Lid allowing for a thermal interface material with fluidity in a lidded flip chip package

A lid allowing for a thermal interface material with fluidity in a lidded flip chip package, comprising:

• a top piece with an upper side and a lower side, a foot at the lower side of the top piece, a reservoir structure including a storage tunnel, an injection tunnel, a sealing ring, and a plug structure including a hole and a plug;
• wherein the sealing ring is mounted at the lower side of the top piece, which seals a peripheral edge region at a top surface of a flip chip and/or seals a peripheral region around a flip chip and at a top surface of a substrate so as to form a sealed gap between the flip chip and the top piece;
• wherein the lid further includes a ring-form of cavity at the upper side of its top piece and an island as a portion of the top piece which is surrounded by the ring-form of cavity, a pattern of notch formed at a bottom of the ring-form of cavity, and a covering piece mounted in the ring-form of cavity so as to cover the pattern of notch and form the storage tunnel and the injection tunnel;
• wherein the storage tunnel has two ends, one end, called inner end herein of the said two ends connects to the sealed gap through a connecting hole, the plug structure is formed at the other end, called outer end herein of the said two ends;
• wherein the injection tunnel has two ends, one end, called inner end herein of the said two ends connects to the sealed gap, and the plug structure is formed at the other end called outer end herein of the said two ends;
• and
• wherein the sealed gap is completely filled with a thermal interface material having fluidity, a portion of the storage tunnel is filled with the same thermal interface material, and the remaining portion of the storage tunnel is filled with a gas.