JP4435618B2 - Crystal oscillator for surface mounting - Google Patents

Description

  The present invention relates to a surface mount crystal oscillator (hereinafter referred to as a surface mount oscillator), and more particularly to a surface mount oscillator in which a crystal piece is mounted on an IC chip.

(Background of the Invention) Since a surface-mounted oscillator is small and lightweight, it is built in a portable electronic device as a frequency and time reference source. In recent years, further miniaturization has progressed, and one of these is a proposal of a surface-mounted oscillator in which a crystal piece is mounted on an IC chip by the present applicant (Patent Document 1).

FIG. 2 is a diagram for explaining a conventional example. FIG. 2A is a cross-sectional view of a surface mount oscillator, and FIG. 2B is a plan view of an IC chip.

  The surface-mount oscillator is configured by integrally housing an IC chip 2 and a crystal piece 3 in a concave container body 1 made of laminated ceramic. In the IC chip 2, an oscillation circuit (not shown) excluding the crystal piece 3 (crystal resonator) is integrated on the lower surface side to form a circuit function region P indicated by a mesh line, and the upper surface side is a non-circuit function region.

  Each IC terminal 4 including at least an output terminal Vo, a power supply terminal Vc, a ground terminal E, and a pair of crystal terminals X1, X2 is formed on the lower surface from the circuit function region P of the IC chip 2. Among these, the pair of crystal terminals X1 and X2 are led out as X1 'and X2' on the upper surface, which is a non-circuit functional area of the IC chip 2, by the through electrode 5. Normally, each circuit terminal 4 is formed outside the circuit function area.

  Then, each circuit terminal (not shown) formed on the inner bottom surface of the container body 1 by ultrasonic thermocompression bonding of each IC terminal 4 except for the crystal terminals X1 and X2 provided on the lower surface of the IC chip 2 using bumps 6. ) Is electrically connected and fixed. Each circuit terminal is led to the outer surface as a surface mount terminal (not shown).

  The crystal piece 3 has excitation electrodes (not shown) on both main surfaces, and for example, extraction electrodes are extended on both sides of one end. Both ends of the extended end portion of the extraction electrode are fixed (mounted) electrically connected to a pair of crystal terminals X1 'and X2' provided on the upper surface of the IC chip 2 by, for example, a conductive adhesive 7. . In addition, the code | symbol 8 in a figure is a cover, and is joined to the container main body 1 by seam welding etc.

  With such a configuration, the IC chip 2 on which the crystal piece 3 is mounted is connected to the inner bottom surface of the container body 1 by the bumps 6. Therefore, the height dimension and the planar area can be reduced as compared with the case where the crystal piece 3 is mounted on an inner wall step portion (not shown) or the case where each IC terminal 4 is connected by wire bonding.

JP 2001-28516 A JP 2002-9193 A

(Problem of the prior art) However, in the surface mount oscillator having the above configuration, since each circuit terminal 4 is formed on the outer periphery of the IC chip 2, the IC chip 2 is enlarged. The circuit terminal 4 is provided on the outer periphery in order to prevent the circuit function region P from being damaged by the applied pressure while applying ultrasonic vibration during ultrasonic thermocompression bonding. However, even in this case, since the circuit function region P is on the fixing surface side, there are severe conditions on the ultrasonic output, temperature, pressure, and the like, which makes it difficult to manufacture.

(Object of the Invention) An object of the present invention is to provide a surface-mount oscillator that facilitates manufacture by reducing the size of an IC chip to facilitate further miniaturization and preventing damage in the circuit function area.

According to the present invention, as shown in the claims (Claim 1), the lower surface of the IC chip is fixed to the inner bottom surface of the container main body by ultrasonic thermocompression bonding using bumps, and the crystal on the upper surface of the IC chip. In a surface-mount crystal oscillator having a chip mounted thereon, the lower surface side of the IC chip is a non-circuit functional region, and the upper surface side of the IC chip is an integrated circuit function region of an oscillation circuit. At least an output terminal, a power supply terminal, a ground terminal, and a pair of crystal terminals of the oscillation circuit are formed on the upper surface in a region facing the circuit function region, and the IC chip is connected to the output terminal, the power supply terminal, and the ground terminal by a through electrode. The structure is derived to the lower surface which is a region facing the circuit function region on the upper surface side of the substrate.

  With such a configuration, the integrated circuit function area of the oscillation circuit is on the upper surface side of the IC chip, and the output terminal, power supply terminal, and ground terminal other than the crystal terminal are led to the lower surface of the non-circuit function area, It is set as thermocompression bonding using a bump or ultrasonic thermocompression bonding.

  Therefore, the applied pressure including ultrasonic vibration at the time of ultrasonic thermocompression is relaxed by the non-circuit functional region, and there is no direct impact on the circuit functional region. Thereby, even if each circuit terminal is extended downward rather than the outer periphery (outside) of the circuit function area, it is not damaged during ultrasonic thermocompression bonding. Therefore, the IC chip itself can be made smaller and further miniaturization is further promoted. And conditions such as ultrasonic output, heating temperature, and pressure during ultrasonic thermocompression can be relaxed, facilitating manufacture.

  FIG. 1 is a view for explaining an embodiment of the present invention. FIG. 1 (a) is a cross-sectional view of a surface mount oscillator, and FIG. 1 (b) is a plan view of an IC chip. In addition, the same number is attached | subjected to the same part as a prior art example, and the description is simplified or abbreviate | omitted.

In the same manner as described above, the surface-mounted oscillator has the crystal chip 3 mounted on the upper surface of the IC chip 2 by the conductive adhesive 7 and the lower surface of the IC chip 2 is concaved by ultrasonic thermocompression bonding using the bumps 6. It is fixed to the inner bottom surface of 1.

  In this embodiment, the upper surface side of the IC chip 2 is a circuit function region P in which oscillation circuits are integrated, and the lower surface side is a non-circuit function region. Then, an IC terminal 4 including at least an output terminal Vo, a power supply terminal Vc, a ground terminal E, and a pair of crystal terminals X1 and X2 from the circuit function region P is formed on the upper surface of the IC chip 2. These are provided above the circuit function region P.

  Among these, the output terminal Vo, the power supply terminal Vc, and the ground terminal E are led out to the lower surface of the IC chip as Vo ′, Vc ′, E ′ by the through electrode 5. That is, the output terminal Vo ′, the power supply terminal Vc ′, and the ground terminal E ′ led to the lower surface are located below the circuit function area P. And it connects with the circuit terminal of the inner bottom face in the container main body 1 by the ultrasonic thermocompression bonding using the bump 6 like the above.

  With such a configuration, the circuit terminals 4 are led out upward and downward within the outer periphery of the circuit function region P of the IC chip 2, so that the IC chip itself can be made small. Therefore, it is possible to promote downsizing of the surface mount oscillator.

  Then, with the circuit function region P as the upper surface side, the power supply terminal Vc ′ and the ground terminal E ′ to be subjected to ultrasonic thermocompression are the lower surfaces located below the circuit function region P. Therefore, it is possible to prevent destruction of the circuit function area during ultrasonic thermocompression bonding, and ease the manufacturing by relaxing conditions such as ultrasonic output, heating temperature, and pressure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a cross-sectional view of a surface mount oscillator, and FIG. 1B is a plan view of an IC chip. FIG. 2A is a cross-sectional view of a surface mount oscillator, and FIG. 2B is a plan view of an IC chip.

  1 container body, 2 IC chip, 3 crystal piece, 4 circuit terminal, 5 through electrode, 6 bump, 7 conductive adhesive, 8 cover

Claims (1)

In a surface-mount crystal oscillator in which a lower surface of an IC chip is fixed to an inner bottom surface of a container body by ultrasonic thermocompression using a bump and a crystal piece is mounted on the upper surface of the IC chip, the lower surface of the IC chip The non-circuit function area is the non-circuit function area, the upper surface side of the IC chip is an integrated circuit function area of the oscillation circuit, and the upper surface of the IC chip is at least the output terminal of the oscillation circuit in the area facing the circuit function area Forming a power terminal, a ground terminal, and a pair of crystal terminals, and leading the output terminal, the power terminal, and the ground terminal to a lower surface that is a region facing the circuit function region on the upper surface side of the IC chip by a through electrode. A featured crystal oscillator.

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