Abstract: According to an exemplary embodiment, a method of forming a vertical device is provided. The method includes: providing a protrusion over a substrate; forming an etch stop layer over the protrusion; laterally etching a sidewall of the etch stop layer; forming an insulating layer over the etch stop layer; forming a film layer over the insulating layer and the etch stop layer; performing chemical mechanical polishing on the film layer and exposing the etch stop layer; etching a portion of the etch stop layer to expose a top surface of the protrusion; forming an oxide layer over the protrusion and the film layer; and performing chemical mechanical polishing on the oxide layer and exposing the film layer.

Abstract: A tapered countersink drill bit includes at least two screwing knifes and at least one two screwing trenches and a rod body; a length of an edge of the left lateral side of each screwing knife being shorten than that of an edge of the right lateral side thereof; each screwing knife including a front drilling head; a tapered portion formed at a backside of the front drilling head; a rear drilling head formed at a backside of the tapered portion; the screwing angle of each screwing knife being identical from the front drilling head to the rear drilling head; and a screwing angle of each screwing trench being identical from the front drilling head to the rear drilling head; a width between two adjacent knifes at a front end of the rear drilling head being longer than a width between two knifes at rear ends of two rear drilling head.

Abstract: A screw includes a head, a rod extending from a lower end of the head and a tapered drilling portion extending from a lowest end of the rod; the rod having a normal thread with a predetermined length; the normal thread extending from a lower end of the head to the tapered drilling portion, but having a predetermined distance from a tip end of the tapered drilling portion; an umbrella thread extending from a lower end of the normal thread to the tip end of the tapered drilling portion; the umbrella thread being formed by an upper thread surface and a lower thread surface. A second angle between the upper thread surface of the normal thread and the lower thread surface of the normal thread becomes larger and larger from the end near the normal thread to an end near the tip end.

Abstract: A screw capable of cutting and compressing dregs in an object to be drilled has a tapered head with a larger upper end and a small lower end, and a tapered surface being formed between the larger upper end and the small lower end; and at least one rib winding around the tapered surface of the head. Each of the rib is formed by an outer wall and an inner wall the connection of the inner wall and outer wall is formed as a sharp knife portion which winds around the tapered surface of the tapered head; and the outer wall is inclined so that a lower distal side of the outer wall is more near a center axis of the tapered head; and the inner wall is inclined so that an upper distal end of the inner wall is more near a center axis of the tapered head.

Abstract: A screw comprises: a screw head; a first screw rod extending from the screw head; and a second screw rod extending from a lower end of the first screw rod; a third thread and a fourth screw alternatively circles around the second screw rod; an angle between an upper surface of the third thread and an adjacent lateral surface of the fourth thread being larger than 90 degrees; and an angle between an upper surface of the fourth thread and a lateral surface of the third thread being larger than 90 degrees. Or only one thread circles around the second screw rod; an angle between an upper surface of the thread and an adjacent lateral surface of the second screw rod being larger than 90 degrees. There may be only one thread circling on the first screw rod, or two threads alternatively circling around the first screw rod.

Abstract: A screw capable of cutting and compressing dregs in an object to be drilled has a tapered head with a larger upper end and a small lower end, and a tapered surface being formed between the larger upper end and the small lower end; and at least one rib winding around the tapered surface of the head. Each of the rib is formed by an outer wall and an inner wall the connection of the inner wall and outer wall is formed as a sharp knife portion which winds around the tapered surface of the tapered head; and the outer wall is inclined so that a lower distal side of the outer wall is more near a center axis of the tapered head; and the inner wall is inclined so that an upper distal end of the inner wall is more near a center axis of the tapered head.

Abstract: A screw capable of cutting and compressing dregs in an object to be drilled comprises: a tapered head with a small lower end; at least one rib being formed on and winds around the tapered area of the head. Each rib is formed with an outer wall having a first slope with respect to an outer wall of a tapered surface of the head and an inner wall with a second slope with respect to an outer wall of the tapered surface. Connection of the inner wall and outer wall is formed as a sharp knife portion. Each rib winds around the tapered surface of the head with an angle being equal to or larger than 360 degrees. By using the structure above said, dregs in screwing are compressed into the object to tighten the screw to the object to be drilled and no dregs expose out.

Abstract: A screw comprises: a screw head; a first screw rod extending from the screw head; and a second screw rod extending from a lower end of the first screw rod; a third thread and a fourth screw alternatively circles around the second screw rod; an angle between an upper surface of the third thread and an adjacent lateral surface of the fourth thread being larger than 90 degrees; and an angle between an upper surface of the fourth thread and a lateral surface of the third thread being larger than 90 degrees. Or only one thread circles around the second screw rod; an angle between an upper surface of the thread and an adjacent lateral surface of the second screw rod being larger than 90 degrees. There may be only one thread circling on the first screw rod, or two threads alternatively circling around the first screw rod.

Abstract: A crack-proof screw comprises a head; a rod having a first end extending from the head and having a rod thread near the head and expanding threads far away from the head; each expanding thread encircled through an angle smaller than 360 degrees; the screwing direction of the expanding thread being identical to or different from that of the rod thread; a tapered tail extending from a second end of the head; the expanding threads on the rod being near the tapered tail; the tapered tail having two drilling threads; each drilling thread can be extended to or not extended to the tip end of the tapered tail.

Abstract: A crack-proof screw comprises a head; a rod having a first end extending from the head and having a rod thread near the head and expanding threads far away from the head; each expanding thread encircled through an angle smaller than 360 degrees; the screwing direction of the expanding thread being identical to or different from that of the rod thread; a tapered tail extending from a second end of the head; the expanding threads on the rod being near the tapered tail; the tapered tail having two drilling threads; each drilling thread can be extended to or not extended to the tip end of the tapered tail.

Abstract: A drilling screw with compound threads comprises a head at one of the screw; a drilling tip at another thereof; a screwing rod extending from the head to the drilling tip; a middle section of the rod being formed with a flange; at least one tightening thread formed on the rod and between the flange and the head; at least one drilling thread formed on the screwing rod and extended between the flange and the drilling tip; and at least one expanding thread formed on the screwing rod and extended between the flange and the drilling tip. The thread angle of the expanding thread is identical to that of the drilling thread. A height of the expanding thread is smaller than that of the drilling thread and the spiral direction of the expanding thread is opposite to that of the drilling thread. The drilling operation is performed smoothly and firmly.

Abstract: A screw with a recess in the head of the screw comprises a screw head; a recess formed in the screw head; a plurality of blocks protruded from a periphery wall of the recess; each block having at least two inclined walls; each of the inclined walls having a slope identical to a slope of the wall. Each block has two inclined walls; and the connection of the inclined walls belonging to one block is formed as an acute angle. Or each block has three inclined walls which are formed as a trapezoidal shape.

Abstract: A screw with a drilling tail comprises: a screw head, a drilling tail, a rod portion between the screw head and the drilling tail, and at least one first threads on the rod portion, wherein the helix angle at one end of each thread near the drilling tail becomes larger than the helix angle at other portion of the thread so as to form a guide thread section which covers a range not over half circle of the rod portion; and a distal end of the guide thread section is at an upper end of the drilling tail. There is one or two first threads. The screw with a drilling tail further comprises a second thread between the screw head and the at least one first thread.

Abstract: A screw with two threads having different orientations is disclosed. The screw having a flat surface at a bottom side of the screw head; an annular recess being formed in the flat surface and around the screw rod; an upper thread formed at an upper portion of the screw rod; and a lower thread connected to the upper thread and formed on a lower portion of the screw rod and the tapered portion; a thread pitch of the lower thread being equal to that of the upper thread; an outer diameter of the lower thread on the screw rod being equal to that of the upper thread. Furthermore, each of upper thread and lower thread has a triangular cross section; and the slope angle of an upper side of each of the upper thread and lower thread is greater than that of the lower side of the respective one of the upper thread and lower thread.

Abstract: A screw with a recess in the head of the screw comprises a screw head; a recess formed in the screw head; a plurality of blocks protruded from a periphery wall of the recess; each block having at least two inclined walls; each of the inclined walls having a slope identical to a slope of the wall. Each block has two inclined walls; and the connection of the inclined walls belonging to one block is formed as an acute angle. Or each block has three inclined walls which are formed as a trapezoidal shape.

Abstract: A screw which can be more quickly screwed into a work piece and has better chip-exhausting effect. The screw has a rod body and higher thread and lower thread formed on the rod body. On a conic section of the screw, a cutting thread with another guide angle larger than the guide angle of the lower thread directly extends from the lower thread. Accordingly, the lower thread of the screw has better cuffing, drilling and chip-exhausting function. Alternatively, the screw can have single thread or double threads with equal height. On a predetermined section of the rod body of the screw, a cutting thread with changed guide angle is directly formed as a part of the thread to achieve better cutting, drilling and chip-exhausting function.

Abstract: A screw which can be more quickly screwed into a work piece and has better chip-exhausting effect. The screw has a rod body and higher thread and lower thread formed on the rod body. On a conic section of the screw, a cutting thread with another guide angle larger than the guide angle of the lower thread directly extends from the lower thread. Accordingly, the lower thread of the screw has better cuffing, drilling and chip-exhausting function. Alternatively, the screw can have single thread or double threads with equal height. On a predetermined section of the rod body of the screw, a cutting thread with changed guide angle is directly formed as a part of the thread to achieve better cutting, drilling and chip-exhausting function.

Abstract: A screw with better anti-pull quality. The screw has a rod body and at least one thread formed on the rod body. The inclination of the lower face of the thread is larger than zero degree, while smaller than the inclination of the upper faces of the thread, whereby the thread of the screw is downward inclined to achieve a better anti-pull effect.

Abstract: A screw with thread having different orientations comprises a first thread extending to a tip of the screw; a second thread; a distal end of the second thread being formed with a cutting thread; a distal end of the first cutting thread being a cambered thread near the tip of the screw; a screwing angle of the cutting thread is larger than other portion of the second thread. Moreover, a distal end of the first thread is formed with a first cutting thread; a distal end of the first cutting thread being a cambered thread near the tip of the screw. A screwing angle of the first cutting thread is larger than other portion of the second thread. Furthermore, the screw may have only the second thread, but the first screw can be neglected.

Abstract: Screw having quick drilling speed and smoothened expulsion of chips. The normal thread formed on the stem of the screw directly extends through the conic section of the tail end of the screw to the tip thereof by a larger guide angle. The thread between the changing point of the guide angle of the thread and the tip of the conic section serves as a thread with cutting/drilling and chip-expelling function. Therefore, the cutting/drilling and chip-expelling thread of the screw is directly formed by means of changing the guide angle of the normal thread of the screw.