Follow the assumption, not the abstract. Nearly every die-attach patent is written as though the chip being attached is flat and its surface is smooth. US12696825B2, issued 28 July 2026 to Denso Corporation and naming Tomohito Iwashige and Takeshi Endo, does the opposite. Claim 1 begins by preparing "the semiconductor chip that is warped and includes one surface having a plurality of protrusions". The distortion is not a defect the method tries to prevent; it is a starting condition the method is built around.

That is a supply-chain fact expressed as claim language. Power semiconductor dies warp because they are joined between supporting members with mismatched thermal expansion, and they carry protrusions because the top surface has functional structure on it. Sinter a supporting member directly onto a surface that is both curved and bumpy and the joint gets voids exactly where heat most needs to leave.

What the method does about it

The answer in claim 1 is to build the flat surface rather than demand one. A first constituent member containing a sintering material is heated and pressurised onto the chip's protruding surface to form a pre-joining layer. That layer fills the spaces between the protrusions, contacts them, and presents a flat surface on the side away from the chip. Only then is the second supporting member arranged on that flat surface through a second constituent member, and heated and pressurised in turn. The finished upper joining portion is formed by both.

Claim 2 adds that the pre-joining layer is pressed through a cushioning member — the compliant element that lets uniform pressure reach a non-uniform surface. Claim 3 is the manufacturing economy: the lower joining portion, on the opposite face of the chip, is pressurised at the same time as the first constituent member. One press stroke, both sides.

The method according to claim 1, wherein the semiconductor chip is warped such that the one surface is curved convexly or the other surface is curved convexly.— Semiconductor device and method for manufacturing the semiconductor device, US12696825B2

Claim 16, quoted above, covers warpage in either direction — the joined surface bulging outward or the opposite one doing so. Claim 17 mirrors it for the device claim. Covering both convexities matters because which way a die bows depends on the stack and the thermal history, and a claim limited to one direction would be trivially avoided by a process that produced the other.

The device claim and the materials

Claim 5 is the second independent claim and describes the resulting structure rather than the process. Its distinctive limitation is that the upper joining portion contains multiple pressure-sintered layers with intermediate metal layers between them acting as a supporting layer, and that those intermediate layers "are deformed to conform to a warped profile of the one surface of the semiconductor chip". The metal in the joint is doing mechanical work — taking the shape of the bent die so the layers above it can be flat.

Claim 4 lists what the constituent members may be: a silver paste, a silver sheet made by removing the solvent, a preformed structure with an intermediate metal layer sandwiched by silver sheets, or the copper equivalents of each, with the intermediate layer being bulk silver, copper or aluminium or a sintered layer mainly composed of silver or copper. Silver and copper sinter paste are the established high-reliability alternatives to solder in power modules, so the materials list is conventional; the structure imposed on them is not.

Two claims worth reading together are 7 and 8. Both depend from claim 6 and they are mutually exclusive: claim 7 requires the sintered intermediate layer to have higher atomic density than the pressure-sintered layers, claim 8 lower. Claiming both directions of the same property is legitimate alternative claiming, and it signals that the applicant did not want the position to depend on which density relationship a given process happens to produce. In a sintered joint the density of a layer reflects how completely the metal particles have coalesced under heat and pressure, and that varies with the press profile, the paste and the geometry underneath. Claiming the intermediate layer as either denser or less dense than its neighbours covers the outcome whichever way a given line's process settles.

Routing note first: Denso is one of the largest automotive component suppliers, and power modules of this kind are the building blocks of traction inverters and onboard chargers. But the record itself never recites a vehicle, an inverter or any automotive application. The sector framing here comes from the assignee, not from the document, and nothing in the patent limits it to automotive use.

A granted patent establishes an enforceable position on what it claims. It does not establish a product, a programme, a production volume or a supply agreement, and this record discloses none of those — no cost, no thermal performance figure, no reliability data, no cycle count. The application behind a July 2026 grant was filed years earlier, so the cadence indicates where sustained engineering effort has been rather than what ships next.

Two published-text irregularities are reproduced rather than repaired. Claim 5 punctuates its element list with "a second supporting member:" — a colon where the surrounding elements take semicolons. And claim 4 runs "sandwiched by copper sheets, when the first constituent member is formed of" without a conjunction, where the parallel claim 9 inserts "and" at the same junction. Neither changes scope; both are the kind of thing that survives into an issued patent unnoticed.