DK179268B1

DK179268B1 - Mass production of small temperature sensors with flip chips

Info

Publication number: DK179268B1
Application number: DKPA201270293A
Authority: DK
Inventors: Karlheinz Wienand; Karlheinz Eckert; Gernot Hacker; Thomas Jost
Original assignee: Heraeus Sensor Technology Gmbh
Priority date: 2011-06-01
Filing date: 2012-05-31
Publication date: 2018-03-19
Also published as: AT511498B1; CN102809442B; AT511498A2; DE102011103828B4; CN102809442A; DK201270293A; DE102011103828A1; AT511498A3

Abstract

For producing a temperature sensor having a conductive trace structured in 3 tiers, the conductive trace of a sensor tip is structured from a platinum tier, and is connected to a conductive trace segment on both the front and back sides of a 10-30 mm long plastic strip, in one layer leading from one plate to the other between two 20-200 µm spaced plates, thereby extending the sensor tip with a conductive trace segment made of a Pt structure on an inorganic plate with copper conductive traces along the plastic strip. Spaced from the plastic strip, two contact fields made of copper are bridged with the platinum structure. The Pt structure with the Cu conductive traces and therefore the two plates thereon are connected to one another via contact fields, by printing and burning contact fields made of AgPt or AgPtPd paste onto the platinum structure, and a tin solder, which contains Ag, Cu or Pb, is applied to the conductive trace segment made of copper, and the contact fields are soldered with the soft solder to the fired on metal paste. More particularly, a ceramic printed circuit board as a sensor tip is soldered lengthwise onto the plastic strips, and the plastic strips are fixed between two leads of a cable.

Description

<¹θ> DANMARK (10)

<¹²> PATENTSKRIFT

Patent- og

Varemærkestyrelsen (51) Int.CI.: G01K 7/18(2006.01) (21) Ansøgningsnummer: PA 2012 70293 (22) Indleveringsdato: 2012-05-31 (24) Løbedag: 2012-05-31 (41) Aim. tilgængelig: 2012-12-02 (45) Patentets meddelelse bkg. den: 2018-03-19 (30) Prioritet: 2011-06-01 DE 102011103828.4 (73) Patenthaver: Heraeus Sensor Technology GmbH, Heraeusstrasse 12-14,63450 Hanau, Tyskland (72) Opfinder: Karlheinz Wienand, Mudweg 4, DE-63741 Aschaffenburg, Tyskland Karlheinz Eckert, Eifelstrasse 8, Gründau 63584, Tyskland Gernot Hacker, Wingertstrasse 21, DE 63654 Büdingen, Tyskland Thomas Jost, Hauptstrasse 45, Kirchzell 63931, Tyskland (74) Fuldmægtig: Awapatent A/S, Strandgade 56,1401 København K, Danmark (54) Benævnelse: Mass production of small temperature sensors with flip chips (56) Fremdragne publikationer:

US 6241146 B1 EP 2312288 A1 WO 2011/024724 A1 US 4901051 A US 4050052 A EP 2154501 A2 (57) Sammendrag:

For producing a temperature sensor having a conductive trace structured in 3 tiers, the conductive trace of a sensor tip is structured from a platinum tier, and is connected to a conductive trace segment on both the front and back sides of a 10-30 mm long plastic strip, in one layer leading from one plate to the other between two 20-200 pm spaced plates, thereby extending the sensor tip with a conductive trace segment made of a Pt structure on an inorganic plate with copper conductive traces along the plastic strip. Spaced from the plastic strip, two contact fields made of copper are bridged with the platinum structure. The Pt structure with the Cu conductive traces and therefore the two plates thereon are connected to one another via contact fields, by printing and burning contact fields made of AgPt or AgPtPd paste onto the platinum structure, and a tin solder, which contains Ag, Cu or Pb, is applied to the conductive trace segment made of copper, and the contact fields are soldered with the soft solder to the fired on metal paste. More particularly, a ceramic printed circuit board as a sensor tip is soldered lengthwise onto the plastic strips, and the plastic strips are fixed between two leads of a cable.

Fortsættes ...

The present invention relates to a method for producing temperature sensors, in which fitp chips are fabricated on a panel before being separated for attachment onto printed circuit boards.

US 6 241 146 B1 discloses a process for manufacturing a sensor arrangement for temperature measurement with a temperature-sensitive measuring resistance which has a thin, metal resistance layer eiectricaily insulated toward the outside, and exposed contact surfaces on a ceramic substrate. The contact surfaces are connected electrically conducting and directly mechanically fast with high temperature-resistant conductor paths electrically insulated from one another on a ceramic carrier element. The measuring resistance is bonded and attached by application to and subsequent firing on a carrier element prepared prior to outfitting. A platinum-containing thick film conducting paste serves as a means for attachment and bonding. Contact surfaces for connecting a plug or cable are arranged at the end of the carrier element facing away from the measuring resistance. The temperature sensor, a standard component in the form of a flat measuring resistance, is applied to the ceramic carrier element without the use of wires as an SMD component. The sensor arrangement manufactured by the process is suited for temperature measurements even above 400 DEG C. The process is economical in that it uses a few standardized individual component parts and easily automatable operation steps.

DE 39 39 165 Cl discloses a temperature sensor in which a plastic foil is connected on the front and back sides to a connecting cable, and a component is arranged on one side of the foil and is connected via a conductive trace on both the front and back sides to the connecting cabie. However, the cable contacting is an impediment to automated fabrication. Flexible foils of this type are described in other documents as objects which, in contrast to plates, are flexible, referred to as flexible circuit boards. The adjective therefore describes the difference from a plate, and therefore neither a plate nor a printed circuit board.

DE 87 16 103 U1 describes contacting at both ends of a measuring resistor via conductive traces of a printed circuit board, wherein contacting is implemented via a feedthrough to a conductive trace on the back side of the printed circuit board. In terms of permanently reliable and precise temperature measurement, and in terms of reproducibility and a sturdy construction, this assembly leaves room for improvement.

DE 295 04 105 U1 discloses a connection printed circuit board with a meandering current path between a connecting cable and a functional component. Contacting on the back side is not provided.

DE 31 27 727 relates to a device for measuring temperature, in which resistors are arranged on the front and back sides of a substrate plate, and are each electrically contacted on the corresponding sides. An additional printed circuit board is not provided.

EP 0 809 094 discloses a method for producing a sensor assembly for temperature measurement comprising a temperature-sensitive measuring resistor, which has a thin metal film as a resistive layer and contact surfaces on a ceramic substrate, wherein the resistive layer is covered by an electrically insulating protective layer, and the contact surfaces are connected in an electrically conductive fashion and directly mechanically secured to conductive traces, which are electrically insulated from one another, on a hightemperature-resistant printed circuit board. The measuring resistor is contacted at one end of the printed circuit board. At the end of the printed circuit board opposite the measuring resistor, contact surfaces for connecting a carrier or cable are arranged. On the contact surfaces for contacting and attaching the measuring resistor, a still moist thick-film conductive paste is applied to the printed circuit board, immediately prior to placement of the measuring resistor on the high-temperature-resistant printed circuit board; the measuring resistor is then placed with its free contact surfaces on the paste, and is burned onto the printed circuit board at temperatures of up to IGOO’C, and is thereby contacted and fastened. In one embodiment, a plug connector contact surface is arranged on both the front and back sides of the carrier circuit board. However, this method is costly.

DE 197 42 236 discloses a temperature sensor having an elongated printed circuit board, which has at [east one conductive trace on a substrate made of temperature-resistant materials with an electrically insulating surface, wherein two connecting contact fields, which are connected to the conductive trace, are arranged on the surface for the purpose of electrical connection by means of a melting process to the ends of connecting leads of a connecting cable. A first connecting contact field is located on the front side and a second connecting contact field is located on the back side of the printed circuit board. The printed circuit board is made of epoxy, triazines, polyimsdes, or poSytetraftuoroethylene. The conductive trace is configured as meandering from a top view, and is embodied as a tier in the area of the connecting contact fields. With this, a sensor has been provided for permanently reliable, precise temperature measurement, which offers a simple, sturdy construction and high quality.

AT 502636 relates to the production of a temperature sensor, according to which a connecting cable is connected to each end of a current path on both the front and back sides of a plastic strip. The chips are attached to one another in a eiegant manner, very efficiently, via the contact surfaces on the conductive traces. The flip chip is a bridge, attached to contact fields between the conductive traces on the plastic strip. To this extent, the electrical contacts must be capable of withstanding a mechanical load. For this reason, a costly metallization on and around the narrow sides of the chips is carried out. Such treatments of chips after their separation are costly and in some cases can impair quality.

The problem addressed by the present invention is that of increasing quality and simplifying mass production.

According to the invention, flip chips are attached in a mechanically stable manner, without metallization of the end faces. According to the invention, the chip is fabricated on a panel before being separated.

With mass production, the problem of simplification and conserving materials without degrading sensor sensitivity also exists. If the area of the contact fields were to be diminished, the mechanical attachment would be reduced. If, for further simplification of mass production, the meander were to be shortened for heat decoupling on the plastic circuit board, a degraded response time and, associated with this, lower measuring precision would be expected. In this respect, if is surprising that, according to the invention, with straight conductive traces on a shorter plastic circuit board, hardly any effects on response time are realized.

To solve the problem, despite substantially shortened conductive traces for heat decoupling on reduced-size plastic circuit boards, precise sensors are produced in that the conductive traces extend straight, and the plastic circuit boards, adapted thereto, are decreased in size in ail dimensions.

The problems are solved by the features of the independent claim. Preferred embodiments are described in the dependent claims.

According to the invention, temperature sensors for calculating heating costs are provided, which with shorter conductive traces on a plastic circuit board measuring less than 20 mm In length still offer an excellent response time, even with a width of less than 5 mm.

According to the invention, for the mass production of temperature sensors, the conductive traces of which are structured for 3 tiers that are arranged parallel to one another, for each separable strip and for each tier a copper conductive trace and contact fields are structured on both the front and back sides of a plastic foil. Every two contact fields provided for attachment of a chip are coated with soft solder, particularly tin solder, which contains Ag, Cu or Pb. As the third tier, resistors having a resistance of at least 100 ohms are structured from a thin film, particularly a platinum thin film, on an inorganic plate between contact fields at longitudinal ends. A platinum paste, particularly AgPt or AgPtPd paste, Is printed and burned onto the contact fields. The resistors serve as sensor tips. Therefore, they are structured from the platinum tier In a curved shape. Once the Inorganic plate has been separated into chips, the chips are attached to the contact fields with the soft solder, with the platinum structure as a segment of the conductive trace being connected on both the front and back sides of the plastic strip for each segment of the conductive trace. According to the invention, the conductive trace In one layer - which contains two of these tiers - leads from one plate to the other between two plates, which are spaced 20-200 pm from one another by the platinum thick film and the soft solder layer. In this, the platinum structure structured on the inorganic plate as a segment of the conductive trace is extended with a conductive trace segment made of copper along the plastic strip. With the conductive trace segment made of platinum, two contact fields made of copper are bridged, spaced from the plastic strip. By connecting the conductive trace segments made of Pt to those made of Cu, the two plates are attached to one another via contact fields. By printing and burning contact fields made of AgPt or AgPtPd onto the conductive trace segments made of platinum, and applying the tin solder, which contains Ag, Cu or Pb, to the conductive trace segments made of copper, and by soldering the contact fields with the soft solder to the burned-in metal paste, the chips are attached to the plastic plate. Therefore, each of the platinum structures, spaced from the plastic strips, bridges two contact fields made of copper.

This mass production method enables the manufacture of highquality miniaturized sensors, each with a straight-line copper conductive trace between contact fields on both the front and back sides of the plastic strips.

To further simplify mass production, the plastic plate can be separated into strips in sections so that the cable can be attached more efficiently.

To produce a mini temperature sensor, the conductive trace of which is structured in 3 tiers, a platinum tier is structured in a curved shape to form a measuring resistor having a resistance of at least 100 ohms, and is connected to a straight-line conductive trace segment on the front and on the back side of a plastic strip. To this end, according to the invention, the conductive trace in one layer - containing two of these tiers -- leads from one plate to the other between two plates, which are spaced 20-200 pm from one another. In addition, the platinum structure is spaced from the plastic strip by bridging two contact fields made of copper.

For this purpose, the Pt structure with the Cu conductive traces and therefore the two plates thereon are connected to one another via contact fields by printing and burning contact fields made of AgPt or AgPtPd paste onto the platinum structure, and a tin solder, which contains Ag, Cu or Pb, is applied to the conductive trace segment made of copper, and the contact fields are soldered with the soft solder to the fired-on metal paste.

The bridge between the contact fields on the plastic strip, soldered in this manner, enables precise sensors with substantially shortened copper conductive traces for heat decoupling on reduced-size plastic printed circuit boards, in that the conductive traces extend straight and the plastic circuit boards, adapted thereto, are decreased in size In all dimensions. More particularly, a ceramic printed circuit board as a sensor tip is soldered to the plastic strip lengthwise thereto. The narrower sensor tip can thereby be inserted contact-free on the wider plastic strip into a protective tube.

The sensor according to the invention can be particularly easiiy fastened between two leads of a cable using its plastic strip. The plastic strip is held in place between the leads. This simple technique eliminates other immobilization and insulation measures, and eliminates many potential sources of error or structures susceptible to wear. The fastened chip, self-centered between the leads of a cable, can be guided particularly easily with the cable into a protective tube.

According to the invention, two plates protect the platinum section of the conductive trace in the manner of a sandwich, by soldering contact fields comprising a thick film of Pt and another noble metal on the conductive trace segment made of platinum to the conductive trace segment made of copper using a tin solder, so that the contact fields connect the conductive trace segments made of Pt and of Cu, and therefore the two substrates, to one another, and thereby fasten them mechanically to one another.

Thus a miniaturized temperature sensor is produced, in which a conductive trace structure arranged in 3 tiers, in one layer which contains two of these tiers, leads between two plates from one plate to the other In such a way that a conductive trace segment made of copper is extended along a plastic strip with a conductive trace segment made of Pt on an inorganic substrate to the sensor tip; the conductive trace in the sensor tip is structured in a curved shape, and is connected via a feedthrough to a conductive trace segment on the back side of the plastic strip.

The sensor tip thereof has a platinum conductive trace that is at least 10 mm long, 3 to 100 pm wide and 0.1 to 5 pm thick, and has a resistance of at least 100 ohms, on a 1 to 10 mm² surface of a 0,1 to 1 mm thick ceramic plate, with a length to width ratio of 1,2 to 2.5, wherein the platinum conductive trace transitions at its two ends into fields that are enlarged 20 to 500 times, onto each of which an AgPt or AgPtPd thick film is fastened, which is in turn fastened with the soft solder to a contact field of the plastic strip. The ceramic substrate is therefore also held on the piastic strip, which is embodied according to the invention as a 10 to 30 mm long and 1 to 5 mm wide plastic plate, on which a straight section of the conductive trace made of copper extends on both the front and back sides. The back-side section of the conductive trace is connected by means of a feedthrough to a contact field on the front side of the piastic strip. The three other ends of the two straight conductive trace segments are enlarged to form contact fields. The two contact fields for attaching the ceramic wafer are coated with a tin solder, with which the platinum thick film is soldered.

A bridge chip of the temperature sensor having a conductive trace made of platinum is attached via contact fields to two conductive trace segments made of copper, wherein this attachment represents the electrical connection of the conductive trace segment made of platinum and the conductive trace segment made of copper. The substrate of the flip chip is a ceramic plate 0.1 to 1 mm thick, particularly 0.3 to 0.7 mm thick, and having a 1 to 10 mm², particularly 2 to 5 mm² rectangular surface, with a preferred aspect ratio of 1.2 to 1.8, particularly 1.3 to 1.6. Substrates that are too thin or too long are more difficult to process and are mechanically non-usabie if, due to a iack of rigidity, they can generate short-circuits. Thicker substrates diminish measuring predsion, as do square substrates. Although piastre substrates are less costly to produce, they are unsuitable for conductive traces made of platinum. Conductive traces made of platinum simplify temperature measurement in relation to other conductive traces. On this substrate of the flip chip, the conductive trace made of a platinum thin film, as a sinuous, 0,1 to 1 mm, particularly 0.3 to 0.7 mm long, 10 to 100 pm, particularly 20 to 30 pm wide, and 1 to 5 pm, particularly 1 to 3 pm thick platinum conductive trace, transitions at its two ends into contact fields that are enlarged by 2 to 10 times, particularly 3 to 6 times. Shorter, narrower, wider and thinner platinum conductive traces diminish measuring precision. Longer platinum conductive traces require larger substrates. Thicker platinum conductive traces require more thin-film coatings. Thick-film platinum conductive traces diminish measuring precision. If the thin-film contact fields are larger, there is less space for the platinum conductive trace. Smaller thin-film contact fields diminish measuring precision.

The circuit board is a 10 to 30 mm long and 1 to 5 mm wide, rigid, 0.3-0.4 mm thick, fiber-reinforced plastic strip, particularly made of epoxy, triazine, polyimide or fluoropolymer and glass fibers. Other plastics may not satisfy the thermal requirements. Thicker, wider and shorter circuit boards diminish measuring precision. Longer circuit boards must be thicker due to rigidity, thinner circuit boards must be shorter due to rigidity requirements and narrower due to mechanical loadability requirements. Ä conductive trace made of copper extends on the front side and on the back side of the plastic strip. Measuring precision is best with pure copper and not with stiver. The dependency of measuring sensitivity with respect to admixtures in the copper is low, based upon the dependency thereof with respect to the dimensions of the conductive traces, printed circuit boards or substrates. Leading one of the two conductive traces on the front side of the printed circuit board 10 and the other conductive trace on the back side thereof permanently ensures effective electrical insulation of these from one another and simplifies the connection of the leads of a cable in that the substrate is shifted between the leads, or one lead is shifted to each side of the circuit board. This self-centering not only ensures a simple attachment of the leads, safe from: short-circuiting, but also stabilizes the printed circuit board 10 held between the leads, which is therefore precisely fixed in place and can be more easily inserted into a protective tube. In the protective tube, seif-centering effects a more secure spacing of the conductive traces from the protective tube. This eliminates the need for spacers and is permanently secure. To this extent, a self-centering use of the printed circuit board for immobilization between two leads of a connecting cable is enabled.

The conductive trace on the back side is connected by means of feedthrough 15 to a contact field 14 on the front side of the circuit board 10, and the three other ends of the two conductive traces 12 are structured as wide contact fields 11, 13, which are coated with tin solder, wherein the two contact fields 13, 14 are coated with a tin solder 2 for attaching the ceramic plate, with which the platinum thick film 3 is soldered. For reasons of stability, the attachment on the contact field 14 and the current feedthrough 15 are spaced from one another. The contact fields of this plastic printed circuit board are full-surface and enable a simple, efficient contacting and adequate stability of the contacts. Larger contact fields or wider conductive traces diminish measuring precision, but so do narrower conductive traces.

The conductive trace on the back side between the feedthrough 15 and the contact field is arranged in a straight line near the center of the plastic printed circuit board 10.

In the region of the contact fields 13, 14, the substrate Is fastened parallel across the printed circuit board 10. In the region of the curves of the conductive trace, the plastic printed circuit board 10 is electrically insulated, free of conductive traces.

Each of the thick films is attached to a contact field of a printed circuit board, and therefore, they also hold the ceramic substrate on the punted circuit board.

In mass production, for producing temperature sensors according to the invention, flip Chips are fabricated on a panel before being separated for attachment to printed circuit boards. For this purpose, it is decisive that the flip chips have an inorganic substrate, on which, prior to separation of the panel, a flat, thin film has been structured to form a conductive trace between two contact fields. The separated flip chips are then attached to a panel having a fiber-reinforced plastic base, e.g., a BT epoxy foil, onto repeating units of the panel. In this respect, the printed circuit boards are structured as repeating units of a fiber-reinforced plastic foil, coated on both sides with copper Sayers, are provided with a contact feedthrough, and after being equipped with the flip chips, are separated. The three structured tiers are then connected to form a contiguous conductive trace of the temperature sensor, wherein the conductive traces of the flip chip are connected to those of the printed circuit board via contact fields, to which the flip chip is attached as a bridge.

According to the invention, temperature sensors, with a printed circuit board for immobilization between two leads of a cable, and the production thereof can be provided, in which a conductive trace made of piatinum is connected via two contact fields to two conductive traces of the printed circuit board, wherein the platinum conductive trace, as a 0.1 to 1 mm tong, 10 to 100 pm wide and 1 to 5 pm thick platinum conductive trace on a 1 to 10 mm²rectangular surface of a 0.1 to 1 mm thick ceramic plate, in the thin-film technique, transitions at its two ends into contact fields that are enlarged by 2 to 5 times.

In the following examples, the invention will be specified in greater detail in reference to the set of drawings.

Figure 1 shows the bridging with a flip chip.

Figure 2 shows the side of a circuit board with contact fields for bridging.

Example 1

A 300 mm x 150 mm x 0.4 mm glass fiber-reinforced BT epoxy foil 10, coated on both sides with 50 pm copper, is structured in 1000 units 10 measuring 15 mm x 3 mm. Each unit 10 is provided at one end with a contact feedthrough 15 and at the other end with a contact field 11 measuring 3.5 x 2.5 mm, on both the front and back sides. The large contact field 11 is connected via the conductive trace 12 to the smalt contact field 13. On the back side, the contact feedthrough 15 is connected to the large contact field via a straight conductive trace. On the front side, two smaller contact fields 13, 14 that extend 1.5 mm in the longitudinal direction of the printed circuit board 10 are created and are bridged with a flip chip 40, The contact feedthrough 15 Is carried out on one of the small contact fields 14. Between the other small contact field 13 and the large contact field 11, a straight conductive trace 12 measuring 1mm in width is structured.

The contact fields are coated with soft solder 2. The soft solder 2, particularly that of the smalt contact fields 13, 14, contains tin, stiver and copper.

The flip chip 40 is attached only to contact fields. In contrast to conventional SMD components, the flip chip contains no solder contacts on Its end surfaces. In mass production, the flip chips 40 are attached to the panel.

For producing the flip chips, a 2~pm-thick platinum thin film is lithographically structured on a 0.5-mm-thick ceramic plate, in units each measuring 2 X 1.5 mm, to sinuous platinum conductive traces, each measuring 50 mm in length and 20 pm in width, and each having a resistance of approximately 1000 ohms, as a meander, each between two contact fields. As a pad 3, a Pt-Ag paste is applied and burned in. The units are then separated into chips 40. The separated chips 40 are attached to the panel with the burnedin Pt-Ag paste 3 on the soft solder 2 via the small contact fields 13, 14 made of copper. For this purpose, the separated chips are not metallized beforehand on and around their narrow sides, which is a customary step for corresponding SMD components.

The panel is separated. The large connecting contact fields 11, 17 are fixed in pairs between two-core cables between the pairs of leads. The loaded circuit board 10 therefore centers itself between the leads of a cable.

Fastened to the cable, a self-centered insertion into a metallic protective tube is followed. The self-centering and the flip chip attachment prevent a shortcircuit inside the metal tube. The beauty of this technique lies in its simplicity as a basis for high safety, since no components are required for spacing conductive traces from the protective tube. Flexible printed circuit boards would not be usable, because they are not plates, and therefore do not possess the rigidity that is necessary for mass production. Mechanical protection of the measuring resistor is no longer necessary, since the measuring resistor is protected by the metal-free area between the small contact fields 13, 14 on the foil IQ. Ä glass passivation 61 or glass ceramic 61 protects the measuring resistor from chemical attacks.

Example 2

A glass fiber-reinforced BT epoxy foil, measuring 150 mm x 100 mm x 0.3 mm and coated on both sides with 50 pm copper, is structured into 500 particularly small units 10 measuring 10 mm x 2.5 mm. Each unit 1 Is provided at one end with a contact feedthrough 15 and at the other end with a contact field 11 measuring 2.5 x 2 mm, on both the front and back sides. On the back side, the contact feedthrough 15 is connected to the contact field via a straight conductive trace. On the front side, two smaller contact fields 13, 14 that extend 1 mm in the longitudinal direction of the printed circuit board 10 are created and are bridged with a flip chip 40. The inner of the small contact fields 13 is connected to the large contact field 11 during structuring of the copper coating via a conductive trace 12. The current feedthrough 15 is carried out on the outer of the small contact fields 14. Between the contact feedthrough 15 and the large contact field, a straight conductive trace measuring 1 mm in width is structured.

The contact fields 11, 13, 14 are coated with soft solder. The soft solder 2 of the small contact fields is a tin alloy that contains silver or copper.

The flip chip 40 is attached to its contact fields only via its pad 3 that is anchored to the substrate. In contrast to customary SMD components, the flip chip 40 contains no solder contacts on its end surfaces, in mass production, the flip chips 40 are attached to the panel

For producing particularly small flip chips, a platinum thin film 1 pm thick is lithographically structured on a 0.3-mm-thick ceramic plate in 1.5 x 1 mm units to form sinuous platinum conductive traces, each 30 mm in length and 20 pm in width, and having a resistance of approximately 1000 ohms, as a meander between two contact fields. Each of the contact fields is structured at the two longitudinal ends of each rectangular unit as a comb that is open toward the outside. On these combs, a Pt-Pd-Ag paste is applied up to the edges of the end surfaces, and is burned in. The burned-in paste 3 adheres directly in the structured holes in the platinum contact fields, and particularly securely to the ceramic substrate of the flip chip 40. Finally, the units are separated into chips, but are not then metallized on the narrow sides. The separated chips 40 are attached to the panel only with the fired-on Pt-AgPd paste 3 on the soft solder 2 via the small contact fields 13, 14. The panel is divided into rows of two, in which the large connection contact fields 11 point toward the outside. These connection contact fields 11 are fixed in pairs between two-core cables between the pairs of leads, and are then separated. The loaded printed circuit board therefore centers itself between the leads of a cable. Fastened to the cable, a self-centered insertion into a metallic protective tube is followed. The self-centering and the flip chip attachment prevent a short-circuit inside the metal tube. The beauty of this technique iies in its simplicity as a basts for high safety, since no components are required for spacing conductive traces from the protective tube.

A glass passivation 61 or glass ceramic 61 for protecting the measuring resistor protects the measuring resistor against chemical attacks. Mechanically, the measuring resistor is protected by the metal-free area between the small contact fields 13, 14 on the foil 10. An epoxy resin as a masking lacquer protects the printed circuit board against chemical attack. Mechanically, it is protected by the self-centering.

Example 3

A glass fiber-reinforced polyimide foil, measuring 200 x 150 x 0.3 mm and coated on both sides with 20 pm copper is structured as 1000 units 10 measuring 10 x 3 mm. Thereby, each unit is provided at one end with two contact fields 11, each measuring 3.5 x 1.5 mm, specifically one on the front side and one on the back side, and at the other end with two contact fields 13, 14, each measuring 1.5 x 1 mm, on the anterior side or front side. There, the two small contact fields 13, 14 are bridged by a flip chip 40. One of the small contact fields 14 is connected to the current feedthrough 15, while the other is connected via a straight conductive trace 12,1 mm in width, to the large contact field 11. The substrate of the flip chip 40 is a ceramic plate measuring 0.1 to 0.5 mm, particularly 0.2 to 0.3 mm thick, and having a 1 to 5 mm², particularly a 2 to 3 mm², rectangular surface with a preferred aspect ratio of 1.2 to 2.5, particularly 1.3 to 2.0. Substrates that are too thin or too long are more difficult to process and are not mechanically usable if they can generate short-circuits due to a lack of rigidity. Thicker substrates diminish measuring precision, as do square substrates. Although plastic substrates are less expensive to produce, they are unsuitable for conductive traces made of platinum. Conductive traces made of platinum simplify temperature measurement in relation to other conductive traces. On this substrate of the flip chip, the conductive trace made of platinum thin film, as a sinuous platinum conductive trace having a resistance of at least 100 ohms, particularly 500 to 10 000 ohms, and measuring at least 10 mm, preferably 20 to 500 mm, particularly 40 to 200 mm in length, 3 to 100 pm, particularly 20 to 30 pm in width, and 1 to 5 pm, particularly 1 to 3 pm In thickness, transitions at both of its ends into contact fields that are enlarged by 2 to 10 times, particularly 3 to 6 times. Especially thinner, but also shorter, narrower and wider platinum conductive traces diminish measuring precision. Longer platinum conductive traces require larger substrates. Thicker platinum conductive traces require more thin film coatings. Thick-film platinum conductive traces diminish measuring preDK 179268 B1 cision. if the thin-film contact fields are wider, less space remains for the platinum conductive trace. Narrower thin-film contact fields diminish measuring precision.

Layer sequence:

pm ceramic sheet pm platinum thin film - platinum conductive trace + thin-film contact fields

Composite = (AgPt) + binder Soft solder - Sn + Ag pm copper layer ~ contact field 3 x 1.5 mm, copper conductive trace 5 x 0.5 mm

0.3 mm plastic strips 10 x 2.5 mm 10 pm copper layer Soft solder

0.5 mm ceramic plate pm platinum thin film ~ platinum conductive trace + thin-film contact fields

Composite - (PtAg) + binder Soft solder - Sn + Ag pm copper layer = contact field 3x1.5 mm, copper conductive trace 5 x 0.5 mm

0.35 mm plastic strip 15 x 2.5 mm - current feedthrough 15 pm copper layer Soft solder

Reference signs:

SAC soft solder /’ tin solder platinum thick-film pad printed circuit board / foil / unit large contact field conductive trace

13,14 small contact fields contact feedthrough 40 flip chip 61 glass passivation

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Claims

patent claims

1.2

Fig. 1

61 10.

1, A method of manufacturing temperature sensors in which flip chips (40) are fabricated on a panel before being separated for attachment to a circuit board (10), wherein the flip chips (40) have an inorganic substrate on which, prior to separating the flip chips (40), structured a flat patin thin film to form a structured conductive platinum groove between two contact fields (3) of each flip chip (40), characterized by the print peptads (10) being structured as repeating units made of a fiber-reinforced plastic film, coated on both sides, a front and a back, with copper layers forming a conductive copper groove (12) on each side of each printed circuit board (10), provided with a contact lead (15), a back section of conductive copper groove (12) is connected by means of the contact lead (15) to a first contact field (14) on the front of the circuit board (10), and the ends of the two conductive copper grooves (12) are expanded to form a second contact field (13) and e a third contact field (11) on the front of the circuit board (10) and, after being equipped with the flip-chips (40), is separated from each other and a flip-chip (40) and a circuit board (10) are connected so that they form a continuous conductive groove for a three-storey temperature sensor, where the structured conductive platinum groove of the flip chip (40) is connected to the conductive copper grooves (12) of the circuit board (10) via the first and second contact fields (14) of the circuit board (10). , 13), on which the flip chip (40) is attached as a bridge, and wherein the structured conductive platinum groove is structured as a curved shape from the flat patein thin film, and is connected to the two conductive copper grooves (12) on the front and back. the back side of the circuit board (10), wherein the continuous conductive trace of the temperature sensor manufactured in this way leads in one layer - comprising two of the three floors - between the flipchip (40) and the circuit board (10), and where the flipchip (40) and the circuit board (10) are spaced at a range of 20-200 pm f in which the structured conductive platinum groove of the flip-chip (40) is extended with the conductive copper grooves (12) along the printed circuit board (10), the first and second contact surfaces (14, 13) of copper plate (14, 13) connected through the structured conductive platinum groove spaced from the circuit board (10); and the structured conductive plate groove is connected to the two conductive copper grooves (12), and wherein the flip chip (40) and the circuit board (10) are connected to each other via the first and second contact feature (14, 13) of the circuit board (10) and the fhp chip (40) contact facts (3), by providing flip-chip (40) contact fields (3) by printing and burning AgPt paste or AgPtPd paste on the structured conductive platinum track, and by applying a tin softener (2) containing Ag, Cu or Pb, ti! the conductive copper grooves (12), and by soldering the first and second contact fields (14, 13) of the printing plate (10) to the burnt metal paste of the contact faces (3) of the flip-chip (40) with the tin soft solder (2).

2. I I Claims Nos:

because they relate to parts of the patent application that do not comply with the prescribed requirements to such an extent that no meaningful search can be performed, specifically:

2 /:

fMmsH Fato? Asm Öma

SEARCH REPORT - PATENT Application No. PA 2012 70293 1. 1 1 Certain claims were found unsearchable (See Box No. I). 2. 1 1 Unity of invention is lacking prior to search (See Box No. II). A. CLASSIFICATION OF SUBJECT MATTER G01K 7/18 (2006.01) According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) IPC & CPC: G01K, H01C, H05K Documentation searched other than minimum documentation to the extent that such documents are searched in the fields DK, NO, SE, FI: IPC classes as above. Electronic database consulted during the search (name of database and, where practicable, search terms used) EPODOC, WPIAP, FULLTEXT: ENGLISH C. DOCUMENTS CONSIDERED TO BE RELEVANT Category * Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim no. X US 6241146 B1 (WIENAND et al.) 2001-06-05 1.3 to 6 Y See in particular: col. 1.11. 35-50; col. 2.11. 35-60; col. 3.11. 26-64; col. 4.11. 10-20; col. 4.11. 64-65; col. 5.11. 30-35; col. 5.1. 61 - col. 6.1. 15, 7-9 and figures. X EP 2312288 Al (JUMO GMBH & CO KG) 2011-04-20. 1 A See in particular, [0028-0030], fig. 3, and FIG. 5th 2-9 5 ^ 1 Further documents are listed in the continuation of Box C. * Special categories of cited documents: P Document published prior to the filing date but later than the A Document defining the general state of the art which is not priority date claimed. considered to be of particular relevance. T Document not in conflict with the application but cited to D Document cited in the application. An Earlier application or patent but published on or after the filing date. understand the principle or theory underlying the invention. X Document of particular relevance; the claimed invention cannot be considered novel or cannot be considered to involve an inventive step when the document is taken alone. Y Document of particular relevance; the claimed invention cannot be considered to involve an inventive step when the document is combined with one or more other such documents, such L Document which may throw doubt on priority claim (s) or which is cited to establish the publication date of another citation or other special reason (as specified). O Document referring to an oral disclosure, use, exhibition or other betyder. combination being obvious to a person skilled in the art. Document member of the same patent family. Danish Patent and Trademark Office Date of completion of the search report Helgeshøj Allé 81 DK-2630 Taastrun December 4, 2015 Denmark Authorized officer Telephone No. +45 4350 8000 Facsimile No. +45 4350 8001 Carsten Köbler Telephone No. +45 4350 8532

Search Report

SEARCH REPORT - PATENT Application No. PA 2012 70293 C (Continuation). DOCUMENTS CONSIDERED TO BE RELEVANT Category * Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim no. X WO 2011/024724 Al (MURATA MANUFACTURING CO) 2011-03-03. 1 A See in particular [0021-0022], [0027], [0029], fig. 6, and protective layer (16, e.g., [0055]). 2-9 Y US 4901051 A (MURATA et al.) 1990-02-13. See in particular resistance pattern (2), fig. 2, col. 2.11. 55-65. 7-9 Y US 4050052 A (REICHELT et al.) 1977-09-20. See in particular fig. 1 and abstract. 7-9 A EP 2154501 A2 (MELEXIS NV) 2010-02-17. See in particular abstract, and figures. 1-9

Search Report

SEARCH REPORT - PATENT Application No. PA 2012 70293 Box No. In Observations where certain claims were found unsearchable

This search report has not been established in respect of certain claims for the following reasons:! □ Claims Nos:

because they relate to subject matter not required to be searched, namely:

The method according to claim 1, characterized in that the printed circuit board (10) is 10 to 30 mm long and 1 to 5 mm wide, and a straight section of the conductive copper groove (12) is structured on both the front and back thereof, the back section of the conductive copper groove is connected by means of the contact penetration (15) to the first contact feature (14) on the front of the circuit board (10), and the three other ends of the two straight conductive copper groove segments (12) are expanded to form the second contact field (13) and third contact field (11) on the front side of the print pad (10), where to attach the flip-chip (40), the first and second contact faces (14, 13) are coated with the tin soft solder (2), by means of which the flip-chip (40) of the navy-piatin-thick-contact contact (3) is fixed by soldering.

The method according to claim 1 or 2, characterized in that the circuit board (10) is fixed between two conductors of a cable.

The method according to any one of claims 1-3, characterized in that, as a measuring resistor, with a resistance of at least 100 ohms, the structured conductive platinum groove of the flip-chip (40) is at least 10mm long, 3 to 100 µm wide and 0.1 to 5 µm thick and structured on a 1 to 10 mm ² surface of a 0.1 to 1 mm thick ceramic plate (40) whose length to width ratio is between 1.2 and 2.5, where the structured conductive platinum groove of the chip (40) is expanded at both ends by 20 to 500 times, and at each end

In 5 of these expanded fields, the AgPt or AgPtPd thick film is incinerated to provide the contact fields (3) of the flip chip (40).

The method according to any one of claims 1-4, characterized in that the contact fields (3) of the flipchip (40) with the burnt platinum paste are fixed to the first and second contacting faces (14, 13) of the printed circuit board (10).

10 with the tsn solder (2), and consequently, the first and second contacting faces (14, 13} of the printed circuit board (10) and the contact fields (3) of the chip chip (40) also hold the inorganic or ceramic substrate along the printed circuit board (10). .

3. I I Claims Nos .: because of other matters.

Box No. II Observations where unity of invention is lacking prior to the search

The Danish Patent and Trademark Office found multiple inventions in this patent application, as follows:

Search Report

SEARCH REPORT - PATENT Application No. PA 2012 70293 SUPPLEMENTAL BOX Continuation of Box [.]

Search Report