v3.26.1
Cover
Jul. 14, 2026
Document Information [Line Items]  
Document Type 8-K
Amendment Flag false
Document Period End Date Jul. 14, 2026
Entity File Number 001-42514
Entity Registrant Name Archimedes Tech SPAC Partners II Co.
Entity Central Index Key 0002028516
Entity Tax Identification Number 00-0000000
Entity Incorporation, State or Country Code E9
Entity Address, Address Line One 2093 Philadelphia Pike #1968
Entity Address, City or Town Claymont
Entity Address, State or Province DE
Entity Address, Postal Zip Code 19703
City Area Code 725
Local Phone Number 312-2430
Written Communications true
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company true
Elected Not To Use the Extended Transition Period false
Units [Member]  
Document Information [Line Items]  
Title of 12(b) Security Units, each consisting of one Ordinary Share, par value $0.0001 per share, and one-half of one redeemable Warrant
Trading Symbol ATIIU
Security Exchange Name NASDAQ
Ordinary Shares [Member]  
Document Information [Line Items]  
Title of 12(b) Security Ordinary Shares
Trading Symbol ATII
Security Exchange Name NASDAQ
Warrants [Member]  
Document Information [Line Items]  
Title of 12(b) Security Warrants
Trading Symbol ATIIW
Security Exchange Name NASDAQ