What is prior art, and what is the on-sale bar? Both come from 35 U.S.C. 102, the novelty provision of the Patent Act. The section lists the events that, if they occur before the effective filing date of a claimed invention, bar a patent on it: the invention being patented, described in a printed publication, in public use, on sale, or otherwise available to the public. Each of those is a category of prior art. The "on sale" item is the on-sale bar specifically — a rule that a commercial offer to sell the invention before the filing date can defeat patentability, even if the sale came from the inventor's own company. The unifying idea is that the patent system rewards bringing something new; if the invention was already out in the world before filing, the novelty needed for a patent is gone.

The operative language is in section 102(a)(1). The statute provides that a person shall be entitled to a patent unless:

the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.— 35 U.S.C. § 102(a)(1), source

Read the list as five triggering events tied to one cutoff. "Patented" and "described in a printed publication" cover documentary prior art — an earlier patent or any published description anywhere in the world. "In public use" covers non-secret use of the invention. "On sale" is the commercial-activity trigger: an offer for sale or a sale of the invention. And "or otherwise available to the public" is a catch-all added in the America Invents Act phrasing, capturing public availability that does not fit the named categories. All five are measured against the same line: "before the effective filing date of the claimed invention." That date — the actual filing date, or an earlier priority date the application is entitled to — is the clock against which every prior-art event is judged.

Why the on-sale bar matters in a fast-moving sector

The on-sale clause has bite in industries where products move from lab to commercial offer quickly, and the semiconductor sector is one of them. A device sampled to a customer, an interconnect structure offered in a product line, or a packaging method embodied in a part that is offered for sale can all start the on-sale analysis. The risk a 102 analysis manages is that an invention's own commercialization, if it precedes the patent filing, becomes the prior art that bars the patent. That is why IP and product timelines are coordinated: the filing should precede the public-availability events the statute lists, or the inventor must rely on the narrow exceptions the statute provides. The point for a reader assessing a patent is that the effective filing date is not a formality; it is the line that determines what counts as prior art against the claims.

The 102(a)(2) category: earlier-filed applications

Section 102 has a second prong beyond the public-availability events of 102(a)(1). Under 102(a)(2), a person is also not entitled to a patent if the claimed invention was described in a patent or in a published patent application that was effectively filed before the effective filing date of the claimed invention and names another inventor. This is the prior-art category that captures secret prior filings — an earlier application that was not yet public when the later inventor filed, but that later published or issued, reaches back to its own effective filing date as prior art. The two prongs work together: 102(a)(1) handles things that were publicly available before filing, while 102(a)(2) handles earlier-filed applications by others that surface later. For a semiconductor field with heavy, fast filing activity by competing assignees, the 102(a)(2) prong matters because a rival's quietly pending application, once published, can become prior art as of its filing date against a later filer's claims to the same structure. The exceptions in 102(b) include provisions addressing this prong as well, notably where the earlier and later filings share common ownership. The point is that a complete novelty analysis runs both prongs, not just the on-sale and publication events most people picture when they hear "prior art."

The exceptions in section 102(b)

Section 102 does not stop at the bar. Subsection 102(b) provides exceptions, the most consequential being a one-year grace period for certain disclosures made by the inventor (or derived from the inventor) shortly before filing — a disclosure by the inventor within one year before the effective filing date is not, under the statute's terms, prior art under 102(a)(1) against that inventor's own application. There are also exceptions addressing disclosures and prior filings within the same ownership for the 102(a)(2) category of earlier-filed applications. These exceptions are limited and specific; they soften the bar at its edges without changing the core rule that pre-filing public availability is prior art. A reader applying 102 to a real record has to check both the (a) triggers and the (b) exceptions before concluding anything about novelty.

The structure is concrete on any granted record. United States Patent US10672707B2, "Low aspect ratio interconnect," carries an effective filing date on its face; under section 102 that date is the line against which any earlier publication, public use, or sale of the same interconnect structure would be measured as prior art. The same analysis applies to every patent: find the effective filing date, then ask whether the claimed subject matter was patented, published, in public use, on sale, or otherwise available to the public before it.

What the record shows is the statutory novelty rule. Under 35 U.S.C. 102(a)(1), an invention that was patented, described in a printed publication, in public use, on sale, or otherwise available to the public before the effective filing date is barred from patenting; the on-sale clause makes a pre-filing commercial offer one such bar. Section 102(b) supplies limited exceptions, including a one-year grace period for the inventor's own disclosures. The statute does not decide whether any specific sale or publication bars a given patent — that turns on the facts of the event, what it disclosed, and its date relative to the effective filing date. But it fixes the categories of prior art and the cutoff, and for a semiconductor IP reader the operative move is always the same: pin the effective filing date, then test the listed events against it.