JP2014195235A - Resonator with integrated temperature sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integrated resonator and semiconductor temperature sensor device having excellent thermal coupling between a resonator and a temperature sensor.SOLUTION: A diode (or a semiconductor circuit functionally equal to a diode) (1) is formed on a top face of a silicon substrate (2). A resonance element mount pad (3) is formed on the same substrate surface, a resonance element (4) is mounted on the substrate (2) using a conductive adhesive (6), and the mount pad (3) and the resonance element (4) are electrically connected. A silicon cap (5) mounted on the substrate (2) is used for forming a hermetic seal enclosure of the resonance element (4) together with the substrate (2). A user access pad (8) is formed on the other surface (bottom face) of the substrate (2), and a through silicon via (7) is used to electrically connect the resonance element (4) and the diode (1) to the user access pad (8).

Description

  The present invention relates to an electronic resonator. More specifically, the present invention relates to a resonator having an integrated temperature sensor in which a semiconductor temperature sensing element such as a silicon diode is integrated into a resonance element and is closely thermally coupled. Relating to forming.

  In many applications, for example, a resonator such as a quartz crystal resonator is used instead of a temperature compensated oscillator. In such applications, frequency change compensation due to changes in ambient temperature is computationally performed by application system software. Such computational temperature compensation requires the ability to accurately sense the temperature of the resonator. In the initial implementation, a temperature sensing component, such as a thermistor, is installed on the system PCB in the proximity of the resonator. However, any temperature difference between the resonator and the temperature sensing component results in significant computational temperature compensation errors that increase as the rate of change in ambient temperature increases. Various packaging solutions have been developed with the aim of bringing the resonator and temperature sensing components close together in a spatial and thermal sense. These solutions typically use an aluminum oxide ceramic package that houses both the resonator and temperature sensing components.

  Semiconductor diodes can be used as temperature sensing components instead of thermistors. For such a device, the present invention provides an alternative to housing the resonator and diode using a ceramic package, i.e., in the present invention, the unpackaged diode die itself contains the resonator. It is the part that supports and surrounds. Such a structure provides a close thermal connection between the resonator and the diode, thus significantly reducing the temperature difference between the two elements.

  Therefore, it is an object of the present invention to provide an alternative form of resonator that is closely thermally coupled and integrated into a semiconductor temperature sensor, or at least to provide a useful option for the general public. .

In a first aspect, the present invention generally comprises:
A semiconductor substrate having two main surfaces, on which at least one diode or a circuit functionally equivalent to the diode is formed on one main surface;
A resonant element closely associated with the substrate and mounted on one of its two major surfaces;
A plurality of conductive elements formed on the other of the two main surfaces of the substrate;
The diode circuit and the resonant element are electrically connected to at least some of the conductive elements, and at least some of the electrical connections are formed through conductive vias across the substrate. It is said to consist of a resonator and diode device.

  Preferably, the substrate is a silicon substrate and each substrate via is a through silicon via (TSV).

  Preferably, the resonant element is a quartz crystal resonant element. Alternatively, the resonant element may be another known type, for example a MEMS resonator.

  Preferably, the resonant element is housed in a hermetically sealed space formed by mounting a cap on the surface of the substrate on which the resonant element is mounted. Alternatively, the substrate on which the resonant element is mounted may be placed in a single cavity that surrounds the ceramic package, and the cavity may be hermetically sealed with a lid.

  Preferably, the diode circuit is formed on the same substrate surface on which the resonant element is mounted. Alternatively, the diode circuit may be formed on the opposite surface of the substrate, in which case the number of TSVs required for electrical connection to external conductive elements is reduced.

  Hereinafter, a preferred embodiment of the present invention will be described by way of example with reference to the accompanying drawings.

1 shows a first embodiment of the present invention. 2 shows a second embodiment of the present invention. 3 shows a third embodiment of the present invention. 4 shows a fourth embodiment of the present invention.

A first embodiment of the present invention is shown in FIG.
The diode (or a semiconductor circuit functionally equivalent to the diode) (1) is formed on the upper surface of the silicon substrate (2). A resonant element mount pad (3) is formed on the same substrate surface, and the resonant element (4) is mounted on the substrate (2) using a conductive adhesive (6), and the mount pad (3) and the resonant element ( 4) is electrically connected. A silicon cap (5) attached to the substrate (2) is used with the substrate (2) to form a hermetic seal enclosure of the resonant element (4). A user access pad (8) is formed on the other surface (bottom surface) of the substrate (2), and the resonant element (4) and the diode (1) are connected to the user access pad (7) using the through silicon via (7). 8) is electrically connected.

A second preferred embodiment of the present invention is shown in FIG.
This embodiment includes essentially the same components as the embodiment shown in FIG. The main difference from the second embodiment is that the diode (or a semiconductor circuit functionally equivalent to the diode) (1) is formed on the silicon substrate (2) opposite to the surface on which the resonant element (4) is mounted. It is to be formed on the surface. Compared to the first embodiment, the effect of the second embodiment is that no TSV is required to connect the diode circuit (1) to the user access pad (8), and therefore a TSV ( 7) the number is reduced. However, there is a trade-off that the thermal coupling between the resonant element (4) and the temperature sensing diode (1) is weak compared to the first preferred embodiment shown in FIG.

A third preferred embodiment of the present invention is shown in FIG.
In this embodiment, rather than using a silicon cap (element 5 in FIG. 1) to create a hermetic seal environment for the resonant element (4), the resonant element (4) is mounted as in FIG. The substrate (2) is placed in the cavity of the ceramic package (14) and the cavity is hermetically sheathed using the lid (15). In order to maintain the necessary electrical connection, a conductive pad (9) formed on the lower surface of the substrate (2), a conductive pad (10) formed on the inner surface of the ceramic package (14), and a conductive ball (12) is used as is well known in the art. This embodiment maintains the close thermal coupling characteristic of the first preferred embodiment between the resonant element (4) and the temperature sensing diode (1), but produces the device of the first embodiment. It is well suited for a single unit process flow rather than a preferred wear process flow.

A fourth preferred embodiment of the present invention is shown in FIG.
In this embodiment, the silicon cap (element 5 in FIG. 2) is not used to create a hermetic seal environment for the resonant element (4), but the resonant element (4) is mounted as in FIG. The substrate (2) is placed in the cavity of the ceramic package (14) and the cavity is hermetically sheathed using the lid (15). In order to maintain the necessary electrical connection, a conductive pad (9) formed on the lower surface of the substrate (2), a conductive pad (10) formed on the inner surface of the ceramic package (14), and a conductive ball (12) is used as is well known in the art. This embodiment maintains the close thermal coupling characteristic of the second preferred embodiment between the resonant element (4) and the temperature sensing diode (1), but produces the device of the second embodiment. It is well suited for a single unit process flow rather than a preferred wear process flow.

1: Diode 2: Silicon substrate 3: Resonant element mount pad 4: Resonant element 5: Silicon cap 7: Through silicon via 8: User access pad 9, 10: Conductive pad 12: Conductive ball 14: Ceramic package 15: Lid

Claims (1)

A semiconductor substrate having two main surfaces, on which at least one diode or a circuit functionally equivalent to the diode is formed on one main surface;
A resonant element closely associated with the substrate and mounted on one of the two major surfaces;
A plurality of conductive elements formed on the other of the two main surfaces of the substrate;
The diode circuit and the resonant element are electrically connected to at least some of the conductive elements, and at least some of the electrical connections are formed through conductive vias across the substrate, Body resonator and diode device.

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