Interconnect Flux is water-soluble.
Press Release Summary:

Designed for use in BGA bumping and board level attachment, WS-364 water-soluble paste-flux can be applied by pin-transfer or stencil printing. It can be cleaned using room-temperature water and offers high yield in BGA bumping process. Available in syringes or cartridges, halide-free product is suitable for Sn/Pb and Pb-free applications.
Original Press Release:
Indium Corporation Introduces New Interconnect Flux
Indium Corporation has introduced a new high viscosity paste-flux, called WS-364, designed for use in BGA bumping and board level attachment. This new water-soluble flux has excellent cleanability using room temperature water.
With a wide process window, WS-364 can be applied by pin-transfer or stencil printing and offers exceptionally high yield in the BGA bumping process. Halide-free with excellent solderability, WS-364 is suitable for Sn/Pb and Pb-free applications and is available in syringes or cartridges.
Indium Corporation is a three-time Frost & Sullivan Award-winning supplier of electronics assembly materials, including solder pastes, solder preforms, fluxes, Pb-Free solder alloys, underfill materials, die-attach materials, and more. The company is also the world's premiere supplier of commercial grade and high-purity indium. Factories are located in North America, Europe, and Asia. Founded in 1934, the company is ISO 9001 registered.
For more information on WS-364, visit Indium Corporation of America at www.indium.com or email askus@indium.com.