Stealth patterning formation for bonding improvement

1 . A method comprising:

forming a patterned treating mask over a first surface dielectric layer of a first package component, wherein first portions of the first surface dielectric layer are exposed through the patterned treating mask;

performing a selective plasma treatment on the first portions of the first surface dielectric layer that are exposed through the patterned treating mask to form first treated portions;

removing the patterned treating mask; and

bonding a second surface dielectric layer in a second package component to the first surface dielectric layer.

2 . The method of claim 1 , wherein the selective plasma treatment is performed using a process gas selected from the group consisting of nitrogen (N 2 ), oxygen (O 2 ), argon, and combinations thereof.

3 . The method of claim 1 , wherein the first package component comprises a wafer that comprises a plurality of dies, and wherein the first treated portions in each of the plurality of dies have a same pattern as patterns of the first treated portions in other dies among the plurality of dies.

4 . The method of claim 1 further comprising activating the first surface dielectric layer using a forming gas comprising nitrogen (N 2 ) and hydrogen (H 2 ).

5 . The method of claim 4 , wherein the selective plasma treatment is performed after the activating.

6 . The method of claim 1 , wherein the selective plasma treatment is performed with a bias power.

7 . The method of claim 1 , wherein the first treated portions have widths in a range between about 1 μm and about 20 μm, and pitches in a range between about 1 μm and about 100 μm.

8 . The method of claim 1 further comprising, after the selective plasma treatment, performing a vacuum break to expose the first package component to air, wherein the vacuum break results in the first treated portions of the first surface dielectric layer to have an increased oxygen atomic percentage.

9 . The method of claim 1 further comprising performing an additional selective plasma treatment on second portions of the second surface dielectric layer to form second treated portions.

10 . The method of claim 9 , wherein after the bonding, one of the first treated portions is bonded to one of the second treated portions.

11 . A method comprising:

forming a first package component comprising:

forming a first surface dielectric layer comprising:

forming first portions extending from a surface of the first surface dielectric layer into the first surface dielectric layer, wherein the first portions have a first oxygen atomic percentage, wherein the forming the first portions comprises a treatment process using a process gas comprising oxygen; and

forming second portions separating the first portions from each other, wherein the second portions have a second oxygen atomic percentage lower than the first oxygen atomic percentage.

12 . The method of claim 11 , wherein during the treatment process, the first portions are exposed, and the second portions are covered by a treatment mask.

13 . The method of claim 11 , wherein the first package component comprises a die, and wherein the first portions have shapes of a plurality of rings, with outer rings encircling respective inner rings.

14 . The method of claim 11 , wherein the first portions have widths in a range between about 1 μm and about 20 μm, and wherein the first portions have pitches in a range between about 1 μm and about 100 μm.

15 . The method of claim 11 further comprising bonding a second package component to the first package component, wherein the second package component comprises a second surface dielectric layer, and the second surface dielectric layer is bonded to the first surface dielectric layer.

16 . The method of claim 11 , wherein the first portions are treated as extending into the first surface dielectric layer for a depth smaller than about 100 Å.

17 . The method of claim 11 , wherein the first portions have a thickness smaller than about 100 Å.

18 . A method comprising:

forming a device die comprising:

forming a silicon-containing dielectric layer comprising:

forming first portions extending from a top surface of the silicon-containing dielectric layer to an intermediate level between the top surface and a bottom surface of the silicon-containing dielectric layer, wherein the first portions are in second portions, and the second portions extend from the top surface to the bottom surface, wherein the first portions have a higher oxygen atomic percentage than the second portions.

19 . The method of claim 18 , wherein the forming the first portions comprises performing a selective treatment process using an oxygen-containing process gas, and wherein during the selective treatment process, the second portions are masked from being treated.

20 . The method of claim 18 , wherein the first portions form a plurality of rings.