Interposers with circuit modules encapsulated by moldable material in a cavity, and methods of fabrication

1. A circuit assembly comprising a plurality of levels “Li” where Li varies from L 0 through Ln, i being an integer varying from 0 to n, wherein n is an integer greater than one, the circuit assembly comprising a substrate whose top side comprises a cavity comprising a bottom wall;

wherein the level L 0 comprises:

the bottom wall;

a plurality of through-holes each of which passes through the bottom wall;

a plurality of conductors (“L 0 conductors”) in respective through-holes;

wherein at least part of level L 1 overlies at least part of level L 0 , and wherein level L 1 comprises one or more circuit modules each of which has one or more contact pads each of which is electrically connected to one or more L 0 conductors;

wherein for each level Li other than L 0 and L 1 :

at least part of level Li overlies at least part of level Li- 1 ;

each level Li comprises one or more circuit modules each of which has one or more contact pads each of which is electrically connected to one or more L 0 conductors by one or more first electrically conductive paths lying in the cavity, each first electrically conductive path passing through each level L 1 through Li- 1 ;

wherein at least one first electrically conductive path passes through more than one of the levels L 1 through Ln- 1 .

2. A circuit assembly comprising a plurality of levels “Li” where Li varies from L 0 through Ln, i being an integer varying from 0 to n, wherein n is an integer greater than one, the circuit assembly comprising a substrate whose top side comprises a cavity comprising a bottom wall;

wherein the level L 0 comprises:

the bottom wall;

a plurality of through-holes each of which passes through the bottom wall;

a plurality of conductors (“L 0 conductors”) in respective through-holes;

wherein for each level Li other than L 0 and L 1 :

at least part of level Li overlies at least part of level Li- 1 ;

each level Li comprises one or more circuit modules each of which has one or more contact pads each of which is electrically connected to one or more L 0 conductors by one or more first electrically conductive paths lying in the cavity;

wherein the substrate comprises:

a first substrate comprising the bottom wall; and

a second substrate comprising sidewalls of the cavity, the second substrate being attached to the first substrate;

wherein an interface region of the first and second substrates is not uniform with respect to at least one of: chemical composition, density, elasticity modulus, conductivity, dielectric constant, ultrasound propagation speed for one or more wavelengths, light propagation speed for one or more wavelengths not exceeding an infrared wavelength.

3. The circuit assembly of claim 1 further comprising a plurality of first encapsulant layers made of a moldable material, wherein each level L 1 through Ln- 1 comprises at least one first encapsulant layer laterally encapsulating the one or more circuit modules at that level.

4. The circuit assembly of claim 3 wherein at least a first portion of each first encapsulant layer rises at least as high as a top surface of at least one circuit module laterally encapsulated by the first encapsulant layer;

wherein at least the first portion of each first encapsulant layer reaches down at least as low as a bottom surface of at least one circuit module laterally encapsulated by the first encapsulant layer;

wherein at least the first portion of each first encapsulant layer is formed in a single curing operation with no separately cured sub-layers.

5. The circuit assembly of claim 4 wherein for each first electrically conductive path passing through any first encapsulant layer, the first electrically conductive path comprises a vertical segment passing through the first encapsulant layer.

6. The circuit assembly of claim 3 wherein at least one level Li with i greater than 0 comprises at least one horizontal segment in at least one first electrically conductive path passing through the level's first encapsulant layer, the horizontal segment being below the first encapsulant layer of the level Li.

7. The circuit assembly of claim 6 wherein the horizontal segment overlies the first encapsulant layer of the level Li- 1 and at least one die of the level Li- 1 , the die being covered by the first encapsulant layer of the level Li- 1 .

8. A circuit assembly comprising a plurality of levels “Li” where Li varies from L 0 through Ln, i being an integer varying from 0 to n, wherein n is an integer greater than one, the circuit assembly comprising a substrate whose top side comprises a cavity comprising a bottom wall;

wherein the level L 0 comprises:

the bottom wall;

a plurality of through-holes each of which passes through the bottom wall;

a plurality of conductors (“L 0 conductors”) in respective through-holes;

wherein for each level Li other than L 0 and L 1 :

at least part of level Li overlies at least part of level Li- 1 ;

each level Li comprises one or more circuit modules each of which has one or more contact pads each of which is electrically connected to one or more L 0 conductors by one or more first electrically conductive paths lying in the cavity;

wherein the assembly further comprises:

a plurality of first encapsulant layers made of a moldable material, wherein each level L 1 through Ln- 1 comprises at least one first encapsulant layer laterally encapsulating the one or more circuit modules at that level; and

one or more second electrically conductive paths in the cavity, wherein each second electrically conductive path does not have electrical functionality but is for enhancing heat removal from the circuit assembly to the ambient, wherein each second electrically conductive path extends from an L 0 conductor through one or more levels other than L 0 .

9. The circuit assembly of claim 3 wherein each first encapsulant layer has a planar top surface.

10. The circuit assembly of claim 1 wherein each through-hole through the bottom wall is vertical, and each L 0 conductor is vertical.

11. A manufacturing method comprising:

obtaining a structure comprising:

a substrate whose top side comprises a cavity comprising a bottom wall, the substrate comprising a plurality of through-holes (“L 0 through-holes”) each of which passes through the bottom wall;

a plurality of conductors (“L 0 conductors”) each of which passes through a respective L 0 through-hole;

a conductive layer underlying the bottom wall and electrically connected to each L 0 conductor;

attaching one or more circuit modules (“L 1 circuit modules”) to a bottom of the cavity to electrically connect one or more contact pads of each L 1 circuit module to one or more L 0 conductors;

forming an encapsulant layer (“L 1 encapsulant layer”) of a moldable material to laterally encapsulate the one or more L 1 circuit modules;

forming one or more through-holes (“L 1 through-holes”) in the L 1 encapsulant layer, each L 1 through-hole exposing a feature provided by, or electrically connected to, at least one L 0 conductor; and

electroplating conductive material into the L 1 through-holes onto the features exposed by the L 1 through-holes, to form one or more L 1 conductors, each L 1 conductor passing through a respective L 1 through-hole, wherein the electroplating comprises providing an electroplating current flowing through the features, the L 0 conductors, the conductive layer, and a terminal of an electric power source coupled to the conductive layer.

12. The method of claim 11 wherein the substrate comprises:

a first substrate comprising the bottom wall; and

a second substrate comprising sidewalls of the cavity, the second substrate being attached to the first substrate; and

obtaining the structure comprises attaching the first substrate to the second substrate to provide said substrate.

13. The method of claim 11 further comprising forming a redistribution layer on the bottom of the cavity, wherein said features are at a top of the redistribution layer, the redistribution layer electrically connecting the features to the L 0 conductors.

14. The method of claim 11 further comprising:

attaching one or more circuit modules (“L 2 circuit modules”) inside the cavity to electrically connect one or more contact pads of each L 2 circuit module to one or more L 1 conductors;

forming an encapsulant layer (“L 2 encapsulant layer”) of a moldable material to laterally encapsulate the one or more L 2 circuit modules;

forming one or more through-holes (“L 2 through-holes”) in the L 2 encapsulant layer, each L 2 through-hole exposing a feature provided by, or electrically connected to, at least one L 1 conductor; and

electroplating conductive material into the L 2 through-holes onto the features exposed by the L 2 through-holes, to form a plurality of L 2 conductors, each L 2 conductor passing through a respective L 2 through-hole, wherein the electroplating comprises providing an electroplating current flowing through the L 1 conductors, the L 0 conductors, the conductive layer, and a terminal of an electric power source coupled to the conductive layer.

15. A circuit assembly comprising:

a substrate whose top side comprises a cavity comprising a bottom wall;

a plurality of through-holes each of which passes through the bottom wall;

a plurality of conductors in respective through-holes;

a plurality of circuit modules in the cavity, each circuit module having one or more contact pads;

a plurality of first encapsulant layers overlying one another in the cavity, wherein each first encapsulant layer is made of a moldable material and laterally encapsulates one or more of the circuit modules;

a plurality of first electrically conductive paths each of which lies in the cavity and passes through one or more first encapsulant layers to connect at least one contact pad of at least one circuit module to at least one of said conductors, at least one of the first electrically conductive paths passing through more than one of the first encapsulant layers.

16. A circuit assembly comprising:

a substrate whose top side comprises a cavity comprising a bottom wall;

a plurality of through-holes each of which passes through the bottom wall;

a plurality of conductors in respective through-holes;

a plurality of circuit modules in the cavity, each circuit module having one or more contact pads;

a plurality of first encapsulant layers overlying one another in the cavity, wherein each first encapsulant layer is made of a moldable material and laterally encapsulates one or more of the circuit modules;

a plurality of first electrically conductive paths each of which lies in the cavity and passes through one or more first encapsulant layers to connect at least one contact pad of at least one circuit module to at least one of said conductors;

wherein the substrate comprises:

a first substrate comprising the bottom wall; and

a second substrate comprising sidewalls of the cavity, the second substrate being attached to the first substrate;

wherein an interface region of the first and second substrates is not uniform with respect to at least one of: chemical composition, density, elasticity modulus, conductivity, dielectric constant, ultrasound propagation speed for one or more wavelengths, light propagation speed for one or more wavelengths not exceeding an infrared wavelength.

17. The circuit assembly of claim 15 wherein at least a first portion of each first encapsulant layer rises at least as high as a top surface of at least one circuit module laterally encapsulated by the first encapsulant layer;

wherein at least the first portion of each first encapsulant layer reaches down at least as low as a bottom surface of at least one circuit module laterally encapsulated by the first encapsulant layer;

wherein at least the first portion of each first encapsulant layer is formed in a single curing operation with no separately cured sub-layers.

18. The circuit assembly of claim 17 wherein each encapsulant layer has a planar top surface.

19. The circuit assembly of claim 15 further comprising one or more horizontal electrically conductive interconnects each of which belongs to at least one first electrically conductive path passing through a first encapsulant layer overlying the horizontal electrically conductive interconnect.

20. A circuit assembly comprising:

a substrate whose top side comprises a cavity comprising a bottom wall;

a plurality of through-holes each of which passes through the bottom wall;

a plurality of conductors in respective through-holes;

a plurality of circuit modules in the cavity, each circuit module having one or more contact pads;

a plurality of first encapsulant layers overlying one another in the cavity, wherein each first encapsulant layer is made of a moldable material and laterally encapsulates one or more of the circuit modules;

a plurality of first electrically conductive paths each of which lies in the cavity and passes through one or more first encapsulant layers to connect at least one contact pad of at least one circuit module to at least one of said conductors;

one or more second electrically conductive paths in the cavity, wherein each second electrically conductive path does not have electrical functionality but is for enhancing heat removal from the circuit assembly to the ambient, wherein each second electrically conductive path begins at a conductor in the through-hole and extends through one or more of the encapsulant layers.

21. The circuit assembly of claim 15 wherein each through-hole through the bottom wall is vertical, and each conductor in each through-hole in the bottom wall is vertical.

22. The circuit assembly of claim 1 wherein each said circuit module is a die or a multi-chip module.

23. The circuit assembly of claim 1 wherein at least one first electrically conductive path passing through more than one of the levels L 1 through Ln comprises a vertical segment terminating at a contact pad attached to a contact pad of at least one said circuit module at a level other than L 1 .

24. The circuit assembly of claim 1 wherein at least one first electrically conductive path passing through more than one of the levels L 1 through Ln comprises a vertical segment terminating at a contact pad attached to a contact pad of at least one said circuit module at a level other than L 1 and other than L 2 .

25. The circuit assembly of claim 1 wherein the substrate is uniform medium with respect to chemical composition, density, elasticity modulus, dielectric constant, ultrasound (US) propagation speed for one or more US wavelengths, and infrared radiation propagation speed for one or more infrared wavelengths.

26. The method of claim 11 wherein each said circuit module is a die or a multi-chip module.

27. The circuit assembly of claim 15 wherein each said circuit module is a die or a multi-chip module.

28. The circuit assembly of claim 15 wherein at least one first electrically conductive path passing through more than one of the first encapsulant layers comprises a vertical segment terminating at a contact pad attached to a contact pad of at least one said circuit module laterally encapsulated by one of said first encapsulant layers overlying at least one other one of said first encapsulant layers.

29. The circuit assembly of claim 15 wherein at least one first electrically conductive path passing through more than one of the first encapsulant layers comprises a vertical segment terminating at a contact pad attached to a contact pad of at least one said circuit module laterally encapsulated by one of said first encapsulant layers overlying at least two other ones of the said first encapsulant layers.

30. The circuit assembly of claim 15 wherein the substrate is uniform medium with respect to chemical composition, density, elasticity modulus, dielectric constant, ultrasound (US) propagation speed for one or more US wavelengths, and infrared radiation propagation speed for one or more infrared wavelengths.