CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent Application No. 2020-093018 filed on May 28, 2020, the content of which is hereby incorporated by reference into this application.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a semiconductor detector and a method of manufacturing the same. For example, the present invention relates to a technique effectively applied to a semiconductor detector measuring energy of electromagnetic wave on the basis of an electric charge amount of electric charge carriers being generated by making incidence of the electromagnetic wave into a depletion layer applied with a drift electric field, the electric charge carriers being moved to and collected in a reading electrode by the drift electric field, and the present invention relates to a method of manufacturing the same.

BACKGROUND OF THE INVENTION

A silicon drift detector is often used for a fluorescent X-ray analyzer because of having higher resolution even in low energy and because not liquid nitrogen but a Peltier element is allowed to be used in cooling and others. In such a silicon drift detector, the electric charge carriers being generated by making the incidence of the electromagnetic wave into the depletion layer are moved to the reading electrode by the drift electric field in a state in which the depletion layer is expanded to the entire semiconductor substrate by application of a reverse bias voltage to a p-n joint portion formed in the semiconductor substrate.

This silicon drift detector includes the reading electrode having an extremely small size, and therefore, has an advantage that is a small electrostatic capacitance (parasitic capacitance) of the reading electrode. Thus, in the silicon drift detector, noises due to the parasitic capacitance are reduced. As a result, the silicon drift detector can measure the electromagnetic wave with the low energy, and can be used for, for example, fluorescent X-ray measurement.

For example, Japanese Patent Application Laid-Open Publication No. 2019-190934 (Patent Document 1) describes a technique related to a silicon drift detector.

SUMMARY OF THE INVENTION

A signal based on the electric charge amount collected to the reading electrode of the silicon drift detector is weak. Therefore, an amplifier is electrically connected to the reading electrode, and an amplified signal is generated by this amplifier from the signal based on the electric charge amount collected to the reading electrode. Then, the electromagnetic wave energy is measured on the basis of the generated amplified signal.

While the silicon drift detector including the reading electrode is formed in a first semiconductor chip, the amplifier is formed in a second semiconductor chip that is different from the first semiconductor chip. The reading electrode formed in the first semiconductor chip and the amplifier formed in the second semiconductor chip are electrically connected to each other by, for example, a wire.

However, when the reading electrode and the amplifier are connected to each other by the wire, the wire necessarily contains a parasitic capacitance and a parasitic inductance. Therefore, the noises due to the parasitic capacitance and the parasitic inductance are superimposed on the signal output from the reading electrode. Particularly, since the signal based on the electric charge amount collected to the reading electrode is weak, even small noises cause adverse influence. Therefore, in order to improve sensitivity of the semiconductor detector including the silicon drift detector and the amplifier to the measurement of the electromagnetic wave energy, an electric connection structure connecting the amplifier and the reading electrode for achieving suppression of the parasitic capacitance and the parasitic inductance is desirable.

An objective of the present invention is to provide a technique capable of improving a performance of a semiconductor detector.

Other object and novel characteristics will be apparent from the description of the present specification and the accompanying drawings.

A semiconductor detector according to an embodiment measures energy of electromagnetic wave on the basis of an electric charge amount of electric charge carriers being generated by making incidence of the electromagnetic wave into a depletion layer applied with a drift electric field, the electric charge carriers being moved to and collected in a reading electrode by the drift electric field.

The semiconductor detector includes a first semiconductor chip that has a reading electrode and a reading electrode pad electrically connected to the reading electrode formed therein and a second semiconductor chip that has an amplifier electrically connected to the reading electrode pad and that is connected with the first semiconductor chip in a flip-chip connection state. In this case, an underfill is injected into a gap between the first semiconductor chip and the second semiconductor chip except for a first connection portion connecting the reading electrode pad and the amplifier.

A method of manufacturing a semiconductor detector according to an embodiment includes a step of preparing a first semiconductor chip that has a reading electrode and a reading electrode pad electrically connected to the reading electrode formed therein, a step of preparing a second semiconductor chip that has an amplifier, a step of connecting the first semiconductor chip and the semiconductor chip in a flip-chip connection state so that the reading electrode pad and the amplifier are electrically connected to each other, and a step of injecting an underfill into a gap between the first semiconductor chip and the second semiconductor chip except for a first connection portion connecting the reading electrode pad and the amplifier.

According to an embodiment, a performance of a semiconductor detector can be improved.

