Radio frequency module and method for manufacturing the same
A radio frequency module includes a wiring substrate, a plurality of components mounted on an upper surface of the wiring substrate, a sealing resin layer laminated on the upper surface of the wiring substrate and covering the plurality of components, a groove formed in an upper surface of the sealing resin layer and extending between predetermined components of the plurality of components, and a shielding wall made of conductive paste in the groove. The sealing resin layer has a stepped area defining the higher portion and lower portion in the upper surface. The groove intersects the stepped area when the wiring substrate is seen in plan view.
1. A radio frequency module comprising:
a wiring substrate;
a plurality of components mounted on a principal surface of the wiring substrate;
a sealing resin layer laminated on the principal surface of the wiring substrate and covering the plurality of components;
a groove provided in the sealing resin layer and extending between a component and another component of the plurality of components; and
a shielding wall made of a conductor and arranged in the groove,
wherein the sealing resin layer has a stepped area in an opposite surface of the sealing resin layer that is opposed to a surface of the sealing resin layer that is in direct contact with the principal surface of the wiring substrate, and
the groove intersects the stepped area when the wiring substrate is seen in plan view,
wherein the stepped area comprises a higher surface, a lower surface and a stepped surface that links the higher surface to the lower surface.
2. The radio frequency module according to claim 1 , wherein the shielding wall includes a first portion in which a portion of the groove on a higher portion side of the stepped area in the sealing resin layer, the portion ending before the stepped area and not reaching the stepped area, is filled with the conductor up to a height of the higher portion and a second portion in which a remaining portion of the groove on the higher portion side of the stepped area is filled with the conductor up to a height of a lower portion of the stepped area, and
the groove has an unfilled region not filled with the conductor, the unfilled region being defined by a stepped area of the first portion and a top surface of the remaining portion of the groove filled with the conductor up to the height of the lower portion of the stepped area in the second portion of the shielding wall.
3. The radio frequency module according to claim 2 , further comprising a shielding film that covers at least the opposite surface of the sealing resin layer and a wall surface defining the unfilled region of the groove.
4. The radio frequency module according to claim 3 , wherein a width of the unfilled region of the groove is wider than a width of a portion of the groove other than the unfilled region when viewed in a direction perpendicular to the principal surface of the wiring substrate.
5. The radio frequency module according to claim 3 , wherein the stepped area is inclined from the higher portion toward the lower portion.
6. The radio frequency module according to claim 2 , wherein a width of the unfilled region of the groove is wider than a width of a portion of the groove other than the unfilled region when viewed in a direction perpendicular to the principal surface of the wiring substrate.
7. The radio frequency module according to claim 6 , wherein the stepped area is inclined from the higher portion toward the lower portion.
8. The radio frequency module according to claim 2 , wherein the stepped area is inclined from the higher portion toward the lower portion.
9. The radio frequency module according to claim 2 , wherein the stepped area has a shape in which a stepped corner portion is chamfered.
10. The radio frequency module according to claim 1 , wherein the shielding wall is provided by fully filling the groove with the conductor.
11. The radio frequency module according to claim 10 , wherein the stepped area is inclined from the higher portion toward the lower portion.
12. The radio frequency module according to claim 1 , wherein the stepped area is inclined from the higher portion toward the lower portion.
13. The radio frequency module according to claim 1 , wherein the stepped area has a shape in which a stepped corner portion is chamfered.
14. The radio frequency module according to claim 1 , wherein the groove and the stepped area obliquely intersect with each other in the plan view.
15. The radio frequency module according to claim 1 , wherein the stepped area in the sealing resin layer is curved in the plan view.
16. The radio frequency module according to claim 1 , further comprising a shielding film that covers at least the opposite surface of the sealing resin layer,
wherein the shielding wall includes a portion on a higher portion side of the stepped area and a portion on a lower portion side thereof, both of the portions being arranged separately, and
the shielding film further covers a wall surface defining the groove between the portion on the higher portion side and the portion on the lower portion side of the shielding wall.
17. The radio frequency module according to claim 1 , wherein the lower surface is substantially parallel with the higher surface, the stepped surface extends in a direction perpendicular to the higher surface and the lower surface, and
the higher surface is provided on an outermost surface of the sealing resin layer that is opposite to the surface of the sealing resin layer that is in direct contact with the principal surface of the wiring substrate, and the lower surface is closer to the principal surface of the wiring substrate than the higher surface.
18. A method for manufacturing a radio frequency module, the method comprising:
a preparation step of preparing a component-sealed structure including a wiring substrate, a plurality of components mounted on a principal surface of the wiring substrate, and a sealing resin layer laminated on the principal surface of the wiring substrate and covering the plurality of components, the sealing resin layer having a stepped area in an opposite surface of the sealing resin layer that is opposed to a surface of the sealing resin layer that is in direct contact with the principal surface of the wiring substrate;
a shielding wall forming step of forming a groove in the sealing resin layer, the groove extending between a component and another component of the plurality of components and intersecting the stepped area when the wiring substrate is seen in plan view, and of forming a shielding wall in the groove; and
a shielding film forming step of forming a shielding film that covers at least the opposite surface of the sealing resin layer by using a film deposition technique,
wherein the shielding wall forming step includes
a first step of forming a section of the groove in the opposite surface of the sealing resin layer on a higher portion side of the stepped area by laser processing, the section extending to near the stepped area, a second step of forming a first portion of the shielding wall by filling the section of the groove formed in the first step with conductive paste,
a third step of forming a remaining portion of the groove by laser processing, and
a fourth step of forming a second portion of the shielding wall by inserting the conductive paste into the remaining portion of the groove up to a height of a lower portion side of the stepped area in the sealing resin layer and of forming an unfilled region not filled with the conductive paste in the groove, and
in the shielding film forming step, the shielding film covers a wall surface defining the unfilled region of the groove, together with the opposite surface of the sealing resin layer.
19. A method for manufacturing a radio frequency module, the method comprising:
a preparation step of preparing a component-sealed structure including a wiring substrate, a plurality of components mounted on a principal surface of the wiring substrate, and a sealing resin layer laminated on the principal surface of the wiring substrate and covering the plurality of components, the sealing resin layer having a stepped area in an opposite surface of the sealing resin layer that is opposed to a surface of the sealing resin layer that is in direct contact with the principal surface of the wiring substrate;
a shielding wall forming step of forming a groove in the sealing resin layer, the groove extending between a component and another component of the plurality of components and intersecting the stepped area when the wiring substrate is seen in plan view, and of forming a shielding wall in the groove; and
a shielding film forming step of forming a shielding film that covers at least the opposite surface of the sealing resin layer by using a film deposition technique,
wherein the shielding wall forming step includes
a fifth step of forming a portion of the groove extending to near the stepped area on a higher portion side of the stepped area and a portion of the groove extending to near the stepped area on a lower portion side of the stepped area by laser processing,
a sixth step of forming the shielding wall including a portion on the higher portion side of the sealing resin layer and a portion on the lower portion side thereof, both of the portions being arranged separately, by filling the portion of the groove extending to near the stepped area on the higher portion side and the portion of the groove extending to near the stepped area on the lower portion side with conductive paste, and
a seventh step of forming a remaining portion of the groove other than the portions formed in the fifth step by laser processing, and
in the shielding film forming step, the shielding film covers a wall surface defining the remaining portion of the groove, together with the opposite surface of the sealing resin layer.