Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28D—WORKING STONE OR STONE-LIKE MATERIALS
  • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
  • B28D5/0058—Accessories specially adapted for use with machines for fine working of gems, jewels, crystals, e.g. of semiconductor material
  • B28D5/0082—Accessories specially adapted for use with machines for fine working of gems, jewels, crystals, e.g. of semiconductor material for supporting, holding, feeding, conveying or discharging work
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
  • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
  • B23K26/062—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam
  • B23K26/0622—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
  • B23K26/0624—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses using ultrashort pulses, i.e. pulses of 1ns or less
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/36—Removing material
  • B23K26/40—Removing material taking account of the properties of the material involved
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28D—WORKING STONE OR STONE-LIKE MATERIALS
  • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28D—WORKING STONE OR STONE-LIKE MATERIALS
  • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
  • B28D5/04—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor by tools other than rotary type, e.g. reciprocating tools
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2101/00—Articles made by soldering, welding or cutting
  • B23K2101/36—Electric or electronic devices
  • B23K2101/40—Semiconductor devices
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2103/00—Materials to be soldered, welded or cut
  • B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T83/00—Cutting
  • Y10T83/04—Processes
  • Y10T83/0448—With subsequent handling [i.e., of product]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T83/00—Cutting
  • Y10T83/202—With product handling means

Definitions

• the present invention relates to a method and an apparatus for the production of thin disks or films from semiconductor bodies such as polycrystalline blocks (ingots) or monocrystalline rods.
• wire saws are used to cut brittle-hard workpieces (such as silicon).
• brittle-hard workpieces such as silicon
• two methods are used (description DE 19959414). Separating lapping involves the use of a slurry, while the cutting grains are firmly bonded to the wire during cutting.
• the separation process is carried out by a relative movement of wire and workpiece. This relative movement is achieved in DE 19959474 in that the workpiece is rotated about its longitudinal axis.
• the wire is moved and e.g. guided by pulleys several times through the workpiece so that many discs can be separated simultaneously.
• grating multi-wire saws (DE 19959414) are particularly suitable since the wire is not stressed mechanically by the deflection.
• the splitting of single crystal silicon rods as described in US 2004055634 may be an interesting alternative for the production of silicon wafers.
• the lateral surface of a silicon rod is irradiated locally with ion, electron or laser beams in order to generate targeted lattice defects. This is preferably along a line which is given by the crystal axes, so that the later cleavage plane corresponds to a crystal lattice plane.
• the splitting process takes place, for example, by mechanical shearing forces along the generated grating defects. When splitting no sawing losses. Further advantages are pure cleavage surfaces, a fast splitting process, as well as very flat surfaces.
• US 2004055634 indicates a potential benefit of 10,000 wafers per meter of silicon rod length.
• DE 3403826 describes a method in which a notch in the circumferential surface of a circumferential notch is locally heated with a laser. With a thermal shock treatment, the disc is then blasted off the bar. By machining the notch, however, it is expected that the thickness of the silicon wafer is limited downwards.
• US 2005199592 also describes a separation method for separating silicon by means of laser radiation. However, this is the separation of silicon wafers in single chips. For example, an Nd: YAG laser is used
• the material processing works with focused laser beams where the working area is limited to the immediate surroundings of the focus.
• DE 19518263 describes a device for material processing in which the laser radiation is guided in a liquid jet onto the material surface.
• the focused laser steel is coupled by means of a special nozzle in the most laminar liquid jet possible.
• This method is also used when cutting silicon wafers. In this case, cutting widths of typically 50 microns are achieved, which are essentially determined by the liquid jet.
• this process produces melt zones which, after re-solidification, can impair the mechanical stability of the workpieces. The melting zones can be significantly reduced when working with shorter laser pulses.
• the small cutting widths can only be achieved when working within the limited depth of focus.
• the gap width increases accordingly due to the beam focusing.
• the present invention is based on the object, a method for producing thin semiconductor films, in particular silicon films by separating semiconductor bodies and to provide a device for carrying out this method.
• a brittle-hard material such as semiconductor material
• the method of the present invention advantageously advantageously utilizes the property that semiconductor wafers become more and more flexible the thinner they are.
• Such a method is particularly advantageous if the production of the semiconductor film by separating one Surface of a semiconductor block takes place, or if the production of the semiconductor film is carried out by tangential separation from the mantle surface of a semiconductor rod.
• the production of the semiconductor film is carried out by tangential separation from the mantle surface of a semiconductor rod.
• the method according to the invention can be used to particular advantage if clearance for the separating tool is created by the spreading of the already separated part of the semiconductor foil from the semiconductor body, wherein the clearance is defined by the surfaces on the semiconductor body, the tip of the cutting tool and the semiconductor facing surface of the spread semiconductor film is formed.
• a pulsed, highly focused laser beam can be used, and / or a probe with liquid or gaseous etching medium. It may also be advantageous if the separation takes place under vacuum or under a special gas atmosphere.
• a focused laser beam modifies the semiconductor material and the modified semiconductor material is removed with a liquid or gaseous etching medium.
• the method according to the invention can advantageously be carried out with a device which has means for spreading apart the free-cut part of the semiconductor film and means for supporting the freely cut part of the semiconductor film.
• the means for spreading apart the free-cut part of the semiconductor film may be formed as tensile and / or pressure means and act on the cut-free part of the semiconductor film. They can be designed, for example, as electrostatically operating devices and act on the cut-free part of the semiconductor film. But they can also be designed as devices which operate with negative or positive pressure. Especially with vacuum working devices that engage the cut portion of the semiconductor film, are advantageous.
• the means for supporting the free-cut portion of the semiconductor film are advantageously designed as a support roller and support the already separated part of the semiconductor film from such that a minimum bending radius of the spread semiconductor film is not exceeded.
• the support roller is formed so that the splayed semiconductor film is merely elastically deformed.
• An apparatus for carrying out the method can be realized advantageously, for example, if the cutting tool is realized by a pulsed laser whose pulse length is smaller than 10e-9s, wherein the pulsed laser It should have a high beam quality and be highly focused.
• a laser with linear intensity profile can be used.
• This medium can be glass fibers.
• a fiber laser can advantageously be used. Equally advantageous may be to use a frequency-multiplied laser.
• Figure 1 is a schematic diagram of the separation process
• Figure 2 is a schematic diagram of the tangential separation
• FIG. 3 shows a schematic diagram of the tangential separation according to FIG. 2 with free space
• Figure 4 is a schematic diagram of the multiple tangential
• FIG. 5 is a schematic diagram of the separation process according to
• FIG. 1 shows a highly schematic representation of a semiconductor body 1, which is arranged on a machine tool, not shown, by means of a holder (also not shown).
• a separating tool 2 is in engagement with the semiconductor body 1 and serves to separate a half Semiconductor body, such as a silicon block, consist of a material that is difficult to work because it has a certain brittle hardness.
• the common processing methods are already described in more detail in the introduction to the description.
• the cutting tool according to the invention may be embodied as a focused laser beam, a tapered glass fiber as the medium for the laser beam, a probe with etching medium, a mechanical tool or another suitable cutting tool.
• the following is based on a highly focused laser beam as a separation tool 2, which can produce a parting line 4 with only a very small gap width 5.
• a separation tool 2 which can produce a parting line 4 with only a very small gap width 5.
• the free space 6 is bounded by the separating surface 7 on the semiconductor body 1, the tip of the separating tool 2 and a surface 8 of the spread semiconductor film 3 facing the semiconductor 1, as will be described in more detail later on FIG.
• the spread is effected by means which exert tensile or compressive forces on the already separated region of the semiconductor film 3.
• these tensile or compressive forces are indicated by two arrows Pl and P2, the arrow Pl symbolizing the compressive forces and the arrow P2 the tensile forces.
• the means for spreading apart the semiconductor film 3 can be realized by mechanically attacking elements or by non-contact elements. It makes sense to make the spread electrostatically. But also by means of a vacuum spreading of the semiconductor film can be realized. Likewise, through a targeted air Shot the already separated area of the semiconductor film 3 are spread so that the required space 6 for the cutting tool 2 is available.
• the resulting joint width 5 of the parting line 4 is no longer determined by the width of the cutting tool 2, but only by the width of the tip 9 of the cutting tool 2, which can be significantly narrower than, for example, a saw wire, as in the state the technique is used to produce silicon wafers.
• the separation loss of semiconductor material is accordingly reduced considerably, because the loss-determining joint width 5 can be considerably reduced compared to the prior art.
• the area-related silicon consumption is significantly reduced, because the working area, ie the joint width 5 is limited to the area around the focus of the cutting tool 2.
• means for supporting the free-cut portion of the semiconductor film 3 are provided, which are formed as a support roller 10 and support the already separated part of the semiconductor film 3 such that a minimum bending radius of the spread semiconductor film 3 does not fall below becomes.
• the arrangement and the geometry of the support roller 10 is chosen so that the splayed semiconductor film 3 is only elastically deformed.
• the arrangement of the support roller 10 may be on a non-illustrated Werk- Grooved slide so made that it can follow the separation cut. This ensures that the already separated region of the semiconductor film 3 is always optimally supported.
• FIG. 2 shows how, in a manner analogous to that described with reference to FIG. 1, a film 3 is separated from the outer surface of a semiconductor rod 11.
• the same or equivalent elements are provided to avoid repetition with the same reference numerals, with a detailed description of these similar elements is unnecessary.
• the tip 9 of a highly focused laser beam acts as a separating tool 2 separating a semiconductor film 3 from the rotating semiconductor rod 11.
• the round shape of a semiconductor rod 11 also makes it possible to simultaneously cut a plurality of semiconductor foils 3, 31, 32 from a semiconductor rod 11, which is shown schematically in FIG.
• the three semiconductor films 3, 31, 32 shown schematically here are supported by three support rollers 10, 101, 102 in the manner already basically described. Again, the same or equivalent elements are provided with the same reference numerals, so that a repetition of already described can be omitted.
• FIG. 3 shows that a clearance 6 for the cutting tool 2 on the rotating semiconductor rod 11 is created by the separating surface 7 and the surface facing the semiconductor rod 11 on the semiconductor foil 3, without the tip of a tool being shown here.
• Figure 5 shows, looking back on Figure 1, a free space 6 for a not shown separating tool according to this figure 1. Again, the same or equivalent elements with the same reference numerals.
• a laser is used as a separating tool 2 whose beam is focused by suitable optical means such as a cylindrical lens or a diffractive optical element such that instead of a point-shaped intensity profile a line-shaped intensity profile for separating the semiconductor film 3 is formed. Furthermore, it makes sense to line up several line-shaped intensity profiles in such a way that a dividing line is formed over the entire width of the semiconductor body 1, 11, so that the entire cutting line can be quasi-continuously removed (with the repetition rate of the laser).
• the marginal rays of the focused laser beam which are facing the semiconductor body 1, 11 should ideally run parallel to the edge of the semiconductor body 1, 11.
• the marginal rays in the vicinity of the tip 9 of the cutting tool 2 follow the bending radius of the semiconductor foil 3, 31, 32 and with increasing distance from the focus (tip of the cutting tool 2) creates a gap that increases.
• the semiconductor material generally silicon
• the semiconductor material in the parting line may initially only be modified and then selectively removed (mainly modified material) with a gaseous etching medium or an etching liquid.
• Femtosecond fiber lasers are, for example, suitable as the laser source.
• frequency multiplication is advantageous with high efficiency because the energy density of the ablation threshold decreases for shorter wavelengths.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Plasma & Fusion (AREA)
• Laser Beam Processing (AREA)
• Processing Of Stones Or Stones Resemblance Materials (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Family Cites Families (7)

• 2007
  • 2007-04-17 DE DE200710018080 patent/DE102007018080B3/de not_active Expired - Fee Related
• 2008
  • 2008-04-15 JP JP2010503351A patent/JP2010525559A/ja active Pending
  • 2008-04-15 DE DE200811001002 patent/DE112008001002A5/de not_active Withdrawn
  • 2008-04-15 EP EP08748746A patent/EP2139657A1/de not_active Withdrawn
  • 2008-04-15 KR KR1020097022306A patent/KR20100015895A/ko not_active Application Discontinuation
  • 2008-04-15 WO PCT/DE2008/000628 patent/WO2008125098A1/de active Application Filing
  • 2008-10-15 US US12/596,149 patent/US20100117199A1/en not_active Abandoned

Non-Patent Citations (1)

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