Method of electroless deposition of thin metal and dielectric films with temperature controlled stages of film growth
View Patent ↗The method of the invention comprises accumulating experimental data or obtaining existing data with regard to the optimal time-temperature relationship of the deposition process on various film-formation stages for various materials, forming nuclei of a selected material on the surface of the treated object in the first stage under first temperature-controlled conditions for the formation of nuclei of said selected material, converting the nuclei of the aforementioned selected material into island-structured deposited layer of said material by causing lateral growth of the nuclei under second temperature-controlled conditions; converting the island-structure layer into a continuously interconnected cluster structure by causing further lateral growth of said island-structured deposited layer under third temperature-controlled conditions; forming a first continuous film of said material under fourth temperature controlled conditions which provides said first continuous film with predetermined properties; and then completing the formation of a final coating film by growing at least one subsequent continuous film of said material under fifth temperature-controlled conditions until a film of a predetermined thickness is obtained. The fifth temperature-controlled conditions may be characterized by a pulse-mode or step-like variations of temperature in time with rapid cooling or heating for obtaining high degree of crystallinity or for increase in the rate of deposition. The method of the invention could be realized with the use of the electroless deposition apparatus with instantaneous cooling or heating of the object, e.g., a semiconductor substrate, in a deposition chamber.
1. A method of forming a film on an object, said method comprising:
positioning the object within an electroless deposition apparatus having means for instantaneous temperature control of said object;
electrolessly depositing a material upon the object;
instantaneously changing the temperature of said object by said means of instantaneous control at one or more predetermined times during the step of electrolessly depositing the material, wherein the predetermined times correspond to different film-growth stages of the material, wherein the different film-growth stages comprise:
a first stage in which nuclei of the material are formed on said object;
a second stage in which the nuclei are converted into an interconnected cluster structure; and
a third stage in which the interconnected cluster structure is converted into a continuous layer
cleaning said object subsequent to the step of electrolessly depositing the material upon the object; and
depositing a plurality of layers having different physical characteristics onto said contiguous layer subsequent to the step of cleaning the object, each one of said plurality of layers being deposited within a temperature range for obtaining its respective different physical characteristics.
2. The method of claim 1 , wherein said film comprises an amorphous structure.
3. The method of claim 1 , wherein said object is a semiconductor substrate.
4. The method of claim 1 , wherein said different physical characteristics comprise different degrees and nature of crystallinity.
5. The method of claim 1 , wherein said different physical characteristics comprise different deposition materials.
6. The method of claim 1 , wherein said different physical characteristics comprise different thicknesses.
7. The method of claim 1 , wherein the step of depositing the plurality of layers comprises instantaneously changing the temperature of the object by the means of instantaneous control at one or more predetermined times corresponding to different film-growth stages of at least one of the plurality of layers.
8. The method of claim 1 , further comprising replacing a deposition solution within the electroless deposition apparatus between depositing at least two of said plurality of layers.
9. The method of claim 1 , wherein at least one of said plurality of layers comprises a crystalline structure.
10. The method of claim 1 , wherein said instantaneous control of temperature comprises changing the temperature of said object during a period of time ranging from fractions of a second to several seconds.
11. The method of claim 1 , wherein the step of depositing the plurality of layers comprises pulsing the temperature of said object.
12. A method of forming a film of at least one deposition material on an object in an electroless deposition process, said method comprising:
forming nuclei of the deposition material on a surface of said object under first temperature-controlled conditions and during a first period of time;
converting said nuclei into island structures during a second period of time and under second temperature-controlled conditions distinct from the first temperature conditions, wherein the step of converting said nuclei comprises growing said deposition material substantially in a lateral direction from said nuclei parallel to said object;
converting said island structures into an interconnected cluster structure by causing further lateral growth of said island structures under third temperature-controlled conditions;
forming a first continuous layer of said deposition material under fourth temperature controlled conditions distinct from the third temperature-controlled conditions; and
forming a coating layer upon the first continuous layer under fifth temperature-controlled conditions.
13. The method of claim 12 , further comprising instantaneously changing the temperature of said object between the steps of:
forming nuclei of the deposition material and converting the nuclei into island structures; and
converting the island structures into the interconnected cluster structure and forming the first continuous layer of the deposition material, wherein said instantaneously changing the temperature of the object comprises changing the temperature of the object during a period of time ranging from fractions of a second to several seconds.
14. The method of claim 12 , wherein the fourth temperature-controlled conditions comprise a higher temperature range than the third temperature-controlled conditions.
15. The method of claim 12 , wherein the fourth temperature-controlled conditions comprise a lower temperature range than the third temperature-controlled conditions.
16. The method of claim 12 , further comprising forming one or more intermediate layers above the first continuous layer prior to the step of forming the coating layer, wherein the step of forming the one or more intermediate layers comprises pulsing the temperature of the object.
17. A method for forming a film on an object, comprising pulsing the temperature of the object between at least two distinct temperature ranges during a continuous electroless deposition process of the film.
18. The method of claim 17 , further comprising:
depositing nuclei of a deposition material on a surface of said object at a first temperature;
depositing the deposition material at a second temperature distinct from the first temperature to interconnect the nuclei; and
depositing the deposition material at a third temperature distinct from the second temperature to form a continuous layer on the surface prior to the step of pulsing.
19. The method of claim 18 , wherein the step of pulsing comprises depositing layers of the deposition material having different degrees and nature of crystallinity.