JP2006278943A - High frequency circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably join a ceramic board to a carrier with a solder even when a curve or swell occurs in the ceramic board or carrier, thereby preventing a leakage of radio waves from a waveguide. <P>SOLUTION: This high frequency circuit board comprises a multilayered ceramic board 1 on which a plurality of pads 8 are formed on a joining face to a carrier board 2 and semiconductor electronic parts 5 are mounted for propagating radio waves, and the carrier board 2 which has waveguide holes 7 for passing the radio waves propagated by the semiconductor electronic parts 5 and retains the multilayered ceramic board 1. Bumps 10a, 10b are formed in the plurality of pads 8 of the multilayered ceramic board 1 by a high temperature solder, respectively, and the plurality of bumps 10a, 10b are joined to the carrier board 2 by a low temperature solder 11 with a lower melting temperature than the bumps 10a, 10b, whereby the multilayered ceramic board 1 is joined to the carrier board 2. The bumps 10a, 10b are formed so that the heights are different so as to follow a face shape of the carrier board 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-frequency circuit board comprising a ceramic substrate on which a circuit for transmitting and receiving radio waves is mounted, and a carrier having a waveguide hole for allowing the radio waves transmitted and received by the ceramic substrate to pass therethrough and holding the ceramic substrate. More particularly, the present invention relates to a bonding structure between a ceramic substrate and a carrier.

  A high-frequency circuit such as a radar includes a ceramic substrate on which a circuit for transmitting and receiving radio waves is mounted, and a carrier that has a waveguide hole for passing the radio waves transmitted and received by the ceramic substrate and holds the ceramic substrate. Often used is a high-frequency circuit board. Conventionally, these ceramic substrate and carrier have been joined by a plate-like solder as a brazing material, but in the case of a plate-like solder, when the plate-like solder is melted and hardened, a void in which air is trapped is formed. As a result, there is a problem that isolation of the waveguide portion cannot be ensured in many cases.

  In order to solve such a problem, in Patent Document 1, a plurality of pad portions arranged in a lattice pattern are provided on the back surface of the ceramic substrate, that is, the bonding surface with the carrier, and high-temperature solder is further provided on the plurality of pad portions. As a spacer for obtaining a predetermined distance from the carrier by providing bumps of a certain height formed in step 1, supply low temperature solder to the carrier side and heat at a temperature at which the low temperature solder melts and the high temperature solder does not melt Therefore, the ceramic substrate and the carrier are joined.

JP 2003-68930 A

  Although the surface state of the ceramic substrate is generally not flat, when a recess (cavity) for mounting an IC is formed on the surface of the ceramic substrate, the firing state becomes uneven due to the change in the thickness of the ceramic substrate. In many cases, more remarkable warpage and undulation occur on the joint surface with the carrier. Further, when the carrier is formed at a low cost by press working, the parts are warped. As described above, when soldered parts are joined together by soldering, the bumps of a certain height are provided as in Patent Document 1, so that the amount of solder is insufficient at a location where the gap is large. In addition, when defects such as the solder fillet width is too narrow or the fillet is not connected occur, and these defects occur around the waveguide, radio waves leak from the defective part, increasing passage loss and Problems such as deterioration of isolation characteristics due to leakage into other adjacent ports occur. Thus, the gap management between the ceramic substrate and the carrier is very important in obtaining a normal fillet shape. Although there is a method of polishing the surface as a method of correcting the warp of the ceramic substrate or the carrier, it is not effective because it leads to an increase in the cost of components.

  The present invention has been made in view of the above, and even when the ceramic substrate or the carrier is warped or swelled, the ceramic substrate and the carrier are securely joined with the brazing material, and the radio wave from the waveguide portion is obtained. An object of the present invention is to obtain a high-frequency circuit board that can prevent leakage.

  In order to solve the above-described problems and achieve the object, the present invention includes a first substrate on which a plurality of pad portions are formed on a joint surface with a second substrate and a circuit for transmitting and receiving radio waves is mounted. And a second substrate that holds the first substrate, and has bumps made of high temperature solder on a plurality of pad portions of the first substrate. In the high-frequency circuit board formed by joining each of the plurality of bumps and the second substrate with a low-temperature solder having a melting temperature lower than that of the bumps, the first substrate and the second substrate are joined. The bumps are formed to have different heights so as to follow the surface shape of the second substrate.

  According to this invention, the height of each bump is formed so as to follow the surface shape of the second substrate.

  According to the present invention, since the height of the bump formed on the first substrate is varied so as to follow the surface shape of the first substrate, the first or second substrate is warped or wavy. However, it is possible to stably join the low-temperature solder as the brazing material, and it is possible to prevent the fillet shape abnormality due to insufficient solder or excessive solder. As a result, the bonding state around the waveguide can be stabilized, the leakage of radio waves can be prevented, and the passage characteristics and isolation characteristics can be improved.

  Embodiments of a high-frequency circuit board and a method for manufacturing the same according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a high-frequency circuit board constituted by a multilayer ceramic substrate 1 and a carrier substrate 2, and FIG. 2 shows a high-frequency circuit board in a state where a part of the multilayer ceramic substrate 1 is omitted. 3 shows the front surface side of the multilayer ceramic substrate 1, FIG. 4 shows the back surface side of the multilayer ceramic substrate 1, and FIG. 5 shows the carrier substrate 2. As shown in FIG.

  As shown in FIGS. 1 to 3, an IC mounting recess (cavity) that is a recess as a semiconductor mounting area is provided at the center of the surface side of a multilayer ceramic substrate (first substrate in the claims) 1. ) 4 is formed, and a semiconductor electronic component 5 including a circuit for transmitting and receiving radio waves is mounted on the IC mounting recess 4. Between the electronic components 5 and between the electronic components 5 and the multilayer ceramic substrate 1 are connected by wiring wires 6.

  On the other hand, on the back surface side of the multilayer ceramic substrate 1, as shown in FIG. 4, a plurality of pad portions 8 made of a material having good solder wettability are arranged in a lattice pattern. On these pad portions 8, bumps made of high-temperature solder are formed in order to ensure the distance between the multilayer ceramic substrate 1 and the carrier substrate 2. When such a grid-like pad portion 8 is employed, there is an advantage that impurities such as flux flow out into the groove between the pad portions 8 during bump formation. Further, on the back surface side of the multilayer ceramic substrate 1, a portion facing the waveguide hole 7 formed in the carrier substrate 2 functions as an input / output part of the dielectric waveguide formed in the multilayer ceramic substrate 1. A waveguide opening 9 is formed. In the waveguide opening portion 9, the ceramic surface is exposed, and a plurality of pad portions 8a formed with an area smaller than that of other portions are arranged around the ceramic surface.

  The carrier substrate 2 (second substrate in the claims) is made of metal and supports the multilayer ceramic substrate 1 as shown in FIGS. A plurality of waveguide holes 7 are formed in the carrier substrate 2. In this case, screw holes 20 for fixing the carrier substrate 2 to other components (not shown) are formed at the four corners of the carrier substrate 2.

  FIG. 6 shows a cross section when the multilayer ceramic substrate 1 and the carrier substrate 2 are joined with solder as a brazing material. In this case, the multilayer ceramic substrate 1 is warped upward and the carrier substrate 2 is warped downward. In the first embodiment, in other words, the gap between the multilayer ceramic substrate 1 and the carrier substrate 2 so that the bumps 10a and 10b formed by the high-temperature solder on the respective pad portions 8 and 8a follow the surface shape of the carrier substrate 2. The heights of the bumps 10a and 10b are made different so that the bump height is high at a portion where the gap is large and the bump height is low at a portion where the gap is small. In FIG. 6, 10a shows a bump with a high height, and 10b shows a bump with a low height. The multilayer ceramic substrate 1 and the carrier substrate 2 are joined by joining the bumps 10a and 10b having different heights and the carrier substrate 2 with the low-temperature solder 11 having a melting temperature lower than that of the bumps 10a and 10b.

  In manufacturing such a high-frequency circuit board, first, lattice-like pad portions 8 and 8a as shown in FIG. 4 are formed on the joint surface of the multilayer ceramic substrate 1 with the carrier substrate 2, and these pad portions are formed. Bumps 10a and 10b having different heights are formed on high temperature solders 8 and 8a. When the multilayer ceramic substrate 1 and the carrier substrate 2 are joined, the change in the gap between the two parts is confirmed in advance, and the bump height is made different according to the gap, so that each bump height is different from that of the carrier substrate 2. Follow the surface shape.

  The warp and undulation state of the multilayer ceramic substrate 1 varies depending on the shape of the IC mounting recess 4 and firing conditions, but depending on the product, the same tendency may be obtained after the shape and conditions are determined. Further, also in the carrier substrate 2, it is possible to quantify the position and the amount of the gap where the gap between both parts is maximized by intentionally unifying the warping direction by sheet metal processing or the like.

  Bumps having different heights can be formed by increasing or decreasing the amount of solder supplied to each of the grid-like pad portions 8 and 8a of the multilayer ceramic substrate 1. When the solder is supplied by screen printing or the like, the thickness of the supplied solder depends on the thickness of the printing mask (stencil), and thus cannot be changed for each location. The amount of solder supply can be increased or decreased by arranging the patterns in accordance with the pattern of the grid-like pad portions 8 and 8a and varying the opening area of the print mask with respect to the pad portions 8 and 8a. Moreover, when supplying solder with a dispenser, bump height in arbitrary places can be changed by increasing / decreasing the solder discharge amount of a dispenser for each pad part 8 and 8a. That is, the bump height increases as the solder supply amount increases.

  When bumps having different heights are formed on the multilayer ceramic substrate 1 in this way, the low-temperature solder 11 is supplied to portions of the carrier substrate 2 corresponding to the pad portions 8 and 8a of the multilayer ceramic substrate 1. The supply of the low-temperature solder to the carrier substrate 2 side is performed by, for example, normal screen printing. Therefore, the thickness of the low temperature solder 11 is constant.

  Next, after positioning the multilayer ceramic substrate 1 on the carrier substrate 2, the whole is heated at a temperature lower than the melting temperature of the bump and higher than the melting temperature of the low-temperature solder to melt the low-temperature solder, and the bump and carrier A solder fillet is formed as a solder joint for joining the substrate 2.

  As described above, in the first embodiment, the height of the solder bumps 10a and 10b on the multilayer ceramic substrate 1 side is made to follow the surface shape of the carrier substrate 2, so that the ceramic substrate and the carrier are warped and undulated. Even when there is, it is possible to stably join the low-temperature solder as the brazing material, and it is possible to prevent the fillet shape abnormality due to insufficient solder or excessive solder. In addition, in a configuration in which a ceramic substrate having a radio wave transmission / reception function or a carrier substrate with a waveguide is bonded, it is possible to stabilize the bonding state around the waveguide that affects characteristics, and to prevent leakage of radio waves. It is possible to prevent this, and pass characteristics and isolation characteristics can be improved.

Embodiment 2. FIG.
A second embodiment of the present invention will be described with reference to FIG. In the second embodiment, high-temperature solder is used on the pad portion 8a (see FIG. 4) around the waveguide opening 9 formed at a position facing the waveguide hole 7 formed in the carrier substrate 2. The height of the bump to be formed is formed higher than the height of the bump formed on the other pad portion.

  As described above, in the second embodiment, the height of the bump formed on the pad portion 8a around the waveguide opening 9 is formed higher than the height of the bump formed on the other pad portion. Therefore, the state in which the periphery of the waveguide opening 9 is always in contact with the carrier substrate 2 can be obtained, and the solder bonding around the waveguide opening 9 can be performed in the bonding with the carrier substrate 2 by low-temperature solder. It becomes possible to stabilize the state. Accordingly, leakage of radio waves from the waveguide portion can be prevented, and the passage characteristics and isolation characteristics of the waveguide portion can be improved.

  Incidentally, in the prior art disclosed in Patent Document 1, as shown in FIG. 8, the height of the bumps 10 made of high-temperature solder is made constant, so that a multilayer ceramic substrate is used as shown in FIG. 1 and the carrier substrate 2 are warped or undulated, the amount of solder is insufficient at the location where the gap is large, resulting in defects such as the solder fillet width being too narrow or not being connected to the fillet. When it occurred around the wave tube, radio waves leaked from the defective portion, causing problems such as an increase in passage loss and degradation of isolation characteristics.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIGS. FIG. 10 shows a high-frequency circuit board constituted by the multilayer ceramic substrate 1 and the carrier substrate 3, and a part of the multilayer ceramic substrate 1 is omitted. FIG. 11 shows the carrier substrate 3, and FIG. 12 shows a cross section when the multilayer ceramic substrate 1 and the carrier substrate 3 are joined with solder as a brazing material. 10 to 12, the same reference numerals are given to components having the same functions as those of the previous embodiment, and duplicate descriptions are omitted.

  In the third embodiment, two types (high temperature solder and low temperature solder) are not used as in the previous embodiment, but only one type of solder 12 is used. Further, a spacer 13 which is a protrusion for supporting the multilayer ceramic substrate 1 is provided at least in the vicinity of the waveguide hole 7 in the carrier substrate 3.

Unlike the bumps used in the first and second embodiments, the spacers 13 need to be arranged optimally. In order to stabilize the solder state in the waveguide portion, it is effective to make the gap between the multilayer ceramic substrate 1 and the carrier substrate 2 at the position of the waveguide hole 7 constant. It is ideal to form the waveguide at the position of the waveguide, but in reality, it is disposed at a position away from the waveguide hole 7 due to the following restrictions.
A spacer cannot be disposed on the waveguide hole 7.
Since the periphery of the waveguide hole 7 must be covered with solder in order to prevent leakage of electromagnetic waves, no spacer can be disposed at a location adjacent to the waveguide hole 7.
Depending on the product, a choke structure may be required on the outer periphery of the solder, and the spacer 13 cannot be disposed in that region.

  As described above, the spacer method has a problem that the position of the waveguide section where the gap variation is to be suppressed and the position of the spacer 13 are separated. In the third embodiment, even when the warp of the multilayer ceramic substrate 1 varies, the spacer arrangement can stabilize the solder joint state around the waveguide hole 7 by suppressing the gap variation in the waveguide position. To choose.

  Therefore, in the third embodiment, as shown in FIGS. 10 and 11, the spacer 13 is located around the waveguide hole 7 and has a warped shape extreme point (maximum point or minimum point) of the multilayer ceramic substrate 1. It is arranged on the side close to (point). In the high-frequency circuit board shown in FIG. 12, the multilayer ceramic substrate 1 has an upward convex shape, and its maximum point is substantially at the center. Therefore, in this case, the spacer 13 is provided near the central portion around the waveguide hole 7.

  Next, it will be proved by using FIGS. 13 to 16 that it is advantageous to arrange the spacer 13 on the side closer to the pole than on the side closer to the pole than the waveguide hole 7. FIGS. 13 and 14 are ½ models of the multilayer ceramic substrate 1 and show two states of the planar shape. 13 and 14, the carrier substrate 2 (not shown) is a straight line parallel to the horizontal axis x. In the following, for simplicity, it is assumed that the carrier substrate 2 is warped 0 mm, and the case where the amount of warpage of the multilayer ceramic substrate 1 changes is described. FIG. 13 shows the multilayer ceramic substrate 1 with a flatness P = 0 mm (ideal flat state), and FIG. 14 shows the flatness P = P0 mm when the standardity of the flatness P is 0 ≦ P ≦ P0. (Maximum warpage state within the standard). The vertical axis y represents the height of the multilayer ceramic substrate 1, and the horizontal axis x represents the horizontal distance from the center (origin) of the multilayer ceramic substrate 1. In FIG. 14, for the sake of convenience, the center of the radius of curvature when the curved shape is approximated by a circular arc is used as the origin for convenience. Therefore, the extreme point of the warp shape (in this case, the maximum point) is on the vertical axis (y axis) of x = 0.

X _WG on the horizontal axis is a position where the waveguide hole 7 is disposed, X _in is a position away from the X _WG by a predetermined distance δ, and X _out is away from the X _WG by a predetermined distance δ. Shows the position. G _in the in case of arranging a spacer 13 to the position X _in, the height position of the multilayer ceramic substrate 1 at a position X _in, the height position of the multilayer ceramic substrate 1 at a position X _WG of the waveguide tube bore 7 It is a value indicating the difference between Also, G _out position the height of the multilayer ceramic substrate 1 in the X _WG of the case of arranging a spacer 13 in position X _out, the height position of the multilayer ceramic substrate 1 at position X _out, guided tube bore 7 It is a value indicating the difference from the position. P0 is the height distance from the maximum point to the end of the multilayer ceramic substrate 1, L is the distance from the maximum point to the position X _WG waveguide lumen 7.

Therefore, it can be said that the smaller the value of G _in and G _out is, the height variation at the position X _WG of the waveguide tube bore 7 is smaller than the flatness variation. For this reason, if G _in <G _out can be proved, it can be proved that it is advantageous to dispose the spacer 13 on the side closer to the pole than on the side closer to the pole.

The magnitude of G _in and G _out, as shown in Figure 15, the slope q _out at the midpoint of the slope q _in the point X _out and the point X _WG at an intermediate point between the point X _in the point X _WG It is equivalent to large and small. The inclinations q _in and q _out are tangents to the shape curve of the multilayer ceramic substrate 1 at each point. If FIG. 15 can be drawn accurately, q _in <q _out is clear, but the fact that the illustration is correct will be described with an equation.

Substrate warpage will be described by approximating an arc. When the radius of curvature is R, the warpage of the substrate is
x ² + y ² = R ²
It is. Solving for y,
y = √ (R ² −x ² ) (1)
It becomes. If both sides of the above equation are differentiated by x, y ′ = (1/2) * (1 / √ (R ² −x ² )) * (− 2x)
= -X / √ (R ² -x ² ) (2)
It becomes.

FIG. 16 is a graph of equation (2) with R = 1. y ′ is the inclination of the tangent line at each point of the multilayer ceramic substrate 1. According to FIG. 16, it can be confirmed that y ′ increases as the distance from the maximum point (in this case, x = 0) increases. That is, q _in <q _out , and thus G _in <G _out .

Here we verify with specific numerical values. For example, the maximum warp prescribed value P0 = 0.2 mm, the total width W of the multilayer ceramic substrate 1 in the x direction W = 20 mm, the distance L from the center of the substrate 1 to the waveguide hole 7 = 7 mm, the spacer 13 and the waveguide hole 7 When the distance δ is 2 mm, G _in = 0.048 mm and G _out = 0.064 mm. That is, when the flatness P of the substrate 1 varies in the range of 0 ≦ P ≦ 0.2 mm, the gap dimension of the vicinity of the position X _WG waveguide lumen 7, is better to place the spacer 13 on the side closer to the pole, 30% less variation than when placed on the far side. Thus, when the spacer 13 is disposed on the side closer to the pole from the waveguide hole 7, the warpage of the substrate is less than the standard value compared to the case where the spacer 13 is disposed on the side far from the waveguide hole 7 to the pole. even if the varied in, it is possible to suppress variation of the gap dimension of the vicinity of the position X _WG waveguide lumen 7.

  By the way, warpage often occurs on the outer peripheral portion side of the multilayer ceramic substrate 1 during firing. For this reason, when the spacer 13 is provided not on the outer side but on the inner side (center side) around the waveguide hole 7, the gap between the multilayer ceramic substrate 1 and the carrier substrate 3 is always constant without being affected by the warp. Can be secured.

  In the third embodiment, the solder 12 for joining both components may be supplied to the multilayer ceramic substrate 1 side, or may be supplied to the carrier substrate 3 side on which the spacer 13 is formed. . When supplying to the carrier substrate 3 side, when using a printing mask thicker than the protrusion height of the spacer 13, printing is performed in the same manner as when the spacer 13 is not provided by providing an opening in a portion of the printing mask where the spacer 13 interferes. Solder can be supplied at

  Thus, according to the third embodiment, since the spacer 13 is formed in the vicinity of the waveguide hole 7, the gap between the multilayer ceramic substrate 1 and the carrier substrate 3 in the vicinity of the waveguide hole 7 is reduced. The solder joint state around the waveguide hole can be stabilized, and the fillet width is too narrow due to insufficient solder in the vicinity of the waveguide, and the fillet is introduced due to excessive solder. It becomes possible to prevent the fillet shape abnormality such as the drop into the wave tube hole 7. Therefore, leakage of radio waves from the waveguide portion can be prevented, and pass characteristics and isolation characteristics can be improved.

  Incidentally, when the spacer 13 is formed at a position close to the outer periphery of both parts, as shown in FIG. 17, when the gap between the two parts is large in the vicinity of the waveguide hole 7, the solder is insufficient. If a fillet-shaped defect occurs or if the gap between the two parts is large in the vicinity of the waveguide hole 7 as shown in FIG. 18, the amount of solder becomes excessive and excess solder overflows into the waveguide hole. As a result, there is a problem that the passage loss increases or the isolation characteristic deteriorates.

  Further, in the third embodiment, since one kind of solder is used, the upper limit of the solder melting temperature, which is a limitation in the methods of the first and second embodiments, can be eliminated. Temperature management becomes easy. That is, in a structure in which bumps are formed with high-temperature solder, it is necessary to control the heating temperature when melting low-temperature solder within the melting point temperature range of both solders. A combination of solders that increases the difference in melting temperature is required. In recent years, the need to select lead-free solder has been increasing for environmental protection, but in the case of lead-containing solder, there are many solders with different melting temperatures, so it is possible to easily select combinations with a wide temperature range. However, since lead-free solder has fewer types of solder with different melting temperatures, the difference in melting temperature is narrower than that of lead-containing solder. Therefore, strict temperature control is required.

  In the third embodiment, the spacer 13 is provided integrally with the carrier substrate 3. However, for example, a spacer as a separate part such as a bonding wire is attached to the multilayer ceramic substrate 1 or the carrier substrate 3. It may be. Further, when the lower convex carrier substrates 2 and 3 are employed, when the carrier substrates 2 and 3 are screwed to other parts such as the lower antenna substrate through the four screw holes 20, they are positioned at the center portion. There is an advantage that the waveguide hole 7 is surely brought into contact with another component below.

  As described above, the high-frequency circuit board according to the present invention is useful for a high-frequency circuit board including a carrier substrate having a waveguide through which a high frequency passes and a multilayer ceramic substrate on which a circuit for transmitting and receiving a high frequency is mounted. is there.

It is a perspective view which shows the external appearance structure of a high frequency circuit board. It is a perspective view which shows the external appearance structure of the high frequency circuit board of the state which abbreviate | omitted some multilayer ceramic substrates. It is a perspective view which shows the external appearance structure of the surface side of a multilayer ceramic substrate. It is a perspective view which shows the external appearance structure of the back surface side of a multilayer ceramic substrate. It is a perspective view which shows the external appearance structure of a carrier substrate. 3 is a cross-sectional view showing a bonding structure between a multilayer ceramic substrate and a carrier substrate in the high-frequency circuit board according to Embodiment 1. FIG. FIG. 6 is a cross-sectional view showing a bonding structure between a multilayer ceramic substrate and a carrier substrate in the high-frequency circuit board according to the second embodiment. It is sectional drawing which shows a prior art. It is sectional drawing which shows a prior art. FIG. 6 is a perspective view showing an external configuration of a high-frequency circuit board according to a third embodiment. 6 is a perspective view showing an external configuration of a carrier substrate used for a high-frequency circuit board according to Embodiment 3. FIG. FIG. 6 is a cross-sectional view showing a bonding structure between a multilayer ceramic substrate and a carrier substrate in the high-frequency circuit board according to Embodiment 3. It is a figure which shows the relationship between the position of a multilayer ceramic substrate in an ideal plane state, and a gap. It is a figure which shows the relationship between the position of a multilayer ceramic substrate in the state of maximum curvature within a specification, and a gap. It is a figure which shows the inclination of the board | substrate in a waveguide part inner side and an outer side. It is a figure which shows the relationship between the inclination of a board | substrate, and a horizontal position. It is sectional drawing which shows the joining structure which has arrange | positioned the spacer in the outer peripheral part. It is sectional drawing which shows the joining structure which has arrange | positioned the spacer in the outer peripheral part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multilayer ceramic substrate 2 Carrier substrate 3 Carrier substrate 4 IC mounting recessed part 5 Semiconductor electronic component 6 Wiring wire 7 Waveguide hole 8, 8a Pad part 9 Waveguide opening part 10, 10a, 10b Bump 11 Low-temperature solder 12 Solder 13 Spacer 20 Screw hole

Claims (5)

A plurality of pad portions are formed on the joint surface with the second substrate, and a first substrate on which a circuit for transmitting and receiving radio waves is mounted, and a waveguide hole for allowing the radio waves transmitted and received by the circuit to pass therethrough. And a second substrate for holding the first substrate, bumps are respectively formed on the plurality of pad portions of the first substrate with high-temperature solder, and the plurality of bumps and the second substrate are formed more than the bumps. In the high-frequency circuit board in which the first substrate and the second substrate are joined by joining with a low-temperature solder having a low melting temperature,
A high-frequency circuit board, wherein the bumps are formed to have different heights so as to follow the surface shape of the second substrate. A plurality of pad portions are formed on the joint surface with the second substrate, and a first substrate on which a circuit for transmitting and receiving radio waves is mounted, and a waveguide hole for allowing the radio waves transmitted and received by the circuit to pass therethrough. And a second substrate for holding the first substrate, bumps are respectively formed on the plurality of pad portions of the first substrate with high-temperature solder, and the plurality of bumps and the second substrate are formed more than the bumps. In the high-frequency circuit board in which the first substrate and the second substrate are joined by joining with a low-temperature solder having a low melting temperature,
The height of the bump formed on the pad portion around the waveguide opening in the portion facing the waveguide hole is set to the height of the bump formed on the pad portion other than the pad portion around the waveguide opening. A high-frequency circuit board characterized by being formed higher than the height.   The high-frequency circuit board according to claim 2, wherein the second substrate has an upward convex shape, and the first substrate has a downward convex shape. A first substrate on which a circuit for transmitting and receiving radio waves is mounted; and a second substrate having a waveguide hole for allowing the radio waves transmitted and received by the circuit to pass therethrough and holding the first substrate, In the high-frequency circuit board in which the first substrate and the second substrate are joined by the brazing material,
A high-frequency circuit board characterized in that a spacer for supporting the first substrate is provided at least in the vicinity of the waveguide hole in the second substrate.   The high-frequency circuit board according to claim 4, wherein the spacer is formed on a side near the pole of the first substrate in the vicinity of the waveguide hole.

Images