JP6536283B2 - High frequency module and method of manufacturing high frequency module - Google Patents

Description

The present invention relates to a high frequency module and a method of manufacturing the high frequency module, and, for example, to a high frequency module mainly used for a wireless communication device, a radar device, or an imaging device using a frequency of millimeter wave band or more.

  A waveguide interface using a flange or the like is used to connect the waveguides in the ultra high frequency module of the millimeter wave band (30 GHz) or more. In addition, a waveguide-microstrip line converter is used to input and output high frequency signals to and from the semiconductor chip (see, for example, Non-Patent Document 1 or Non-Patent Document 2).

FIG. 6 is a schematic perspective view of a high frequency module using a conventional waveguide-microstrip line converter, in which windows are opened in the waveguides 51 ₁ and 51 ₂ and a microstrip line 55 is provided. The mounting substrate 54 is pierced through the waveguides 51 ₁ and 51 ₂ as a probe and covered with the connection cavity 53. In this case, the probe-coupled waveguide - and has a microstrip line converter 57 _1, 57 _2.

FIG. 7 is an explanatory view of a waveguide-microstrip line converter, FIG. 7 (a) is a schematic perspective view, and FIG. 7 (b) is an equivalent circuit diagram. Shape of the mounting substrate 54 provided with a window size and the microstrip line 55 provided in the waveguide 51 _1, waveguide by projecting amount - for the performance of the microstrip line converter 57 ₁ is changed largely, in the fabrication Requires very strict precision in processing and assembly.

In this case, the back-short waveguide 52 ₁ and provided, lambda / 4 in the equivalent circuit shown in FIG. 7 (b) with 1/4 of the depth of the wavelength lambda of the high-frequency signal to a lower portion of the waveguide 51 ₁ The short stubs 56 are formed. Such waveguide - in the case of forming a high frequency module using a microstrip line converter 57 ₁ will be mounted the semiconductor chip to the mounting substrate 54.

FIG. 8 is an explanatory view of a conventional face-up mounting type high frequency module, and FIG. 8 (a) is a perspective plan view, and FIG. 8 (b) is an alternate long and short dash line connecting AA 'in FIG. It is sectional drawing along. Connect the waveguide 51 ₂ having a waveguide 51 ₁ and the back short waveguide 52 ₂ having a back short waveguide 52 ₁ in connection cavity 53, mounting substrate ₅₄ 1 therein, 54 ₂ Are attached to the waveguides 51 ₁ and 51 ₂ so as to protrude. The semiconductor chip 59 is connected to the microstrip lines 55 ₁ and 55 ₂ provided on the mounting substrates 54 ₁ and 54 ₂ by bonding wires 60. At this time, the ground pads (not shown) provided on the semiconductor chip 59 and the ground pads 58 ₁ and 58 ₂ provided on the mounting substrate 54 are similarly connected by the bonding wires 60.

  Such face-up mounting uses the bonding wire 60 that is inductive, so the loss of high frequency signals is large. Therefore, flip chip mounting is performed to reduce the loss of high frequency signals. FIG. 9 is an explanatory view of a conventional flip chip type mounted high frequency module, and FIG. 9 (a) is a transparent plan view before mounting a semiconductor chip, and FIG. 9 (b) is after mounting the semiconductor chip. It is sectional drawing in alignment with the dashed-dotted line which connects AA 'in Fig.9 (a).

As shown, the semiconductor chip 59 is connected to the microstrip lines 75 ₁ and 72 ₂ provided on the mounting substrate 71 by bumps 75. In this case, the protruding portions at both ends of the mounting substrate 71 become waveguide-microstrip line converter waveguide converters 74 ₁ and 74 ₂ . The ground pads 73 are also connected by the ground bumps provided on the semiconductor chip 59.

FIG. 10 is an equivalent circuit diagram of a conventional flip chip mounting type high frequency module, and a waveguide-microstrip line converter 74 is provided between the waveguides 51 ₁ and 51 ₂ and the microstrip lines 72 ₁ and 72 _{2. 1} , 74 ₂ are connected. Also, the microstrip lines 72 ₁ and 72 ₂ and the semiconductor chip 59 are grounded by the bumps 75 and the parasitic capacitance 76. Incidentally, the parasitic capacitance 76 is a parasitic capacitance formed between the microstrip line ₇₂ 1, 72 ₂ and the ground pad 73.

  FIG. 11 is a manufacturing flow diagram of a conventional high frequency module. First, a flip chip mounting substrate is prepared, and a semiconductor chip judged to be non-defective after inspection is flip chip bonded to the flip chip mounting substrate. Next, the high frequency module on which the semiconductor chip is mounted is inspected, and the high frequency module determined to be a non-defective product is shipped.

Japanese Patent Application Publication No. 06-236937 JP 2005-244349 A

A. Tessmann, et al. “A Broadband 220-320 GHz Medium Power Amplifier Module,” Compound Semiconductor Integrated Circuit Symposium (CSICs), 2014 A. Tessmann, et al. “A 243 GHz Low-Noise Amplifier Module for Use in Next-Generation Direct Detection Radiometers,” Proceedings of the 8th European Microwave Integrated Circuits Conference, pp. 220, 2013

  However, in the conventional manufacturing method, after fixing the mounting substrate to the module, the semiconductor chip inspected in advance is flip-chip mounted. The inspection of the waveguide-microstrip line converter can not be done until the final inspection of the module. In addition, since inspection is conducted as the characteristics including the semiconductor chip and the bump connection portion, it is difficult to identify the defective portion when there is a defect.

  Since the mounting substrate once bonded can not be moved, it is difficult to adjust the fixing position even if there is a defect in the characteristics of the waveguide-microstrip line converter. There is a problem that a semiconductor chip once fixed with a conductive adhesive is broken if it is forcibly removed and can not be reused. In particular, since semiconductor chips for the ultrahigh frequency band are expensive, there is a demand for testing the waveguide-microstrip line converter before mounting the semiconductor chips.

  Therefore, it is an object of the present invention to inspect a waveguide-microstrip line converter alone in a method of manufacturing a high frequency flip chip mounting substrate, a high frequency module, and a high frequency module.

  From one aspect to be disclosed, a substrate and a pair of input / output microstrip lines provided at both ends of the substrate and facing each other, a through line connecting the pair of input / output microstrip lines, and both sides sandwiching the through line There is provided a high frequency flip chip mounting substrate comprising: a plurality of grounding pads provided on the substrate.

  Further, from another aspect to be disclosed, two waveguides, a connection cavity connecting the two waveguides, and the connection cavity fixed to the connection cavity and guiding both ends thereof with the connection part of the waveguides A high frequency flip chip mounting substrate which is a wave tube-microstrip line converter, and includes a pair of input / output microstrip lines facing each other and a through line connecting the pair of input / output microstrip lines; And an electronic device chip connected to the input / output microstrip line and having a signal bump connected to the signal bump, and having the through line grounded at a position of 1⁄4 of the wavelength of the signal from the connection portion of the signal bump. A high frequency module is provided.

  Further, according to still another disclosed aspect, the method includes a step of testing the characteristics of the electronic device chip, a pair of input / output microstrip lines facing each other, and a through line connecting the pair of input / output microstrip lines. The high frequency flip chip mounting substrate is fixed in a connection cavity connecting two waveguides, and the waveguide-microstrip line conversion is made in the vicinity of the connection portion between the waveguide and the flip chip mounting substrate. Testing the characteristics of the waveguide-microstrip line converter by introducing a high frequency signal into the waveguide and testing the characteristics of the waveguide-microstrip line converter Signal bumps of an electronic device chip after testing the characteristics of the input / output microstrip line of the high frequency flip chip mounting substrate later Forming a high frequency module by being flip chip bonded so as to be connected to the ground of the signal line from the connection portion of the signal bump to a quarter of the wavelength of the signal to form a high frequency module; And a step of testing. A method of manufacturing a high frequency module is provided.

  According to the disclosed high frequency flip chip mounting substrate, the high frequency module, and the method of manufacturing the high frequency module, it becomes possible to inspect the waveguide-microstrip line converter alone.

It is explanatory drawing of the high frequency module of embodiment of this invention. It is an explanatory view of a flip chip mounting substrate and a semiconductor chip used for a high frequency module of Example 1 of the present invention. It is a manufacture flowchart of the high frequency module of Example 1 of this invention. It is an explanatory view to the middle of the manufacturing process of the high frequency module of Example 1 of the present invention. It is explanatory drawing of FIG. 4 or subsequent ones of the manufacturing process of the high frequency module of Example 1 of this invention. FIG. 6 is a schematic perspective view of a high frequency module using a conventional waveguide-microstrip line converter. It is explanatory drawing of the conventional waveguide-micro strip line converter. It is explanatory drawing of the conventional face up mounting type high frequency module. It is explanatory drawing of the conventional flip chip mounting type high frequency module. It is an equivalent circuit schematic of the conventional flip chip mounting type high frequency module. It is a manufacture flowchart of the high frequency module of the prior art Example 1. FIG.

  Here, the high frequency module according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory view of a high frequency module according to an embodiment of the present invention, FIG. 1 (a) is a transparent plan view before mounting an electronic device chip, and FIG. 1 (b) is an electronic device chip. It is sectional drawing along the dashed-dotted line which connects AA 'in FIG. 1 (a) after mounting.

  As shown in FIG. 1A, the high frequency flip chip mounting substrate 10 is provided with the left and right input / output microstrip lines 11 and the through lines 12 connecting them, with the through lines 12 interposed therebetween. A number of grounding pads 13 are provided on both sides. The input / output microstrip line 11 and the through line 12 are usually formed integrally, and in practice there is no boundary or distinction between them.

The high frequency for flip-chip mounting substrate 10 fixed to protrude into the waveguide 1 _1, 1 _2, covered with a connection cavity 2. In this case, protrusion and the waveguide 1 ₁ across the frequency for flip-chip mounting substrate 10, 1 waveguide by a portion of the ₂ - microstrip line converter 14 _1, 14 ₂ are formed. Waveguide in this state - performing characteristics of the microstrip line converter 14 _1, 14 ₂ test.

As shown in FIG. 1 (b), the electronic device chip 20 is mounted on the high frequency flip chip mounting substrate 10 whose characteristic inspection has been completed. The electronic device chip 20 is connected to the input / output microstrip line 11 by the signal bumps 21 and is connected to the through line 12 by the grounding bumps 22 at a position of 1/4 of the wavelength λ of the high frequency signal used therefrom. . Therefore, the through line 12 becomes a λ / 4 short stub, and the impedance becomes infinite with respect to the signal of wavelength λ. As a result, the high-frequency signal transmitted to the input microstrip line 11 from the waveguide 51 _1, 51 ₂ is input to the electronic device chip 20 without propagating through line 12.

Incidentally, the side opposite to the side connected with the waveguide 1 _1, 1 ₂ of the connection cavity and waveguide interface is provided with a flange or the like, a high frequency via at least two waveguide interface Signals are input and output. An antenna may be connected instead of the waveguide interface. Further, 1 _1, 1 ₂ in the two waveguides, in order to reduce signal loss, it is desirable to provide a back-short waveguide to form a lambda / 4 short stub.

  It is desirable that the ground conductor be provided in a solid pattern except the insulation separation portion with the signal pad on the surface provided with the signal pad of the electronic device chip 20, and on the mounting surface side of the high frequency flip chip mounting substrate 10 Connection with a plurality of grounding pads 13 provided on both sides of the through line 12 is facilitated. The signal bumps 21 and the grounding bumps 22 may be provided on the electronic device chip 20 side, or may be provided on the high frequency flip chip mounting substrate 10 side. Although a semiconductor chip is typically used as the electronic device chip 20, another electronic device chip such as a superconducting device chip may be used.

As a method of manufacturing the high frequency module according to the embodiment of the present invention, first, the characteristics of the electronic device chip 20 are tested. Also, a hollow casing for connecting _two waveguides 1 ₁ and 12 with a high frequency flip chip mounting substrate 10 having a pair of input / output microstrip lines 11 facing each other and a through line 12 connecting the same. It is fixed in the body 2. In this case, the waveguide _{1 1, 1 2} and the connecting portion near the waveguide with high frequency for flip-chip mounting substrate 10 - a micro-strip line converter ₁₄ 1, 14 _2.

Then, the waveguide _{1 1, 1 2} the waveguide by introducing a high-frequency signal to the - to test the characteristics of the microstrip line converter ₁₄ 1, 14 _2. For the signal of the electronic device chip 20 after testing the characteristics of the input / output microstrip line 11 of the high frequency flip chip mounting substrate 10 after the characteristics of the waveguide-microstrip line converter 14 ₁ , 14 ₂ are tested Connect the bumps 21. At this time, the through line 12 and the grounding bump 22 are connected at a position of 1/4 of the wavelength λ of the high frequency signal from the connection portion of the signal bump 21 to form a high frequency module. Finally, the characteristics of the high frequency module are tested. .

As described above, in the embodiment of the present invention, since the through line 12 connecting the input / output microstrip line 11 is provided on the flip chip mounting substrate 10, the waveguide-microstrip line converter 14 ₁ , It becomes possible to inspect the characteristics of 14 ₂ alone. By testing before mounting the expensive electronic device chip 20, chip loss can be eliminated and cost can be reduced. In addition, in the evaluation, it is possible to measure the through characteristic at the waveguide interface, and it is simple because it is not necessary to probe the transmission line substrate.

Further, the waveguide - microstrip line converter 14 _1, 14 ₂ of the characteristic after the inspection is, when mounting the electronic device chip 20, because through line 12 is grounded so that the lambda / 4 short stub The through line 12 does not affect the characteristics of the high frequency module.

  Next, with reference to FIGS. 2 to 5, the manufacturing process of the high frequency module according to the first embodiment of the present invention will be described. FIG. 2 is an explanatory view of a flip chip mounting substrate and a semiconductor chip used for the high frequency module according to the first embodiment of the present invention. FIG. 2A is a plan view of a flip chip mounting substrate. The input / output microstrip line 32 provided on the flip chip mounting substrate 31 and the through line 33 connecting the same are patterned as one unit. In addition, a plurality of grounding pads 34 are provided on both sides of the through line 33 between which the through line 33 is interposed.

  FIG. 2B is a plan view showing the surface on the connection side of the semiconductor chip 36, and a ground conductor pattern 38 of a solid pattern is provided so as to surround the signal pads 37 provided on the left and right. Further, signal bumps 39 are provided in advance on the signal pads 37, and grounding bumps 40 are provided in advance on the ground conductor pattern 38 as well. Note that the grounding bumps 40 are always provided at the position λ / 4 from the signal bumps 37 along the signal propagation direction.

  FIG. 3 is a manufacturing flow of the high frequency module according to the first embodiment of the present invention. First, a flip chip mounting substrate is prepared, the flip chip mounting substrate is attached to a waveguide, and the characteristics of the waveguide-microstrip line converter are inspected. This state will be described with reference to FIG.

FIG. 4 is an explanatory view up to the middle of the manufacturing process of the high frequency module according to the first embodiment of the present invention, and FIG. 4 (a) is a perspective plan view showing an attached state, and FIG. 4 (b) is its equivalent circuit FIG. As shown in FIG. 4A, the flip chip mounting substrate 31 is fixed to the waveguides 41 ₁ and 41 ₂ so as to protrude therefrom, and is covered with the connection cavity 43. At this time, the waveguide-to-microstrip line converter 35 is formed by the protruding portions at both ends of the flip chip mounting substrate 31 and a part of the waveguides 41 ₁ and 41 ₂ . In this state, the characteristic inspection of the waveguide-microstrip line converter 35 is performed. Also in this case, the back short waveguides 42 ₁ and 42 ₂ for forming the λ / 4 short stubs are provided in the lower part of the waveguides 41 ₁ and 41 ₂ .

In this state, as shown in FIG. 4 (b), between the waveguide 41 _1, 41 ₂ and output microstrip line 32 is a waveguide - connected by microstrip line converter 35. Further, the microstrip line 32 and the through line 33 are connected, and a parasitic capacitance 44 connects between the two. The parasitic capacitance 44 is a parasitic capacitance formed between the microstrip line 32 and the ground pad 34. Therefore, since the microstrip lines 32 on both sides are connected by the through line 33, the waveguide-to-microstrip line converter 35 is mounted before the semiconductor chip is mounted by sending a high frequency signal from the waveguide interface. It can be tested alone.

  Referring again to FIG. 3, when the characteristics of the waveguide-to-microstrip line converter 35 are determined to be good as a result of the inspection, the semiconductor chip determined to be a non-defective product is separately tested for characteristics and flip chipped. The high frequency module is inspected by mounting it on the mounting substrate 31. This state will be described with reference to FIG.

  FIG. 5 is an explanatory view after FIG. 4 of the manufacturing process of the high frequency module according to the first embodiment of the present invention, FIG. 5 (a) is a cross sectional view after mounting a semiconductor chip, and FIG. It is a circuit diagram. As shown in FIG. 5A, the semiconductor chip 36 is connected to the input / output microstrip line 32 by the signal bumps 39 and is grounded at a position of 1/4 of the wavelength λ of the high frequency signal used therefrom. 40 are connected to the through line 33. Therefore, the through line 33 becomes the λ / 4 short stub 45, and the impedance becomes infinite with respect to the signal of the wavelength λ.

In this state, as shown in FIG. 5 (b), between the waveguide 41 _1, 41 ₂ and output microstrip line 32 is a waveguide - connected by microstrip line converter 35. The microstrip line 32 and the semiconductor chip 36 are connected by the signal bump 39, and the signal bump 39 and the microstrip line 32 are grounded by the λ / 4 short stub 45 by the through line 33 and the parasitic capacitance 44. It is done. Therefore, the high frequency signal is input to the semiconductor chip 36 without propagating to the through line 33. The high frequency module determined to be non-defective in this inspection will be shipped.

  As described above, in the first embodiment of the present invention, since the through line is provided on the flip chip mounting substrate, characteristics of only the characteristics of the waveguide-microstrip line converter are obtained before the semiconductor chip is mounted. It can be tested alone. By inspecting the waveguide-microstrip line converter portion which requires the highest accuracy in mounting, it is possible to reduce the loss of the highest cost semiconductor chip.

The following appendices will be added to the embodiment of the present invention including the first embodiment.
(Supplementary Note 1) A substrate and a pair of input / output microstrip lines provided at both ends of the substrate and facing each other, a through line connecting the pair of input / output microstrip lines, and provided on both sides across the through line What is claimed is: 1. A high frequency flip chip mounting substrate comprising: a plurality of ground pads.
(Supplementary note 2) The high frequency flip chip mounting substrate according to supplementary note 1, wherein the through line is formed integrally with the pair of input / output microstrip lines.
(Supplementary Note 3) Two waveguides, a connection cavity connecting the two waveguides, and a waveguide-microstrip line fixed to the connection cavity and having both ends connected with the waveguide connection part A high frequency flip chip mounting substrate comprising a converter, a pair of input / output microstrip lines facing each other, and a through line connecting the pair of input / output microstrip lines, and the high frequency flip chip mounting An electronic device chip in which a bump such as a signal is connected to the input / output microstrip line in the substrate for the signal, and the through line is grounded at a position of 1⁄4 of the wavelength of the signal from the connection portion of the signal bump; The high frequency module characterized by having.
(Supplementary note 4) The high frequency module according to supplementary note 3, wherein the two waveguides have a waveguide interface on the opposite side to the portion to be the waveguide-microstrip line converter.
(Supplementary note 5) The high-frequency module according to supplementary note 3 or 4, wherein the two waveguides have a back short waveguide.
(Supplementary Note 6) The surface of the electronic device chip on which the signal pad is provided is provided with a ground conductor except for the signal pad and the insulation separation portion between the signal pad and the signal pad, and the ground conductor is the flip The high frequency module according to any one of claims 3 to 5, wherein the high frequency module is electrically connected to a plurality of grounding pads provided on the mounting surface side of the chip mounting substrate with the through line interposed therebetween.
(Supplementary Note 7) The high frequency module according to any one of Supplementary notes 3 to 6, wherein the electronic device chip is either a semiconductor chip or a superconducting device chip.
(Supplementary Note 8) A process for testing the characteristics of the electronic device chip, and for mounting a high frequency flip chip having a pair of input / output microstrip lines facing each other and a through line connecting the pair of input / output microstrip lines Fixing the substrate in a connection cavity connecting the two waveguides, and making the vicinity of the connection portion between the waveguide and the high frequency flip chip mounting substrate the waveguide-microstrip line converter Introducing a high frequency signal into the waveguide to test the characteristics of the waveguide-microstrip line converter, and for the high frequency after testing the characteristics of the waveguide-microstrip line converter The signal bumps of the electronic device chip after testing the characteristics are connected to the input / output microstrip line of the flip chip mounting substrate A step of forming a high frequency module by flip chip bonding so as to be grounded to the through line at a position of 1⁄4 of a wavelength of the signal from a connection portion of the signal bump, and testing a characteristic of the high frequency module; A method of manufacturing a high frequency module, comprising:

1 ¹ 1 ² waveguide 2 connection cavity 10 substrate for high frequency flip chip mounting 11 input / output micro strip line 12 through line 13 grounding pad 14 ¹ , 14 ² waveguide to micro strip line converter 20 electronic device chip 21 signal bumps 22 ground bumps 31 flip chip mounting substrate 32 input / output microstrip line 33 through line 34 ground pad 35 waveguide-microstrip line conversion unit 36 semiconductor chip 37 signal pad 38 ground conductor pattern 39 signal Bump 40 Grounding bump 41 ₁ , 41 ₂ Waveguide 42 ₁ , 42 ₂ Back short waveguide 43 Connection cavity 44 Parasitic capacitance 45 λ / 4 short stub 51 ₁ , 51 ₂ Wave guide 52 ₁ , 52 ₂ back short waveguide 53 connected cavities 54, 54 _1, 54 ₂ mounting base 55 _1, 55 ₂ microstrip line 56 lambda / 4 short stub ₅₇ 1, 57 ₂ waveguide - microstrip line converter ₅₈ 1, 58 ₂ grounding pad 59 semiconductor chip 60 bonding wire 71 mounting substrate 72 ₁ , 72 ₂ micro strip line 73 grounding pad 74 ₁ , 74 ₂ waveguide-micro strip line converter 75 bump 76 parasitic capacitance

Claims (3)

With two waveguides,
A connection cavity connecting the two waveguides;
A pair of input / output microstrip lines which are fixed to the connection cavity so that both ends thereof form a waveguide-microstrip line converter together with the connection portion of the waveguide, and the pair of input / output microlines A high frequency flip chip mounting substrate including a through line connecting strip lines;
The signal bump is connected to the input / output microstrip line on the high frequency flip chip mounting substrate, and the through line is grounded at a position of 1⁄4 of the signal wavelength from the connection portion of the signal bump. And an electronic device chip. The surface of the electronic device chip on which the input / output pad is provided is provided with a ground conductor except for the input / output pad and the insulation separation portion between the input / output pad and the input / output pad.
The high frequency module according to claim 1 , wherein the ground conductor is electrically connected to a plurality of grounding pads provided on the mounting surface side of the flip chip mounting substrate with the through line interposed therebetween. . Testing the characteristics of the electronic device chip;
A high frequency flip chip mounting substrate comprising a pair of input / output microstrip lines facing each other and a through line connecting the pair of input / output microstrip lines is fixed in a connection cavity connecting two waveguides Using the waveguide-microstrip line converter in the vicinity of the connection between the waveguide and the high frequency flip chip mounting substrate;
Introducing a high frequency signal into the waveguide to test the characteristics of the waveguide-microstrip line converter;
A signal bump of an electronic device chip after testing the characteristics is connected to the input / output microstrip line of the high frequency flip chip mounting substrate after testing the characteristics of the waveguide-microstrip line converter Forming a high frequency module by flip chip bonding so as to be grounded to the through line at a position of 1⁄4 of the wavelength of the signal from the connection portion of the signal bump;
Testing the characteristics of the high frequency module.

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