Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
  • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
  • G06V40/12—Fingerprints or palmprints
  • G06V40/13—Sensors therefor
  • G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing

Definitions

• the invention specified in claim 1 is based on the problem of creating a simple and economical method for producing flexible metallic fine structures with structural finenesses of less than 100 ⁇ m.
• the method should also be suitable in particular for the production of the sensor field of sensor arrangements for recording fingerprints.
• the invention is based on the knowledge that the disadvantages associated with the processing of flexible carrier materials can be avoided if a thin base layer made of a flexible organic material is first applied to a rigid auxiliary carrier and after the production of the metallic fine structures without the risk of Detach damage from the auxiliary carrier.
• a gentle detachment of the base layer from the auxiliary carrier can be carried out by laser ablation from the back of the auxiliary carrier, provided that the auxiliary carrier consists of a material which is at least largely transparent to the laser radiation used.
• the solution according to the invention offers the following advantages: application of thin-film technology on a rigid auxiliary carrier also enables the formation of multilayered fine structures.
• auxiliary carrier Detaching the single-layer or multi-layer structure from the auxiliary carrier is possible quickly and inexpensively. - The assembly of ICs, passive components and sensors can still be done on the auxiliary carrier, for example by gluing or soldering.
• the auxiliary carrier can be used several times.
• the degree of flexibility can be adjusted by the material and thickness of the lowest base layer.
• the flexible circuit can be transferred to any, even three-dimensional, carrier.
• the flexible circuits can also be used at elevated ambient temperatures.
• the flexible fine structures are chemically very stable.
• the embodiment according to claim 2 enables the auxiliary carrier to be permeable to the laser radiation of approximately 90%.
• the embodiment according to claim 3 also enables the auxiliary support to be permeable to the laser radiation of approximately 90%, although here the relatively low costs for an auxiliary support made of borosilicate glass must also be emphasized.
• the development according to claim 4 enables an improved adhesion of the base layer during the processing of the by applying an adhesive layer on the auxiliary carrier Construction.
• an adhesive layer made of titanium, which is transparent to the laser radiation when the base layer is detached, is preferred.
• the adhesive layer with an extremely small layer thickness can be applied favorably by sputtering onto the auxiliary carrier.
• the embodiment according to claim 7 enables extremely simple and economical application of the base layer to the auxiliary carrier.
• a film made of a thermostable polyimide is preferred, especially since this enables the use of the finished product even at an elevated ambient temperature.
• the film can then have a very high surface quality by applying a plan coating, which enables the formation of the finest metallic structures.
• the development according to claim 10 enables the application of a second layer of metallic fine structures, that is to say, for example, the creation of a second wiring layer, the flexibility of the entire structure being retained after being detached from the auxiliary support.
• a second layer of metallic fine structures that is to say, for example, the creation of a second wiring layer
• Through-plating between the two wiring layers can be realized in a simple manner by introducing holes in the insulation layer.
• the embodiment according to claim 12 enables effective handling protection of the entire multilayer structure by the application of a passivation layer.
• the method according to the invention can be used, in particular, for the production of inexpensive sensor arrangements for recording fingerprints.
• FIG. 1 shows a partial top view of the sensor field of a sensor arrangement for recording fingerprints
• FIG. 2 shows a section along the line II-II of FIG. 1,
• FIG. 3 shows an arrangement for detaching the multilayer structure according to FIG. 2 from the auxiliary carrier
• FIG. 4 shows a possible application of flexible fine structures produced according to the invention for three-dimensional packaging.
• FIG. 1 shows a partial top view of the sensor field of a sensor arrangement for recording fingerprints, the multilayer structure of the sensor field being evident from the section shown in FIG. 2.
• the individual layers of the multilayer structure are shown in an exploded state in FIG. 2.
• the sensor field shown in greatly simplified form in FIGS. 1 and 2 is a multi-layer structure for producing a capacitive sensor arrangement for recording fingerprints.
• An at least partially comparable multilayer structure of a sensor field is evident, for example, from EP-B-0 459 808.
• auxiliary support 1 made of borosilicate glass is assumed.
• an adhesive layer 2 made of titanium is applied by sputtering.
• a base layer 3 is then applied to this adhesive layer 2.
• this base layer 3 is a film made of a thermostable polyimide, which has a thickness of 50 ⁇ m and is applied by lamination. Subsequently, the base layer 3 is spun on by an insulation material planarized, this process being shown in FIG. 2 by a separately represented planarization 4.
• the subsequent production of metallic fine structures 5 can in principle be carried out using subtractive technology, additive technology or semi-additive technology.
• the fine structures 5 are produced semi-additively as conductor track structures.
• a photoresist (not shown in the drawing) is applied to the planarization 4 sputtered over the entire area with a layer sequence of titanium and palladium and structured in such a way that, for example, galvanic gold or galvanic or chemical copper can be deposited. After stripping the photoresist, the regions of the regions which do not correspond to the desired fine structures 5
• a photostructurable insulation layer 6 is then applied to the fine structures 5, into which holes 61 which have a diameter of 25 ⁇ m, for example, are made by exposure and development.
• holes 61 which have a diameter of 25 ⁇ m, for example, are made by exposure and development.
• vias 71 are then produced, which form electrically conductive connections between the two structure levels and complete the structuring for the sensor field and the chip contact.
• the thickness of the fine structures 5 and 7 can be, for example, between 1 ⁇ m and 5 ⁇ m.
• the width of the individual structures and the distance between these structures can easily be realized with dimensions of significantly less than 50 ⁇ m.
• the sensor field is provided with a passivation layer 8, which consists, for example, of BaTiO3, Al2O3 or SiO3.
• the multi-pole control ICs of the sensor arrangement are contacted by means of gluing or soldering.
• SnPb bumps are generated galvanically in thin-film technology and, after remelting, serve as solder deposits for chip contacting in flip-chip technology.
• the multi-layer structure consisting of several interrelated individual arrangements is separated into individual sensor fields down to the adhesive layer 2, for example with an Nd: YAG laser.
• the layer structure is ablated from the auxiliary carrier with the help of an excimer laser, which is operated with XeF (wavelength 350 nm).
• the laser ablation mentioned above is carried out with the aid of an arrangement shown schematically in FIG.
• the laser radiation LS of the excimer laser is directed in the direction of arrow 9 onto a deflecting mirror 10 and deflected onto the surface of the auxiliary carrier 1 via telecentric imaging lenses 11 and 12.
• the auxiliary carrier 1 and the structure A consisting of the layers 3 to 8 are arranged on an XY table, not shown in FIG. 3, which performs a scanning with a relative movement between the laser beam LS having a rectangular beam profile and the auxiliary carrier 1 enables. This scanning movement is indicated in FIG. 3 by arrows 13.
• the adhesive effect between the adhesive layer 2 and the base layer 3 is at least largely eliminated in a cold process, so that the structure A can be detached, as is indicated in FIG. 3 by the arrow 14.
• the laser radiation LS cancels the effect of this adhesive in a comparable manner.
• the auxiliary carrier 1 with the adhesive layer 2 can be reused after cleaning.
• FIG. 4 shows in a highly simplified schematic representation how flexible fine structures 15 produced by the method according to the invention can be used for three-dimensional packaging. After active and passive components 16 and / or sensors have been glued or soldered to the last wiring level, they can be stacked on top of one another by simple folding after the laser ablation described above. The 3D package produced in this way can easily be contacted with BGA.
• the method according to the invention can also be used to produce multi-layer coils. Initially, a number of single or multi-layer, flexible coils in a spiral form are produced. These can now be overlaid by folding. This makes it possible to produce coils with high inductance at low cost.

Landscapes

• Engineering & Computer Science (AREA)
• Human Computer Interaction (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Multimedia (AREA)
• Theoretical Computer Science (AREA)
• Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
• Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
• Parts Printed On Printed Circuit Boards (AREA)
• Laminated Bodies (AREA)
• Image Input (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=7879324

Family Applications (2)

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Family Cites Families (10)

• 1999
  • 1999-08-24 JP JP2000568045A patent/JP2002523789A/ja active Pending
  • 1999-08-24 WO PCT/DE1999/002631 patent/WO2000013129A2/fr not_active Application Discontinuation
  • 1999-08-24 EP EP99953565A patent/EP1116165A2/fr not_active Withdrawn
  • 1999-08-27 EP EP99953626A patent/EP1116166B1/fr not_active Expired - Lifetime
  • 1999-08-27 AT AT99953626T patent/ATE218727T1/de active
  • 1999-08-27 WO PCT/DE1999/002695 patent/WO2000013130A2/fr active IP Right Grant
• 2001
  • 2001-02-28 US US09/796,214 patent/US6481294B2/en not_active Expired - Lifetime

Non-Patent Citations (1)

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