Btu International (BTUI) 10-K 2006 FY Annual report

Exhibit 32.1

CERTIFICATION PURSUANT TO

SECTION 1350, CHAPTER 63 OF TITLE 18, UNITED STATES CODE,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

Pursuant to Section 1350, Chapter 63 of Title 18, United States Code, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, the undersigned, as President and Chief Executive Officer of BTU International, Inc. (the “Company”), does hereby certify that to his knowledge:

1) the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 (the “Report”) fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2) the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company for the periods covered by the Report.

/s/ Paul J. van der Wansem

Paul J. van der Wansem

President, Chief Executive Officer and Chairman of the Board

Dated: March 16, 2007