Molded heat sink and method of making same

1. A heat sink for use with a heat generating component, the heat sink comprising:

a molded cooling block including a molded cooling passage form receiving a cooling medium, wherein the cooling block is configured to be positioned in sufficient heat transfer relationship with respect to the heat generating component so that the cooling medium receives heat from the heat generating component; and

a heat transfer member sealed against the cooling block, the heat transfer member being configured to be closely associated with the heat generating component to transfer heat from the heat generating component to the cooling medium, wherein the heat transfer member partially defines the cooling passage such that the cooling passage is spaced away from the heat generating component when the heat sink is used with the heat generating component, wherein the heat transfer member is configured to directly contact the cooling medium when the cooling medium is received in the cooling passage, and the cooling passage is configured such that no cooling medium flows between the heat transfer member and the heat generating component when the heat sink is used with the heat generating component and the cooling medium is received in the cooling passage.

2. The heat sink of claim 1 wherein the cooling block comprises molded plastic.

3. The heat sink of claim 1 wherein the cooling block comprises a composite material.

4. The heat sink of claim 1 wherein the cooling block comprises molded metal.

5. The heat sink of claim 1 wherein the cooling block includes a plurality of the cooling passages, and the cooling passages include an inlet passage, an outlet passage, multiple laterally extending passages, multiple first passages that connect the inlet passage to the lateral passages, and multiple second passages that connect the lateral passages to the outlet passage, and wherein the heat transfer member partially defines each of the laterally extending passages and the heat transfer member is configured to extend between the inlet passage and the heat generating component when the heat sink is attached to the heat generating component.

6. The heat sink of claim 5 wherein the heat transfer member is configured to directly contact the cooling medium when the cooling medium is received in the laterally extending passages.

7. An electronic circuit assembly comprising:

a circuit assembly body;

a molded cooling clock attached to the circuit assembly body and including a molded cooling passage for receiving a cooling medium, wherein the cooling clock is positioned in sufficient heat transfer relationship with respect to the circuit assembly body so that the cooling medium receives heat from the circuit assembly body when the cooling medium is received in the molded cooling passage; and

a heat transfer member sealed against the cooling block and positioned between the cooling block and the circuit assembly body, wherein the heat transfer member partially defines the cooling passage such that the cooling passage is spaced away from the circuit assembly body, wherein the heat transfer member is configured to directly contact the cooling medium when the cooling medium is received in the cooling passage, and the cooling passage is configured such that no cooling medium flows between the heat transfer member and the circuit assembly body when the cooling medium is received in the cooling passage.

8. The circuit assembly of claim 7 wherein the circuit assembly body includes a substrate made of a first material having a first coefficient of thermal expansion, and the cooling block is made of a second material having a second coefficient of thermal expansion that is substantially similar to the first coefficient of thermal expansion.

9. The circuit assembly of claim 7 wherein the cooling block comprises molded plastic.

10. The circuit assembly of claim 7 wherein the cooling block includes a plurality of the cooling passages, and the cooling passages include an inlet passage, an outlet passage, multiple laterally extending passages, multiple first passages that connect the inlet passage to the lateral passages, and multiple second passages that connect the lateral passages to the outlet passage, and wherein the heat transfer member partially defines each of the laterally extending passages, the heat transfer member extends between the inlet passage and the circuit assembly body, and the first passages each extend in a direction transverse to the inlet passage and the heat transfer member.

11. The circuit assembly of claim 10 wherein the heat transfer member is configured to directly contact the cooling medium when the cooling medium is received in the laterally extending passages.

12. A method for making a heat sink for use with a heat generating component, the method comprising:

molding a material to form a cooling block that includes a molded cooling passage for receiving a cooling medium, wherein the cooling block is configured to be positioned in sufficient heat transfer relationship with respect to the heat generating component so that the cooling medium receives heat from the heat generating component when the cooling medium is received in the molded cooling passage; and

sealing a heat transfer member against the cooling block, the heat transfer member being configured to be closely associated with the heat generating component to transfer heat from the heat generating component to the cooling medium when the cooling medium is received in the cooling passage, wherein the heat transfer member partially defines the cooling passage such that the cooling passage is spaced away from the heat generating component when the heat sink is used with the heat generating component, and wherein the heat transfer member is configured to directly contact the cooling medium when the cooling medium is received in the cooling passage, and the cooling passage is configured such that no cooling medium flows between the heat transfer member and the heat generating component when the heat sink is used with the heat generating component and the cooling medium is received in the cooling passage.

13. The method of claim 12 wherein molding the material includes injection molding plastic material to form the cooling block.

14. The method of claim 12 wherein the material comprises plastic.

15. The method of claim 12 wherein the material comprises a composite material.

16. The method of claim 12 wherein the material comprises metal.

17. The method of claim 12 wherein molding the material comprises molding the material to form the cooling block such that the cooling block includes a plurality of the cooling passages, wherein the cooling passages include an inlet passage, an outlet passage, multiple laterally extending passages, multiple first passages that connect the inlet passage to the lateral passages, and multiple second passages that connect the lateral passages to the outlet passage, and wherein the sealing step comprises sealing the heat transfer member against the cooling block such that the heat transfer member partially defines each of the laterally extending passages and such that the heat transfer member is arranged to extend between the inlet passage and the heat generating component when the heat sink is attached to the heat generating component.

18. The method of claim 17 wherein the heat sink is formed such that the heat transfer member is configured to directly contact the cooling medium when the cooling medium is received in the laterally extending passages.