Foxconn Electronics (Hon Hai Precision Industry) and Siliconware Precision Industries (SPIL) are scheduled to hold a press conference on September 16 to announce that the pair has entered into a strategic alliance and share exchange agreement to finalize their partnership, according to a statement issued by SPIL.

Foxconn and SPIL expect to complete the exchange of shares enabling a strategic partnership between the two on December 1, 2015, SPIL indicated.

"The alliance will not only provide customers with the best integrated service program through future collaboration on technology and business, but also establish a vertical integration of the electronics industry through this alliance," SPIL said in the statement.

SPIL chairman Bough Lin and Foxconn chairman Terry Guo will both be present at the September 16 event to disclose details of the two companies' partnership.

SPIL and Foxconn announced on August 28 plans to form a strategic partnership through share swaps. One Foxconn share will be exchanged for 2.34 SPIL shares in a deal that will make Foxconn the largest shareholder of SPIL.

But earlier during the week of August 24, SPIL confirmed the company had received notice of an unsolicited tender offer by Advanced Semiconductor Engineering (ASE) to buy a major stake in the company.

Lin has urged shareholders of SPIL not to sell their holdings to ASE. ASE's investment in SPIL is unlikely to create a synergy as many customers from both sides are overlapped, Lin was quoted as saying in previous reports.

In response to Lin's remarks, ASE chairman Jason Chang reiterated ASE's plan to buy 5-25% of SPIL and is looking to complete its tender offer for the company on the target date (September 22).