A large part of innovation relies on manipulating variables of known compounds, formulations, devices, systems and processes. Changes in some of these variables lead to inventions that are both novel and non-obvious and thus patent-eligible. Changes in others of these variables merely lead to obvious new technologies because the results could have been predicted by a person of ordinary skill in the art. Consequently, those inventions are deemed obvious and not patent-worthy.1 This latter scenario falls under what the courts and the U.S. Patent and Trademark Office (USPTO) call the doctrine of routine optimization, and many a patent applicant has had his or her patent claims rejected under it. However, the doctrine has an exception that comes into play when the variable is not at the time of invention known or expected to bring about a particular result and thus is not deemed a result-effective variable.

Despite the prevalence of rejections issued by the USPTO under the doctrine of routine optimization and the many ex parte patent prosecution cases in which applicants have tried to argue that a variable is not a result-effective variable, the U.S. Court of Appeals for the Federal Circuit (CAFC) has rarely been called upon to define the parameters of this exception to the doctrine. In In re Applied Materials,2 which was recently decided, the CAFC provided a rare glimpse into its perspective on when to apply the exception.

Development of the Doctrine

In 1955, in In re Aller,3 the U.S. Court of Customs and Patent Appeals (CCPA), the predecessor of the CAFC, was confronted with an appeal from the Board of Patent Appeals and Interferences (BPAI) of the USPTO in which the applicants claimed a process for the production of phenol. The process was different from that of the prior art in that the applicants’ claims specified lower temperatures and higher sulphuric acid concentrations than the prior art disclosed. The CCPA is the predecessor court to the CAFC, and the CAFC has explicitly held that the precedents of the CCPA are binding on it.4

As the court noted, a change in temperature or concentration or both is an unpatentable modification when it results in optimum reaction conditions that differ from the prior art in degree but not in kind. Consequently, the court affirmed the rejection of the claims and emphasized, “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.”5 This became known as the doctrine of routine optimization. The doctrine is intuitively logical for variables that when changed lead to expected changes in results and thus may be deemed result-effective.

Twenty-two years later the CCPA decided In re Antoine,6 which involved a wastewater treatment device in which wastewater was continuously passed through a tank. Semi-immersed contactors (disks) were continuously rotated to aerate their immersed portions and thereby to aerate both microorganisms that grew on the contactors and the wastewater itself.

The claimed device had a ratio of tank volume to contactor area of 0.12 gallons per square foot, and the applicants alleged that that value was optimum because it maximized treatment capacity so that the effectiveness of a given contactor would be maximized. The prior art disclosed the same basic structure and stated that efficiency could be increased to 95 percent by increasing the area of the contactor, but the prior art was silent with respect to quantitative design parameters. The examiner rejected the claims based on this art noting that the suggestion of increasing efficiency by increasing contactor area while keeping throughput constant implied keeping the tank volume constant. Consequently, a person of ordinary skill in the art would arrive at the claimed invention because this disclosure would lead one to increase tank volume to surface area ratio in order to increase efficiency. The BPAI affirmed.

When the CCPA took up the case, it framed the issue as “[t]he controlling question is simply whether the differences (namely the value of 0.12 and its property) between the prior art and appellant’s invention as a whole would have been obvious.”7 It then answered the question in the negative, noting that the prior art failed to teach that treatment capacity is a function of tank volume or the tank volume to contactor area ratio. Directly addressing In re Aller, the CCPA emphasized an exception to the doctrine of routine optimization, noting that the doctrine is not applicable when “the parameter optimized was not recognized to be a result-effective variable.”8 Thus, before the doctrine of routine optimization can be applied to an invention, any variable that is allegedly optimized must have been recognized as causing or would have been expected to cause the alleged benefit after having been changed.

Four years later, in 1981, the CCPA decided In re Yates,9 in which it again found a variable not to be result-effective. In that case there was neither teaching nor evidence in the prior art of the claimed relationship of the variable and the result.

The applicants claimed a process for oxidizing an olefin to an unsaturated aldehyde. The process differed from that disclosed in the prior art in that the applicants claimed 25-80 percent conversion of olefin to product with acid production of less than 2 percent unsaturated acid. The BPAI acknowledged that the prior art did not suggest this result. However, it took the position that because the olefin-aldehyde conversion is also an oxidation reaction, any competent chemist would have recognized that varying the degree of conversion of olefin to aldehyde would modify the percentage production of acid.

One prior art reference disclosed over 80 examples from 10 prior art patents of olefin to aldehyde oxidation reactions using various oxidation catalysts similar to those used by the applicants. However, in the table there was no correlation of any kind between conversion and selectivity. Instead, regardless of the degree of conversion, the percentage of acid was generally in the 3-10 percent range and no clear relationship between the conversion and acid production was apparent. Because nothing in the prior art results suggested the effect of the applicants’ variable, the CCPA reversed, emphasizing that the degree of conversion in the prior art was not recognized to be a result-effective variable.

‘In re Applied Materials’

This summer, the CAFC revisited the issues that the CCPA addressed more than 30 years ago in Aller, Antoine, and Yates. In Applied Materials, which was decided in August, the CAFC provided evidence of what it believes are examples of variables that are result-effective and thus justify invocation of the doctrine of routine optimization.

In Applied Materials, the CAFC was called upon to decide whether certain patent claims that were directed to tools that could be used to improve the efficiency of making integrated circuits were obvious in view of the prior art. Integrated circuits are formed by depositing conductive, semi-conductive, and insulative layers on a substrate. These materials are then etched to form the features of the circuits. During production of the circuits, it is necessary to flatten the layers in order to render them planar. One method by which to do this is to use rotating polishing pads in the presence of a polishing slurry.

The prior art pads facilitated flattening of the surfaces. However, according to the applicants many of them also caused an uneven distribution of the slurry and the accumulation of waste material. The invention at issue was directed to an improved pad with grooves. The patent applicants claimed that their pads advantageously distributed the slurry, removed waste material and possessed increased pad life.

Among the features of the claims were specific ranges for the depth, width and pitch of the grooves. The claims also recited that the side walls were substantially perpendicular to the polishing surface.

During prosecution, the examiner identified three prior art references that disclosed pads with grooves. None of the references described precisely the same combination of physical features as recited in the claims at issue, but in combination they disclosed overlapping ranges. Consequently, the examiner deemed the claims obvious in view of the cited art. The BPAI affirmed, noting that the prior art disclosed values that overlapped the claimed ranges, the dimensions were result-effective variables, and the applicants failed to provide evidence of unexpected results.

The applicants appealed to the CAFC, arguing that the prior art did not address the impact of altering each dimension of the grooves on pad performance. Thus, according to the applicants, the dimensions were not known to be result-effective variables and their optimization could not be deemed routine. The applicants also suggested that even if any individual dimension alone were deemed to be a result-effective variable, the combination of multiple dimension variables could not have been routinely optimized because there were trade-offs among the several results that were obtained based on the selection of those variables.

The CAFC affirmed the BPAI, citing both Aller and Antoine as the appropriate guideposts for applying the doctrine of routine optimization and the limitation on that doctrine that is dictated by the requirement that any optimized variable be result-effective. As an initial matter, the CAFC noted that the mere fact that the prior art disclosed overlapping ranges provided sufficient motivation to optimize the ranges. Thus, there is no need for the prior art to teach that variables within range could be optimized or should be optimized.

Additionally, the examiner had pointed to a prior art reference that taught that the number of grooves per area and the groove pitch may be optimized for the type of pad and the slurry in order to achieve a high polishing rate and polishing uniformity. Furthermore, the CAFC noted that the BPAI had found that a person of ordinary skill in the art would have recognized that changing the groove width would affect the polishing rate and uniformity. This latter conclusion flowed because as the CAFC noted, a person of ordinary skill in the art would readily recognize that the number of grooves per area is related to the width of the grooves.

These types of changes in physical sizes had effects that according to the CAFC would have easily been appreciated through routine optimization. Accordingly, the CAFC concluded that the applicants did no more than optimize result-effective variables.

The CAFC also noted that the applicants could have demonstrated non-obviousness by establishing that the claimed ranges were critical or lead to unexpected results. However, the applicants did not provide any such evidence.

Finally, the court noted that the mere fact that multiple result-effective variables were combined would not render their combination beyond the capability of a person of ordinary skill in the art. Instead, the court emphasized that under KSR Int’l v. Teleflex,10 absent a showing of any unpredictability or unexpectedness in the interaction of the variables, there would not be a finding of non-obviousness.

The decision in In re Applied Materials is at first blush perhaps the easiest type of routine optimization case to imagine. The variables were related to physical size. Thus, although there was a plurality of variables, there was nothing in the record that suggested a change in any one or more dimensions would have anything but a predictable result. Accordingly, implicitly there is a suggestion that these types of variables are presumptively routine to optimize.

However, the decision was not unanimous. As Judge Pauline Newman pointed out in her dissent, one could argue that the majority incorrectly framed the issue as whether the differences from the prior art were large or small. She instead took the position that the issue should have been framed as whether it would have been obvious to change a combination of width, depth and pitch in the manner of the patentee with the reasonable expectation that the changed product would possess the advantages that it did. Had the issue been framed as Newman suggested, the rejection would have been reversed, because the patent office offered no evidence for such an expectation of improved properties.


The doctrine of routine optimization prevents patent applicants from obtaining patents that are directed to certain new inventions that are obvious. The easy cases are often when a variable is defined in reference to physical size, temperature or pressure. Typically increasing or decreasing one or more of these variables will have predictable results because they lead to, for example, more or less surface area, a faster or slower reaction or a larger or smaller volume. However, for a given invention even with these variables the result may be contrary to what a person of ordinary skill in the art would expect or for a certain range the results may be unexpected.

Additionally, as one moves from these more typically predictable variables to what may be less predictable variables such as changes in substituents in molecules, the issue becomes more complex. It is under these types of circumstances that one can expect to see more challenges to rejections made under the doctrine of routine optimization because applicants contend that the variables are not result-effective.

Scott D. Locke is a partner at Dorf & Nelson in Rye, and head of the intellectual property and life sciences practice groups.


1. 35 U.S.C. §103(a).

2. Civ. 2011-1461, -1462, -1463 -1464 (Fed. Cir. Aug. 29, 2012).

3. In re Aller, 220 F.2d 454, 456 (CCPA 1955).

4. Giant Food v. Nation’s Foodservice, 710 F.2d 1565, 1569 (Fed. Cir. 1983).

5. In re Aller, 220 F.2d 454, 456 (CCPA 1955).

6. 559 F.2d 618, 620 (CCPA 1977).

7. Id.

8. Id. at 620.

9. 663 F.2d 1054 (CCPA 1981).

10. 550 U.S. 398 (2007).