Is i possible to make an instantiated object appear in that exact position, when using a plane as a collider, using Input.MousePosition?

var shinePrefab : GameObject; var clone : GameObject; var x : float; var y : float;

function Start () {

}

function Update () {

 if(Input.GetMouseButtonDown(0))
 {
     Debug.Log("Pressed left click.");
  Instantiate (shinePrefab, Input.mousePosition,Vector3(x,y,0), transform.rotation,Quaternion.identity);
 

     //Invoke ("Spawn", Random.Range( 0, 1));

     
     Destroy(GameObject.Find("Shine(Clone)"), 3);
     
 }
     
 
 if(Input.GetMouseButtonDown(1))
 {
     Debug.Log("Pressed right click.");
 }
 if(Input.GetMouseButtonDown(2))
 {
     Debug.Log("Pressed middle click.");
 }
 

}