 414 to an intermediate temperature acts to preheat the portion of the substrate that must be annealed to avoid severe thermal stress caused by a sharp temperature change at the edge of the first zone 412. In general, an energy source designed to anneal the substrate will deliver a power density of about 1 W / cm ² to the substrate surface, while an energy source designed to only heat the substrate will deliver a power density of at least 0.1 W / cm ² , Less than the power density required to anneal.

In one embodiment, the annealing zone has a size that matches a discrete die (eg, 40 “dies” are shown in FIG. 1A) or a semiconductor device (eg, a memory chip) formed on the surface of the substrate. . Referring again to FIG. 1A, in one aspect, the boundaries of the anneal zone 104 are annealed and assembled within a “kerf” or “scribe” line 114 forming the boundaries of each die. Has a size. In one embodiment, prior to performing the annealing process, the substrate is aligned to the output of the energy source 102 using alignment marks and other conventional techniques commonly found on the surface of the substrate such that the annealing zone 104 is properly placed on the die. Can be aligned. The sequential placement of the anneal zone 104 such that the anneal zone only overlaps in naturally occurring unused spaces / boundaries between dies, such as scribe or cutting line 114, is achieved in the region where the device is formed on the substrate. And thus reduce the change in the process result between the overlapping annealing regions. Since the need to tightly control redundancy between adjacently scanned zones to ensure uniform annealing across the target zone of the substrate is not caused by the formation of overlap for unused spaces between the dies Silver has the advantage over conventional processes of sweeping laser energy across the surface of the substrate. Limiting redundancy to unused space / boundaries between dies improves the conventional scanning annealing type method using process uniformity results versus adjacent overlapping regions that traverse all of the regions of the substrate. Thus, by the amount of change in exposure to energy delivered from the energy source 102 to treat critical areas of the substrate, the amount of process change is minimized, which is transferred between the anneal regions 104 that are sequentially arranged. This is because any overlap of energy is minimized.

Referring to FIG. 1A, in one example, each sequentially placed annealing zone 104 is a rectangular zone that is about 22 mm by about 33 mm in size (eg, 726 square millimeters (area of mm ² )). . In one aspect, the area of each of the sequentially disposed annealing regions 104 formed on the surface of the substrate is from about 4 mm ² (eg, 2 mm × 2 mm) to about 1000 mm ² (eg, 25 mm x 40 mm). Circular preheating zone 112 may enclose annealing zone 104 and may extend up to about 100 mm beyond the edge of the annealing zone 104. In one embodiment such as shown in FIG. 1A, the preheating region 112 preferably extends at least about 50 mm beyond the edge of the annealing region 9104. The size of the preheating zone or mid-temperature zone over the annealing zone generally depends on the size of the substrate and available energy transfer means. In most embodiments, it is desirable to size the various intermediate temperature zones so that power requirements are minimized while providing the heat dissipation cost management required for the embodiment. In certain embodiments, the mid-temperature zone extends beyond the annealing region by less than 50 mm, less than 100 mm in one or more directions, such as, for example, about 30 mm.

Referring now to FIG. 2, in another example, each annealing portion 208 may have a size similar to the size of the annealing region 104 of FIG. 1A. The preheating zone 20 is shown adjacent to the annealing portion 208 on either side and spans the same space as one size of the annealing portion 208. The preheating zone 210 may extend from about 50 mm to about 100 mm beyond the edge of the annealing portion 208 in some embodiments.

The size of the preheat zone or zone may generally be selected to allow for proper preheating in the preheat zone. In certain embodiments, each preheat zone may be larger than the annealing zone to allow proper preheating. In one embodiment characterized by sequential exposure of successive anneal zones, the time required to preheat the preheat zone to the target temperature may be longer than the time required to anneal the anneal zone. Thus, individual locations on the substrate can be processed in two or three or more preheating processes.

In most embodiments, the energy source can generally be configured to deliver electromagnetic energy to anneal certain target areas of the substrate surface. Typical sources of electromagnetic energy include, but are not limited to, optical radiation sources (eg, lasers), electron beam sources, ion beam sources, microwave energy sources, visible light sources, and infrared sources. In one aspect, the substrate can be exposed with a pulse of energy from a laser that emits radiation at one or more suitable wavelengths for a desired time period. In another aspect, a flash lamp can be used to generate visible light energy for pulsing onto the substrate. In one aspect, the pulse of energy from the energy source is tailored such that the amount of energy delivered to the annealing zone and / or the amount of energy delivered over the period of the pulse is optimized to perform targeting annealing of the target region ( tailor). In one aspect, the wavelength of the laser is tuned such that a substantial portion of the radiation is absorbed by the silicon layer disposed on the substrate. For laser annealing processes performed on silicon containing substrates, the wavelength of the radiation is typically less than about 800 nm and can be delivered at deep ultraviolet (UV), infrared (IR) or other desired wavelengths. In one embodiment, the energy source may be a strong light source, such as a laser, configured to deliver radiation at a wavelength of about 500 nm to about 11 micrometers. In most embodiments, the process generally takes place on a given area of the substrate for a relatively short time, such as on the order of about 1 second or less.

In certain embodiments, the energy source includes a plurality of emitters and at least one of the plurality of emitters emits annealing energy as described above, and at least one of the plurality of emitters emits preheating energy. The preheat energy may be continuous wafer energy or may be delivered in pulses. The preheat energy may be coherent or non-coherent, monochromatic or polychromatic, polar or nonpolar, or any combination thereof or pulsed at an angle. The preheat energy can be delivered as strong white light, as infrared light, as laser light. Strong white light can be transmitted using a xenon lamp. Infrared rays may be transmitted using heat lamps. In certain embodiments, the preheat energy may be delivered as continuous wave radiation and the annealing energy may be delivered in pulses. The preheat energy is generally selected in the amount required for annealing or melting to raise the temperature of the substrate. In one embodiment, the laser can be placed above the working surface and four heat lamps surround the laser to preheat the area around the annealing zone. In another embodiment, four xenon lamps may be used to deliver strong white light instead of heat lamps.

5 is a schematic cross-sectional view illustrating a processing chamber 500 useful for practicing embodiments of the present invention. The processing chamber 500 includes an optically transparent window 506 formed on the chamber body 504. Chamber body 504 forms a processing volume 502. In one embodiment, the processing volume 502 may have an inert environment maintained by the vacuum pump 510 and the inert gas source 512 connected to the processing volume 502.

The substrate support 508 is disposed in the processing volume 502. The substrate support 508 is configured to support and move the substrate 514 disposed on the top surface 516. The energy source 518 is located outside the chamber body 504 and configured to project energy through the optically transparent window 506. The energy source may be configured to project the annealing energy 520 and the preheat energy 522 in one of the ways described herein. The substrate support 508 may be connected to a temperature control unit 524 having cooling and heating capabilities for the substrate 514 disposed over the substrate support 508. The substrate support 508 may be connected to one or more high precision stages 526 that allow for precise alignment and relative movement between the substrate 514 and the energy source 518 during processing.

In one embodiment, optical sensor 528 may be used to assist in alignment of energy source 518 and substrate 514. The optical sensor 528 may be located near the optically transparent window 506 and further connected to a control unit 530 which leads to a high precision stage 526. During alignment, the optical sensor 528 may “look” through the optically transparent window 506 to position visible markings on the substrate 514, such as notches and scribe lines around the die. The control unit 530 processes the signal from the optical sensor 528 and generates a control signal to the high precision stage 526 for alignment adjustment.

As discussed above, due to power requirements, the substrate generally anneals a portion at a time. After each individual annealing, the electromagnetic energy can move relative to the substrate to irradiate the next annealing portion. 6 is a schematic top view of a substrate 600 including 40 rectangular dies 602 arranged in an array. Each die 602 is also limited by scribe lines 604 forming unused regions 606 between the dies. The first energy projection zone 608 is provided for projecting a first amount of energy towards the single die 602. In general, the first energy projection region 608 may cover an area equal to or greater than the area of each die 602, but encompasses an area plus a scribe line 604 of each die 602. An area less than the unused area 606 may be covered, such that energy delivered to the energy projection zone 608 completely covers the die 602 while not overlapping with the neighboring die 602. A second energy projection zone 610 is provided surrounding the first energy projection zone 608 to deliver a second amount of energy to the substrate 600. The first energy amount may generally be different from the second energy amount. In certain embodiments, the first energy amount will have a higher intensity and more power than the second energy amount. In certain embodiments, the first energy amount may be selected to anneal a portion of the substrate surface inside the first energy projection zone 608. In another embodiment, the first energy amount may be selected to preferentially melt portions of the substrate surface inside the first energy projection zone 608. The second energy amount may be selected to preheat the portions of the substrate surface in the second energy projection area 610. The preheat temperature rise of the second energy projection zone 610 may be part of what has been reached within the first energy projection zone 608, such as about 30% to about 70%, or preferably about 50%. The second energy projection region 610 thus maintains the temperature of the substrate surface below reaching within the first energy projection region 608, such that a temperature gradient at the interface between the first energy projection region and the second energy projection region To generate thermal stress in the substrate that is less than the thermal stress required to damage the substrate.

The output of the substrate and / or energy source is positioned and aligned for each die 602 to perform an annealing process on multiple dies 602 that spread across the substrate surface. In one embodiment, curve 612 is defined between the energy projection zones 608 and 610 of the die 602 of the substrate 600 during the annealing sequence performed on each die 602 on the surface of the substrate 600. Shows the relative motion. In one embodiment, relative movement can be achieved by moving the substrate in the x and y directions such that the substrate follows curve 612. In yet another embodiment, relative movement can be achieved by moving the energy projection regions 608 and 610 relative to the stationary substrate 600. The energy projection zones 608 and 610 can be moved by moving an energy source relative to the substrate 60 or by manipulating the energy itself. In one embodiment using electromagnetic energy, the energy can be manipulated using optics without moving the substrate or energy source. For example, one or more mirrors or lenses may direct projected energy towards successive die 602, thus moving energy projection zones 608 and 610.

In addition, a path different from that indicated by curve 612 can be used to optimize throughput and process quality depending on the particular placement of die 602. For example, the optional annealing path may follow a substantially helical pattern, which may proceed in a circular pattern starting with the die 602 near the center of the substrate 60 and extending into a circular pattern, or die 602 at one edge of the substrate. And then proceed into a circular pattern that contracts. In one embodiment, it may be useful to follow an annealing path along a diagonal, which proceeds along a path exiting through the diagonal of die 602. Such a path can minimize the opportunity for overlap of annealing regions on successive dies 602.

As the energy source proceeds along the annealing path, the energy projection zone moves along the surface of the substrate. The second energy projection zone 610 of FIG. 6 takes precedence over the first energy projection zone 608 in all directions. The second energy projection zone 610 may thus utilize a preheated portion of the substrate to anneal in the first energy projection zone 608. Preheating reduces the impact of thermal stress on the substrate, preventing damage to the substrate at the edge of the annealing zone.

In an optional embodiment, the second energy projection zone may be adjacent to the first energy projection zone. For example, the second energy projection zones may be on both sides of the first energy projection zone extending outward in the direction of the annealing path. Thus, a portion of the second energy projection zone, the portion that moves forward of the first energy projection zone as the projected energy moves along the annealing path, may preheat the portions of the substrate to be annealed, while the other portion is annealing zone. Adjust the cooling of the back substrate. Apparatus adapted to perform this kind of annealing process may advantageously have the capability to rotate the energy source when the end of the substrate is reached, such that the energy source moves in different directions and the second energy projection zone is the first energy. Continue ahead of the projection area.

In one embodiment, during the annealing process, the substrate 600 moves relative to the energy projection zones 608 and 610, as shown by curve 612 of FIG. 6. When a particular die 602 is located and aligned within the first energy projection zone 608, the energy source projects a pulse of energy towards the substrate 600 such that the die 602 has a finite duration defined according to a particular annealing process scheme. Exposure to a predetermined amount of energy over time. The duration of the pulse energy is typically short enough so that the relative motion between the substrate 600 and the first energy projection region 608 does not cause any "blur", ie non-uniform energy, across each die 602. Do not cause any distribution or damage to the substrate. Thus, the energy projection zones 608 and 610 can move continuously relative to the substrate 600, while the short focused projection of the annealing energy impacts the various dies 602 in the second energy projection region. Energy impinging the second energy projection region 610 may also be pulsed or continuous. When pulsed, the energy projected toward the second energy projection region generally projects the temperature of the substrate surface in the second energy projection region to the first energy projection region relative to the exposure time of the first energy projection region so as to manage the heat consumption cost of the substrate. It will be a selected feature to raise it to a significant fraction, such as about 30% to about 70%, or more preferably about 50% of the temperature rise delivered to the zone.

For example, if the first energy projection zone experiences a first pulse of incident energy that raises the temperature of the substrate from 20 ° C. to 1,300 ° C., such as a 10 nanosecond laser burst, transfers to the second energy projection area. The second pulse of incidence energy that is to raise the temperature of the substrate in the region to at least about 600 ° C. during the first burst. If desired, the second pulse may be longer than the first pulse to heat the second energy projection zone time. In certain embodiments, it may be useful to surround the first energy projection zone, starting before the first pulse and ending after the second pulse, such that the second energy projection zone is delivered over an interval surrounding the first pulse. Two pulses are allowed to preheat the area to be treated with the first pulse along adjacent areas of the substrate.

In another embodiment, the energy delivered to the second energy projection region may be continuous while the energy delivered to the first energy projection region may be pulsed. In certain embodiments, multiple pulses of energy may be delivered to the first energy projection zone, while continuous energy is delivered to the second energy projection zone.

7 is a schematic cross-sectional view of an apparatus 700 according to another embodiment of the present invention. The apparatus 700 includes a chamber 702 for processing a substrate 704. The substrate is located on a substrate support 706 inside the chamber 702. In the embodiment of FIG. 7, the substrate support 706 appears as a ring because the embodiment of FIG. 7 irradiates the substrate 704 from the front side and the back side. In alternative embodiments, the substrate 704 may be irradiated from only one side and may be disposed on a substrate support, such as the example substrate support 508 of FIG. 5. By the actuator 758, the lift pins 756 raise and lower the substrate support 706 for insertion and removal of the substrate from the chamber 702. Chamber 702 has a bottom 708 and a top 710, which together form a processing volume 712. The top generally has a top wall 726 that forms a top processing volume 712A above the substrate 704. Top 710 may have an opening 714 for mounting and removing a substrate, and a gas inlet 716 for providing a process gas from process gas source 718. Top 710 supports first window 720 made of a material selected for light transmission and absorption properties. The first energy source 722 is located outside of the chamber 702 to direct the first energy 724 towards the first window 720. The first window preferably introduces some or all of the first energy 724 into the chamber 702.

Lower portion 708 of chamber 702 includes lower chamber wall 728 that defines lower processing volume 712B. Bottom 708 may have a gas outlet 730 coupled to pump 732 to remove process gas from chamber 702. The bottom 708 of the chamber 702 houses a second energy source 734. The second energy source 734 includes a plurality of light sources 736 for generating the second energy 738 and directing the second energy 738 towards the substrate 704. The second window 740 covers the plurality of light sources 736. Each light source is received in tube 746 that can be reflected to direct energy from light source 736 toward substrate 704. Light source 736 is generally powered by power source 742. In the embodiment of FIG. 7, power from power source 742 is routed through switching box 744, which can route from power source 742 to one or more of the light sources 736. By controlling the operation of the switching box 744, the light source 736 can be selectively energized.

In many embodiments, the light source 736 will be an infrared light generator, such as a heat lamp, but the light source can also be configured to generate wide-spectrum light, ultraviolet light, or a combination of wavelengths across the broad spectrum from ultraviolet to infrared. . In certain embodiments, the light source 736 may be a white light lamp, such as a halogen lamp or flash lamp. The second energy 738 generated by the light source 736 heats a portion of the substrate 704 to an elevated temperature that is not sufficient to anneal the substrate. Thus, the light source 736 functions as a preheat energy source. Thus, the portion of the substrate 704 that is processed by the second energy 738 is the preheat zone 746.

In many embodiments, first energy source 722 may be a laser capable of generating light at a wavelength readily absorbed by substrate 704. In another embodiment, the first energy source 722 may be a flash lamp or white light source. The first energy 724 generated by the first energy source 722 heats a portion of the substrate 704 to an elevated temperature sufficient to anneal the portion of the substrate 704. Thus, the first energy source 722 functions as an anneal energy source. The portion of the substrate 704 processed by the first energy 724 is thus the annealing zone 748.

As mentioned above, the substrate 704 is preferably processed into portions. Actuator 750 is provided to position first energy source 722 over annealing region 748. The controller 752 operates the actuator 750 to position the actuator 750 on the annealing zone 748 and the first energy source 722 and directs the switching box 744 toward the preheating zone 746. It is operated to switch power to one or more light sources 736 to direct. In this way, a portion of the substrate is preheated before annealing. The controller 752 preheats 746 and annealing zone 748 so that any portion of the substrate 704 that is annealed is first preheated but most of the substrate 704 remains at an ambient temperature forming the ambient zone 754. It is operated to move together.

8A and 8B are graphs showing temperature-time profiles for two embodiments of the present invention. Each graph shows the temperature of one point on the surface of the substrate undergoing heat treatment according to an embodiment of the present invention. As described above, the substrate moves relative to an energy source that directs energy towards the substrate surface. In FIG. 8A, when an exemplary point on the substrate surface moves from an ambient zone to a first preheat zone, the temperature of that point is changed from ambient temperature within ambient temperature interval 800 to first preheat temperature within first preheat interval 802. Move. When the exemplary point moves from the first preheat zone to the second preheat zone, the temperature of the point moves from the first preheat temperature in the first preheat interval 802 to the second preheat temperature in the second preheat interval 804. . The embodiment of FIG. 8A shows four zones formed on a substrate surface, a peripheral zone, two preheating zones, and an annealing zone. When an exemplary point on the substrate surface moves from the second preheat zone to the annealing zone, the temperature of the point moves from the second preheat temperature in the second preheat interval 804 to the annealing temperature in the annealing interval 806. When the exemplary point moves back from the annealing zone into the lower temperature zone, the first preheat interval 802 in the second cooling interval 810, in the state of the second preheat interval 804 in the first cooling interval 808. And finally to the ambient state within the second peripheral gap 812. It should be noted that alternative embodiments may be characterized by temperature during cooling intervals 808 and 910 that are different from the temperature in preheat intervals 802 and 804. Thus, the temperature in the cooling interval 808 may be higher or lower than the temperature in the preheat interval 802, and the temperature in the cooling interval 810 may be higher or lower than the temperature in the preheat interval 804. It should be understood that similar embodiments may feature only one preheat interval or two or more preheat intervals. In addition, certain embodiments may feature only one cooling interval or two or more cooling intervals.

The graph of FIG. 8B shows the temperature-time profile of one point on the substrate surface undergoing heat treatment according to another embodiment of the present invention. In the embodiment of FIG. 8B, an exemplary point on the substrate surface moves from ambient spacing 850 to first preheat spacing 852 similar to the embodiment of FIG. 8A. The exemplary point then moves into a second preheat interval 854 which is characterized by a changing temperature-time profile. In this embodiment, as the exemplary point moves through the second preheat interval 854, the temperature at that point rises from the first preheat temperature to the second preheat temperature. The rise may be linear as shown in the interval 854, or may have some other profile, even a short interval of decreasing temperature within the generally elevated temperature-time profile of the second preheat interval 854. Include. The exemplary point moves into the annealing interval 856 and then into the first cooling interval 858, which also has a variable temperature-time profile, much like the variable temperature-time profile of the second preheat interval 854. . The example point then moves into a second cooling interval 860, followed by a first peripheral interval 862.

9 is a flowchart showing a method 900 according to an embodiment of the present invention. At 910, the substrate is provided to a thermal processing chamber. At 920, a plurality of zones are formed on the surface of the substrate. Each zone is treated using electromagnetic energy with different levels of power. In most embodiments, there are at least three zones, but embodiments of the invention are contemplated to feature two zones or more than three zones. In most embodiments, the one or more zones are anneal zones that are treated with electromagnetic energy selected to anneal the surface of the substrate. In certain embodiments, it may be desirable to melt the substrate surface in one or more annealing zones. In most embodiments, one or more zones are preheating zones. In certain embodiments, one or more zones may combine preheating and cooling zones, while in other embodiments one or more zones may be merely preheating or cooling zones.

In one aspect, the substrate is disposed on the substrate support and the first amount of electromagnetic energy is directed towards the first portion of the substrate. In addition, a second amount of electromagnetic energy is directed towards the second portion of the substrate, the first portion of the substrate surrounding the second portion of the substrate, the first amount of electromagnetic energy preheating the first portion of the substrate, The second amount of electromagnetic energy anneals the second portion of the substrate. The first and second amounts are moved across the substrate to maintain a constant spatial relationship between the two quantum of energy, causing the region of the substrate in the first and second portions to move as the energy moves.

In another aspect, the electromagnetic energy delivered into the two quantums may be some desired characteristic. Each amount of energy may be coherent or non-coherent, monochromatic or polychromatic, polar or nonpolar, and continuous or pulsed at an angle. Each amount of energy may be delivered by one or more energies, a strong white light lamp, a flash lamp, or a combination thereof. The two quantum of energy may only be delivered by electromagnetic energy of different intensities, or the two quantums may differ by a certain target angle in certain above-described properties. In one example, the first amount may be delivered by one or more lasers, each delivering at least 100 W / cm ² of power at a wavelength less than about 850 nm. The laser can be a pulsed or continuous wave energy source. In a pulsed embodiment, pulsing can be realized by periodic power to the laser or by optical switching intermittently blocking laser light coming from the optical assembly. In another example, the second amount may be delivered by one or more lamps that deliver incoherent light to the second portion at a power level less than 50 W / cm ² , such as about 25 W / cm ² .

10 is a flow diagram summarizing a method 1000 according to another embodiment of the present invention. At 1010, the substrate is located on a substrate support in the thermal processing chamber. At 1020, the first source of electromagnetic energy is directed towards the first portion of the substrate. At 1030, the second source of electromagnetic energy is directed towards the second portion of the substrate at the same time. As described herein, one of the sources may be configured to deliver an anneal source and the other may be configured to deliver preheat energy. At 1040, the substrate is moved relative to the first and second energy sources. Substrate movement causes the transferred energy to move across the substrate surface to anneal the entire surface in portions. In the embodiment of FIG. 10, the energy source is substantially stationary while the substrate moves, but certain embodiments may feature an energy source, or movement of energy, in addition to movement of the substrate. Movement of the substrate is generally performed by using a movable substrate support, such as a precision stage that can position the substrate at a precise location within the device.

In most embodiments, the zones are maintained at different temperatures. In certain embodiments, the zones are heated by directing electromagnetic energy of various types and intensities towards the substrate surface. In the embodiment of FIG. 9, each zone is irradiated at 930 using electromagnetic energy of different power levels. In other embodiments, additional heat may be transferred to the substrate by the use of a heated substrate support in contact with the back side of the substrate. In other embodiments, portions of the substrate may be selectively cooled by a cooled substrate support in contact with the back side of the substrate. The temperature in one or more of the zones is selected to anneal the surface of the substrate. The temperature in one or more of the zones is selected to preheat the surface of the substrate and is lower than the temperature required to anneal the substrate surface. One zone, which may be an anneal zone, accommodates the maximum power level. The other zones accept smaller power levels. One or more zones, which may be warm-up zones, may accommodate elevated power levels below the maximum power level. Other zones can accommodate negligible power or can be cooled. Certain zones may be ambient zones, where the temperature of the substrate is maintained at ambient temperature.

In certain embodiments, different zones may be irradiated using different sources of electromagnetic energy. One or more lasers may provide electromagnetic energy. The first laser may generate energy to anneal a portion of the substrate in one zone, and the second laser may generate energy to preheat a portion of the substrate in another zone. In an alternative embodiment, the plurality of lasers may preheat portions of the substrate. In another embodiment, for example, in the embodiment of FIG. 7, one or more heat lamps may preheat portions of the substrate.

In embodiments where multiple zones include an anneal zone, zones that provide preheating or cooling functions may be formed to facilitate preheating or cooling. In an exemplary embodiment having an annealing zone having a preheating zone on one side and a cooling zone on the opposing side, the preheating zone and the cooling zone can have a tapered shape, the first edge being at the edge of the annealing zone. Abutting and covering the same space as the edge of the annealing zone, the second edge faces the first edge and is shorter than the first edge to form a trapezoidal shape. In an alternative embodiment, the preheating and cooling zones may be triangular in shape, each edge covering the same space as the edge of the anneal zone, respectively. In another alternative embodiment, the tapered ends of the preheating and cooling zones are curved and in some embodiments may be parabolic or semicircular.

A plurality of zones with different temperatures and geometries can be rapidly exposed by exposing portions of the substrate surface to electromagnetic energy designed to cause the motion of atoms within the substrate lattice, while maintaining thermal stress below the threshold level at which the substrate will be damaged when passed. Allow annealing. The heating and cooling zones allow the annealing treatment to start from an elevated temperature, accelerating the highest temperature ramp-up and cooling during the annealing. The tapered shape of the preheating and cooling zones may allow to minimize thermal exposure of portions of the substrate that are not annealed, such that unwanted movement of atoms that may be relocated by the annealing process, or atoms that may be in a desired position prior to the annealing process Minimize. In general, the number and shape of the heating and cooling zones may be selected to facilitate the target annealing process.

The above-described embodiment generally features regions having a substantially constant temperature. The first zone is maintained at the first temperature and the second zone is maintained at the second temperature or the like. In other embodiments, one or more of the zones may have a temperature gradient to facilitate heating or cooling near the annealing zone. In embodiments of three zones, for example, the first zone, which may be a preheating zone, may have an increasing temperature gradient towards the second zone, which may be an annealing zone. In addition, the third zone, which may be a cooling zone, may have an increasing temperature gradient towards the second zone. The temperature gradient provides the same general function as the tapered zone shape described above. The temperature gradient can be set within a given zone by using optics to adjust the delivered energy to achieve the target temperature profile.

In one exemplary embodiment, a single energy source of sufficient power to anneal the substrate may be oriented to direct electromagnetic energy towards the substrate. Lenses having defocusing characteristics may be disposed between the energy source and the substrate. The lens may have a first portion defocusing a corresponding portion of electromagnetic energy and a second portion that does not focus or change a second portion of additional electromagnetic energy. For example, if a laser is used as a source of electromagnetic energy and shaping optics are used to form a circular annealing energy beam with a diameter of 2 mm, the lens may be outside a concentric annular ring with a radius of 1.5 mm. It can be disposed between the substrate and the shaping optics having a circular central portion with a radius of 0.5 mm surrounded by. The circular central portion can have neutral optics and, if desired, can focus a portion of the annealing energy beam incident on the portion. The concentric annular exterior of the lens may be safe to reduce the intensity of the exterior of the annealing energy beam. The reduced intensity energy then impinges on the surface of the substrate with sufficient power to preheat the preheated portion of the surface without annealing the surface of the substrate, while the unchanged or unfocused portion anneals the annealed portion in the preheated portion.

11 is a flow diagram summarizing a method 1100 according to another embodiment of the present invention. The substrate is located on the substrate support in the thermal processing chamber at 1102. A plurality of zones are formed on the substrate support at 1104. The first portion of the zones is maintained at ambient temperature at 1106. The ambient temperature may be room temperature in certain embodiments or may be elevated in other embodiments. In most embodiments, the ambient temperature is less than about 200 ° C., but certain embodiments may feature an ambient temperature as high as 350 ° C. The ambient temperature can be maintained by the use of a heated substrate support or by irradiating the substrate with electromagnetic energy suitable for the target heating.

At 1108, the preheat energy is provided to the second portion of the zone defined to heat the second portion of the zone formed at one or more intermediate temperatures higher than the ambient temperature. Each zone may be heated to the same intermediate temperature, or to a different intermediate temperature. Zones close to the region to be annealed may generally be maintained at a temperature equal to or higher than the temperature of the zone from the region to be further annealed. In embodiments in which the second portion comprises one or more zones, the intermediate temperature may be raised in a stepwise manner from ambient temperature to annealing temperature. The temperature difference between the intermediate temperature and the ambient temperature is generally about 10% to about 90% of the temperature difference between the annealing temperature and the ambient temperature, such as about 30% to about 70%, for example about 50%. In an exemplary embodiment in which the second portion comprises two zones, the temperature difference between the intermediate temperature zone and the ambient zone may be about 40% of the temperature difference between the annealing temperature and the ambient temperature, while the second intermediate temperature The difference between the zone and the ambient zone is about 60% of the difference between the annealing temperature and the ambient temperature.

At 1110, the annealing energy is provided to the third portion of the zone defined to heat to one or more annealing temperatures above ambient and intermediate temperatures to heat the third portion of the defined zone and is selected to anneal the substrate surface. The annealing zone, including the third portion of the defined zone, can have any spatial relationship described herein. In addition, different annealing temperatures may be applied to different temperature zones if desired.

At 1112, one or more of the aforementioned temperatures may be sensed and used to control the transfer of preheat energy, annealing energy, or both to maintain a thermal gradient between zones below a threshold level. In certain embodiments, one or more thermal imaging devices may be used to sense the temperature of the various zones. The temperature of one zone can be compared with the temperature of another zone to determine if the thermal gradient between zones is excessive. The energy delivered to one or more zones of the sensed zones may be adjusted based on the sensed temperature to increase or decrease the thermal gradient between the two zones. When the substrate is annealed by moving the energy source, the detector may be positioned with the energy sources such that the annealing and preheat zones follow the substrate. If the substrate is annealed simply by moving energy (eg using a mirror), similar optics may be used to focus the detector on the portion of the substrate being processed under the direction of the controller, or the entire substrate may be sampled. And a computer can be used to determine the thermal gradient of interest.

Yes

In one exemplary embodiment, the substrate may be located on a support of the heat treatment apparatus. The substrate may be held in place on the support by any means known in the art, including electrostatic or vacuum means. The laser is positioned and oriented over the substrate, producing a beam of light impinging the substrate in a direction substantially perpendicular to the plane of the substrate. The laser can be coupled to an optical assembly adapted to position the laser in three dimensions. The laser can be applied to deliver laser energy up to 10 kW / cm ² for the annealing zone of the substrate measuring 22 mm x 33 mm. The laser is preferably tuned to a wavelength readily absorbed by the substrate, such as smaller than 800 nm for the silicon substrate.

In operation, the laser can be switched using an electrical switch coupled to a power source or an optical switch coupled to a laser or optical assembly. The switch can be configured to switch the laser on or off at microseconds less than one, such that a pulse of energy from which the laser lasts from about 1 ms to about 10 milliseconds (msec). To be delivered.

For this example, the preheated light source is co-located with the laser in the optical assembly. The preheating light source can be another laser, xenon lamp, or heating lamp and can be applied to deliver up to 500 W of electromagnetic energy to a substantially circular area that is concentric and about 2 cm in diameter surrounding the annealing area. The preheat light source can be focused using a suitable lens and mirror to capture and direct all of the energy of the preheat light source. The preheat light source can be located in a housing located proximate to the laser source to illuminate the area of the substrate surrounding the area where light from the preheat source is annealed. The preheating source may be angled slightly to center the preheating area around the annealing area. Optionally, the preheat light source can project energy onto the substrate substantially perpendicular to the plane of the substrate, and optics are used to scatter light over the preheating area surrounding the annealing zone. The preheat light source can then be advantageously positioned relative to the laser, allowing the preheating area to extend further from the annealing area in the direction of the annealing path. The optical assembly can additionally be adapted to rotate to allow the preheated light source to maintain a useful position relative to the laser when the annealing path changes direction.

The processing apparatus is preferably configured to move the substrate relative to the optical assembly by the use of a movable stage of the type known in the art. In operation, the stage positions the substrate under the optical assembly such that the target area of the substrate is exposed to the optical assembly. The preheating light source can shine continuously and irradiate the substrate with preheating energy when no annealing energy is present. The continuous preheat energy heats the surface of the substrate in the region surrounding the anneal target region to at least 600 ° C. The laser fires one or more pulses in the target annealing area. The pulse is short enough (brevity) to allow the stage to move continuously along the annealing path without blurring the laser pulse. The preheat zone moves along the surface of the substrate as the stage moves and heats portions of the substrate to the target preheat temperature when the portions of the substrate reach the target annealing region. Thus, portions of the substrate immediately adjacent to the target annealing region are not damaged by thermal stress by high thermal gradients at the edges of the target annealing region.

In an optional and exemplary embodiment, the laser may be surrounded by two to four preheat energy sources spaced around the laser in the optical assembly. The use of multiple preheat sources allows for uniform preheating over the entire preheating area of the substrate. Alternatively, the laser can be performed by two different preheat energy sources adapted to irradiate different areas of the substrate. One preheat energy source can be applied to irradiate a circular region of, for example, about 3 cm in diameter and another preheat energy source illuminate a concentric circular region of about 1.5 cm in diameter, which is also concentric with the annealing region. Thus, two preheating regions are formed. The two preheating sources can deliver similar amounts of energy, allowing the source looking into a wider area to produce a smaller temperature rise than more focusing sources. In one embodiment, the preheating source illuminating the large area may heat the area to a temperature of 300 ° C. or higher, while the preheating source illuminating a smaller area within the wider preheating area may cause the smaller area to be reduced by incremental energy. Heating to 700 ° C. or higher. The anneal pulse can then anneal the substrate by delivering sufficient energy to raise the temperature of the anneal region to 1,200 ° C. or higher without melting the substrate material.

In another exemplary embodiment, a single energy source can be used. For example, a laser can be applied to produce a single column of light that can be used for both preheat energy and annealing energy. Optical devices including mirrors, lenses, filters, and beam-splitters are generally used to tune the laser light to have the desired polarity or coherence. Such optical devices also include a lens that defocuss a portion of the radiant light. The defocusing portion of the laser light can then be directed to an area surrounding the annealing area. For example, a laser with suitable optical devices assembled can produce interference light in a cylindrical beam of about 1 mm diameter. The beam may be directed through a lens having a circular non-refractive central portion of about 0.8 mm diameter and an annular defocusing outer portion having an inner radius of 0.8 mm and an outer radius greater than 1 mm. The portion of the laser beam that passes through the non-reflective portion of the lens that anneals the exposed portion of the substrate continues to reach the substrate such that the portion of the laser beam that passes through the defocusing portion of the lens heats the region to a low temperature. Spreading and intensity over a large area is reduced.

While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be invented without departing from the basic scope of the invention.

Claims (15)

Positioning the substrate on the movable substrate support;
Directing a first amount of heating energy towards a first fixed location under a portion of the substrate;
Directing a second amount of heating energy towards a second fixed location under a portion of the substrate;
Moving the substrate support to treat the selected zone of the substrate by sequentially placing each selected zone over the first anchor position and then over the second anchor position; And
Maintaining a portion of the substrate at a temperature below 500 ° C.,
Substrate processing method.
The method of claim 1,
The second positive heating energy has sufficient power to anneal a portion of the substrate,
Substrate processing method.
The method of claim 2,
Wherein the first positive heating energy has a power that is less than the power required to anneal a portion of the substrate.
Substrate processing method.
Preheating the preheated portion of the substrate surface by applying energy to the preheated portion; And
While preheating the preheated portion of the substrate, annealing the annealed portion of the substrate in the preheated portion by applying incremental energy to the annealed portion,
Method of annealing a substrate surface.
A movable substrate support;
A first energy source oriented to direct annealing energy towards a first portion of the surface of the substrate support;
A second energy source oriented to direct preheat energy towards a second portion of the surface of the substrate support; And
An optical assembly for receiving the first energy source and the second energy source,
A device for heat treating a substrate.
The method of claim 5, wherein
The first energy source is a laser and the second energy source is a laser,
A device for heat treating a substrate.
The method of claim 5, wherein
The first energy source is a laser and the second energy source is a plurality of lamps,
A device for heat treating a substrate.
The method of claim 5, wherein
The optical assembly further comprises a first optical tuner for Safely Annealing Energy and a second optical tuner for Safely Preheating Energy
Device to heat-treat the substrate.
The method of claim 5, wherein
Further comprising a controller coupled to the substrate support,
A device for heat treating a substrate.
A fixed substrate support;
One or more energy sources oriented to direct annealing energy towards the first portion of the surface of the substrate support and preheating energy towards the second portion of the surface of the substrate support;
An optical assembly containing the one or more energy sources; And
An actuator for moving said annealing energy and said preheating energy relative to said fixed substrate support,
Apparatus for heat treating a substrate.
The method of claim 10,
One or more energy sources are lazy,
Apparatus for heat treating a substrate.
The method of claim 10,
The optical assembly further comprises one or more optical tuners to safeguard the annealing energy and the preheating energy,
Apparatus for heat treating a substrate.
The method of claim 10,
Further comprising a controller coupled to the actuator,
Apparatus for heat treating a substrate.
The method of claim 10,
Further comprising a detector for sensing the temperature of one or more portions of the substrate,
Apparatus for heat treating a substrate.
The method of claim 10,
The actuator rotates the optical assembly to orient the annealing energy and the preheating energy,
Apparatus for heat treating a substrate.

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