CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority under 35 U.S.C. § 119 of European Patent application no. 20154940.9, filed on 31 Jan. 2020, the contents of which are incorporated by reference herein.

BACKGROUND

The present specification relates to a method of testing a semiconductor device and to an apparatus comprising a semiconductor device and a test apparatus.

Today's Radio Frequency (RF) transceiver Integrated Circuits (ICs) with integrated radiating elements such as antennae or launchers require testing in production. This testing can include testing of the internal die and testing of the antennae/launchers themselves, as well as the properties of the package that can influence the performance of the antennae/launchers (such as the “artificial dielectric” which is required to achieve the required directional characteristic of the antennae/launchers).

Normally this test can only be done by an external loopback path from transmitter antennae/launchers to receiver antennae/launchers. Tight specification parameters for IC transmit power, transmit and receive antennae/launchers gain and receiver noise figure require this loopback path to be extremely precise, despite the very challenging environmental conditions on production test floors.

In advanced radar transceiver ICs, a recently evolving technology is to integrate transmit and receive antennae into the package (Antennae in Package: AiP). Another technology is to integrate launchers into the package—these launchers are connected via wave guides to external antennae of the package. For such ICs, RF transmitter output power and receiver noise figure are key parameters, but measuring them is extremely difficult because the measurement result depends strongly on a number of conditions such as:the directivity characteristic of the integrated antennae;impedance and matching of the integrated antennae to the on-chip active device (e.g., Low Noise Amplifier (LNA), Power Amplifier (PA));the dielectric properties (e.g., δk and tan δ) of the stack-up material used to realize the radiation directivity of the integrated antennae;x/y and z displacement of the integrated antennae with respect to the reference antenna used for the measurement; andthe contact pressure of the measurement antenna to the IC package.

These dependencies can be mitigated if the RF signals from the IC transmit antennae are fed via an external loopback path to the IC receive antennae, so that the IC can measure the received signal amplitude and phase.

The loopback path can be realized using a waveguide. The parameters of the waveguide such as wall thickness, surface roughness and alignment accuracy to the integrated antennae largely influence the measurements. Therefore, it is desirable to have a standardized loopback device to be used for all cases where RF parameters need to be precisely measured including, for example:validation at the IC manufacturer,validation at the OEM manufacturer;production test at the IC manufacturer,customer reject analysis at the OEM;customer reject analysis at the IC manufacturer;qualification (e.g., life time tests) at the customer site; andadjustment of new external antennae in the field, i.e. in car workshops.

A solution for a standardized loopback device at the various sites, combining high precision, high sensitivity to antenna or launcher misalignments, but low sensitivity to misalignments of this loopback device, is currently not available.

SUMMARY

Aspects of the present disclosure are set out in the accompanying independent and dependent claims. Combinations of features from the dependent claims may be combined with features of the independent claims as appropriate and not merely as explicitly set out in the claims.

According to an aspect of the present disclosure, there is provided an apparatus comprising:a semiconductor device comprising an integrated circuit and a plurality of external radiating elements at a surface of the device, the radiating elements including at least one transmit element and at least one receive element; anda test apparatus for testing the semiconductor device, the test apparatus comprising:a surface for placing against said surface of the device; andat least one waveguide, wherein each waveguide extends through the test apparatus for routing electromagnetic radiation transmitted by one of said transmit elements of the device to one of the receive elements of the device, wherein each waveguide comprises a plurality of waveguide openings for coupling electromagnetically to corresponding radiating elements of the plurality of radiating elements located at the surface of the device,
wherein a spacing between the waveguide openings of each waveguide of the test apparatus is larger than, or smaller than a spacing between the corresponding radiating elements of the device.

According to another aspect of the present disclosure, there is provided a method of testing a semiconductor device, the method comprising:providing a semiconductor device comprising an integrated circuit and a plurality of external radiating elements at a surface of the device, the radiating elements including at least one transmit element and at least one receive element:providing a test apparatus for testing the semiconductor device, the test apparatus comprising:a surface for placing against said surface of the device; andat least one waveguide, wherein each waveguide extends through the test apparatus for routing electromagnetic radiation transmitted by one of said transmit elements of the device to one of the receive elements of the device, wherein each waveguide comprises a plurality of waveguide openings for coupling electromagnetically to corresponding radiating elements of the plurality of radiating elements located at the surface of the device.wherein a spacing between the waveguide openings of each waveguide of the test apparatus is larger than, or smaller than a spacing between the corresponding radiating elements of the device, andtransmitting electromagnetic radiation from at least one said transmit element to at least one said receive element via at least one waveguide of the test apparatus.

By including a deliberate non-zero spacing mismatch between the waveguide openings of each waveguide of the test apparatus and the corresponding radiating elements of the device, sensitivity to further unintended mismatching between the waveguide openings and the radiating elements (e.g. due to manufacturing variations or other sources) may be reduced.

The radiating elements of the semiconductor device may, for instance, comprise antennae and/or launchers. The transmit elements may accordingly, for instance, comprise transmit antennae or transmit launchers, while the receive elements may accordingly, for instance, comprise receive antennae or receive launchers.

A spacing between the waveguide openings of each waveguide of the test apparatus may be larger than, or smaller than, a spacing between the corresponding radiating elements of the device by at least 0.1%. A spacing between the waveguide openings of each waveguide of the test apparatus may be larger than, or smaller than, a spacing between the corresponding radiating elements of the device by at least 1%.

In some embodiments, the spacing between the waveguide openings of each waveguide of the test apparatus may be smaller than the spacing between the corresponding radiating elements of the device. In other embodiments, the spacing between the waveguide openings of each waveguide of the test apparatus may be larger than the spacing between the corresponding radiating elements of the device.

At least one of the waveguides may be configured to route electromagnetic radiation transmitted by one of said transmit elements of the device to a plurality of receive elements of the device. This can allow the plurality of receive elements collectively to be used for testing the transmit element (and vice versa), bearing in mind that the transmit power of the transmit element may exceed the power receivable by a single receive element.

The apparatus waveguide may have:a first branch for conveying electromagnetic radiation transmitted by said transmit element; andat least two further branches coupled to the first branch for route said electromagnetic radiation to said plurality of receive elements.

The semiconductor device may include a semiconductor die located in a package. The surface of the device at which the plurality of external radiating elements are located may be an external surface of the package.

The semiconductor device may include:a semiconductor die located in a package; anda carrier, wherein the package is mounted on a carrier,
wherein the surface of the device at which the plurality of external radiating elements are located is a surface of the carrier.

